Published 6/15/2008

Straight From The Source

Seeing the cold drawing process up close can provide an entirely new appreciation of the barstock used in a shop. Here's how one mill makes the most of the process.

Aerospace

Chris Felix

Former Editor-in-Chief, Production Machining

The company uses an offline cabinet blaster to treat coils. A forklift loads the coils onto the arm of the machine. When the cabinet is closed, the arm turns to spread the coil for thorough shot blasting.

The inline shot blaster for straight bar was purchased new in 2005. These self-destructive machines must be well maintained, as eight motors continuously throw steel shot at the materials.

For better mechanical properties, a furnace is sometimes used for stress relief in the material.

Although three spots are available for drawing on the McKay draw bench, the company typically draws two bars at a time to avoid backlog at the straightener. Four-inch-diameter bar goes one at a time because of the stresses the larger bar puts on the carriage.

The Pam Gray Memorial Atrium and the Martha Gray Metals Reference Library form the main lobby and central business area of Gray America. Features of the company such as these are examples of the entrepreneurial spirit and family nature of the business.

Drawing It Out

Hot-rolled bar is delivered from the mills in the form of straight lengths as long as 48 feet or coils of varying lengths, based on diameter. The first step in the drawing process at the company is to send the material through the shot blast system to remove the hot roll scale, which is abrasive on the cutting tool and would hurt machinability. Another advantage to the shot blasting is the additional roughness it puts on the bar. A good shot-blasted surface helps to keep the oil on the bar as it is drawn. On the McKay draw bench, bars are fed eight across, but separated to allow the shot to completely treat the surface.

Because the coils are so much larger than the individual bars, they require considerably more effort for handling. Initially, they are stored outside, for space considerations. Because they are subject to the elements, they need to be watched more closely. The company turns inventory quickly, and minor rusting is easily remedied with shot blasting. Only after pitting begins (which could occur after several months in the weather) does machinability of the bar become questionable.

Where the larger size of the coils comes even more into play is in the shot blasting process itself. The coils are first blasted offline in a cabinet blaster. Although offline blasting requires an extra handling of the coils, a single cabinet unit can easily feed three or more separate coil-fed drawing lines, eliminating the need to add and maintain three different inline blasters.

When a coil comes in off the truck or out of the stock yard, a forklift carries it to the cabinet blaster. The operator lowers the coil, cuts the bands to loosen it, then loads the coil onto the arm in the cabinet. After a few rotations of the arm, the coil is spread enough for thorough application of the shot in the blasting process. The entire process takes about five minutes, and the coil is then ready to be loaded into the drawing line. According to Mike Mulligan, sales manager, “The offline blaster has a big effect on our production line. In a perfect world, we would shot blast everything inline without touching the coil more than once, but this really does a great job of cleaning the coil and removing the scale. To get the same results inline, we would have to slow the lines down, and that would sacrifice efficiency.”

On one of the coil lines, New Dimension does run an inline blaster, but this is a secondary blasting process that adds a little more roughness to the material so the lubrication will stick better.

After the shot blasting process, the material is sent through the drawing machines. New Dimension has seven separate drawing lines, including a recently added Schumag II-B combined drawing line for producing cold drawn bars from hot roll coils. This machine will also eddy-current rounds and shapes inline.

As one might expect, it’s a noisy, oily environment. Keeping lubrication on the bar as it is drawn down is very critical because so much heat and friction is created. With so much oil in use in an open environment, some is bound to end up on the floors. As New Dimension found out, floor dry is not a good solution for a mill. If it gets into the bar bundles, the abrasive nature of the substance will cause problems with the surface finish of the bars. Instead, the company keeps the floors clean with daily scrubbing and porous mats to absorb the rest.

Straightening is the last operation on the bar before being bundled and shipped. The bars are dropped down and spread on the straightener carriage, allowing it to pick one bar at a time and push it through. As with the other operations, the company tries to eliminate as much operator involvement as possible. In addition to automating the process wherever possible, New Dimension eliminates any “steel on steel” contact in order to preserve the surface of the finished bars.

