A busy year hasn't slowed steel founders' drive for quality.

If there is such a thing as "too busy," many steel founders - like much of the metalcasting industry - are enjoying that particular problem. With orders pouring in and customers ratcheting up production and delivery demands, many shops am running at capacity, and even turning down jobs.

Focusing so much attention on productivity, however, has not slowed steel casters' progress toward making a better, more cost-effective product. The Steel. Founders' Society of America's (SFSA) annual Technical and Operations Conference, held November 10-12 in Chicago, provided an overview of advances in that effort. The 186 attendees participated in a program that featured presentations of 38 technical papers and lively group discussion sessions.

Kicking off a session that emphasized molding processes, Vijay Kumar, Ancast, Inc., Sodus, Michigan, discussed the use of riser sleeves in martensitic stainless and nickel alloy applications. While the chemical composition of riser sleeves has little effect in low-alloy steel casting, the gas-producing characteristics of sleeves can cause defects in high-alloy castings.

Kumar compared exothermic riser sleeves with the insulating variety and discussed the need for quality control standards in the purchase of sleeves. While troubleshooting a gas defect in a high-alloy casting, Kumar said, technicians at Ancast determined that a change in riser sleeves was the cause and devised a test to check their theory. They heated various types of riser sleeves from different suppliers in a furnace to 1610F (876C) for two hours.

"The sleeves were then measured for weight loss as a function of loss on ignition (LOI)," he said. Any lost weight indicated the amount of gas that would be given off by the risers during high-alloy pouring. Kumar concluded that sleeves with an LOI under 5% are acceptable for high-alloy applications.

As customers require closer dimensional tolerance and near-net-shape parts, foundries need to look seriously at their practices to consistently improve final net casting dimensions. In his presentation, Jeff Bybee, Pelton Casteel, Inc., Milwaukee, Wisconsin, suggested several keys to making sure a casting is closely toleranced.

"All casting and pattern equipment designs involve dimensional degrees of freedom," he said. "They can be minimized through cooperative efforts with customer engineering." Foundries should meet with customers before production to discuss critical dimensional features, and exchange engineering information to ensure "no surprise" tooling and pattern development, he said.

Sometimes, quantity can have a positive effect on quality. "High production castings are usually fertile ground for incremental improvements and value engineering," Bybee said. These jobs are a good time to upgrade tooling and molding methods for more accurate and consistent dimensional tolerances. Other beneficial steps, he said, include: comprehensive quality assurance systems; cellular cleaning room design; proper choice of shell or green sand; and "same man/same job" consistency.

According to Nayyar Iqbal, Texas Steel Co., Fort Worth, Texas, one way for busy foundries to shorten lead time is to use reduced cycle heat treating for steel castings. Though not a new concept (it was first used during WWII to speed U.S. tank production), it has not been widely implemented in the industry.

However, modern equipment like high-velocity excess air burners, ceramic fiber insulation, solid-state temperature controllers and temperature-sensing equipment make it possible to substantially reduce treatment cycles for carbon and alloy steels in a range of section sizes. According to Iqbal, these steels can be fully austenitized in up to 50% less time and using less power than conventional heat treatment cycles.

In response to recent aggressive marketing by the forging industry, Malcolm Blair, SFSA, Des Plaines, Illinois, put competition between steel castings and forgings into perspective. "Castings have some significant advantages over forgings," he said, noting several misconceptions.

"It is believed that forgings aren't repaired before shipping, that they don't have internal defects, that they are stronger than castings and they are more efficiently produced," Blair said. To address the last point, he compared the number of steps necessary to produce a single 10-in. valve in a forge shop and a foundry. To forge the part, at least 13 steps are needed, while casting can produce it in nine.

"In determining which process to select," he said of component purchasers, "the crucial considerations are the ability to satisfy the design criteria and the ultimate cost of the component." In their design and modification flexibility, along with the ability to obtain specialized metallurgical properties, castings provide a clear advantage.