Gear Steel: 18CrMnMoB
● Features and Scope:
Nickel-free, large forgings containing low chromium steel, hardenability good, on the strength of a large cross-section stability, better forging, welding and cutting, such as process performance, high temperature performance is also good. Below 450 ℃ of large cross-section for producing a high strength forging temperature, such as the thickness of the hub of the impeller is larger than 300mm, a diameter greater than the rotor and the spindle φ500mm welded structure; can be used for casting.
● Chemical Composition:
Carbon C: 0.17 ~ 0.23
Si Si: 0.20 ~ 0.40
Mn Mn: 1.20 ~ 1.50
Sulfur S: ≤0.030
Phosphorus P: ