Steel produced at the quenched and tempered state according to the United States standard ASTM A-193, widely used for linkages and bolts destined for the oil industry. It is analytically similar to 42CrMo4 of the European standard. The B7M version, produced at higher temperatures, has slightly lower resistance characteristics but greater plasticity.
Standard Reference: ASTM A 193
| EUROPE | ITALY | GERMANY | FRANCE | UK | USA | |||
|---|---|---|---|---|---|---|---|---|
| EN 10083-3: 2006 | (UNI 7845-78) | (DIN 17200 - 89) | (NF A 35-552-86) | (BS 970 pt. 1 - 96) | ASTM | |||
| Grade | N° | Werkstoff | N° | |||||
| (42CrMo4) | (1.7225) | (42CrMo4) | (42CrMo4) | (1.7225) | (42CD4) | (708M40) | B7 | B7M |
| 4140 | 4142 | |||||||
| C | Si | Mn | P/max | S/max | Cr | Mo | Al |
|---|---|---|---|---|---|---|---|
| 0,38 ÷ 0,48 | 0,15 ÷ 0,35 | 0,75÷1,00 | 0,035 | 0,040 | 0,80 ÷ 1,10 | 0,15 ÷ 0,25 | 0,020÷0,050 |
| Size (mm) |
Rp 0,2 (MPa) min |
Rm (MPa) min |
A4 (%) min |
Z (%) min |
Hardness max |
||
|---|---|---|---|---|---|---|---|
| A193 - B7 | ≤M64** | 720 | 860 | 16 | 50 | 321 HB or 35 HRC | |
| ≤M100** | 655 | 795 | 16 | 50 | 302 HB or 33 HRC | ||
| A193 - B7M | ≤M100** | 690 | 550 | 18 | 50 | 235 HB or 99 HRB | |
| * A193-B7: minimum tempering temperature 593°C - * A193-B7M: minimum tempering temperature 620°C. ** Thread diameter. |
|||||||
| Operation | °C |
|---|---|
| Hot forgings deformation | 850÷1150 |
| Normalizing | 850÷880 |
| Soft annealing | 680÷720 |
| Quenching in oil or water | 830÷850 |
| Tempering | 593÷650 |
