CrWMn
CrWMn steel chemical composition (GB / T 1229-2000) w /%
Carbon C: 0.90 ~ 1.05
Si Si: ≤ 0.40
Manganese Mn: 0.80 ~ 1.10
Sulfur S: ≤ 0.03
Phosphorus P: ≤ 0.03
Chromium Cr: 0.90 ~ 1.20
Ni: to allow the residual content of ≤ 0.25
Copper Cu: to allow the residual content of ≤ 0.30
Tungsten W: 1.20 ~ 1.60
Mechanical properties:
Hardness: Annealed, 255 ~ 207HB, indentation diameter of 3.8 ~ 4.2mm; quenching, ≥ 62HRC
Heat treatment and microstructure specifications:
Standard heat treatment: quenching, 800 ~ 830 ℃ oil cooling.
Delivery status: delivery of steel in the annealed condition.
2.13.2 Physical Properties
CrWMn steel critical temperature are shown in Table 2-13-2 its saturation magnetic induction Bs of 1.82 ~ 1.86T; resistance of about 0.24 × 10-6Ω · m.
Table 2-13-2 CrWMn critical temperature of steel
| Critical point | Acl | Acm | Arl |
| Temperature (approximate) / ℃ | 750 | 940 | 710 |
2.13.3 thermal processing
CrWMn steel thermal processing are shown in Table 2-13-3.
Table 2-13-3 CrWMn steel thermal processing
| Item | Heating temperature / ℃ | Start temperature / ℃ | Termination of temperature / ℃ | Cooling |
|
Steel ingot Steel billet |
1150~1200 1100~1150 |
1100~1150 1050~1100 |
880~800 850~800 |
First air-cooled and slow coolingFirst air-cooled and slow cooling |
CrWMn steel with high hardenability. Since the formation of tungsten carbide in the steel after quenching and tempering of steel with chromium and 9SiCr than the more excess carbon steel and higher hardness and wear resistance. In addition, the tungsten can also help save the small grains, so that the steel is good toughness. Therefore, the cutting tool by the CrWMn steel, less chipping phenomenon, and can better keep the blade shape and size. However, the steel is sensitive to the formation of carbide networks, such networks exist, the tool blade with the danger of falling off, thus shortening the life of the tool, therefore, net carbon steel, must be carried out according to their severity forging and normalizing. The steel used to make at work, cutting edge tools without intense hot and quenching requires no deformation of the measuring and cutting tools, such as making knives, long tap, long reamers, special cutters, die, and other types of special tools, and cutting tool of soft non-metallic materials.
