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Taking another road pays off for R.H. Sheppard Co.

Investing in compacted graphite iron production allows this foundry to capitalize on the material's growing domestic and world demand.

R.H. Sheppard Co. is a success story that began in the little city of Hanover, Pennsylvania, in 1935 at the height of the Great Depression.

The company is still located in Hanover, but now it has become a leading producer of essential automotive components and operates a major foundry. Its products and services are used by a wide variety of domestic and foreign companies.

In the beginning, the small company was a successful producer of such esoteric products as wire mesh weaving looms, floor polishers and gasoline powered emergency generator sets. It added a foundry seven years later just to satisfy its own modest casting needs.

Since then, however, both the company and its foundry have changed profoundly. After several shifts in product direction, Sheppard has emerged as an international leader in the design and production of proprietary, heavy-duty power steering systems used on buses, military vehicles, trucks and off-the-road construction equipment.

Virtually all of the company's casting requirements are still met by its own foundry, but it, too, has changed. The once-small, captive shop, now a separate operating division, has become the world's largest producer of compacted graphite iron (CGI) castings. It also is a significant producer of gray, ductile and austempered ductile irons for its constantly growing world customer base.

The foundry's principal products are the large (exceeding 90 lb) CGI housings and related castings used in its parent company's power steering units. These are followed closely by CGI hydraulic valve bodies, pump housings and similar, heavy-duty parts for diverse products requiring critical castings for "life-and-limb" type applications.

"We excel at making intricately cored CGI castings for high-pressure service of the kind most foundries shy away from," said Steve Clark, foundry division manager. "Our hydraulic valve business continues to expand because CGI has proven an excellent material for it, particularly for our overseas markets. It |CGI~ helps smooth the peaks and valleys associated with vehicle components production.

"Customers for austempered ductile iron are starting to come on board now. We've increased ADI production and have added to our heat treating capacity for stress relieving, annealing and normalization. Most ADI production has been for railcar systems, but our power steering division is beginning to use it in some applications. It is a rapidly evolving material for quality metal castings, but CGI remains our principal product."

Founder Set Tempo

Company founder R.H. Sheppard was a tinkerer, an inventor with a remarkably creative mind and a broad entrepreneurial streak, according to his son, company President Peter Sheppard. Just out of college, the elder Sheppard developed what later became a proprietary line of diesel engines that eventually powered thousands of boats, marine generators, and farm and other industrial and military equipment.

Over the years, he refined his diesel engines through numerous patents. In 1949, he began manufacturing the first U.S.-made, rubber-tired, diesel tractors that used another of his inventions--a unique, patented, power steering gear.

The popular tractors ranged from 5-55 hp and featured full hydraulics, a 13-speed transmission, a torque converter and Sheppard's new power steering unit. The unavailability of a willing supplier led Sheppard to develop his own power steering mechanism, adding to the importance of his foundry's role as that business grew.

Gray iron casting production at Sheppard had begun in 1942. By the late 1970s, the foundry was an experienced producer of gray and ductile irons and began casting CGI parts. The newer iron's anti-galling, high strength and high heat transfer characteristics proved essential to the evolution of the company's newer power steering units.

In many applications, CGI clearly outperformed gray and ductile irons for the more demanding operating environments and concomitantly higher working pressures the power steering units were encountering.

Impeccable production skills became the signature of the Sheppard foundry. The success of the company's power steering systems eventually led Sheppard to abandon his consumer lines and concentrate his resources on power steering systems and expand the foundry's role as a casting job shop.

The company now is the major North American producer of compacted graphite and one of the world's leading designers and producers of heavy-duty power steering systems.

Foundry Expansion

In the midst of the current recession that has damaged or closed some of the nation's finest foundries, Sheppard recently added substantially to its metalcasting capabilities.

A newly completed 22,200-sq-ft foundry was built to meet the rising demand for CGI castings and to handle Sheppard's gray, austempered ductile, and ductile iron castings overflow. Total foundry space now exceeds 321,000 sq ft.

