Case-hardening steel 20Ch2N4A intended for heavy duty parts of aircrafts and aircraft structures according to PN-72/H-84035.
| Standards | Steel Grades | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical composition % | |||||||||||||
| C: | Mn: | Si: | P: | S: | Cr: | Mo: | Ni: | V: | Ti: | Cu: | N: | W: | |
| PN | 20H2N4A | ||||||||||||
| 0.16 - 0.22 | 0.30 - 0.60 | 0.17 - 0.37 | <0.030 | <0.025 | 1.25 - 1.65 | - | 3.25 - 3.65 | - | - | <0.2 | - | - | |
| GOST | 20Ch2N4A - 20Х2Н4А - 20Kh2N4A | ||||||||||||
| 0.16 - 0.22 | 0.30 - 0.60 | 0.17 - 0.37 | <0.025 | <0.025 | 1.25 - 1.65 | <0.15 | 3.25 - 3.65 | <0.05 | <0.03 | <0.3 | <0.008 | <0.2 | |
| UNE | 18NiCrMo14 - 18 NiCrMo 14 - F-1556 - F1556 | ||||||||||||
| 0.14 - 0.20 | 0.40 - 0.70 | 0.15 - 0.40 | <0.035 | <0.035 | 1.30 - 1.60 | 0.15 - 0.25 | 3.25 - 3.75 | - | - | - | - | - | |
| ČSN STN | ČSN 16 523 - ČSN 16523 | ||||||||||||
| 0.12 - 0.19 | 0.30 - 0.60 | 0.17 - 0.37 | <0.035 | <0.035 | 1.20 - 1.75 | - | 3.25 - 4.00 | - | - | - | - | - | |
| SAE AISI | SAE 3316 - AISI E3316 - AISI E 3316 | ||||||||||||
| 0.14 - 0.19 | 0.45 - 0.60 | 0.20 - 0.35 | <0.025 | <0.025 | 1.40 - 1.75 | - | 3.25 - 3.75 | - | - | - | - | - | |
| GB/T | 20Cr2Ni4A - 43203 | ||||||||||||
| 0.17 - 0.23 | 0.30 - 0.60 | 0.17 - 0.37 | <0.025 | <0.025 | 1.25 - 1.65 | - | 3.25 - 3.65 | - | - | <0.25 | - | - | |
| JIS | SFVQ 3 - SFVQ3 | ||||||||||||
| <0.23 | 0.20 - 0.40 | <0.40 | <0.020 | <0.020 | 1.50 - 2.00 | 0.40 - 0.60 | 2.75 - 3.90 | <0.03 | - | - | - | - | |
20H2N4A - Description and purpose
Steel for thermal improvement and carburization with high nickel content intended to particularly heavy duty machine parts and aircraft engines. It is characterized by very good hardenability, high core strength and high hardness. Steel for large dimensions parts such as sprockets, heavy duty screws, rocker arms, piston pins, shafts and bushings Products mode of 20H2N4A steel grade are not suitable for welding.
Mechanical and physical properties
- Tensile strength Rm > 1270 MPa
- Yield point Re >1080 MPa
- Notch toughness KU2 > 64 J
- Contraction Z > 45%
- Elongation A > 9%
- Hardness in softened state < 269 HB
- Thermal conductivity λ = ~33,5 W ⋅ m-1 K-1
- Pojemność cieplna cp = 490 J ⋅ kg-1 K-1
- Density ρ = ~7,83 kg/dm3
- Linear Expansion Factor α = ~11,1 ⋅ 10-6 K-1
Heat treatment
- Normalising annealing at 860 - 880 °C
- Softening annealing at 640 - 680℃
- Carburization at 870 - 900℃
- Carbonitriding at 850 - 880℃
- Hardening I in oil at 845 - 875℃
- Hardening II in oil at 760 - 800℃
- Tempering after carburization in air or oil at 150 - 210℃
- Cyanidizing at 840 - 860℃
- Tempering, in order to avoid the fragility, in oil or water at a temperature of 500 - 650℃
In the 20H2N4A grade the company provides:
Related equivalents and determination of steel:
20Ch2N4A, 20Kh2N4A, 18NiCrMo14, 18 NiCrMo 14, F-1556, F1556, ČSN 16 523, ČSN 16523, SAE 3316, AISI E3316, AISI E 3316, 20Cr2Ni4A, 43203, 20Cr2Ni4, 17NiCrMo14, 18NiCrMo14-6, 1.3533, SFVQ 3, SFVQ3, 20Х2Н4А