Heat treating of aluminum and aluminum alloys

Abstract: The general types of heat treatments applied to aluminum and its alloys are: Preheating or homogenizing, to reduce chemical segregation of cast structures and to improve their workability Annealing, to soften strain-hardened (work-hardened) and heat treated alloy structures, to relieve stresses, and to stabilize properties and dimensions Solution heat treatments, to effect solid solution of alloying constituents and improve mechanical properties Precipitation heat treatments, to provide hardening by precipitation of constituents from solid solution....

Heat treating processes for aluminum are precision processes. They must be carried out in furnaces properly designed and built to provide the thermal conditions required, and adequately equipped with control instruments to insure the desired continuity and uniformity of temperature-time cycles. To insure the final desired characteristics, process details must be established and controlled carefully for each type of product. The general types of heat treatments applied to aluminum and its alloys are: Preheating or homogenizing, to reduce chemical segregation of cast structures and to improve their workability Annealing, to soften strain-hardened (work-hardened) and heat treated alloy structures, to relieve stresses, and to stabilize properties and dimensions Solution heat treatments, to effect solid solution of alloying constituents and improve mechanical properties Precipitation heat treatments, to provide hardening by precipitation of constituents from solid solution. INGOT PREHEATING TREATMENTS (HOMOGENIZING) The initial thermal operation applied to ingots prior to hot working is referred to as "ingot preheating", which has one or more purposes depending upon the alloy, product, and fabricating process involved. One of the principal objectives is improved workability. The microstructure of most alloys in the as-cast condition is quite heterogeneous. This is true for alloys that form solid solutions under equilibrium conditions, and even for relatively dilute alloys  ANNEALING The distorted, dislocated structure resulting from cold working of aluminum is less stable than the strain-free, annealed state, to which it tends to revert. Lower-purity aluminum and commercial aluminum alloys undergo these structural changes only with annealing at elevated temperatures. Accompanying the structural reversion are changes in the various properties affected by cold working. These changes occur in several stages, according to temperature or time, and have led to the concept of different annealing mechanisms or processes. Recovery. The reduction in the number of dislocations is greatest at the center of the grain fragments, producing a subgrain structure with networks or groups of dislocations at the subgrain boundaries. With increasing time and temperature of heating, polygonization becomes more nearly perfect and the subgrain size gradually increases. In this stage, many of the subgrains appear to have boundaries that are free of dislocation tangles and concentrations. Recovery annealing is also accompanied by changes in other properties of cold worked aluminum. Complete recovery from the effects of cold working is obtained only with recrystallization. Recrystallization is characterized by the gradual formation and appearance of a microscopically resolvable grain structure. The new structure is largely strain-free-there are few if any dislocations within the grains and no concentrations at the grain boundaries. Grain Growth After Recrystallization. Heating after recrystallization may produce grain coarsening. This can take one of several forms.  PRECIPITATION HARDENING General Principles of Precipitation Hardening. The heat treatable alloys contain amounts of soluble alloying elements that exceed the equilibrium solid solubility limit at room and moderately higher temperatures. The amount present may be less or more than the maximum that is soluble at the eutectic temperature. Nature of Precipitates and Sources of Hardening. Intensive research during the past forty years has resulted in a progressive accumulation of knowledge concerning the atomic and crystallographic structural changes that occur in supersaturated solid solutions during precipitation and the mechanisms through which the structures form and alter alloy properties. In most precipitation-hardenable systems, a complex sequence of time-dependent and temperature-dependent changes is involved. Kinetics of Solution and Precipitation. The relative rates at which solution and precipitation reactions occur with different solutes depend upon the respective diffusion rates, in addition to solubilities and alloy contents. Bulk diffusion coefficients for several of the commercially important alloying elements in aluminum were determined by various experimental methods. Nucleation. The formation of zones can occur in an essentially continuous crystal lattice by a process of homogeneous nucleation. Recent investigations provide evidence that a critical vacancy concentration is required for this process and that a nucleation model involving vacancy-solute atom clusters is consistent with certain effects of solution temperature and quenching rate. The nucleation of a new phase is greatly influenced by the existence of discontinuities in the lattice. Since in polycrystalline alloys grain boundaries, subgrain boundaries, dislocations, and interphase boundaries are locations of greater disorder and higher energy than the solid-solution matrix, they are preferred sites for nucleation of precipitates.  Quenching Quenching is in many ways the most critical step in the sequence of heat treating operations. The objective of quenching is to preserve as nearly intact as possible the solid solution formed at the solution heat treating temperature, by rapidly cooling to some lower temperature, usually near room temperature. Critical Temperature Range. The fundamentals involved in quenching precipitation-hardenable alloys are based on nucleation theory applied to diffusion-controlled solid state reactions. The effects of temperature on the kinetics of isothermal precipitation depend principally upon degree of supersaturation and rate of diffusion. Quenching Medium. Water is not only the most widely used quenching medium but also the most effective. It is apparent that in immersion quenching, cooling rates can be reduced by increasing water temperature. Conditions that increase the stability of a vapor film around the part decrease the cooling rate; various additions to water that lower surface tension have the same effect.  Aging at Room Temperature (Natural Aging) Most of the heat treatable alloys exhibit age hardening at room temperature after quenching, the rate and extent of such hardening varying from one alloy to another. No discernible microstructural changes accompany the room-temperature aging, since the hardening effects are attributable solely to the formation of zone structure within the solid solution. Since the alloys are softer and more ductile immediately after quenching than after aging, straightening or forming operations may be performed more readily in the freshly quenched condition.  Precipitation Heat Treating (Artificial Aging) The effects of precipitation on mechanical properties are greatly accelerated, and usually accentuated, by reheating the quenched material to about 100 to 200oC. The effects are not entirely attributable to a changed reaction rate; as mentioned previously, the structural changes occurring at the elevated temperatures differ in fundamental ways from those occurring at room temperature. These differences are reflected in the mechanical characteristics and some physical properties. A characteristic feature of elevated-temperature aging effects on tensile properties is that the increase in yield strength is more pronounced than the increase in tensile strength. Also ductility, as measured by percentage elongation, decreases. Thus, an alloy in the T6 temper has higher strength but lower ductility than the same alloy in the T4 temper.  Precipitation Heat Treating Without Prior SoIution Heat Treatment Certain alloys that are relatively insensitive to cooling rate during quenching can be either air cooled or water quenched directly from a final hot working operation. In either condition, these alloys will respond strongly to precipitation heat treatment.  Precipitation Heat Treating Cast Products The mechanical properties of permanent mold, sand, and plaster castings of most alloys are greatly improved by solution heat treating, quenching, and precipitation heat treating, using practices analogous to those employed for wrought products.

