What is EN353 used for?

Parts that need a very hard, wear-resistant surface over a tough core, mainly gears, pinions, pins and shafts. It is case hardened (carburised) rather than through hardened.

What is the case hardness of EN353?

About 58–62 HRC on the surface after carburising, quenching and low-temperature tempering.

Both are case-hardening steels used for gears. EN353 contains nickel and molybdenum for a tougher core; 20MnCr5 is common in European drawings. Follow the drawing, or ask your designer if the core strength matters.

← Back

EN353 case-hardening steel

Also called: EN 353, 15NiCr1Mo12, case hardening steel, carburising steel, EN353 material

EN353 is a low-carbon nickel-chromium-molybdenum steel made for case hardening. After carburising and quenching it has a very hard, wear-resistant surface (about 58–62 HRC) over a tough core, which is why it is widely used in India for gears, pinions and pins.

Quick facts

Type: Low-carbon alloy case-hardening steel
Main alloys: Nickel, chromium and a little molybdenum
Case hardness: About 58–62 HRC after carburising and hardening
Typical case depth: About 0.5–1.5 mm, chosen for the part
Core: Tough, around 30–40 HRC depending on section
As supplied: Annealed or normalised, for machining

Equivalent grades

Standard	Grade
BS 970 (old)	EN353
IS (India)	15NiCr1Mo12 is the commonly quoted equivalent
Similar grades used instead	20MnCr5, 17CrNiMo6 or SAE 8620, depending on the core strength needed

Sources give slightly different equivalents for EN353. If it matters, name the grade, standard and required core strength on the drawing, and ask for the mill test certificate.

Typical chemical composition

Element	%
Carbon (C)	About 0.12–0.20
Manganese (Mn)	About 0.60–1.00
Nickel (Ni)	About 1.00–1.50
Chromium (Cr)	About 0.75–1.25
Molybdenum (Mo)	About 0.08–0.15

Heat treatment (case hardening)

Carburising: about 880–920 °C, long enough to reach the case depth wanted
Hardening: quench in oil, often after reheating to about 780–820 °C
Tempering: about 150–200 °C to relieve stress while keeping the case hard
Copper plating or paint stops carbon going into areas that must stay soft (threads, holes)
Grind after hardening where the size is critical; leave allowance for it

Typical uses

Gears, pinions and crown wheels
Shafts and spindles that need a hard-wearing surface
Gudgeon pins, king pins and cam followers
Splined shafts and couplings

Need parts made in EN353 case-hardening steel?

Post your requirement free. Workshops that take your kind of work see it and get in touch. You only talk to the ones that fit.

Get started

Related job work

Machines

CNC lathe

Materials

Questions

What is EN353 used for?: Parts that need a very hard, wear-resistant surface over a tough core, mainly gears, pinions, pins and shafts. It is case hardened (carburised) rather than through hardened.
What is the case hardness of EN353?: About 58–62 HRC on the surface after carburising, quenching and low-temperature tempering.
EN353 or 20MnCr5?: Both are case-hardening steels used for gears. EN353 contains nickel and molybdenum for a tougher core; 20MnCr5 is common in European drawings. Follow the drawing, or ask your designer if the core strength matters.

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 8 October 2026.