New Dimension Metals has refined its cold drawn bar process so it can provide quality and options in materials while maintaining its family business principles. Mr. Mulligan explains, “Many people look at business in such a way that you either have to be a low-cost producer or a value-added supplier, and the guys in the middle get squeezed out. Our goal is to fulfill a specific need in the supply chain, and our role can vary depending on the customer needs and the requirements of the job. We strive to understand and meet the customers’ needs and not be constrained by preconceived notions of what a supplier should be.”

Material Concerns

The hottest topic in the industry right now for raw materials seems to be cost and the surcharges and pricing of steel. Iron ore is at record highs, and scrap is in a very short supply. But perhaps the biggest contributor is the weak dollar, drastically limiting the supply of foreign steel—in particular, 12L14. This grade’s source is foreign-dominated, with essentially only one domestic melt source. The majority of 12L14 melt comes from either Europe (primarily Great Britain and Germany) or South America.

Cold draw mills such as New Dimension, as sort of middle men in the supply process, buy from the hot mills, produce the finished bars and deliver them to the customer. The hot mills add the surcharges, based on the market conditions. These surcharges, then, are typically handed down through the supply chain, all the way to the shops.

Mr. Mulligan explains, “The hot mills are dictating the prices. We don’t have much choice but to pass it on to our customers. We encourage them to pass the cost on to their customer base. In a sense, we’re in the same boat as the machining world, as consumers of steel with no real control of the prices. So we do constantly try to improve the processes that we control and look for the latest opportunities where our efforts can provide value to the customers.”

New Dimension has been trying to be as transparent as possible when it comes to fluctuating prices. “We can arm our customers with information about what’s happening,” Mr. Mulligan says. “We let them know what our scrap dealers and suppliers are telling us. We don’t have a crystal ball, but we at least give them our best estimate about what to expect based on the information that’s out there, and then guide them in how to deal with the challenges.”

Cold draw mills find themselves dealing with immovable forces on both sides. The hot mills set the prices while shops pull the other direction because of established customer contracts with little or no variance. But the shops need to be disciplined about passing the costs on to the customers whenever possible, or they will be the ones losing the profits at the end of the day. And that’s never easy.

United We Stand

Every company should have its niche or specialty. Sometimes, though, a combination of core competencies can bring about a situation where the whole is greater than the sum of its parts. New Dimension Metals was established as part of such a collection of companies.

Gray America Corp. is the parent company of four subsidiaries: New Dimension is the cold draw bar mill, L&H Threaded Rods is a U-bolt manufacturer, A-Lab is a metals testing laboratory and Scarlet & Gray is a truck line.

John C. Gray, owner of Gray America, worked in the steel industry for the better part of his career. As a manufacturer’s rep with Youngstown Sheet and Tube, covering the state of Indiana, he regularly called on L&H Threaded Rods in Muncie. When L&H went up for sale in the late 1970s, he bought it and moved it to Dayton, Ohio, a few years later.

The company continued making U-bolts, used to hold the leaf springs on truck suspensions, for the heavy-duty trucking industry. Because L&H was buying a lot of cold drawn bars, Mr. Gray thought it would be a good idea to integrate vertically and work into the business supplying cold drawn material. He bought a used draw bench and Schumag drawing line from a closed mill in Gulfport, Mississippi, and started drawing material for L&H.

As the company picked up a couple more draw lines over time, it quickly became apparent that it had more capacity than L&H could consume on its own. In 1990, New Dimension Metals became its own entity, supplying L&H while selling steel to the outside world, including screw machine companies and service centers.

For quality control and material traceability at L&H and New Dimension, Mr. Gray started a metallurgical testing laboratory. He knew, in providing materials to shops and U-bolts for heavy-duty trucking, a lab would be a strong asset for liability reasons alone. A-Lab Corp., as it was named, became yet another profit center for the business as it quickly grew. Today, this part of the business does 95 percent of its work for outside customers.

The other leg of the business is Scarlet & Gray Corp. This freight company, unlike A-Lab, does about 80 percent of its work for Gray America. It specializes in delivering finished goods to the parent company’s customers and hauling raw materials to the plant. It also contracts with other firms, though, to deliver industrial materials.

The Gray America companies fulfill specific requirements in the metals industry while sharing resources. The four separate entities accomplish their goals in ways that complement each other and achieve a higher level of success than if done individually.