The Advantages and Disadvantages of ERP

The Advantages and Disadvantages of ERP

There are a number of powerful advantages to Enterprise Resource Planning. It has been used to solve a number of problems that have plagued large organizations in the past. At the same time, it is not without a number of disadvantages. Being able to weigh the two will allow a company to decide if this solution will properly meet their needs.

It should first be noted that companies that fail to utilize systems such as ERP may find themselves using various software packages that may not function well with each other. In the long run, this could make the company less efficient than it should be.

There are a number of processes that a company may need to integrate together. One of these processes is called design engineering. When a company is in the process of designing a product, the process of actually creating it is just as important as the end result. ERP can be useful in helping a company find the best design process. Another area where ERP can be useful is order tracking. When a company receives orders for a product, being able to properly track the orders can allow the company to get detailed information on their customers and marketing strategies. If different software packages are being used, this data may not be consistent. 

Perhaps one of the most important advantages of ERP is its accounting applications. It can integrate the cost, profit, and revenue information of sales that are made, and it can be presented in a granular way. Enterprise Resource Planning can also be responsible for altering how a product is manufactured. A dating structure can be set up which can allow the company to be informed of when their product should be updated. This is important, because it will allow the company to keep better track of their products, and it can allow the products themselves to be produced with a higher level of quality. Another area where ERP can be an indispensable tool is the area of security. It can protect a company against crimes such as embezzlement or industrial espionage. 

However, with all the advantages that ERP offers, there are a number of disadvantages as well. Perhaps one of the biggest disadvantages to this technology is the cost. At this time, only large corporations can truly take advantage of the benefits that are offered by this technology. This leaves most small and medium sized businesses in the dark. A number of studies have shown that the biggest challenges companies will face when trying to implement ERP deals with investment. The employees must be continually trained on how to use it, and it is also important for companies to make sure the integrity of the data is protected. 

ERP has a number of limitations. The success of the system is fully dependent on how the workers utilize it. This means they must be properly trained, and a number of companies have attempted to save money by reducing the cost of training. Even if a company has enough money to implement ERP, they may not be able to successfully use it if they do not have enough money to train their workers on the process of using it. One of the biggest problems with ERP is that it is hard to customize. Very few companies can effectively use ERP right out of the box. It must be modified to suit their needs, and this process can be both expensive and tedious. Even when a company does begin changing the system, they are limited in what they can do.

Most ERP vendors will not allow the structure of the software to be altered. One advantage to ERP is that making the necessary changes to use it may actually make a company less competitive in the market. In addition to the costs involved with implemented ERP and training workers to use it, the ERP vendors may charge additional license fees, putting a strain on companies that do not have enough resources to pay for them. The technical support of ERP departments has been questioned, and a number of problems could arise due to security, since corporate representatives must give sensitive information to the tech support department. 

Heading off health hazards : Guidelines for working injury free

Heading off health hazards

Guidelines for working injury free

By Derek Baker

March 1, 2010

Each year more than 700,000 Americans injure their eyes at work equating to more than 2,000 eye injuries each day. About 90 percent of which could have been prevented if proper eye protection were used. Safe work practices, along with properly selected and worn PPE can help reduce many of these potential health hazards and help you to make sure you don't become a statistic.

Use caution when removing PPE or touching your face and eyes as these are the leading cause of foreign body eye injuries.

