The Founding of Akron Steel Treating

Gord Montgomery, sales rep for AFC-Holcroft (an IQT licensed furnace and IntensiQuench system builder), visited Akron Steel Treating Co and the IQ Technology Center for Intensive Quenching in December 2009. During his visit I was able to share the unique story of how Akron Steel Treating actually started.

In 1925, my father, Prosper Paolucci Powell, started working for The Firestone Tire & Rubber Company in Akron, Ohio. He was the first Italian-American to go through the apprenticeship program, and became a Journeyman Machinist. Part of his training was spent in the heat treating department of the Metal Products Division of Firestone. During WWII he managed the third shift of their heat treating department.

One morning, in 1943, after his shift at Firestone, my dad drove up to our home on Glenwood Avenue, and saw a green Army car parked in the driveway. Since this was during World War II, his first thought was that he was drafted! He went passed our driveway and went a block down the street to Carl’s Tap Room, a neighborhood bar. He called my mother and asked, “What is a car  from the US Army doing in our driveway?” My mom said there were two Army personnel that wanted to talk to “Prosper Powell,” but they didn’t say why, and that he should come home.

When my dad came home, the Army officer asked my father if he could heat treat some parts for the Army. My dad said that he could, but why weren’t they asking somebody at Firestone? They explained they needed 50,000 redesigned firing pins heat treated as soon as possible. The original design of the firing pin extended out of the rifle. When our troops were using these rifles in the jungles in the south Pacific islands, there was a vine that would snag on the firing pin and discharge the weapon unexpectedly. The weapons going off unintentionally would not only reveal our troops’ positions, but cause injury to our own people. The newly designed firing pin was smaller and did not stick out of the rifle.

The Army officer explained that they did not want too many folks knowing about this issue, and wanted the new firing pins to be heat treated by my dad, personally, “on the QT.” My dad said that he would do the heat treating on the new firing pins, but, if not at Firestone’s plant, then where? They pointed to the large, 3-car, brick garage in the backyard of our house. My dad said, “This is a residential neighborhood. You can’t do heat treating here, and besides I don’t have any heat treating equipment!” The Army officer replied, “We are the Army, we can do anything.”

A few days later an Army truck showed up with a salt pot and a little box furnace. They ran a 220-volt electrical supply into the garage, soaped over the garage windows, so no one could peer inside. My dad fabricated the needed oil quench tank, tongs, fixtures, workbenches, and the like, and Akron Steel Treating was officially launched! After the original batches of firing pins were done, my father received more from the Army – apparently another heat treater was warping the pins from improper racking. (Distortion control in heat treating has been a real issue for a very long time!)

For the last year of the war, word spread in the Akron tool and die community that Pros (rhymes with “floss”) Powell had a heat treat shop in his garage. So my dad would find miscellaneous tools and dies, in need of heat treating, between the screen door and the house door each morning when he came home from working the night shift at Firestone Metal Products. My mom, Anna, would sometimes get into the act by tempering parts in the house oven per my dad’s orders. (Real “cookbook” heat treating!)

At the end of WWII,  my dad called his contacts at the Army arsenal, and asked them what they wanted him to do with the equipment in his garage. They said, “Make us an offer.” My dad said, “I don’t have any money!” to which they replied, “We’ll take it!” (Proof that the value of heat treating equipment is tied closely to the current market for heat treating services.) A few months after the war ended, my dad, with just a few weeks shy of 20 years of service at “a real good job at Firestone,” turned in his notice at Firestone Metal Products. He moved Akron Steel Treating to a more suitable location on High Street, just south of downtown Akron. When Firestone Metal Products closed its heat treating facilities, my dad bought some of the equipment. We still have a couple of the little tool room furnaces (with new instruments) at AST today.

