Structural alloy steel 30HN2MFA, 38ChN3MFA, 38HN3MFA for thermal improvement, used in power engineering, aviation, automotive and reinforcement industries for heavy duty parts according to GOST 4543-71, PN-72/H-84035.
|Chemical Composition %|
|0.26 - 0.33||0.3 - 0.6||0.17 - 0.37||<0.030||<0.030||0.6 - 0.9||0.2 - 0.3||2.0 - 2.5||0.15 - 0.30||<0.2||-||-||-|
|GOST||30ChN2MFA - 30KhN2MFA - 30ХН2МФА|
|0.27 - 0.34||0.3 - 0.6||0.17 - 0.37||<0.025||<0.025||0.6 - 0.9||0.2 - 0.3||2.0 - 2.4||0.10 - 0.18||<0.3||<0.03||-||<0.2|
|GOST||30ChN3M2FA - 30HN3M2FA - 30KhN3M2FA - 30ХН3М2ФА|
|0.26 - 0.32||0.2 - 0.5||0.17 - 0.37||<0.025||<0.022||1.2 - 1.7||0.40 - 0.65||3.0 - 3.5||0.10 - 0.20||<0.25||-||-||-|
|GOST||38ChN3MFA - 38KhN3MFA - 38ХН3МФА|
|0.33 - 0.40||0.25 - 0.50||0.17 - 0.37||<0.025||<0.025||1.2 - 1.5||0.35 - 0.45||3.0 - 3.5||0.10 - 0.18||<0.30||-||-||<0.2|
|GOST||30ChN2MFA-Sh - 30KhN2MFA-Sh - 30ХН2МФА-Ш|
|0.33 - 0.40||0.25 - 0.50||0.17 - 0.37||<0.025||<0.025||1.2 - 1.5||0.35 - 0.45||3.0 - 3.5||0.10 - 0.18||<0.3||<0.03||-||<0.2|
30HN2MFA and 38ChN3MFA - specification and applications
30HN2MFA material is a special, rare steel grade with great hardenability for products with medium and large dimensions, used to produce particularly heavy machinery, engines, vehicles, and rifle barrels in the air industry, automotive, power and defense industries in environments of lowered and elevated temperatures. The best properties are obtained to a dimensions of 80mm.
The 38ChN3MFA grade, in turn, classified by GOST as steel for heavy-duty parts and components of machinery, equipment and structures for power/aviation industries- turbine rotors, shafts, turbines, components subjected to high pressures, aviation constructions. The 38HN3MFA, compared to 30HN2MFA, has a much higher range of Coal, Chromium and Nickel in the chemical composition.
The steel is used for the production of drive shafts, axles, connecting rods, shafts, rotors, discs, planetary gear components, cardan shafts, and barrels of rifles. Products in the 30HN2MFA grade are prone to flaking and exhibit limited weldability, insensitivity to tempering and their heat treatment is carried out with cooling in the oil.
Rolled and forged materials in this grade do not exhibit corrosion resistance and their weldability is particularly limited - it requires pre-heating of the product. Steel most commonly delivered after softening annealing.
General mechanical and physical properties:
- Tensile strength Rm > 880 MPa
- Yield point, Re > 780 MPa
- Elongation, A > 9%
- Contraction, Z > 45%
- Notch toughness, KU2 > 48J
- Linear expansion factor, α20-100℃ = ~10,9 ⋅ 10-6 K-1
- Heat conductivity λ20℃= 54,34 W ⋅ m-1 ⋅ K-1
- Hardness in an annealed condition < 241 HB
Mechanical properties of 30HN2MFA grade for individual dimensions
|< 16mm||16 - 40mm||40 - 100mm||100 - 250mm|
|Tensile strength, Rm (MPa)||980 - 1130||880 - 1030||780 - 930||690 - 830|
|Yield point, Re (MPa)||880 - 1030||740 - 880||640 - 780||590 - 740|
|Elongation, A5 (%)||9 - 15||9 - 15||10 - 16||12 - 18|
|Impact resistance, KM (J/cm2)||60 - 120||70 - 140||70 - 140||90 - 180|
Heat treatment - processes, temperatures and cooling:
- Softening annealing with slow cooling at a temperature of 650 - 700℃
- Normalizing annealing with cooling in calm air at 840 - 880℃
- Hardening in oil at 845 - 875℃
- Tempering with cooling in water or oil at 630 - 730°C
Virgamet company in the beforementioned grade provides:
- Hot-rolled bars 30HN2MFA, 38ChN3MFA
- Forged bars 30HN2MFA, 38ChN3MFA
- Forgings 30HN2MFA, 38ChN3MFA
- Forged rings 30HN2MFA, 38ChN3MFA
30HN2MFA steel, its alternatives and equivalents according to other standards:
30ChN2MFA, 30KhN2MFA, 30ХН2МФА, 30ChN3M2FA, 30HN3M2FA, 30KhN3M2FA, 30ХН3М2ФА, 30HN2MFAŻ, 30ChN2MFA-Sh, 30KhN2MFA-Sh, 30ХН2МФА-Ш, 38ChN3MFA, 38KhN3MFA, 38ХН3МФА.