Welding, cutting, and grinding processes hold many potential health hazards. The most notable of these are injuries that result from eye and face impacts, arc radiation, inhalation of airborne contaminants, and noise. According to the organization Prevent Blindness of America, more than 700,000 Americans injure their eyes at work each year. That equates to more than 2,000 eye injuries each day, 90 percent of which could have been prevented if proper eye protection were used. Of the 700,000 eye injuries, 15,335 of them occurred while using welding equipment. According to the Bureau of Labor Statistics (BLS), 52,780 nonfatal facial injuries resulted in lost work time in 2004—36,680 of those were eye injuries.

Be Wise, Protect Your Eyes

Eye injuries can be classified into three categories:

• Foreign body
• Penetrating and blunt force
• Arc welding radiation exposure

Foreign Bodies. Foreign body injuries are the most prevalent, but often are not related to welding, cutting, or grinding. Foreign body injuries usually occur postoperation, when grinding chips, metal pieces, or other small particles are brushed, rubbed, or fall into the eye as other tasks or work is being performed.

Even though you may have selected and worn the correct personal protective equipment (PPE), normal human behaviors such as removing headgear or safety equipment laden with metal shavings at the end of the day; wiping sweat from your brow; or simply scratching or rubbing your eyes, eyebrow, or forehead where metal shavings are ground into the fingers or resting on the skin of a sweaty face can cause foreign body injury. Of the 36,680 eye injuries stated previously, 35.6 percent of those were caused by rubbing.

Failing to wear safety glasses increases your chance of sustaining a blunt force eye injury.

Penetrating and Blunt Force. These eye injuries often result from a direct blow to the eye and eye area. PPE eyewear designed in accordance with ANSI Z87.1-2003 Occupational and Educational Personal Eye and Face Protection Devices standard are designed to cover, at a minimum, the eye socket area of the majority of the population. These design criteria are specified to reduce the chance of objects having a direct path to the eye. Of the 36,680 eye injuries, 19 percent were caused by being struck by a flying object.

Following safe work practices and selecting and wearing proper ANSI Z87 marked PPE are the best ways to help reduce overall eye and face injuries. As noted earlier, a spectacle's basic design intent is to protect the eye area from direct impact. Goggles are designed to cover the eye area, and some provide additional protection from dust, mist, and splashes. Face shields are designed to cover the eye area, but they also help protect the face against certain flying objects. It is important to note, however, that the ANSI Z87.1 standard requires the use of spectacles as primary eye protection under all face shields and welding helmets so that in the event the face shield or welding helmet is lifted up, the eyes are still covered by the spectacles.

Consider taking additional measures to help reduce your chance of eye injuries. Wear a head covering that can be removed easily at the end of the workday to cut down on the chance of metal chips and particles becoming entrapped in the hair or top of the head. Be careful when you remove these head coverings as well as when you shower to reduce potential fallout of particles.

Failing to wear safety glasses increases your chance of sustaining a blunt force eye injury.

PPE that incorporates powered and supplied-air options may be another means to help reduce eye injuries. These types of PPE often cover a large portion of your head and face and increase your comfort level by providing constant airflow across the head and face. This added comfort increases the likelihood of the product being worn, and worn correctly, further reducing potential injuries and helping enhance productivity.

Gloves also may reduce the chance of metal particles becoming ingrained in the skin, potentially reducing the rub-in effect.

Arc Radiation Exposure. Exposure to arc welding radiation is another form of eye injury. The three types of light emitted from a welding arc are ultraviolet (UV), visible, and infrared (IR). Visible light is the portion of light that can be seen by the eye easily. UV and IR light cannot be seen but are extremely dangerous and can cause painful and immediate eye injuries commonly known as "arc eye," which is essentially a sunburn of the cornea.

Multiple overexposures to UV and IR light can cause cumulative eye injuries that, if left unprotected, can ultimately lead to blindness and other permanent eye injuries. In addition to eye injuries, constant exposure to UV light may also damage the skin and contribute to skin cancer and other skin conditions. Using sunblock with an SPF of 50 or higher may also help protect you from overexposure to UV light.

According to the ANSI Z87.1 standard, you are required to wear primary eye protection under all welding helmets. Primary eye protection constitutes Z87 or Z87+ marked safety spectacles or goggles that will effectively block most of the UV light spectrum. Wearing safety spectacles under the welding helmet can significantly reduce eye damage from UV light even while the helmet is in the up position. Some specialty safety spectacles can provide additional protection against the IR component of light.

Overexposure to UV light causes "arc eye," or in other words a sunburn of the cornea.

A quality autodarkening welding helmet may help reduce eye injuries caused by arc radiation. Typically, welders who wear an autodarkening helmet leave the helmet in the down position more frequently than traditional passive welding helmets. This helps protect the eyes from stray and reflected arc radiation and also flying objects that contribute to foreign body and blunt force eye injuries. A quality autodarkening helmet can help reduce your exposure to arc radiation and other foreign body eye injuries, and may enhance productivity and comfort.

Inhaling Airborne Contaminants

Some welding, cutting, and grinding processes produce airborne contaminants that may require you to use a respiratory protection device. These contaminants can be in the form of particles or gases and vapors. Some examples of particles are metal fumes, dusts, and mists; examples of gases and vapors are ozone, fluorides, and shielding gases.

