M2 1.3343 SKH51 round bar tool steel High Speed
1. Supply Range
M2 Steel Round Bar: diameter 2mm – 200mm
HSS M2 Steel Flat: thickness 2-20mm x width 10-100mm
Steel Plate: thickness 2-200mm x width 200-610mm
Surface Finish: Black, Rough Machined, Turned or as per given requirements.
2. Specifications and Equivalents
| Country | USA | German | Japan |
| Standard | ASTM A600 | DIN EN ISO 4957 | JIS G4403 |
| Grades | M2 | 1.3343 | SKH51 |
3. ASTM M2 Tool Steel Chemical Composition
| ASTM A600 | C | Mn | P | S | Si | Cr | V | Mo | W | |||||||
| M2 regular C | 0.78 | 0.88 | 0.15 | 0.40 | 0.03 | 0.03 | 0.20 | 0.45 | 3.75 | 4.50 | 1.75 | 2.20 | 4.50 | 5.50 | 5.50 | 6.75 |
| DIN ISO 4957 | C | Mn | P | S | Si | Cr | V | Mo | W | |||||||
| 1.3343 | 0.86 | 0.94 | … | … | … | … | … | 0.45 | 3.80 | 4.50 | 1.70 | 2.10 | 4.70 | 5.20 | 5.90 | 6.70 |
| JIS G4403 | C | Mn | P | S | Si | Cr | V | Mo | W | |||||||
| SKH51 | 0.80 | 0.88 | … | 0.40 | 0.03 | 0.03 | … | 0.45 | 3.80 | 4.50 | 1.70 | 2.10 | 4.70 | 5.20 | 5.90 | 6.70 |
4. AISI HSS M2 Tool Steel Mechanical Properties
- Physical Properties of HSS M2 Material
| Density | 0.294 lb/in3 (8138 kg/m3) |
| Specific Gravity | 8.15 |
| Modulus of Elasticity | 0.294 lb/in3 (8138 kg/m3) |
| Thermal conductivity | 24 Btu/ft/hr/°F 41.5 W/m/°K |
| Machinability | 65% of a 1% carbon steel |
- AISI M2 Tool Steels Mechanical Properties
| Mechanical properties | Metric | Imperial |
| Hardness, Rockwell C (tempered at 1150°F, quenched at 2200°F) | 62 | 62 |
| Hardness, Rockwell C (as hardened, quenched at 2200°F) | 65 | 65 |
| Compressive yield strength (when tempered at 300°F) | 3250 MPa | 471000 psi |
| Izod impact unnotched (when tempered at 300°F) | 67 J | 49.4 ft-lb |
| Abrasion (loss in mm3, as-hardened; ASTM G65) | 25.8 | 25.8 |
| Abrasion (loss in mm3, tempered at 1275°F; ASTM G65) | 77.7 | 77.7 |
| Poisson’s ratio | 0.27-0.30 | 0.27-0.30 |
| Elastic modulus | 190-210 GPa | 27557-30458 ksi |
- M2 Steels Thermal Properties
| Thermal properties | Metric | Imperial |
| CTE, linear (@20.0 – 100°C/ 68.0 – 212°F) | 10 μm/m°C | 5.56 μin/in°F |
| CTE, linear (@20.0 – 500°C/68.0 – 932°F) | 12.2 μm/m°C | 6.78 μin/in°F |
| CTE, linear (@20.0 – 850°C/68.0 – 1560°F) | 12.6 μm/m°C | 7 μin/in°F |
5. Forging of AISI M2 High Speed Steel
Pre heat M2 HSS steel slowly and uniformly to 850-900°C. The heat should then be increased more quickly to the forging temperature of 1050-1150°C. If during the forging the temperature of the M2 high speed tool steel material drops below 880-900°C, re-heating will be necessary. Cool the M2 steel component very slowly after forging.
6. Heat Treatment of M2 Steel HSS
- Anneal
Heat to 1600° F, soak thoroughly at heat. Furnace cool 25° F per hour to 900° F, air cool to room temperature. Approximate annealed hardness 241 Maximum Brinell.
Stress Relief of Unhardened Material: Heat slowly to 1200 to 1250° F. Soak for two hours per inch of thickness at heat. Slow cool (furnace cool if possible) to room temperature.
- Harden
Heat slowly to 1550° F, soak thoroughly, heat to 1850° F, soak thoroughly. Soak time in the furnace varies from a few minutes to 15 minutes, depending tool size, heat capacity of the furnace, and the size of the charge. – Heat to 2150 to 2200° F for max. toughness and minimum distortion. – Heat to 2250 to 2275° F for max. hardness and abrasion resistance.
- Quench
For full hardness, oil quench to 150-200° F. Air quench to 150° F. When quenching in hot salt maintain the quench just above the Ms temperature. After equalizing withdraw parts from the hot salt and air cooled to 150° F.
- Temper
Double temper is mandatory, three tempers are sometimes preferred. Soak for 2 hours per inch of thickness. Air cool to room temperature between tempers. The best tempering range for hardness, strength and toughness is 1000 to 1050° F.
| Temper° F | Rockwell “C” | Temper° F | Rockwell “C” |
| As-quenched | 64 | 900 | 64 |
| 400 | 63 | 1000 | 65.5 |
| 500 | 62.5 | 1050 | 63.5 |
| 600 | 62.5 | 1100 | 61.5 |
| 700 | 62.5 | 1150 | 60 |
| 800 | 63.5 | 1200 | 53 |
More grades we can supply.
D2 | 1.2379 | SKD11
H13 | 1.2344 | SKD61
D3 | 1.2080 | SKD1
O1 | 1.2510 | SKS3
L6 | 1.2714 | SKT4
JIS DC53
O2 | 1.2842
D6 | 1.2436 | SKD2
H11 | 1.2343 | SKD6
H10 | 1.2365 | SKD7
H12 | 1.2605 | SKD62
S7 | 1.2355
M2 | 1.3343 | SKH51
M35 | 1.3243 | SKH55
M42 | 1.3247 | SKH59
P20+Ni | 1.2738
420 | 1.2083
P20 | 1.2311
P20+S | 1.2312
S136 | S136H
718 | 718H
4140 | 42CrMo4| SCM440 | EN19
4340 | EN24
8620 | 1.6523 | SNCM220
34CrNiMo6 | 1.6582
30CrNiMo8 | 1.6580
