What is Clamp Tempering?

A reader recently posed a question about “Clamp Tempering” (the original question can be found below). “The Monty Heat Treat News” is certainly familiar with clamping parts during tempering to reduce distortion, however the question had a different spin to it. For instance a global manufacturer of chain saw bars clamps the bars before loading into a temper oven, however this reader was asking about a process where the clamp and the heating are an integral unit.

As it turns out we have an answer for you, Lindberg Heat Treating (now part of Bodycote) built a number of these units for their own personal use. Read on for the details

“JULY 11/2022; Good Morning Gord, I worked for Lindberg Heat Treating in Melrose Park and Minneapolis for 16 years the early 70s to mid 80s. We built our own heated platens with rod heating elements thermocoupled and controlled. Some were just flat others were custom made to the customers part. We used them for clamp tempering, short times at higher temperatures and also for clamp aging BeCu and 17-4ph. The results were for the most part very good. The process was labor intensive though.”

“JULY 7/2022; Many years ago Lindberg Heat Treat had at least 12 unique systems for tempering stampings. The technology was called “Clamp Temper Press” and the idea behind it was that hot stampings could be clamped during the temper process to reduce distortion. Most of them had three or four heated platen’s and were closed up to about 20,000 lbs. of clamping pressure. A heat treater remembers the technology but has been unable to find out who made the systems or if they are even available any longer. While similar to this picture (from Parker Trutec) the units in question had heated platens. If any of our readers has knowledge about this technology we would appreciate hearing about it.”

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