Hexavalent chromium (CrVI) is one of the potential particulate exposures regulated by OSHA. In February 2006, OSHA required employers to measure worker exposure to hexavalent chromium and establish control measures accordingly. OSHA reduced the permissible exposure limit (PEL) from a value of 52mg/m3 to a value of 5mg/m3 or a drop in exposure limits by more than an order of magnitude. OSHA has given employers until May 31, 2010, to place engineering controls in place, and if that is not feasible, to develop an effective respiratory protection program.

In most cases, an N95 particulate filter provides sufficient filtering capabilities. Depending on the results of worker air sampling and exposures, a half-facepiece respirator, such as a disposable filtering facepiece respirator with an assigned protection factor (APF) of 10, or a powered or supplied-air respiratory system providing an APF of 1,000, may be required.

Overexposure to IR light causes "arc eye," or in other words a sunburn of the cornea.

In addition to hexavalent chromium, other respiratory hazards may be present depending on the application or process. If air quality is in question, you should consult an industrial hygienist to perform a workplace assessment of your facility.

Noise Hazards

Welding, cutting, and grinding processes are often noisy and may require hearing conservation programs to mitigate noise hazards in these types of areas. There are five required elements of OSHA's hearing conservation standard, 29 CFR 1910.95:

• Noise monitoring
• Annual hearing testing
• Hearing protection methods
• Annual training
• Recordkeeping

Environments that have a time weighted average (TWA) greater than 85 dBA require a hearing conservation program. As part of the program if the TWA is greater than 90 dBA, workers must wear hearing protection to reduce the TWA to less than 90 dBA. Additionally, employers must provide a suitable variety of hearing protection devices—two or more—to allow options for employees regarding fit and comfort.

The best hearing protectors are those that are worn correctly, have good fit, are worn consistently, and are comfortable. Many types of hearing protection devices (HPDs) are offered on the market today. HPDs include disposable foam earplugs, reusable molded earplugs, banded devices, and earmuffs with and without built-in communications.

When selecting an HPD, consider the performance or noise reduction and attenuation of the device. Also consider the effect the HPD has on communications and whether it will cause any adverse safety concerns while being worn. Next consider the comfort of the HPD throughout the wearing period. A device may be comfortable at first but become uncomfortable over a period of time. Next consider the ease of use: Is it easy to remove and reinsert into the ear, and is it compatible with other PPE used in the environment?

Last, consider the physical properties and ask how durable the device needs to be and the initial and long-term investment of the device. These basic questions will help you in selecting a suitable HPD.

Reg:aluminum beverage cans

 

ALUMINUM/TIN CANS RECYCLING

Aluminum cans are the real success story of the recycling movement. By far, the most valuable component in the consumer waste stream, they enjoy the greatest public recognition as a recycled household item. Aluminum cans are often the economic backbone of municipal and private recycling programs. The price can fluctuate with the commodity price for new aluminum, but aluminum can scrap has always had a strong price in comparison to other recyclables.

Aluminum cans are collected in a variety of ways. In some countries, cans are returned through deposit schemes. With these systems you pay a deposit or fee when you purchase a full container. When the container is empty, you return it to a designated collection site and your fee is refunded. This collection method is very effective but the cost usually exceeds the recycling value for the containers. Buy back collection mechanisms is still very popular in many parts of the western hemisphere. People are offered money for aluminum cans that they collect and redeem at a recycling center or reverse vending machine. Most locations buy the cans by weight but some of the older systems pay for each can. Voluntary drop off locations are still in use in much of the EEC, and in more rural parts of the US. Many of these programs have been replaced by blue box programs, where a number of household recyclables are picked up at the curb and taken to large recycling facilities that sort and package the items for sale.

Recyclers can process aluminum cans in a number of ways. Small low volume processors will normally flatten cans and sell them to a nearby wholesaler. Larger operations will bale, densify or in some cases shred cans for shipment to aluminum consumers. The aluminum companies have defined specifications on how aluminum cans should be prepared.

How, exactly are the cans recycled ? After collection and processing the aluminum UBC ( Used Beverage Cans) are shipped by truck, railcar or sea container to smelting plants. The bales of cans are unloaded and tested for quality and moisture content. After inspection, the bales of cans are broken up in a shredder into small pieces. These shredded cans are then conveyed into a De-lacquering oven to remove the paint and residual moisture. The hot shredded aluminum is then passed over a small screen to remove and dirt and contaminants and fed directly into a reverbatory furnace. Heated to 1400 degrees Fahrenheit ( 650 Centigrade) the cans melt and blend in with the molten metal already in the furnace. A mixture of salt and KFl are added as a flux to help separate out any oxides (dross) that are skimmed off.

