8620 SAE 8620 AISI 8620 Alloy Steel - Steel Overview - 1010|1015|1020|1025|1045|1018|1117|1035|1040|1050|1215|4140|4150

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.

8620 is a low nickel - chromium - molybdenum medium hardenability, case hardening (carburizing) steel, generally supplied in the as rolled condition with a maximum brinell hardness of 280 (Rc30).Characterised by good core strength and toughness in small to medium sections with case hardness up to Rc62 when carburized, hardened and tempered.8620 can also be used (uncarburised) as a high tensile steel, which when suitably hardened and tempered can be utilized for various applications requiring good tensile strength and reasonable toughness.

8620 is a low alloy case hardening steel which is supplied to American standard SAE 8620 and AISI 8620. 8620 can be carburised, which will achieve a tough core with a hard wear resistant case. 8620 provides a combination of toughness and wear resistance. 8620 is supplied in either the as rolled or annealed condition for subsequent case hardening.

Pre hardened and tempered (uncarburized)

8620 can be further surface hardened by nitriding but will not respond satisfactorily to flame hardening or induction hardening due to its low carbon content.8620 (carburized) is used extensively by all industry sectors for light to medium stress components and shafts requiring high surface wear resistance with reasonable core strength and impact properties.

Typical uses are: Arbors, Bearings, Bushings, Cam Shafts, Differential Pinions, Guide Pins, King Pins, Pistons Pins, Splined Shafts, Ratchets, Sleeves etc.This material is characterized by a hard outer surface, combined with a ductile interior for higher strength.

The above values are average and may be considered as representative of 8620 hot roll

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.

Working

Steel of an 8620 alloy can be worked into shape through pounding, rolling or bending prior to carburizing, although after carburizing it is recommended only finish machining (such as polishing) be done to prevent weakening the outer layers of the steel. Extensive carving on the surface could remove the extra layers of carbon, leaving the worked part weak.

Welding

Some pieces made of the alloy are either too intricately shaped or large to be made out of one piece of steel. In these cases, arc welding may be used on 8620 alloy steel. It is recommended that the piece itself be heated before and after welding, in order to strengthen the seams.