AISI 8620 Steel | 1.6523 | 21NiCrMo2 | SNCM220

AISI 8620 Steel is a low alloy nickel, chromium, molybdenum case hardening steel, generally supplied in the as rolled condition with a maximum hardness HB 255max. SAE steel 8620 offers high external strength and good internal strength, making it highly wear resistant. AISI 8620 steel has a higher core strength than grades 8615 and 8617.

SAE 8620 alloy steel is flexible during hardening treatments, thus enabling improvement of case/core properties. Prehardened and tempered (uncarburized) 8620 can be further surface hardened by nitriding but will not respond satisfactorily to flame or induction hardening due to its low carbon content.

Steel 8620 is suited for applications which require a combination of toughness and wear resistance. This grade is commonly supplied in round bar.

Chemical composition

Heat treatment Related

Annealing of 8620 Alloy structural steel

Slowly heated to 850 ℃ and allow enough times, let the steel to be thoroughly heated, Then cool slowly in the furnace. The 8620 alloy steel will get MAX 250 HB （Brinell hardness）.

Hardening of 8620 Alloy structural steel

Heated slowly to 880-920°C, Then after adequate soaking at this temperature quench in oil. Temper as soon as tools reach room temperature.

Machinability of SAE 8620 Steel

The 8620 alloy steel is readily machined after heat treatment and/or carburizing, should be at a minimum so as not to impair the hardened case of the part. Machining may be done by conventional means prior to heat treatment – after carburizing machining is usually limited to grinding.

Welding of 8620 Materials

The alloy 8620 may be welded as the rolled condition by conventional methods, usually gas or arc welding. Preheating at 400 F is beneficial and subsequent heating after welding is recommended – consult the approved weld procedure for the method used. However, welding in the case hardened or through-hardened condition is not recommended

Application of ASTM 8620 Steel

AISI 8620 steel material is used extensively by all industry sectors for light to medium stressed components and shafts requiring high surface wear resistance with reasonable core strength and impact properties.

Typical applications are Arbors, Bearings, Bushings, Cam Shafts, Differential Pinions, Guide Pins, King Pins, Pistons Pins, Gears, Splined Shafts, Ratchets, Sleeves and other applications where it is helpful to have a steel that can be readily machined and carburized to controlled case depths.

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