Molten aluminum is checked for proper chemistry and then tapped ( removed) from the furnace and poured into large molds that cast sheet ingots. These large rectangular ingots ( 20 to 40,000 lbs each) are allowed to cool and harden. When they are needed, the top and bottom surface of the sheet ingot ( alloy 3105) is milled to a smooth surface in a process called "Scalping". The scalped ingot is then passed between two giant steel rollers in a large rolling mill. The sheet is passed through a few more times until it is about 1/2 an inch (1.25 Cm) thick and maybe 1000 feet (300 meters)long. This long sheet is then annealed to soften it and passed to a series of rollers in a finishing mill where it acquires the necessary hardness and thickness. The edges are trimmed in a slitter and the coil is rolled up for shipment to a can manufacturer. The finished coil may be 2 miles (3 kilometers)long and made from over 1.2 million recycled cans. 
If not properly recycled, an aluminum can will still be on the surface of the earth after 500 years. Aluminum recycling can reduce air pollution by 95%. It can save 90% to 95% of the energy required to manufacture aluminum from recycled aluminum cans than from aluminum core.

If each person recycles one aluminum can in each month, 1,750 to 3,500 gallons of gas can be saved

Tin cans can be processed in bales or into high density bricks for direct shipment into a steel mill. Material can be shipped via railcar, van trailer, dump trailer, flatbed or in walking floor trailers. Like aluminum, each mill has preferences on how they want material packaged and delivered. It takes a fairly substantial baling press to make a decent tin can bale. The product must be tight, especially if you are shipping on a flatbed truck. We currently purchase tin cans in the east, midwest and southern US and Canada. Let us know what you have available and we will contact you with a price.

Tin can bundles are relatively low in value and are seldom imported. The value to recyclers depends mostly on the amount of freight it takes to reach a steel mill. Recycling processors were paid between $30 and $80 a ton for baled tin cans picked up at their facilities in 1998. Fortunately, this material is abundant and easy to process so the handling costs are fairly low. Because they are magnetic, they are sorted from other recylables automatically with a magnetic conveyor belt. These belts usually feed the steel directly into an automatic baling press which produce mill quality 1000 to 2000 lb bales that are ready for shipment.

An interesting video for Aluminum Recycling

http://www.youtube.com/watch?v=AOpGhAdQFEY

Project Cost Management

Project Cost Management

By Joseph Phillips

I'm not a huge fan of country music, but Lyle Lovett is one of my favourites. How can you not like Lyle Lovett? After all, he married Julia Roberts. (Ah, Julia Roberts, if you've read my articles before, you know how much I admire that smiling beauty. Sure, she snubbed Keifer, dumped Lyle, had a set of twins, and refuses to return my phone calls. Still, she is Julia Roberts.) Anyway, the point I'm trying to make is that I like Lyle Lovett's music: rhythm and blues, big band, good ol' country. In one of Lovett's songs, he croons, "Would you like a kiss?" She said, "Thank you, no. I'll take some M-O-N-E-Y." Project managers are like the girl in Lovett's song:

• Management asks, "Would you like more time?" We respond, "Thank you, no. I'll take some M-O-N-E-Y."
• Customers offer, "Would you like to reduce the scope?" We answer, "Thank you, no. I'll take some M-O-N-E-Y."
• Sponsors demand a speedier schedule. We respond, "Thank you, no. I'll take some M-O-N-E-Y."

Get the point?

From IT to construction, most projects have to purchase materials: routers and cables, shingles and cement, and so on. We almost always must buy some things to complete the project work. Think back to your last project; didn't you have to buy something? A piece of software. A book. A large double-cheese and sausage pizza for your team. Someone, you or the organisation you work for, had to cough up the cash to buy that stuff.

Regardless of scope or schedule, projects need funds to complete the work. Technically, even projects that use only labour have funds attached to them; someone, somewhere is paying for that labour. What happens if you don't have the correct amount of funds to complete the project scope? Your project is doomed.

Got Your Money on Your Mind?

How do we know what a project will cost? We really don't, until the project is complete. I sound more like a car mechanic than a project manager, but the truth is, and this may sting just a little, we can't know the final project cost until the project is complete because we can't accurately predict the future.

What we can do is create an estimate. An estimate is more than pulling a random number out of the air, adding 20% for good measure, and then saying, "That'll work." A real estimate evolves as project details become available. This is progressive elaboration. Project estimates start out broad, and as the project deliverables come into focus we're able to more accurately define our estimates.

Each estimate should provide an acceptable range of variance, the conditions of the estimates, and any assumptions made by the estimate provider. For example, an estimate to build a new warehouse may state that the warehouse will cost $350,000, +/- 10%, is valid for 30 days, and assumes that the warehouse will be built in the month of June.

Notice the range of variance, the assumptions, and the stated work? A good estimate clearly defines what the project will accomplish, the assumptions made, how long the estimate is valid, and how much the project will cost based on current information. A good estimate presents to the stakeholder everything relevant to the proposed work, without holding back any secrets. If there's a disagreement in price, assumptions, or range variance, it's better to discuss this issue now rather than four months into the project execution.

