Is 8620 the same as 20MnCr5?

No, but they are used for similar parts. 8620 has nickel and molybdenum; 20MnCr5 relies on manganese and chromium. Follow the drawing's grade.

Can SAE 8620 be through hardened?

Its carbon is low, so it is normally carburised. It can be hardened and tempered for moderate strength in the core only.

SAE 8620 steel: equivalents, properties and uses

SAE 8620 is a low-carbon nickel-chromium-molybdenum steel, the most widely used case-hardening steel in American drawings. Carburised, it gives a hard surface (about 58–62 HRC) over a tough core, and it machines and welds well before hardening.

Quick facts

Type: Low-carbon alloy case-hardening steel
Main alloys: Nickel, chromium, molybdenum
Case hardness: About 58–62 HRC after carburising
Core: Tough, about 25–40 HRC depending on section
Weldability: Good before hardening
As supplied: Annealed or normalised

Equivalent grades

Standard	Grade
SAE / AISI	8620
EN / DIN	20NiCrMo2-2, 1.6523
BS 970	805M20 (close)
Similar steels	20MnCr5, EN353

Equivalents are close, not identical. Name the grade and standard on the drawing.

Typical chemical composition

Element	%
Carbon (C)	About 0.18–0.23
Manganese (Mn)	About 0.70–0.90
Nickel (Ni)	About 0.40–0.70
Chromium (Cr)	About 0.40–0.60
Molybdenum (Mo)	About 0.15–0.25

Values are typical. The exact limits depend on the standard and supplier; ask for the mill test certificate when it matters.

Typical uses

Gears, ring gears and pinions
Camshafts, shafts and splined shafts
Pins, bushes and fasteners that need a hard surface
Oil-field and agricultural machine parts

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Questions

Is 8620 the same as 20MnCr5?: No, but they are used for similar parts. 8620 has nickel and molybdenum; 20MnCr5 relies on manganese and chromium. Follow the drawing's grade.
Can SAE 8620 be through hardened?: Its carbon is low, so it is normally carburised. It can be hardened and tempered for moderate strength in the core only.

The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 9 October 2026.