The Background of IntensiQuench

Some of the intensive water quenching methods have been around for at least 40 years. “Timed water quenching,” interrupted quenching, high velocity spray quenching with water have all been around for a long time. There is some confusion in the heat treating community as to where the IntensiQuench process fit into all of these methods. Suffice to say that the other methods of quenching do not combine all the elements that IntensiQuench has assembled to both limit part distortion and maximize compressive stresses. My partner in IQ Technologies Inc., Dr. Nikolai Kobasko, FASM, began his work with intensive quenching back in the 1970′s in the former Soviet Union. One of the main reasons that IntensiQuench is relatively unknown in North America is that approach in Western countries was to create “better alloys” with higher hardenability to get the properties that were needed from oil quenching of steel parts. The oil quench is very robust and relatively forgiving method of quenching most alloys of steel. The approach in the former Soviet Union was to try “to do more with less.” The steel plants in the USSR were very large facilities employing thousands of people making large quantities but fewer varieties of steel. Since the ability to tweak alloys was not market driven as in North America, the metallurgists got more creative with the processing methods for the alloys that were widely available.

Another reason that IntensiQuench processes has not flourished in heat treating practice is it flies in the face of most conventional heat treater’s wisdom – the faster the quench, the more likely you are to crack or distort the part. Even the renowned metallurgy Professor Jack Wallace at Case Western University, in Cleveland, Ohio, recoiled at the thought of quenching parts in cold water. In 1997, when my partner Dr. Michael Aronov was introducing the process to a gathering of heat treaters and metallurgists from the Cleveland area, and looking for a demonstration site, Professor Wallace told me “It will never work… the parts will explode in the quench.” (His grad assistant on the other side of Professor Wallace nodded in agreement.) Being a lawyer by training, and working in sales at Akron Steel Treating, I was too ignorant to know that you “cannot quench 52100 in water.” Several months later, under a project funded by the Edison Materials Technology Center (EMTEC) and the Ohio Department of Development, we did just that. We heated several 52100 bearing rings in a small atmosphere furnace at AST and intensively quenched the tapered rings (for the Dr. Kobasko determined number of seconds) in a relatively crude 500-gallon IntensiQuench system built at the AGA Research Labs in Cleveland, Ohio – where Michael Aronov worked at the time. After witnessing the trials at AST, Professor Wallace, in his early 80′s at the time, became one of our greatest supporters. Professor Wallace and his team at CWRU wrote several papers about the benefits of IntensiQuench. The benefits of rapid water quenching of S5 punches and H-13 dies was the subject of technical papers written with Professor Wallace.

The lack of computing power to optimize the compressive stress distribution and to predict by modeling the proper recipe to get the desired results from the higher quench rates. Dr. Kobasko created empirical models as well as mathematical models to predict the beneficial effects of intensive cooling rates during the martensitic phase transformation, versus traditional, less intensive, quenching methods. The advent of faster computer models to do the many calculations needed to stimulate the complex physics and thermodynamics that are going on simultaneously in the quenching of a steel part – temperature and phase transformation changes causing size changes – shrinking then growing; with shifting stress distribution changes; and all within the confines of the part covered. The newer 3-D finite element models, such as Deformation Control Technologies’ DANTE model are a tremendous help to IDT predicting what is going on during the quenching of various shaped parts made with various alloys.

Still an area of concern is lack of complete databases for different alloys of steel. More attention should be paid for developing these databases for cooling capacity of quenchants and optimized chemical composition of steels. But even with the lack of complete data base information, once the IntensiQuench trials are done for a particular part with the date from the high speed data loggers, the process is under precise control.

The surface case hardness uniformity in a load of carburized 8620 truck universal joint crosses in the 36″ X 72″ X 36″ AFC-Holcroft integral quench furnace equipped with IntensiQuench water tank is +/- 1 HRC point on the four truions checked at four point on each truion — that’s 2,000 Rockwell readings. The core is similarly uniform and with 8620 too hard — so 1018 is better (and lower cost) choice.

What goes on at the interface of the hot part surface and the water in the quench system in another area of complex events. IQ Technologies also works with Computational Fluid Dynamics (CFD) modeling company, Airflow Sciences Corporation of Michigan. Higher and higher water flow rates do not always translate into better quench uniformity and assure the elimination of dead zones in the quench. The newer modeling tools have enabled the application of IntensiQuench, uniformly, to more complex parts.

Obviously, there are practical limitations as to the sizes and the geometry of parts that can be uniformly intensively water quenched. Very small parts will not develop higher compressive residual surface stresses since they quench through almost instantaneously. Parts with blind holes can create real issue too. However, IntensiQuench equipment can and has been used to uniformly quench fasteners made of “water-hardening” grades of steel and even solution treat aluminum and titanium parts.