There are three major estimate types that project managers should rely on:

• The Ballpark Estimate is also known as the rough order of magnitude (ROM). A ROM estimate is based on high-level objectives, provides a bird's-eye view of the project deliverables, and has lots of wiggle room. Most ROM estimates, depending on the industry, have a range of variance from -25% all the way to +75%. Like I said, lots of wiggle room.
• The project manager shouldn't invest too much time in creating these initial estimates, just as the customer shouldn't place too much confidence in the accuracy of the ROM estimate. Unfortunately for both parties, there's a consistent breakdown in expectations when it comes to ROM estimates. Typically the project manager blindly throws out the ROM estimate like a bride tossing her bouquet, and the customer clings to the ROM bouquet like the maid of honour at the same wedding. ROM estimates, regardless of your role in the project, are simply for eyeballing the project's initial perceived costs.
• The Budget Estimate (or top-down estimate) is a bit more accurate. Formulated fairly early in the project's planning stage, the budget estimate is most often based on analogous estimating, taking budget lessons learned from a similar project and applying them to the current project. Do a little maths magic and we've got ourselves a budget estimate. Abra-cadaver!
• With the budget estimate, we start at the top and work our way down into the project details. Like the ROM, this estimate should include conditions, a range of variance, and any assumptions that went into your calculations. A budget estimate is quick, but not very accurate. The range of variance on the budget estimate is from -10 percent to +25 percent.
• The Definitive Estimate (or bottom-up estimate) is the most accurate of the estimate types, but takes the most time to create. The definitive estimate requires a work breakdown structure (WBS). A WBS is not a list of activities. (I know, everyone at your office says it is, but they're all wrong.) A WBS is a deliverables-oriented decomposition of the project scope. That's decomposition of the deliverables that your project will create for the customer, nouns, not verbs.

For example, suppose you need to create a network from scratch in your organisation's headquarters. Your WBS will stem from the project name HQ Network. Below HQ Network, you create a family tree of major deliverables: LAN, WAN, server room, workstations, and so on. Then you decompose these major deliverables into smaller deliverables.

Your WBS should use a code of accounts to number each deliverable in the WBS. For example, assume that the HQ Network is project number 427. The WAN section of this project might be 427.1, and the elements under the WAN deliverables would then be 427.1.1, 427.1.2, and so on. This code of accounts clarifies for all participants the deliverable that is being referenced, providing an accurate record for any element the project manager promises as part of the project completion. You don't have to use a code of accounts, but it's easy enough to implement, and can save time downstream.

You need a WBS in order to create the definitive estimate because you and/or your experts will account for the cost of each deliverable. In some organisations, that cost can include more than just the materials, it may take into account labour, consultants, team development, and so on. The point is that each deliverable in the WBS can have time and costs associated with it. Depending on the size of your project, you may want or need to create a WBS dictionary to take advantage of the code of accounts for each of the WBS elements: defining each element, the party responsible for the element, time and costs associated with each component, and other notes or relevant facts.

A WBS dictionary, coupled with the code of accounts, helps to prevent or resolve miscommunications, provide accurate references, and organise the project deliverables. Tied to the WBS dictionary are time, costs, and relevant info on each deliverable. Now you and Larry from Accounting can be best friends forever. You can move to any deliverable in the project and give an accurate estimate of what each thing will cost to implement.

A definitive estimate takes lots of time to create, but it's the most accurate estimate you can provide. You may know this as a bottom-up estimate because you start from zero (the bottom) and account for each freakin' thing the project will purchase, create, or deliver. The range of variance on a definitive estimate is relatively low: -5% to +10%. This makes sense because it's much easier to predict how much something will cost when you can see everything the project will create. How many projects have you been involved in where you can see everything the project will create from the word go? Probably not too many, or only projects that you've completed repeatedly and therefore know exactly what's expected. For example, an IT integrator may have a project template that defines all of the work to implement a prepackaged solution in any environment.

While definitive estimates are ideal for accuracy, they're not easy to create because so much effort has to go into the project before the project manager can create the definitive estimate. This requires education not just for you as project manager, but for your stakeholders, who need to understand that the only way a precise estimate can be created is to invest time in the project itself, by creating the WBS.

With any type of estimate, the project manager must provide the range of variance and an explanation of how the estimate was created. Without these explanations, the customer is led to believe that the price you've quoted, the price you've "promised," is the final price that the customer will see. And should the price tag change, there'll be hell to pay.

Got Your Mind on Your Money?

As the project moves toward completion, there will likely be a need to revise the project's price. If the project started with a ROM estimate, the original estimate could be wildly wrong. The customer who reads the ROM estimate should know that the final cost is likely to be much different from that estimate. No doubt the customer will be anxious to hear your more accurate definitive estimate.

Of course, from ROM to definitive, estimates can be just plain wrong. It's not fun to have to approach your sponsor, stakeholders, or customer with hat in hand and beg, plead, scrounge for more cash because your project estimate was way, way off. Poor planning is the major cause of poor estimates. Rushed estimates, bloated estimates, or estimates that are "low-balled" just to get the project moving are bound for budget reviews, unpleasant conversations, and project reassessments.

