Overview & Definitions of Services Offered

To demonstrate the broad range of services offered by Akron Steel Treating and to define their meaning and features, refer to the following:

1. Aerospace Heat Treating: Heat treating services done to a higher standard of control to assure higher part performance and to increase reliability.
   See Nadcap.
2. Annealing: Heat treatment that makes metals (steel, aluminum, etc.) soft and ductile. Facilitates part shaping, stamping, or machining operations. Removes unwanted stresses and strains. Makes parts more stable.
3. Atmosphere Heat Treating: Heat treating done under a controlled, gaseous environment, usually devoid of oxygen. By controlling the gases surrounding the part at high temperatures, the part surface can be protected or enhanced. See, Neutral Hardening and Carburizing.
4. Austempering: Heat treatment for steels and cast irons (ductile iron) that makes parts ductile and tough. After heating to transformation or austenitizing temperature, parts are quenched in salts or hot oil.
5. Ausquenching: See, Austempering and Martempering.
6. Blast Cleaning: Using steel grit or shot to remove scale or oxide from the surface of metal parts. Facilitates post-heat treat grinding or finishing. (More aggressive cleaning than sand blasting.)
7. Carburizing: Steel parts are heated to 1600F-1750F in a carbon-containing atmosphere, and the carbon atoms are diffused into the surface of the steel making iron nitrides. See, Case Hardening.
8. Case Hardening: Carburized steel parts are heated to transformation temperature and quenched in oil (or water) to produce a part with a very hard shell or “case”, but with a ductile core.
9. Carbonitriding: Steel parts are heated to transformation temperature in a carbon and nitrogen-rich atmosphere to form a hard surface of iron carbides and iron nitrides (after quenching) for resisting sliding wear.
10. Carbon Restoration: A carburization process that is designed to bring the surface of a casting or forging back to its original carbon content and to restore the hardenability of the surface.
11. Cryogenic, Deep Freezing: Parts are cooled under liquid or gaseous nitrogen to -100F to -300F to remove retained austenite in the steel, or to relieve stresses and make a more homogenous, stable structure.
12. Fixture Tempering: Heat treating (usually tempering) done in jigs, under pressure to remove distortion or warpage in parts. Also known as flattening.
13. Hardening: The controlled application and removal of heat (austenitizing, quenching, tempering, freezing) of a metal part to change its physical properties, to enhance part performance or allow further processing.
14. Hardness Testing: Quantifying the relative resistance of metal parts to penetration by a probe of a known size with a given force. Measured in Rockwell, Brinell, Knoop or Vickers scales. Related to tensile strength.
15. Heat Treating: See, Hardening. See also, Annealing.
16. IntensiQuench®: Water quenching with highly agitated water, then cooling in air that creates a finer hardened structure for SupR-Strong™ parts.
17. Martempering: A heat treating process where parts are heated to the transformation temperature (> 1300F), then cooled in a molten salt or hot oil (350F – 650F). Used to reduce part distortion.
18. Metal Testing, Metallographic: Determining the microstructure of steel or other metallic parts to predict or to assure their physical properties, e.g., tensile strength, ductility, hardness. Done on a polished sample under a microscope.
19. Metallurgical: Advice on selection and treatment of steel alloys and other metals (aluminum, copper, bronze, brass, stainless steel) to optimize part performance in a given application and to minimize part costs.
20. Nadcap Certified (National Aerospace and Defense Contractor Accreditation Program): A third-party certification program to meet the highest quality processing standards and documentation under AMS-6875,* AMS-2759, etc. * Also, ISO 9001:2000 Certification.
21. Normalizing: A heat treat process to bring the microstructure into a condition that facilitates subsequent processes by making the part more homogenous in structure. Usually done on castings or forgings.
22. Neutral Hardening: Heat treating done in an oxygen-free environment that is chemically neutral to the surface of the steel. Endothermic atmosphere or nitrogen blankets are used.
23. Precision Gas Carburizing: A gaseous carburizing process where the gas mixtures, time and temperatures are all controlled continuously throughout the process through digital controls and oxygen probes.
24. Quenching: The rapid, but controlled, cooling (in air, inert gas, oil, salt, or water) of hot metal parts to produce a desired change in the microstructure of the material. See, Intensive Water Quenching (IntensiQuench®); Marquenching, Austempering and Ausquenching.
25. Selective Hardening: Heat treating processes that harden only one area of a part. Also may mean a physical barrier (copper plate or stop-off) is applied to prevent carburization and hardening of an area of the part.
26. Solution Treating: A heat treating process that prepares the material for subsequent low temperature precipitation hardening by artificial aging. Allows “soft” parts to be finished to size before the aging process.
27. Spheroidize Annealing: A “softening” of steel by heating and then cooling very slowly to provide a metallurgical structure that looks like “spheres” or “balls.” Allows the metal to be stamped or formed more easily.
28. Steel Hardening: See, Hardening.
29. Straightening: A post-heat treat process to bring shafts, blades, or other parts into tolerance for straightness.
30. Stress Relieving: A heat treating process (usually below 1250F) to remove welding, cold working or other internal strains to avoid part movement during later heat treatment or machining.
31. Tempering: After the hardening process parts are usually very hard, but too brittle to use reliably. Tempering is a subsequent heating process to lower the hardness and to increase ductility.
32. Testing: Metallurgical: See, Metal Testing.
33. Thermal Processing: See, Heat Treating.
34. Vacuum Heat Treating: Heat treating done on parts inside a vessel that has had most of the ambient air removed before heat-up. Since there is no oxygen present, the parts come out “bright.”