Constructed at a cost of $6 million, the foundry expansion is a textbook example of the success of aggressive product management and marketing that has kindled interest in the decades-old CGI technology.

CGI has been gaining favor among users of highly stressed castings requiring lightness, strength and durability. The material is a useful alternative to gray and ductile irons, combining the best attributes of each. It also is seen as a practical, cost-effective competitor to the expanding use of aluminum castings in the automotive industry.

Depending on its application, CGI can shave 25-35% off the weight of a similar cast iron part. When comparable aluminum casting costs are factored in, CGI is an attractive alternative for manufacturers seeking to shed product pounds and costs while maintaining quality. The new foundry addition has allowed Sheppard to expand its annual production of CGI by 66% to satisfy that burgeoning interest.

Sheppard Staple: CGI

The R.H. Sheppard Co. is the largest U.S. producer of CGI castings and ranks among the top three CGI foundries worldwide.

This increasingly popular iron is no newcomer to the foundry industry, tracing its discovery to the 1920s and its commercial use in castings to the early 1970s. A member of the cast iron family, CGI also is known as vermicular iron because of the worm-like appearance of the graphite flakes in its structure. The signature graphite shape results in mechanical and physical properties that closely resemble the valued characteristics of gray and ductile irons.

The graphite structure of CGI is intermediate to that of the nodular graphite in ductile iron and the flake-like graphite in gray iron. Unlike gray iron, the graphite flakes in CGI are not interconnected, and can be described in comparison to gray iron's graphite flakes as being shortened, more rounded and thickened, a shape resulting from certain combinations of alloying elements.

This iron offers cost and weight advantages plus high strength and good thermal conductivity, machinability, damping, and excellent fatigue and castability properties.

Making CGI

Four furnaces--one 8-ton, two 20-ton and a 35-ton--supply the current daily melt of 90 tons, soon to be augmented by a new 40-ton channel furnace later this year.

Melting operations are marked by close attention to details. Alloy additions are carefully weighed and placed in paper bags marked with the weight of metal to which the specific alloy packed should be added. Receiving ladles hang on overhead crane load cells so that an exact amount of metal can be tapped that is sufficient to fill the next set of molds to be poured. Precise scheduling minimizes the amount of metal that needs to be pigged after pouring. Nitrogen is bubbled up through the bottom of the ladles to assure proper alloy mixing.

The heart of the new foundry building is the automated pouring line that uses the largest Hunter HMP-32/HV-32R carousel molding center in the country. Fed by a Hunter molding machine, the 20-station machine contains space for 66 molds in a circular cooling magazine before transferring the molds to an elevated AISCO shakeout drum machine.

After shakeout, the parts are conveyed to a blast cabinet and to a sorting table. Shakeout sand is then collected, sent through a magnetic belt separator and reclaimed.

In the "old" foundry, an in-house-engineered conveyorized mold handling system uses 1200 electric eyes to control the movement and position of each mold as it progresses along three parallel conveyor lines. Each line carries molds for different iron castings. Cooling conveyor lines lead to the shakeout station, where the mold is dumped onto the shakeout conveyor and the bottom board inverted to knock off residual sand.

Sheppard maintains a modern testing laboratory in which it samples all raw materials from sand to charge materials. The metallurgy of each furnace's production is also rigorously tested and documented.

In practice, but subject to customer wishes, ductile iron heats are tested every second melt while gray iron is sampled at every sixth melt. Every fifth CGI heat is tested with a chemical analysis as standard practice, or as required by customers who may specify testing and documentation for every heat or even a test bar from each ladle.

The foundry uses channel furnaces in which the small dilution factor on the heel resulting from back charging 3000 lb an hour during the day is reported to be negligible.

CGI Metallurgy

Positioned metallurgically between gray and ductile irons, CGI unites the best properties of both. A typical comparison of the three would show:

* for a class 30 gray iron-tensile, strengths of 32,000-35,000 psi and Bhn of 170-229;

* for CGI 50,000-60,000 psi tensile, 41,000-45,000 psi yield, 1-2% elongation, 170-229 Bhn;

* for ductile iron 60,000-70,000 psi tensile, 40,000-45,000 psi yield, 10-15% elongation and 170-229 Bhn.