Sometimes, thankfully, it's not the project manager's fault when the estimate must change: The cost of materials has changed, the anticipated time to complete the project work was wrong, or the bases for decisions were faulty. In these instances, the project manager still has to communicate the variances, which isn't fun, but it's easier than taking the blame when that blame is all yours.

Poor estimates can also be the fault of the customer, stakeholders, or even the project sponsor. When the stakeholder is responsible, the increase in cost is usually tied to a change request. Contrary to public opinion, change requests are not good things. Ideally, when the customer and the project sponsor sign off on the scope statement, no changes should ever be made to that scope. Of course, errors and omissions, technological enhancements, and value-added changes all affect the scope's resistance to change.

If the customer demands new deliverables in the project scope, however, a price tag is usually associated with those demands. The monies needed to implement the change have to come from somewhere, and not your wallet. Even changes that replace current scope components may have a price; time and monies may already have been invested in these deliverables. In my opinion, change after the scope statement is a bad, bad thing.

We'll talk more about change management in a future article. For now, know this: When the project scope changes, the budget usually has to change as well. Changes generally cost something, and that means a budget increase.

IT and Project Cost Control

Do you ever feel like you're playing on the budget dartboard? The vendor's cost has increased. The historical information is flawed. Time estimates are incorrect. The project team is spread too thin. The bribe was lower than expected. Excuses, excuses, right?

IT suffers from a universal law: the first-time, first-use penalty. The concept of the first-time, first-use penalty is that it's next to impossible to accurately estimate the cost of something that has never been attempted. IT is so unique, so multifaceted, and has so many fronts that the constant movement of its variables creates a love-hate relationship for any organisation trying to create an IT cost estimate.

Consider any IT project, from replacing hardware to rolling out an entire new system, and I bet you've got a first-time, first-use scenario in there somewhere. Sure, that type of work may have been done before, but not in this project's specific environment. You've got different types of hardware, firmware, software, and don't forget users, banging up against your solutions. All of these factors are often ignored, dismissed, or assumed to be non-issues. Mistake! When it comes to cost and things that can affect cost, the project manager must consider the risk and ramifications of the first-time, first-use penalty. This universal law can spell disaster for any IT project. The longer a project manager goes without at least nodding in the direction of the first-time, first-use penalty, the bigger the pending fall.

Cost and the Project Manager

Project managers are in a tough spot: They're the liaison between the customer and the project team that will complete the customer's project. In most organisations, it's generally easier to get more time than money, and there's usually more concern about how much than how long. Project managers and their stakeholders need to go into any project with a common goal: Identify an affordable scope and a plan of how to achieve it. Too often, and maybe because of the subject matter itself, cost is ignored in project planning. For projects to be successful, someone has to foot the bill, and until the estimate is requested or provided, it's not a mystery, just a constant dread.

Cost management really is like a Lyle Lovett song: It can be painfully sad, honest, and focused on M-O-N-E-Y, without ever really saying that word.

Joseph Phillips is the author of five books on project management and is a PMI Project Management Professional, a CompTIA certified Project Professional, and a Certified Technical Trainer.

Types of Nondestructive Testing

Types of Nondestructive Testing

Liquid Penetrate Testing (PT)

Liquid Penetrant Testing is sometimes called dye penetrant testing (DPI) or liquid penetrant inspection (LPI). One of the most cost effective ndt methods used to test non-ferrous materials. This method locates surface defects in nonporous materials when you apply a fluorescent or non-fluorescent dye penetrant to the surface. This method can detect cracks, fatigue cracks, forging and casting defects.

Magnetic Particle Inspection (MT)

Common ndt method that is capable of detecting surface and subsurface defects in ferrous materials. The method involves the induction of a magnetic field to or around the test specimen. If the material has a surface or near surface flaw it will create magnetic flux. These magnetic fluxes will attract small magnetic particles to the flaw area making it detectable. Also known as Magnetic Particle Inspection (MPI)

Radiographic Testing (RT)

This ndt inspection method uses wavelength electromagnetic radiation to penetrate various materials to detect flaws. This x-ray detection can be used on lead and steel to detected external and internal flaws but cannot be used on plastics. Radiation Safety is very important when using this testing method due to the possible exposure to strong gamma sources in remote sites.

Eddy Current Testing (ET)

Eddy current testing uses electromagnet induction in conductive materials to detect flaws. This method can detect very small flaws in or near the surface of the material. It is limited to conductive material and the surface must be accessible.

Ultrasonic Testing (UT)

Ultrasonic testing takes place when you send short ultrasonic pulse-wave into the material to detect internal flaws or identify different types of material. This method is also commonly used to determine the thickness of material. UT testing can be used on alloys, steel, concrete, wood and composites.

Visual Inspection Testing (VT)

Visual Inspection is the most common and readily available inspection. It is the process of eye fixations on a test specimen. Many times the inspector is trained to look for certain clues that might indicate defects or flaws. Most ndt inspections start with a visual inspection.

NDT Method Summary

NDT Method Summary

No single NDT method will work for all flaw detection or measurement applications. Each of the methods has advantages and disadvantages when compared to other methods. The table below summarizes the scientific principles, common uses and the advantages and disadvantages for some of the most often used NDT methods.

