Case-hardening steel 18H2N4MA, X19CrNiMo4, 1.2764 for heavy-duty equipment according to PN-72/H-84035 standard.
| Standards | Steel Grades | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical composition % | ||||||||||||||
| C: | Mn: | Si: | P: | S: | Cr: | Mo: | V: | Ti: | Ni: | W: | Cu: | N: | ||
| PN | 18H2N4WA | |||||||||||||
| 0.14 - 0.20 | 0.25 - 0.55 | 0.17 - 0.37 | <0.03 | <0.025 | 1.35 - 1.65 | - | - | - | 4.0 - 4.4 | 0.8 - 1.2 | <0.20 | - | ||
| GOST | 18Х2Н4МА | |||||||||||||
| 0.14 - 0.20 | 0.25 - 0.55 | 0.17 - 0.37 | <0.025 | <0.025 | 1.35 - 1.65 | 0.3 - 0.4 | <0.05 | <0.06 | 4.0 - 4.4 | <0.2 | <0.30 | <0.008 | ||
| GOST | 18Х2Н4ВА | |||||||||||||
| 0.14 - 0.20 | 0.25 - 0.55 | 0.17 - 0.37 | <0.025 | <0.025 | 1.35 - 1.65 | < 0.15 | <0.05 | <0.06 | 4.0 - 4.4 | 0.8 - 1.2 | <0.30 | <0.008 | ||
| DIN | X19NiCrMo4 - X 19 NiCrMo 4 - 1.2764 | |||||||||||||
| 0.16 - 0.22 | 0.15 - 0.45 | 0.1 - 0.4 | <0.03 | <0.03 | 1.10 - 1.40 | 0.15 - 0.25 | - | - | 3.8 - 4.3 | 0.3 - 0.5 | - | - | ||
| BS | 835M15 - EN39B | |||||||||||||
| 0.12 - 0.18 | 0.25 - 0.50 | - | <0.035 | <0.035 | 1.00 - 1.40 | 0.15 - 0.30 | - | - | 3.9 - 4.3 | - | <0.40 | - | ||
18H2N4MA / 18H2N4WA - specification and destination
18H2N4WA, 18H2N4MA - steel for heavy duty machine parts, which needs high plasticity of the core and components subjected to variable loads. Used as a steel for gears, crankshafts and heavy duty pins, machine joists and reduction shafts; as a steel for aircraft parts, and steel for parts of internal combustion engines.
It exhibits very good hardenability, however, it is difficult to weld and it is required to preheat the product to a suitable temperature before welding. The minimum surface hardness after thermo-chemical treatment is about 56 HRC. As a medium alloy structural steel, it does not exhibit greater corrosion resistance.
Due to the high cost of the Wolfram and its relatively high content in 18H2N4WA steel, the element was partially replaced with molybdenum in the proportion of 1/3 of the wolfram content in the chemical composition. The change does not significantly affect the properties and parameters of the steel. In the name of the grade W is replaced by M - 18H2N4MA.
Heat treatment of 18H2N4MA steel - temperature, process, conditions
| Thermal and thermo-chemical treatment of 18H2N4MA steel | ||
|---|---|---|
| Softening annealing | 640 - 680℃ | |
| Normalizing annealing | 860 - 880℃ | |
| Cyaniding | 850 - 880℃ | |
| Carburizing | 870 - 900℃ | |
| Hardening (I) after carburization | 935 - 965℃ | in oil or in air |
| Hardening (II) after carburization | 835 - 865℃ | in oil or in air |
| Tempering after carburized and hardening in the air | 150 - 210℃ | in the air or oil |
| Tempering after carburized and hardening in the oil | 525 - 575℃ | in air |
Properties of 18H2N4WA i 18H2N4MA steel:
- Tensile strength, Rm = ≥ 1130 MPa
- Yield point, Re = ≥ 835 MPa
- Elongation, A = ≥ 12%
- Hardness after softening, HB = ≤ 269
- Contraction, Z = ≥50%
- Density ρ = ~7,90 kg/dm³
- Notch toughness, KU2 = ≥ 80 J
- Thermal conductivity, λ20℃ = ~33,5 W⋅m⁻¹ K⁻¹
- Heat capacity cp20-100℃ = 490 J⋅kg⁻¹ K⁻¹
- Linear Expansion Factor, α = ~11,1⋅10⁻⁶ K⁻¹
In the 18H2N4MA and 18H2N4WA grades the company provides:
- Forgings, forged shafts
- Forged round bars, hot-rolled bars
- Forged square bars
- Forged and rolled flat bars
List of equivalents and other determinations of 18H2N4WA i 18H2N4MA steel:
18Ch2N4MA, 18Х2Н4МА, 18KH2N4MА, 18H2N4MA-Sh, 18Ch2N4MA-Sh, 18Х2Н4МА-сш, 18KH2N4MА-Sh, 18H2N4VA, 18Ch2N4VA, 18Х2Н4ВА, 18KH2N4VА, 18H2N4VA-Sh, 18Ch2N4VA-Sh, 18Х2Н4ВА-сш, 18KH2N4VА-Sh, X19NiCrMo4, X 19 NiCrMo 4, 1.2764, 2764, 835M15, 835 M 15, EN 39 B, EN39B, N4CMCH, SNCM815, SNCM 815, SNCM 25, ČSN 16 720, ČSN 16720, 18Cr2Ni4WA, A52183, A 52183