The thermal conductivity and damping characteristics of CGI are considerably better than that of ductile iron and near that of gray iron. Some studies have shown that when compared to high-strength gray iron, CGI can exhibit superior thermal conductivity.

For the power steering housing that Sheppard produces, gray iron was used early on, but its modulus of elasticity prevented an increase in allowable operating pressures. The gray iron housing also required a stress-relieving heat treatment to assure that critical dimensions would be held after machining, but at increased cost per casting.

Ductile iron was an alternative because of its high strength and high modulus of elasticity. However, its poor wear properties caused galling of the cylinder bore surface and seizing of the power steering piston during high-pressure test stand trials.

CGI's high modulus, excellent wear, lubrication properties and improved surface finish allow consistent performance at pressures higher than otherwise possible.

Another positive feature of CGI is its section insensitivity. This means that castings can be produced having various cross sections and still have relatively uniform hardness. Sheppard is manufacturing 50,000-70,000 psi CGI, with the change in tensile strength achieved by varying the ratios of pearlite to ferrite.

In setting quality standards, Sheppard permits no flake graphite in the micro-structure, but does allow up to 20% nodular graphite. The graphite form is susceptible to section sensitivity and as a casting section drops below 1/4 in., it becomes difficult to maintain 20% or less nodularity. A typical Sheppard CGI analysis is 3.5% C, 2.2% Si, 0.04% Mn, 0.03% S, 0.25-0.5% Cu, 0.02-0.27% Mg and 0.15-0.20% Ti.

Once the base iron is right, compacted graphite formation is achieved by adding a Mg-Ce-Ti-Ca ferrosilicon alloy. The amount of alloy necessary to achieve the graphite formation is variable based on the sulfur content. Close control of sulfur is Sheppard's key to consistent CGI production.

"Inoculation is very important as to what kind, how much and where it is used," Clark said. "When we first started using CGI here, the claim was made that you could not hold less than 20% nodularity in a 1/4-in. section. By experimenting, we were down to 10% in 0.022 in. thick section with a 3-in. adjoining wall being completely compacted.

"CGI presents many subtleties. One treatment is the combination of titanium and magnesium as a single alloy in the treatment ladle. We found, however, that this limited our abilities to change from a 1/4 in.-wall to a 1-1/2 to 2-in. wall and still maintain the desired graphite content. So we changed to a two-part system, adding the titanium separately, blending some of it into the treatment ladle and some as a late post-inoculation. Treatment has to change as section thicknesses, volume of iron and as isolated sections within the casting change."

Sheppard uses only certified steel plate, slitter steel, pig iron and its own returns as materials for charging CGI heats. Clark said it is an expensive mix, but is quick to point out that too many foundries learn too late that using common scrap is a decided risk when producing consistent ductile iron or CGI.

For a European customer, the foundry produces basically three distinct structures within a single 3-in. thick casting that requires a certain type of face iron using a particular type of inoculation. The result is probably between 80-85% nodularity on the face of the casting, about 50% in the center and approximately 20% nodularity on the outside. This gives a great heat dissipation effect and a fine face finish but the material requires a high-grade charge mix.

A new series of heavy truck engines using 60 sets of CGI cylinder liners is being tested. Preliminary results indicate that the liners have a 5:1 life cycle over the next best material, showing no evidence of heat checking, tearing, seizing or galling. The ceramic rings the engine manufacturer uses in its new low-emission engine wore out during testing but the test liners were unaffected.

Sand Reclamation

Sheppard installed the first green sand reclamation system in Pennsylvania. The foundry is committed to green sand in a mix containing western bentonite, new sand, sea coal and water blended to have high green and dry strengths.

