Boron steel

Supported standards AICHI
  • SAE, ASTM and EN standards are also supported.
Names of steel types 10B33M, SMnB440 - SMnB445

Product catalog


Type of steel/Chemical composition

Type of steel Main chemical components representative values (%) Characteristics
C Si Mn Cr B
10B33M 0.33 0.25 0.8 ≦0.2 Additives
  • Better cutting, cold processing properties than S45C
  • Achieve equal or better strength than S45C through deep hardening with induction quenching
SMnB440 0.40 0.25 1.5 0.2 Additives
  • Equal induction quenching, mechanical and fatigue strength properties to SCM440
SMnB445 0.45 0.25 1.5 0.2 Additives

10B33: improved manufacturing of induction quenched parts using S45C, S48C and effective stabilization of part strength.
MnB series: Using steel alloys equivalent to SCM440 is effective at reducing material costs for parts.


Adding minor amounts of boron increases hardenability. These alloy-saving structural steels can reduce resource risk and cost.
High hardenability enables deep hardening by induction quenching and ensuring the strength of the product.
Compared with alloy steels with equivalent hardenabilty, the hardness after rolling or normalizing etc. becomes lower, which can improve the cold forgeability and machinability.

Major applications

CVJ intermediate shafts, rear shafts, etc.

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