Orange County Metal Works forms elliptical head from Zirconium 702

Orange County Metal Works preparing a 76. 6" x 1/2" zirconium head for flanging. The Orange, California-based manufacturer has recently developed successful procedures for forming zirconium heads.

One of the more difficult items for zirconium (Zr) fabricators to get their hands on is tank heads. In the past, Zr head manufacturers have been nearly impossible to find. Many head makers do not quote Zr heads. This is either due to failure experienced in forming the material and/ or a lack of expertise. Finding a Zr head was like finding the proverbial "needle in a haystack."

Wah Chang's outside fabrication department went to work looking for this "needle".

In its search, Wah Chang eventually found tank head manufacturer Orange County Metal Works, a Unit of Commercial Intertech Corp. The Orange, California-based manufacturer has been in the business of steel fabricating since 1924. In 1980, Commercial Intertech, a multinational manufacturer of hydraulic components, building systems, and metal products, purchased the company.

Early in 1996, Wah Chang asked Orange County Metal Works to provide a quote on forming heads from ASTM R60702 (Zr-702). At that time, the fabricator had produced heads in various grades of carbon steel, stainless steel, aluminum, and most non-ferrous metals. However, Zr was a material with which the company was not familiar.

After being provided information regarding the material and its formability, Orange County Metal Works agreed to form Zr heads for Wah Chang on an experimental basis. The fabricator ran some sample parts in September of 1996. In this trial run, the company attempted to make heads using two of its forming processes.

One head was produced using its die forming process, while another was formed using a bumped and spun process.

The die formed head was produced without any failure. The bumped and spun head developed some cracks during the knuckling operation of this process.

Although the fabricator was not completely successful on these trial parts, the process gave it enough data to develop procedures that it believed would be successful. Using these procedures, the company has since been successful in forming several semi-elliptical tank ends. It has produced heads for Wah Chang in diameters ranging from 12.75 in. to 55 in. and in thicknesses ranging from 1/4 in. to 5/8 in.

Presently, Orange County Metal Works is in the process of filling another order for Wah Chang. This will consist of some slightly larger heads than those previously formed (one as large as 76" in diameter).

Orange County Metal Works' recent success in the forming of Zr heads, adds to its growing list of capabilities. The company can manufacture heads in sizes ranging from 4 in. to 280 in. and thicknesses ranging from 14 GA to 1 1/2 in. The fabricator has formed heads in stainless steel, aluminum, carbon steel, Hastelloy, nickel, copper-nickel, duplex, clad, bronze, and other non-ferrous metals. It has the capabilities to die form from 4 in. to 48 in. as well as bump and spin to custom diameters from 16 in. to 280 in.

Other products offered by the company include code and non-code man-ways, hinged closures, cones, toriconicals, segmented hemispheres, custom metal stampings, dished-only heads in unlimited diameters, and tank accessories. Additional services include beveling, trimming, joggling, shearing, piercing, heat-treating, stainless polishing, and sandblasting.

For more information on Orange County Metal Works' products and services, call 714-532-6321 or 800-854-3307.

Q&A: Rolling flat bar the hard way

This issue's question and answer article was submitted by Zr fabrications expert Rick Jenkins. Jenkins is V.P., for Sales and Marketing at Industrial Alloy Fabricators, Inc., which is based in Forest Grove, OR. He is a metallurgical engineer and previously worked for Wah Chang for over 20 years. Jenkins submitted the following question that he has been asked about forming zirconium.

Question:

I have been told that zirconium is a difficult material to form. The material does not behave like carbon or even stainless steel. If my company has to roll stiffening rings the hard way, what can we do to make the process easier?

Answer:

Zirconium can be a difficult material to form, but it does behave in a predictable manner. If operations are planned with zirconium's characteristics in mind, potential problems might be greatly reduced before processing begins.

First, recognize that zirconium is an anisotropic material. This means that it has different properties in different directions. Typically, Zr has lower yield strength and higher elongation in the longitudinal direction. This also means it has higher yield strength values and lower elongation in the transverse direction. One can take advantage of this characteristic in flat bar rolling by rolling the hard way as shown in the figure below right (i.e., cut the bars with the long axis in the longitudinal direction). This allows elongation of the bars in the weaker, more ductile, longitudinal direction. It may not be the most economical method, but it is the easiest manufacturing method.

Zirconium is also notch sensitive, so a good edge is very important. The edges used for rolling should be smooth and free of nicks and burrs that can act as stress risers. When shearing the plate to width, grinding should be performed to eliminate these. The price of water jet cutting has dropped over the last few years and should be considered when working with more than two or three bars. Sawing or machining are also operations that will produce smooth edges. The comers should also be rounded to reduce potential stress risers.

