The study of heat treatment and the metallurgy of metals is perhaps the oldest science known to man-kind. If one thinks about that statement, you realize that there was a time that humans used only stone for weapons and digging. Then came the age that carried man into the world of metals.
The writer has come across many people on an international basis who have asked, “What do you do for living?” The answer that I give seems to confound a vast majority of people all over the globe. They do not understand the word “metallurgy.” The usual reply is, “What is that?” Others say, “Never heard of it.”
This article focuses on the heat treater. Most assuredly, it is the heat treater – the person operating the furnace – who can literally make or break the product.
The heat treater – captive or commercial – needs the mindset that if a component needs to be processed a second time, it is costing the company money. Therefore, their philosophy should be: “Do it right the first time because the second time will cost money.”
Generally (but not in all cases), the heat treater is not a graduate metallurgist, but they are the person with the responsibility of getting the component right the first time. How does the heat treater acquire their comprehensive knowledge in order to process the particular metal that is to be heat treated successfully? The writer offers a few considerations to the furnace person for self-tuition.
Buy books! But isn’t that an expensive method of learning? True, if one purchases brand-new books. Here is a consideration. Metal will always respond and has always responded to the heat applied to the metal being treated. In other words, the principles have not changed. There is nothing wrong in purchasing used books. Many booksellers specialize in used technical books for a fraction of the cost of new books. The writer has acquired technical books with sound, solid metallurgical processing in-formation for as low as $3.75. (And that is in today’s current prices.) Generally, a good metallurgical processing book would average around $9.50 and can rise up to say $25 at today’s price levels.
One can put together a very comprehensive library of used books for less than $100. A vintage book published by the American Society of Metals titled The Metallography and Heat Treatment of Iron and Steel by Dr. Albert Sauveur is a prized book (first edition) in ASM’s bookcase in Cleveland. I was able to purchase the fourth edition by McGraw-Hill (1933) for the princely sum of $15.75. The book’s condition is excellent, printed on beautiful gloss paper with photomicrographs and complete metallographic explanations.
A second consideration would be to purchase a simple notebook. Every metal that you process, draw out a sketch and add the analysis from the test certificate. If your manufacturer does not supply you with the test certificate, you then have two choices. You can either stress how much you need the test certificate with the complete actual analysis and mechanical properties of the metal supplied to you for treatment, or you can simply use the AISI specification of analysis and properties.
Log all of the information into your notebook with process temperatures selected; method of cooling; component weight and how the mass was loaded into the thermal-processing furnace; cooling medium and cooling-medium temperature; plus the temperature rise in the liquid cooling medium. You could even include a photo of the load.
On completion of the thermal processing, record ALL of the process conditions/temperatures/results acquired and any problems that occurred (if any). You will very quickly build up your own personal library of heat treatment and results.
Gain a full understanding of hardness and mechanical-property testing. Remember, there are many published books on these subjects that can be purchased – once again, in a used condition.
Where possible, develop an adequate and appropriate metallurgical laboratory. The comment usually is that we cannot afford to put a laboratory in-house. You would be quite correct in that statement if you purchased brand-new equipment, but used equipment should be considered. Because this equipment has been used in a metallurgical laboratory, it is often clean and well cared for.
There are many suppliers of used metallurgical microscopes, microhardness testers, abrasive ma-chines, grinding and polishing machines, fume hoods for etching, etc. You can also find very expensive laboratory benches and furniture in like-new condition. I built my first laboratory when I arrived in the United States and used kitchen cabinets and benches that served my purposes adequately and professionally.
I served my apprenticeship starting in 1955 to 1960 specializing in heat treatment and metallurgy and gained excellent experience in the met lab. In 1970, I immigrated to South Africa. The company I worked for had one HRC hardness test unit (not in the heat-treatment department but some 200 yards away).
I talked the owner into letting me build a laboratory even though I had never built one. I told my partner about what had transpired and that I seriously felt that I did not have enough experience to do it. Her response was, “You know that they don’t know that you don’t know, so don’t tell them. Learn!” I did precisely that. I learned, and it worked.
Another method for you to consider is something I did at the local vo-tech in the U.S. If you want to learn a subject, teach it, and learn it before you present it. It works.
Where there is a will, you will learn. Write your own PowerPoint notes and practice on your colleagues. Who knows? You may soon begin to become a valued expert
Pye Metallurgical International Consulting
David Pye, 911 Backspin Court, Newport News, Va., is a contributing writer.