Figure 1 – Hot and cold fatigue properties of HM1 and 3Cr2W8V

Grade HRC Number of cracks Total depth of cracks/mm Maximum depth of crack/mm
HM1 45 21 0.89 0.135
3Cr2W8V 47.3 8 0.56 1.34

** Test conditions: high frequency induction heating, heating temperature 730~740°C, water cooling, heating 12S, cooling 5S, cycle 630 times.

** GB/T 3Cr2W8V steel is similar as DIN 1.2581, AISI H21 steel

 

Figure 2 - Relationship between quenching temperature and hardness of HM1 steel

Quenching temperature/°C 1040 1060 1080 1100 1130 1150
Hardness/HRC 51.8 53.2 54 55 53.5 52.8

 

Mechanical properties:

 

Figure 3 - Impact toughness after 600°C tempering at different quenching temperatures

Quenching temperature/°C 950 1000 1030 1050 1060 1090 1120
Tempering temperature/°C 600°C x 1.5h x 2 times, air-cooled
Ak/(J/cm2) longitudinal 37 37 37 35 40 33 31
crosswise / / 15 25 16 / /

 

Figure 4 - Impact toughness and fracture toughness at room temperature and high temperature

Grades Hardness (HRC) Impact toughness

Room fracture toughness

KIC(MPa√m)

Room

20°C

300°C 600°C 650°C 700°C
HM1 48~48.3 12.3 19.9 28.4 29.2 27.4 29.5
3Cr2W8V 48.8~49.1 13.0 21.3 25.0 27.4 26.1 32.7

 

Coefficient of thermal conductivity : λ W/(m·K)

Temperature °C 100 400 480 570 670
λ 31.8 30.9 31.8 31.8 31.8

 

Coefficient of linear expansion : α(mm/(mm·°C))

Temperature °C 20~100 20~200 20~300 20~400 20~500 20~600 20~700
Αx 10-6 10.40 12.80 12.90 12.80 12.70 12.30 12.70