Other problems that may be encountered include welding shorter lengths together to make the required length. This can create a couple of potential problems. The weld is considerably harder than the parent metal (due to contamination from welding) and will not bend as well in the area of the weld. The excess weld metal also increases this problem by simply having more metal to bend. The weld bead should be ground flush to eliminate this excess metal. If problems are encountered with the welds breaking in rolling, the manufacturer may wish to stress relieve the bars prior to its rolling operation. This can be accomplished by heating the bars to 1050°F for 30 minutes at temperature. Typically, there will be a minimal amount of discoloration for this operation, since the total heating time is only about one hour.

Figure 1. Rolling flat bar the "hard way" is actually the easiest manufacturing method for producing stiffening rings.

The bars can be removed as soon as you reach the 30 minutes at temperature. This will reduce the thermal stresses left by the welding and thereby reduce the difference in properties in the weld area versus the parent metal.

Care should be taken to ensure that you match parts to be rolled with their rolling direction. If you have one length of bar cut in the longitudinal direction and weld to it another bar cut in the transverse direction, you will find that the rolling operation will not necessarily produce a uniform ring. You may get twisting or a nonsymmetrical ring radius. Therefore, use care in selecting material to weld together prior to forming.

Like titanium and 300 series stainless steel, zirconium work hardens and is more difficult to form than carbon steel. Total deformation should be limited to 40-50% between anneals. There is considerable springback, and typically we have to overform to achieve the desired shape. There are no accepted guidelines on how much to overform, so we use trial and error to develop the parameters for our equipment.

For more information about this Q&A, contact IAF's Rick Jenkins at 503-359-0793.

'98 Nitric Acid Producers Meeting to be held in Jasper, Alberta, Can.

Agrium Redwater Nitrogen Operations will host the 1998 Nitric Acid Producers Meeting at the Jasper Park Lodge in Alberta, Canada, May 18-20. Wah Chang and a contingent of suppliers to the chemical process industries will be on hand to host luncheons (May 19 and 20), evening hospitality events (May 18 and 19), and, most importantly, to offer solutions to challenges facing plant operators and engineers.

According to Roland Schech, Plant Engineer at Agrium Redwater, the meeting will be held in the usual roundtable discussion format, focusing on problem areas of a typical nitric acid plant. "We'll go through an entire operation, from front to back," he says.

Schech pointed out that, in addition to the roundtable, there will be a few vendor presentations, including at least one from a catalyst producer. Wah Chang's Rob Henson is also scheduled to deliver a paper on applications of zirconium in nitric acid plants.

In addition to the conference, Agrium plans to host a plant tour of its Redwater facility on May 21.

For more information about the meeting and tour (including registration), call Agrium's Barb Watkins at 403-998-6895. For further information on the exhibitor and hospitality programs, contact Wah Chang's Sheryl Renzoni at 541-926-4211 ext. 6280. (Space is limited, so sign up soon!)

Agrium Redwater will host the '98 Nitric Acid Producers Meeting, which will be held at the Jasper Park Lodge in Alberta

Corrosion '98 (NACE) scheduled for March 22-27 in San Diego, Ca.

Mark your calendars! NACE's Corrosion/NACExpo'98 Conference will take place in San Diego March 22-27 at the San Diego Convention Center. Stop by booth #1001 in the exhibit hall and visit Allegheny Ludlum, Allvac, and Wah Chang: This team of Allegheny Teledyne companies offers a variety of corrosion resistant metals that stand up to nearly any corrosion challenge. Allegheny Ludlum is a leading producer of stainless steels, Allvac and Wah Chang are producers of titanium, and Wah Chang is a major producer of corrosion resistant niobium and zirconium alloys for chemical and mineral processing as well as other applications. Exhibit hours for NACExpo'98 are Monday (March 23) 5:30-8:00 p.m., Tuesday and Wednesday from 10 a.m.-5p.m. and Thursday from 10a.m.-2p.m. For more information, call NACE at 281-228-6223. (Note: for those who like to plan ahead, NACExpo'99 is scheduled for April 25-30 in San Antonio, Texas.)

ANPSG Meeting a great success!

Wah Chang recently joined 36 co-exhibitors in hosting luncheons and hospitality events (including a grand prize drawing for a travel voucher - see picture below) at the 1997 Ammonium Nitrate Producers Study Group (ANPSG) meeting in Destin, Florida. Over 200 people met to discuss challenges facing ammonium nitrate producers and potential solutions. Many answers were offered by the exhibitors, who offered everything from metals to fabrication to engineering services. Feedback from the producers has been very positive.