Penetrant Testing	Magnetic Particle Testing	Ultrasonic Testing	Eddy Current Testing	Radiographic Testing
Scientific Principles
Penetrant solution is applied to the surface of a precleaned component. The liquid is pulled into surface-breaking defects by capillary action. Excess penetrant material is carefully cleaned from the surface. A developer is applied to pull the trapped penetrant back to the surface where it is spread out and forms an indication. The indication is much easier to see than the actual defect.	A magnetic field is established in a component made from ferromagnetic material. The magnetic lines of force travel through the material, and exit and reenter the material at the poles. Defects such as crack or voids cannot support as much flux, and force some of the flux outside of the part. Magnetic particles distributed over the component will be attracted to areas of flux leakage and produce a visible indication.	High frequency sound waves are sent into a material by use of a transducer. The sound waves travel through the material and are received by the same transducer or a second transducer. The amount of energy transmitted or received and the time the energy is received are analyzed to determine the presence of flaws. Changes in material thickness, and changes in material properties can also be measured.	Alternating electrical current is passed through a coil producing a magnetic field. When the coil is placed near a conductive material, the changing magnetic field induces current flow in the material. These currents travel in closed loops and are called eddy currents. Eddy currents produce their own magnetic field that can be measured and used to find flaws and characterize conductivity, permeability, and dimensional features.	X-rays are used to produce images of objects using film or other detector that is sensitive to radiation. The test object is placed between the radiation source and detector. The thickness and the density of the material that X-rays must penetrate affects the amount of radiation reaching the detector. This variation in radiation produces an image on the detector that often shows internal features of the test object.
Main Uses
Used to locate cracks, porosity, and other defects that break the surface of a material and have enough volume to trap and hold the penetrant material. Liquid penetrant testing is used to inspect large areas very efficiently and will work on most nonporous materials.	Used to inspect ferromagnetic materials (those that can be magnetized) for defects that result in a transition in the magnetic permeability of a material. Magnetic particle inspection can detect surface and near surface defects.	Used to locate surface and subsurface defects in many materials including metals, plastics, and wood. Ultrasonic inspection is also used to measure the thickness of materials and otherwise characterize properties of material based on sound velocity and attenuation measurements.	Used to detect surface and near-surface flaws in conductive materials, such as the metals. Eddy current inspection is also used to sort materials based on electrical conductivity and magnetic permeability, and measures the thickness of thin sheets of metal and nonconductive coatings such as paint.	Used to inspect almost any material for surface and subsurface defects. X-rays can also be used to locates and measures internal features, confirm the location of hidden parts in an assembly, and to measure thickness of materials.
Main Advantages
Large surface areas or large volumes of parts/materials can be inspected rapidly and at low cost. Parts with complex geometry are routinely inspected. Indications are produced directly on surface of the part providing a visual image of the discontinuity. Equipment investment is minimal.	Large surface areas of complex parts can be inspected rapidly. Can detect surface and subsurface flaws. Surface preparation is less critical than it is in penetrant inspection. Magnetic particle indications are produced directly on the surface of the part and form an image of the discontinuity. Equipment costs are relatively low.	Depth of penetration for flaw detection or measurement is superior to other methods. Only single sided access is required. Provides distance information. Minimum part preparation is required. Method can be used for much more than just flaw detection.	Detects surface and near surface defects. Test probe does not need to contact the part. Method can be used for more than flaw detection. Minimum part preparation is required.	Can be used to inspect virtually all materials. Detects surface and subsurface defects. Ability to inspect complex shapes and multi-layered structures without disassembly. Minimum part preparation is required.
Disadvantages
Detects only surface breaking defects. Surface preparation is critical as contaminants can mask defects. Requires a relatively smooth and nonporous surface. Post cleaning is necessary to remove chemicals. Requires multiple operations under controlled conditions. Chemical handling precautions are necessary (toxicity, fire, waste).	Only ferromagnetic materials can be inspected. Proper alignment of magnetic field and defect is critical. Large currents are needed for very large parts. Requires relatively smooth surface. Paint or other nonmagnetic coverings adversely affect sensitivity. Demagnetization and post cleaning is usually necessary.	Surface must be accessible to probe and couplant. Skill and training required is more extensive than other technique. Surface finish and roughness can interfere with inspection. Thin parts may be difficult to inspect. Linear defects oriented parallel to the sound beam can go undetected. Reference standards are often needed.	Only conductive materials can be inspected. Ferromagnetic materials require special treatment to address magnetic permeability. Depth of penetration is limited. Flaws that lie parallel to the inspection probe coil winding direction can go undetected. Skill and training required is more extensive than other techniques. Surface finish and roughness may interfere. Reference standards are needed for setup.	Extensive operator training and skill required. Access to both sides of the structure is usually required. Orientation of the radiation beam to non-volumetric defects is critical. Field inspection of thick section can be time consuming. Relatively expensive equipment investment is required. Possible radiation hazard for personnel.
Penetrant Testing	Magnetic Particle Testing	Ultrasonic Testing	Eddy Current Testing	Radiographic Testing