The foundry at one time was bringing in two truckloads of new sand and disposing of two truckloads of used sand every week. Two years ago, the sand going out was costing $42 a ton plus pickup charges. Since installation of a reclamation system, the foundry now uses about 4-1/2 truckloads of new sand a year and reuses virtually all of its foundry sand.

Molding sand and core butts are carried from three sand collection locations in the foundry to a central reclamation building. Here, they are reclaimed in an automatic system that delumps, calcines and blends new sand and clay before conveying the reclaimed sand back to the molding rooms.

The Future

Sheppard's foundry expects to expand its market share by increasing international CGI sales for its power steering systems and for castings used in high pressure applications, but Peter Sheppard explained that the company also is looking for acquisitions to compliment its heavy-duty vehicle markets.

"We're really a niche producer," he said. "Only a few foundries have the CGI expertise we have. It is a unique material made by a unique process and, we think, by a unique foundry.

"We're still a growing company and the next decade will see us a still larger organization, probably doing much the same kind of work. We will continue to grow internally as our market niche expands and acquisitions will serve to assure that growth.

"We are actively seeking companies with products and processes that will add some diversification or that can use our casting, machining, assembly and testing capabilities. The product is as important to us as to whom we sell it. We have to have a product that fits our quality standard and our style of doing business."

If CGI is so good, why aren't more foundries making it? Because they don't fully understand it, Sheppard said, adding that CGI entails a very slow learning curve.

In the beginning, many foundries tried to make CGI and were not successful or did a poor job of it. With too much nodularity, CGI acts like ductile or it is made too soft (ferritic) and is unmachineable. It also can be made so hard that it is suitable for bank vaults but it can't be machined.

The foundry must have good melting practices, start with good materials and have tight product controls. If these criteria are met, the result is a superior product.

Sheppard Co. and its foundry division have followed such criteria, selecting only products and services that offer the best return on technology and employed capital. They have invested in plant and equipment judiciously and have taken care to use their labor wisely.

It is a strategy that has stood the company in good stead for nearly 60 years and there is no sign that this will change.

Old R.H. would surely approve.

Clark Steers Foundry in New Direction

Steve Clark, foundry division manager, likes to tell of the morning a year ago when he and company President Peter Sheppard visited the newly completed foundry building just after the last construction crew had left.

They stood silently, looking at the expensive, windowless bulk of the huge addition to the "old" foundry buildings that flank it.

Clark said he was deep in thought about startup operations when Sheppard turned to him and said in a quiet voice, "Steve, don't you dare die or even get sick anytime in the next five years."

Clark concedes that he is doing exactly what he has always wanted to do--running a world-class foundry. Admitting to good luck (including being born in Wisconsin where foundries are a way of life), he credits Carl Loper, a metallurgical research professor at the University of Wisconsin-Madison, for introducing him years ago to the benefits of compacted graphite iron (CGI).

"Shortly after I joined the foundry, R.H. Sheppard came down to the shop looking for remedies for a ductile iron wear problem," Clark recalled. "The iron was causing galling and premature failure under the increased pressures that customers were designing into their hydraulic systems.

"I mentioned the properties of CGI that I thought might correct the problem, and after a few questions, he said go to it. I told him that there would be a learning curve while we worked out melting and pouring problems. I was thinking in terms of months; his answer was to give me a week, and then he turned on his heels and left. No more talk."

That was in the spring of 1977 and the foundry was in full production of CGI castings six months later. Today, CGI represents two-thirds of Sheppard's foundry production. The company is one of the world's oldest and largest producers of the material.

"Our advantage is that we run it every day using process routines that allow no deviations," Clark said. "Good CGI is strictly a matter of consistency."
COPYRIGHT 1992 American Foundry Society, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1992, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

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Title Annotation:includes related article; R.H. Sheppard Company Inc.'s compacted iron graphite production
Author:Bex, Tom
Publication:Modern Casting
Date:Jun 1, 1992
Words:3095
Previous Article:'Lifelong learning' - step 1.
Next Article:Understanding ISO 9000: its impact on American foundries and diecasters.
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