Wah Chang would like to thank its co-hosts Alloy Engineering, AstroCosmos, Baker Petrolite, BSL, CDC, Chemineer, C&I Engineering, CRI Catalyst Company, Degussa, Dollinger, Dynamic Materials, Ellett Industries, ENPRO, Engelhard CLAL, H.C. Starck, Industrial Alloy Fabricators, ICF Kaiser, Ionics RCC, Johnson Matthey, Joseph Oat, Kimre, Koch Engineering, KTI Fish, Nalco Exxon, Noble Alloy Valve, Nooter, Ohmstede, PGP Industries, Phoenix, Revak Turbomachinery, Sabin, SPF, Stockhausen, Tricor, Weatherly, and W. L. Gore. Your participation in the exhibit hall and events helped make the 1997 ANPSG meeting a great success!

Wah Chang's Rob Henson (right) awards grand prize to ICI's Darrell Larson (center)

Proper planning the key for large-scale projects requiring zirconium

The use of zirconium has grown in the chemical process industries, with sales doubling between 1986 and 1996. The amount of zirconium used in any single facility has also increased. Today's grass roots plant can require over 200 tons of zirconium to make the plant's equipment that can include the largest process column to the smallest needle valve and all of the equipment in between.

Proper planning of material requirements for a large scale project requiring zirconium is critical to meeting the project schedule and strategic start up. Unlike commodity grade materials where the cost to carry large inventory in various product forms is economical, the cost to carry zirconium inventory capable of supporting a large project is prohibitive. The volume of zirconium required for a large project requires that the material be custom scheduled through the mill production cycle. Wah Chang, however, stocks smaller quantities of zirconium in a wide array of product forms and sizes at its Service Center.

The amount of material the service center carries has increased significantly over the last several years and will continue to grow to meet the needs of the industry.

Mill Product Flow Chart

The accompanying production chart (pgs 6&7) is provided to assist the fabricators and equipment manufacturers, engineering houses, and end users in developing preliminary project planning schedules and identifying the critical path equipment and their respective requirements for zirconium mill products. The time line is designed to show relative production times required to produce various mill products and is based on typical deliveries for large projects. The chart also shows how the different mill products are combined to produce various types of processing equipment. The time required to fabricate and manufacture equipment can vary widely, and subsequently, is not shown on the time line. In general, the size of a piece of equipment as well as its complexity determines its delivery time.

Mill Product Production

Ingot is the starting form for all of the different mill products. The typical ingots produced for the CPI include: grades 702 and 705 for wrought product, low oxygen 702 for clad product, and special chemistry 702 and 705 for cast product. The overall production cycle for zirconium 702 from the raw material, sand, to the final mill product currently ranges from 20 to 25 weeks for zirconium rod and 36 to 42 weeks for plate over 30" in width. The lower volume produced material such as low oxygen 702, cast 702, and wrought and cast 705, can require several more weeks to produce.

Starting from ingot, the dimensions and desired properties of the mill product dictate the required processing time. In general, the increased number of steps involved in producing a final mill product results in longer production times. Intermediate processing includes press forging an ingot into slab or octagonal rounds; rotary forging octagonal rounds into billet and rounds; extruding billets into pipe and tubing; drawing rounds into rod and wire; and rolling a slab into plate. A typical ingot can yield:

• five 96" x 240" x 3/8" plates or

• one thousand six hundred 3/4" OD x 0.065" AW x 20' long tubes.

Wah Chang's in-house equipment is capable of producing a majority of the mill product sizes required for most chemical processing equipment. However, product sizes larger than in-house capabilities, such as most plate used in pressure vessel fabrication and seamless pipe greater than 6" in diameter, are produced by outside fabrication resources.

A typical zirconium ingot can yield five 96 in. x 240 in. x 3/8 in. plates or one thousand, six hundred 3/4 in. OD x 0.065 in. AW x 20ft. long tubes

These products, manufactured by the outside fabrication group, are identified on the chart by green lines.

In the case of plate where the width is greater than 30", Wah Chang utilizes the rolling mills of stainless steel producers to forge and roll zirconium into plate. Because of production set ups required to roll zirconium and the relative lower volumes of zirconium compared to the large volumes of stainless steel rolled at the mills, zirconium struggles for position in the rolling mill's schedules. This is the main reason for the longer deliveries for zirconium plate. Another factor that contributes to the longer deliveries is that pressure vessel fabricators typically order custom sized plates to minimize the amount of welding required. Custom sized plates require special handling and coordination that can add to the delivery time. Wah Chang recently developed a strategy to produce plate in 96" wide by 240" long in standard thicknesses to take advantage of efficiencies gained through standardization and increases in leverage with the rolling mills due to higher volumes. It is believed that the lower cost of these standard plates coupled with the shorter deliveries will offset the additional fabrication costs associated with the smaller sized plates. Wah Chang will continue to provide custom plate sizes to meet the needs of its customers. A quick analysis should reveal whether the standard sized plates offer a more economical approach than custom ordered plates for a specific piece of equipment.

