18CrMo4, 1.7243, 708M20 - Case-hardening steel according to EN 10084.
| Standards | Steel Grades | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical composition % | |||||||||||
| C: | Mn: | Si: | P: | S: | Cr: | Ni: | Mo: | Cu: | Ti: | Al: | |
| PN | 18HGM | ||||||||||
| 0.16 - 0.23 | 0.90 - 1.20 | 0.17 - 0.37 | <0.035 | <0.035 | 0.90 - 1.20 | <0.30 | 0.20 - 0.30 | - | - | - | |
| PN | 15HGM | ||||||||||
| 0.12 - 0.19 | 0.80 - 1.10 | 0.17 - 0.37 | <0.035 | <0.035 | 0.80 - 1.10 | <0.30 | 0.15 - 0.25 | - | - | - | |
| DIN / EN | 18CrMo4 - 1.7243 - 18 CrMo 4 | ||||||||||
| 0.15 - 0.21 | 0.60 - 0.90 | <0.40 | <0.025 | <0.035 | 0.90 - 1.20 | - | 0.15 - 0.25 | - | - | <0.05 | |
| UNE | 18 CrMo 4 - 18CrMo4 - CMO - F-1550 - A-1550 | ||||||||||
| 0.15 - 0.21 | 0.60 - 0.90 | <0.40 | <0.025 | <0.035 | 0.90 - 1.20 | - | 0.15 - 0.25 | - | - | - | |
| ISO | 15CrMo4 - 1.3566 | ||||||||||
| 0.12 - 0.18 | 0.60 - 0.90 | <0.40 | <0.025 | <0.030 | 0.90 - 1.20 | - | 0.15 - 0.25 | <0.30 | - | - | |
| AFNOR | 18 CD 4 - 18CD4 | ||||||||||
| 0.15 - 0.21 | 0.60 - 0.90 | <0.40 | <0.025 | <0.035 | 0.90 - 1.20 | - | 0.15 - 0.25 | - | - | - | |
| JUS | Č4721 - Č.4721 - Č 4721 | ||||||||||
| 0.18 - 0.23 | 0.90 - 1.20 | <0.40 | <0.035 | <0.035 | 1.10 - 1.40 | - | 0.20 - 0.30 | - | - | - | |
| STAS | 21MoMnCr12 - 21 MoMnCr 12 | ||||||||||
| 0.18 - 0.24 | 0.80 - 1.20 | 0.17 - 0.37 | <0.035 | <0.035 | 1.00 - 1.40 | <0.30 | 0.20 - 0.30 | <0.30 | <0.02 | - | |
| BS | 708M20 - 708 M 20 | ||||||||||
| 0.17 - 0.23 | 0.60 - 0.90 | 0.10 - 0.35 | <0.035 | <0.040 | 0.85 - 1.15 | - | 0.15 - 0.25 | - | - | - | |
| MSZ | BCMo 2 - BCMo2 | ||||||||||
| 0.17 - 0.23 | 0.90 - 1.20 | <0.40 | <0.035 | <0.035 | 1.10 - 1.40 | - | 0.20 - 0.30 | - | - | - | |
| IS | 21Cr4Mo2 | ||||||||||
| <0.26 | 0.60 - 0.90 | 0.10 - 0.35 | - | - | 0.90 - 1.20 | - | 0.15 - 0.30 | - | - | - | |
| ČSN / STN | ČSN 15 124 - ČSN 15124 | ||||||||||
| 0.15 - 0.21 | 0.60 - 0.90 | 0.25 - 0.40 | <0.035 | <0.035 | 0.90 - 1.20 | - | 0.15 - 0.25 | - | - | - | |
18CrMo4, 1.7243, 708M20 - specification and applications
High-tensile and ductile steel for construction applications subject to high pressure and varying loads - typically selected for parts with dimensions up to 155mm. Designed for steel rollers, bit cutters, bushings, pinions, and inserts for drill bits. The steel can be welded before carburizing, after preheating.
Mechanical properties - 18CrMo4
| Mechanical and physical properties | ||
|---|---|---|
| Tensile strength | Rm | > 1080 MPa |
| Yield point | Re | > 880 MPa |
| Contraction | Z | > 50% |
| Elongation | A | > 10% |
| Notch toughness | KU2 | > 72 J |
| Hardness in softened state | HB | < 217 HB |
| Density | ρ | 7,85 kg/dm3 |
Mechanical properties for individual dimensions - 18HGM
| Mechanical properties after hardening | ||||
|---|---|---|---|---|
| Properties | Dimensions | |||
| 11mm | 30mm | 63mm | ||
| Tensile strength | Rm | 920 - 1270 MPa | 820 - 1170 MPa | 710 - 1060 MPa |
| Yield point | Re | > 600 MPa | > 540 MPa | > 480 MPa |
| Notch toughness | KU | > 25 J | > 25 J | > 25 J |
| Elongation | A | > 9 % | > 10 % | > 11 % |
Heat treatment of 18CrMo4 steel
| Process | Cooling | Temperatures |
|---|---|---|
| Normalizing annealing | in air | 870 - 900℃ |
Softening annealing | 650 - 700℃ | |
| Carburizing in powder |
| 880 - 950℃ |
| Carburization in salt baths | 900 - 950℃ | |
| Gas carburization | 880 - 900℃ | |
| Hardening (I) |
| 860 - 900℃ |
| Hardening (II) |
| 800 - 840℃ |
Tempering | 170 - 200℃ | |
List of equivalents and other determinations of 18HGM steel:
- Hot-rolled round bars 18CrMo4, 1.7243, 18HGM
- Forgings 18CrMo4, 1.7243, 18HGM
- Forged bars 18HGM, 18CrMo4, 1.7243
In the 18HGN grade the company provides:
18HGM, 15HGM, 18CrMo4, 1.7243, 18 CrMo 4, CMO, F-1550, A-1550, 15CrMo4, 1.3566, 18 CD 4, 18CD4, Č4721, Č.4721, Č 4721, 21MoMnCr12, 21 MoMnCr 12, 708M20, 708 M 20, BCMo 2, BCMo2, 21Cr4Mo2, ČSN 15 124, ČSN 15124