Over the years, IntensiQuench has had many successes. To date the greatest success of IntensiQuench is the application to carburized helicopter gears and through hardening gear rack steels. The small test gears treated with IntensiQuench withstood a 15% higher load for the same fatigue life. This means that the helicopter gear box should be able to safely do more work without major redesign of the helicopter platform.

The IntensiQuench S5 punches that outlast the oil-quenched punches by punching more than twice the number of holes in another success.

The reduction of the carburization cycle by 40% (or the reduction of alloy used for carburized parts) while still obtaining the same hardness gradient as oil quenching is a success. With “Optimal Hardenability” (“OH”) steels (very low alloy, medium carbon steels) coupled with IntensiQuench (“OH+IQ”) the carburization process can be eliminated entirely and the parts have a hardness profile and residual stress distribution that is very similar to that of carburized and oil quenched parts.

With the selection of the proper IntensiQuench, water-then-air cooling cycles, IntensiQuench is successfully applied to many types of gears, rollers, S5 punches, H-13 dies, gun barrels, axles, springs and the like. And  because of the very high cooling rates of IntentiQuench, less alloy, lower hardenability steels, can often be substituted for higher alloy steels that are normally used with oil or gas quenching.

I feel that in the future, IntensiQuench will be come a more “mainstream” technology and capture a significant portion of the heat treating market. There are three drivers that will move IntensiQuench into the “mainstream” of the heat treating market of the 21st century.

Once is the ability to use lower alloy, lower hardenability, less expensive steel alloys with IntensiQuench versus oil or gas quenching and still obtain the needed part properties – tensile strength, ductility, hardened depth, etc. As alloy surcharges rise, so will the demand for ways to limit or eliminate the high cost alloying elements. Two is the ability to produce higher power density parts with IntensiQuench versus traditional quenching methods. Lighter, stronger parts with higher residual compressive stresses on the surface, with or without shot peening, are possible with IntensiQuench and the alloy of steel optimized for use with the process.

Three is the environmental benefits of elimination of the oil quench and the reduction (or elimination) of the energy intensive carburizing cycle. Since IntensiQuench uses plain water as the quenching media, it is an enabling technology for the heat treating of part (even case hardened parts) within the part manufacturing cell in a flexible, single part flow.

The Good, The Bad and the Ugly of Heat Treating Metal

The Good (Strength and Ductility)
The Bad (Part Distortion; High Alloy Costs)
and The Ugly (High Energy Use; Environmental Issues;
Part Cracking and Failure)

I. Basic Definitions:

1. What is heat treating of metal?

Heat treating of metal is the controlled, application and removal of heat to a metal to change the internal, molecular structure of the metal for the purpose of obtaining the desired physical properties; e.g., hardness, tensile strength, ductility, formability, machinability, etc.

2. What is “heat treat hardening” or “quench and temper?”

The strengthening of steel by heat treatment usually means “hardening” with a “quench and temper” (Q+T) process. The Q+T process works by, first, heating the steel to its transformation temperature, the “austenitizing” temperature, or the “critical temperature.” Steel is ~ 90% to 98% iron, plus less than 2% carbon, and other small amounts of other alloys, such as, nickel, chrome, vanadium. (Higher carbon than about 2% carbon is called “cast iron.”) The austenitizing temperature is 1330F or above, depending primarily on the carbon content of the steel. One of the key characteristics of steel at the transformation temperature, is that the steel’s carbon atoms are put into “solution.” Once these “magic carbon atoms” are in “solution,” they are free to move around the still solid iron atoms, and rearrange themselves into different crystal structures or “phases” for that material. If the heated steel is rapidly cooled (“quenched”), the new structure is “frozen” into a hardened structure, called “martensite.” This new structure, or arrangement of carbon and iron atoms, gives the part its hardness and its strength.

The as-quenched, martensitic structure, while very strong, is usually too brittle to be of practical use, so we then temper the part to “draw down” some of the hardness and make the part more ductile. There is usually a trade-off, or a balancing act, that part designers need to consider when specifying a heat treating, hardening process; to balance the need for tensile strength (hard) with ductility (soft).

“Playing in God’s Playground:” Rearranging the atoms to get different properties in the steel parts.

