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Our original material ‘KWS4MA’:replacement material of SUS440C
This is martensitic stainless and be high Abrasion resistance with heat treatment.
Please contact us if you need more details.

KWS4MA Characteristic

Wear and abrasion resistance Hardness as SUS440C over HV700
Corrosion resistance As SUS440C
Abrasion resistance Higher abrasion resistance than SUS440C
Price About 2/3 cost of SUS440C

Comparison chart with other metal

Component, Mechanical properties and physical properties

Table of component

Material C Si Mn P S Ni Cr Mo N
KWS4MA 0.45~0.55 Under0.80 Under0.80 Under0.040 Under0.030 Under0.06 12.5~14.00 - -
SUS440C 0.95~1.20 Under1.00 Under1.00 Under0.040 Under0.030 Under0.06 16.00~18.00 Under0.75 -
SUS420J2 0.26~0.40 Under1.00 Under1.00 Under0.040 Under0.030 Under0.06 12.00~14.00 - -

Mechanical properties and physical properties

Material Hardness
Longitudinal elastic modulus
Specific heat
Heat conductivity
Heat expansion coefficient


μ Ω・㎝

Magnetic permeability
KWS4MA 600~800 7.75 20.6 0.46 24.7 10.6 67 Hard magnetism
SUS440C 600~800 7.75 20.5 0.46 24.2 10.6 60 Hard magnetism
SUS420J2 500~700 7.75 20.6 0.46 25.0 10.4 56 Hard magnetism


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(Site: Tsukuba Plant・Tsukuba Plant Building A)

(Scope: Manufacturing Micro shaft and Metal packing)

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