X40CrSiMo10-2, 1.4731 - valve steel

X40CrSiMo10-2, 1.4731, H10S2M - Silchrom valve steel, chromium-silicon, with the addition of molybdenum for valves of internal combustion engines according to PN-71/H-86022 and EN 10090.

Standard Steel grade
Chemical Composition %
C: Mn: Si: P: S: Cr: Mo: Ni: V: Ti: W: Cu:
PN H10S2M
0.35 - 0.45 <0.7 1.9 - 2.6 <0.035 <0.030 9.0 - 10.5 0.7 - 0.9 <0.5 <0.20 - <0.50 -
EN X40CrSiMo10-2 - X40CrSiMo10 - X 40 CrSiMo 10-2 - 1.4731 - 4731
0.35 - 0.45 <0.8 2.0 - 3.0 <0.040 <0.030 9.5 - 11.5 0.8 - 1.3 <0.5 - - - -
UNE F-3221 - X 40 CrSiMo 10-02 - F3221
0.35 - 0.45 <0.8 2.0 - 3.0 <0.040 <0.030 9.0 - 11.0 0.8 - 1.3 - - - - -
AFNOR Z40CSD10 - Z 40 CSD 10
0.35 - 0.45 <0.8 2.0 - 3.0 <0.040 <0.030 9.5 - 11.5 0.8 - 1.3 <0.5 - - - -
- 4Ch10S2M - 4Х10С2М - 4Kh10S2M - 4H10S2M
0.35 - 0.45 <0.8 1.9 - 3.0 <0.030 <0.030 9.0 - 10.5 0.7 - 1.2 - - - - -
GOST 40Ch10S2M - 40Kh10S2M - 40H10S2M - 40Х10С2М - ЭЛ 107 - EL 107
0.35 - 0.45 <0.8 1.9 - 3.0 <0.030 <0.025 9.0 - 10.5 0.7 - 0.9 <0.6 <0.20 <0.20 <0.20 <0.30
GB/T 4Cr10Si2Mo - S48140
0.35 - 0.45 <0.7 1.9 - 2.6 <0.035 <0.030 9.0 - 10.5 0.7 - 0.9 <0.6 - - - -
MSZ 5776 SZ4 - SZ 4
0.35 - 0.45 0.3 - 0.6 2.4 - 3.0 <0.010 <0.030 9.0 - 10.5 0.8 - 1.2 <0.6 - - - <0.30

X40CrSiMo10-2, 1.4731 - specifications and application

H10S2M special valve steel with pearlitic-martensitic structure - heat-resistant up to 900 ℃, and creep-resistant up to approx. 700 ℃.

Mainly used for heavily loaded exhaust valves and loaded inlet valves for aviation, car and motorcycle engines.

The addition of Molybdenum - Mn in relation to H9S2 steel, improves the strength properties, and increases the temperature of resistance to oxidation by 50 ℃.

H10S2M steel is generally not welded.

Mechanical properties of H10S2M

Mechanical and physical properties at normal temperature
Tensile strength, Rm ≥ 930 MPa
The yield point, Rp0.2 ≥ 740 MPa
Elongation A ≥ 10 %
Density, ρ ~7,72 kg/dm3
Electrical resistance 0.90 om mm2/m
Specific heat at 20 °C 0.11 cal/g

Linear expansion coefficient in the temperature range for H10S2M

Linear expansion coefficient α
20 - 100℃ 10 ⋅10⁻⁶ K⁻¹
20 - 400℃ 12.0 ⋅10⁻⁶ K⁻¹
20 - 500℃ 12.6 ⋅10⁻⁶ K⁻¹
20 - 600℃ 12.9 ⋅10⁻⁶ K⁻¹
20 - 700℃ 13.0 ⋅10⁻⁶ K⁻¹
20 - 800℃ 13.4 ⋅10⁻⁶ K⁻¹

Exemplary strength properties at elevated temperature for H10S2M material

- Steel hardened at a temperature of 1025 ℃ in oil and tempered at 800 ℃

Temperature Short-term tensile test and impact strength test Time creep limit Modulus of elasticity, E kG/mm2
Rr (kG/mm2) a5 (%) U (kGm/cm2) R1/10000
20℃ - - - - 22000
500℃ 67 - - 22 -
600℃ 35 - 42 15.8 17.5 2 -
700℃ 15 - 22 27.6 27.5 0.25 -
800℃ 8 - 12 31.2 37.5 - -
900℃ ~5 48 37.5 - -

Thermal conductivity:

  • at a temperature of 20 °C - 0.04 cal/cm sec °C
  • at a temperature of 600 °C - 0.05 cal/cm sec °C

Heat treatment of X40CrSiMo10-2

H10S2M chromium-silicon steel with the addition of molybdenum is hardened and tempered with cooling in water or air.

After heat treatment, steel acquires tempered martensite structures.

In poor machining, steel is exposed to temper brittleness.

Heat treatment - process and temperature
Softening annealing at 900℃
Hardening in air or water 1010 - 1050℃
Tempering at in oil 720 - 780℃

Substitutes, equivalents and other species designations

X40CrSiMo10-2
X40CrSiMo10
X 40 CrSiMo 10-2
1.4731
4731
F-3221
X 40 CrSiMo 10-02
F3221
Z40CSD10
Z 40 CSD 10
4Ch10S2M
4Х10С2М
4Kh10S2M
4H10S2M
40Ch10S2M
40Kh10S2M
40H10S2M
40Х10С2М
ЭЛ 107
EL 107
4Cr10Si2Mo
S48140
SZ4
SZ 4

Need help? Contact us!

Call or send a message, and our representative
will contact you within 24 hours!

We use cookies
In order to properly operate the Website and for statistical purposes, and if you consent, also to personalize advertising, remarketing and retargeting. If you want to learn more, read on privacy and cookies policy. You can specify the detailed configuration by clicking the button below "Settings".
Cookie preferences
We use cookies

In order to properly operate the Website and for statistical purposes, and if you consent, also to personalize advertising, remarketing and retargeting. If you want to learn more, read on privacy and cookies policy.

More information

If you have any questions about our cookie policy, please ask contact.