| Analysis | Mechanical Properties | Applications | Machineability and Weldability | Heat Treating | Tolerances | Speedy Metals items |
AISI 8620 is an alloy carburizing steel when thermally treated develops a hard outer case with a soft ductile core. Carefully controlled proportions of chromium, nickel and molybdenum are responsible for the extensive use as a carburizing alloy steel, with valuable features including extreme surface hardenability and good internal strength. Has minimum distortion and growth characteristics. 8620 has good machinability and responds well to polishing.
| Carbon (C) | Manganese (Mn) | Silicon (Si) | Chromium (Cr) | Nickel (Ni) | Molybdenum (Mo) | Phosphorus (P) Max | Sulfur (S) Max |
| 18-0.23 | 0.7-0.9 | 0.15-0.35 | 0.4-0.6 | 0.4-0.7 | 0.15-0.25 | 0.035 | 0.04 |
8620 cold roll bars conforms to ASTM A331
| Condition | Tensile Strength (PSI) | Yield Strength (PSI) | Reduction of Area | Elongation in 2" | Brinell Hardness |
| Annealed | 100,000 | 85,000 | 60 | 21 | 185 |
8620 applications include gears, pinions, cams, cranks, clutch shafts, shafting, axles, tie bars, collets, bushings, heavy duty pins, bolting, springs, hand tools, die cases, and a multitude of machinery parts and components.
8620 has a machinability rating at 66% of B1112. Average cutting speed 127 ft/min.
8620 can be forged at 2200° down to 1800° F prior to hardening or carburizing.
8620 is excellent for welding applications
8620 can be hardened to 1500° F followed by water quench. Carburize at 1650° - 1700° F in an appropriate carburizing medium and oil quench to harden. Tempering of carburized parts is done at 250° - 300° F and will result in the alloy having a core strength of approximately 135,000 psi minimum. Tempering of heat treated and water quenched parts (not carburized) is done at 400° - 1300° F, with greater hardness the lower the tempering temperature.
Rounds
| Up to 1-1/2" incl. | -.002 |
| Over 1-1/2 to under 2-1/2 | -.003 |
| Over 2-1/2 to 4" incl. | -.004 |