Here's the recipe for making 112-ton carbon steel 'donut'.



A European mine operator wasn't kidding when he told Ladish Forging he had a big order. Kiln tires are enormous ring-shaped components integral to the production systems of many mining and quarry operations. The kiln tire Ladish delivered to the mine operator is believed to be one of the largest finished forgings produced anywhere last year. Starting as a nearly 12-foot diameter "donut" of 1045 carbon steel, the finished product boasts a 21.5-foot diameter.

Not only was the kiln tire size a challenge, but the production schedule demanded a fast turnaround. Ladish, based in Cudahy, WI, is re-emerging as a kiln tire supplier that can respond in a relatively fast time frame. The kiln tire recently produced is larger than any the company has manufactured in more than 20 years.

The forging process offers an alternative to cast kiln tires. Although forged kiln tires are sometimes more expensive than cast tires, the price difference is considered insignificant when the alternative means an entire operation could be shuttered while a replacement kiln tire is produced and delivered.

The kiln tire arrived at Ladish as a 112-ton forged donut. According to Joe Wilfert, the Ladish sales engineer who manages the company's kiln tire business, a significant amount of activity had to occur before the company accepted the order.

"Because it has been a while since we have been called upon to handle a project this big, we reviewed our entire process to make sure we were ready to accommodate a donut of this size," he says. "For example, we had a section of railroad track outside our building that we knew needed to be upgraded, and the kiln tire order provided the impetus to move that project forward.

"We also double-checked that our overhead cranes could comfortably handle a donut of this size. There were other restrictions we knew we had to plan for, such as making sure the raw material we ordered did not exceed 12 feet in diameter to ensure that it could be routed by rail from a distant state in the continental United States."

All logistic and production criteria were met and the kiln tire was manufactured. The finished seamless rolled ring that Ladish shipped in late September measured 21.5 feet in diameter, 41 inches in height, and 16.5 inches thick.

The kiln tire was forged on Ladish's ring-roll mill, which is the largest in the world. In-house production time took about 12 weeks. The kiln tire required more than 20 discrete...

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