Most parts are machined or stamped when the steel is in its annealed or soft state. In its annealed state, the steel atoms are arranged as shown in Figure 1, called Body Centered Cubic (BCC).

The atoms on the corners of the cube are iron, and the “body” in the center is a carbon atom. The first step of “heat treat hardening” is to heat the part to slightly above its austenitizing temperature (1330F, or above, depending on the type of alloy steel, but always below the melting point for the material). After the part is soaked thoroughly at its austenitizing temperature, some of the atoms in the part (primarily carbon atoms) are able to “move” or dislocate in the iron matrix and reconfigure themselves – the carbon atoms are said to be “in solution.” The part is still solid – it is in a state of “solid-solution” with the iron atoms remaining in a solid state, but the atoms of carbon (and other alloying elements) are free to move about inside the part and rearrange themselves. Metallurgists study the phenomena of combining different alloying agents (nickel, chrome vanadium, boron, etc.) in various amounts and at various temperatures, and what effect they have on the physical characteristics of the steel – better ductility for a given hardness, corrosion resistance, high temperture strength, etc. (We heat treaters just call this “Playing in God’s Playground.”)

The orientation of the atoms in the hot, austenitic phase is called Face Centered Cubic (FCC) and the carbon atoms move to the face of the iron cubes in the metal’s matrix. See Figure 2. At this point, if the part is cooled rapidly enough (“quenched”), the part converts into a hardened, “martensitic” phase; the atoms are arranged as Body Centered Tetragonal (BCT). Because the iron matrix is now longer on one side, tetragonal in shape and not cubic, the hardened structure is now approximately 4% larger in volume than the unhardened part. See Figure 3. (If you cool the part slowly from the austenitizing temperature, it will go back to the soft, “annealed” state, with a BCC structure.)

The martensitic structure is very hard and strong – with a high tensile strength. Unfortunately the as-quenched part is also usually very brittle. To make the part more ductile it is then “tempered” to “draw down” or “draw out” some of the hardness and make the part more ductile. To temper the part it is reheated to a temperature below the critical temperature and soaked for a period of time. Generally, the higher the tempering temperature, the lower the hardness (and lower tensile strength) the part will have, but the higher ductility of the part. Hardness and strength versus ductility and impact resistance – it’s a balancing act that heat treaters constantly struggle to find just the right compressive residual stresses on the part surface. We will discuss the issue of residual compressive stress management in a later blog.

NEXT TIME: We will discuss “Intensive Water Quenching Processes” (Intentiquench®) and how they differ from traditional quenching in oil, polymer or high pressure gas.

More definitions of heat treating processes are available at our Akron Steel Treating Company website: www.akronsteeltreating.com.

The Science of Quenching

The new President of American Society of Materials International (ASM), Dr. Fred Lisy, told membership at the 2009 ASM Awards Dinner, at the Omni Penn Hotel, in Pittsburgh, PA, on October 27, 2009, that the teaching of materials science must use new media technologies.   As “Exhibit A” Dr Lisy then presented an animation clip from Deformation Control Technologies,’ (Cleveland, Ohio, USA) DANTE model,  showing the modeling of the IntensiQuench(R) process on a particular part modeled for IQ Techologies Inc.    The DANTE finite element model shows temperature change during the quench, Austenite and Martensite volume fraction, and minimum principal stress values in the particular part during the intensive water quench process.   A copy of that clip will be made available shortly.

Also at the ASM International meeting, our very own Dr. Nikolai Mykola Kobasko, the Chief Techology Officer of IQ Technologies Inc,  was  inducted as a Fellow of ASM.    Dr. Kobasko was recognized for his substantial and innovative contributions to thermal science, including the development of IntensiQuench processes and modeling of thermal processes.

IntensiQuench, intensive water quenching processes can be applied to many metal parts to enhance part performance, reduce part cost and eliminate oil and polymer quenchants.   IntensiQuench can also fully integrate the heat treating process into the manufacturing cell.

If you would like further information regarding the IntensiQuench process, or other heat treating services offered by Akron Steel Treating Company, please visit our websites: www.akronsteeltreating.com and www.intensivequench.com.     Or you can leave a comment and I will do my best to reply to you in a timely manner.