An interview with A. J. "'Andy" Deibel, general manager, in which is discussed Deibel's use of polymer quenchant from Tenaxol in an integral quench batch-type heat treating furnace.

Mr. Deibel, to the best of your knowledge, is Deibel Heat Treating Company the only commercial heat treating firm using polymer quenchant in an integral quench furnace?
      Oh no. 1 know of at least one olther, and in view of the fact that there are several hundred commercial heat treaters in this country I'm sure there are more. It could be that we are unique in using Tenaxol polymer quenchant in such a large integral quench furnace. The heating chamber of the furnace we're using it in measures 36 inches wide by 48 long by 30 inches high.

Before we get into detail concerning this, would you give us a little background information about Deibel Heat Treating?
      Well, the company was founded in 1951 by my grandfather, Joseph F. Deibel, and my father Joe Deibel, Jr., but not as a commercial heat treating company. Its name was Deibel Shank and Manufacturing Company, devoted to the production of stampings.

How did the evolution to Deibel Heat Treating take place?
      The stampings required heat treatment so we built our own furnace to take care of it. This was during the Korean War and we were very busy. We began taking in outside work and adding more furnaces and it wasn't too long before the heat treating business was much larger than the stamping business.

So Deibel Heat Treating became a separate entity?
      That's right.

When was this?
      That was in 1958.

Can you characterize the type of heat treating you do here? In other words, do you specialize in certain processes or types of work?
      We're not what you'd call highly specialized, but most of our work is high volume atmosphere processing which we do in both continuous and batch furnaces.

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"In 1977 the customer changed the specification, wan ting core properties equivalent to surface properties.., we discovered.., that the best we could get in terms of core properties, using oil, was in the 245 Brinell range. So, as the saying goes, we had a problem.

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How about the size of your company?
      At the present time we employ 42 people and have approximately 26,000 square feet of space. This building was put up in 1964, rebuilt in 1968 and added on to again in 1973. We have still another addition in the planning stage.

Getting back to Tenaxol polymer quenehant, how did you come to incorporate it into your operations?
      The background of it is that for several years we had been running a part, a casing coupling, made of a modified 1541 material.., not a standard grade. These parts were processed to a surface hardness specification in the 286 Brinell range. In 1977 the customer changed the specification, wanting core properties equivalent to the surface properties. We had been running these parts in a large integral quench atmosphere furnace and were quenching out in oil. We discovered after considerable experimentation that the best we could get in terms of core properties, using oil, was in the 245 Brinell range. So, as the saying goes, we had a problem,

What happened next??
       We had been buying various materials from a vendor who also produced a polymer quenchant, so we called them in.

This was not Tenaxol, right?
      Right.

So what happened then?
      We drained the oil from the furnace, wiped down the tank, cleaned the shell and tube core, put in the polymer, and tried some test runs.

How did they turn out?
      Generally speaking, they didn't. Many parts came out soft, and furthermore, in some cases developed cracks. In addition, the furnace developed some rather strange rumbling noises which we couldn't figure out but didn't at all like. No one could figure out what the problem was but several days of intensive testing didn't change anything. I also visited another plant using the same quenchant. They weren't having any problems, but then I didn't learn anything that could help us solve our own. We were, however, producing some parts that were good, but we had to inspect them 100% so the economics of the job were very unfavorable at that point.

What happened then? Is this where you decided to give Tenaxol a try?
      Yes it is. In January, 1978, we switched to Tenaxol's Ucon* HT.

What has been your experience with the Tenaxol product?
      It has been 99% trouble free. We've used it continuously ever since putting it in, we are getting the properties required and we're having no problems at all.

But you did say 99%.
      I could well have said 100%. The "one percent" had to do with start up and didn't really apply to production work. For example, we initially began with a 12 percent concentration and discovered that we have to make minor concentration adjustments to accommodate different sizes of parts, mainly in cross-section thickness. Also, originally we began with a controlled quench temperature of roughly 125°F and learned we do much better holding the temperature in the 95° area. From a production point of view, Tenaxol has worked just fine from day one. We haven't had one bad part using Tenaxol.

What about the furnace? Did you have to make any changes in order to utilize Tenaxol?
      None of any consequence, the furnace, which is a Super Allease from Surface, is being used essentially as it was built. I've read where occasionally changes have to be made, usually to increase quench agitation, but we didn't make any changes in the basic furnace design whatsoever.

What would be an example of the minor changes you did make?
      Oh, about the only one that comes readily to mind is the quench temperature sensor. We had to put on a different one in order to accommodate the lower temperature range.

And you have no dewpoint problems?
      None at all.

How often do you check the quenchant for concentration percentage?
      We were advised that once a week would be entirely adequate. However, we're basically a very conservative company so we do it twice a week.

How do you check for concentration?
      With a refractometer.

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"From a production point of view, Tenaxol has worked just fine from day one. We haven't had one bad part using Tenaxol. . . Tenaxol literally saved a big job for us. It accommodated our customer's specification change, and also has provided some fringe benefits which, when you get right down to it, are not so fringe."

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Do you do anything special with the quenchant . . . filtration, things like that?
      No. We do have a screen before the shell and tube cooler to keep out any possible big stuff -- thus far there hasn't been any -- but other than that we don't do anything special at all. The furnace is rated at 2,500 pounds per load and has a 2,250-gallon quench tank. As I said earlier, we're a very conservative company and we thought the pounds per gallon ratio using polymer quenchant might be too high so we have backed off to 1,500-pound loads, maximum.

What about the rest of your furnaces. Any plans for changing them over to Tenaxol?
      We would like to. We do have some customers who are even more conservative than we are, and even though we can guarantee equal properties it will take some effort to get them to accept a change in quenchant specifications. Presently we are working on converting a 450-gallon open oil quench to Tenaxol. This tank is part of a selective hardening salt process, but we're still in the self-education stage with it.

What do you mean by self-education?
      Simply that quenching into Tenaxol out of salt is not the same as quenching in Tenaxol out of atmosphere. We have to learn what the differences are and more importantly how to handle them. We have no doubts as to the ultimate outcome, but Deibel Heat Treating tends to deal in large volumes of relatively few materials and we always try to make absolutely sure we know what we're talking about before committing to change. Further, on balance, we tend to trust our own data more than that obtained from other sources. So, with this process we are educating ourselves.

It sounds on balance that you are fairly satisfied with Tenaxol.
      More than satisfied. Tenaxol literally saved a big job for us. It accommodated our customer's specification change, and also has provided some fringe benefits which, when you get right down to it, are not so fringe.

Such as?
      No fire hazard is the main one. We've had fires here and they are terrible to deal with. Any quenchant that will relieve that worry is worth pursuing.

*Ucon is a trademark of Union Carbide Corp.