Project Planning

With some basic information describing the general zirconium requirements at the beginning of a project, Wah Chang can improve the delivery of zirconium by staging material in either ingot or slab form depending on the final mill product. By staging, Wah Chang processes zirconium sponge into a universal intermediate form rather than waiting for exact sizes to start an order from the beginning of the production cycle. From a project scheduling perspective, staging ingot and slab provides the end user/engineering house several more weeks to coordinate with their fabricators, valve and pump suppliers, and other vendors to determine final mill sizes. Without prior forecasting, a project may encounter significantly longer deliveries.

Large projects generally require numerous ingots to be processed into various mill products that are subsequently delivered at specific times according to the different fabricator's and manufacturer's schedules. For example, in the case of a large pressure vessel, the ingot set aside for plate to be used as head material is generally sent through the production cycle before the ingot set aside for the internal components because the heads require an intermediate forming step and tend to be needed early in the fabrication sequence, whereas the column internals generally require the vessel shell to be completed before they can be attached. Through coordination with various fabricators and manufacturers, Wah Chang determines their mill product needs and works to develop the production sequence through the mill and Wah Chang's outside fabricators to meet the delivery needs.

With the multitude of intermediate steps involved in producing a final mill product, an equipment design change can have a significant schedule and cost impact. Each mill product reaches a point of no return during its manufacture where changes cannot be made. For small changes, such as adding a nozzle, the Service Center may be able to handle the additional material requirement without affecting the equipment delivery. However, large changes, such as an increase in vessel diameter or a change in wall thickness, may necessitate a complete remake of the mill product that may cause a significant schedule impact. Establishing engineering design deadlines that correspond with material production schedules should be considered. Understanding the schedule impact of a change may help decide the overall merits of the change or steer the decision in a different direction.

In the end, understanding the production flow of zirconium mill products and how their deliveries fit into the overall equipment fabrication schedule and ultimately the project schedule increases the likelihood of meeting the project' s schedule and commitments. Wah Chang hopes that this article and accompanying chart (pgs. 6&7) help the industry with its zirconium needs and encourages fabricators, manufacturers, engineering houses, and end users to contact it with any questions concerning zirconium production and/ or project planning.

Author Larry Duke is a Project Development Manager with Wah Chang. Before joining the company in October 1997, Duke was a Senior Reliability Engineer with Millennium Petrochemicals'. He also headed up the Inspection Group at Millenium's LaPorte, Texas complex. To contact Duke, call 541-967-6916.

Proper planning the key for large scale projects requiring zirconium

Zr in spotlight at Nitrogen Meeting

The use of zirconium (Zr) to combat corrosion problems in the production of nitrogen-based chemicals has a long history. Beginning with the application of zirconium tubes in a urea application in the early 1960' s, zirconium has been specified increasingly in a number of related areas.

Corrosion expert Rob Henson (of Wah Chang) will present a paper discussing the role of Zr in the manufacture of urea, nitric acid, ammonium nitrate, as well as other nitrogen-based products at the Asia Nitrogen '98 conference, February 22-24, 1998 in Kuala Lumpur, Malaysia.

According to Henson, the chemical manufacturers that primarily supply to the agricultural industry are under increasing pressure to comply with environmental mandates in both the production cycle and product purity. The use of zirconium in the production of these chemicals allows for more efficient plant operation, which reduces the emissions of nitrogen oxides and does not contribute to heavy metal contamination of the product like chrome and nickel-containing alloys are prone to do when actively corroding.

Complementing the agricultural application of nitrogen-based products are the chemical and mineral processing applications for these products. The use of nitric acid is expanding as the need for environmentally compatible oxidants grows in both the chemical and mineral industries and as the demand for explosives-grade ammonium nitrate rises. The advent of mineral processes that allow the processing of low-grade ores requires that mass tonnage of ore be processed on a daily basis, and a low cost, effective blasting agent is an integral part of this equation.

Henson's paper will discuss these applications, highlighting and illustrating the application of Zr to solve difficult corrosion problems in the production of chemicals. It will present laboratory data and field trials, providing the reader with an understanding of the versatility of Zr in the nitrogen industry.

For more information about the conference, call British Sulphur at 44 171 837 5600.

New CPI Sales Rep

Rhonda Marshall recently joined Wah Chang's Service Center team. Marshall has 21 years' experience in the metals industry, the last 14 as a Process Engineer. She is an expert in the production of Ti & Zr for commercial applications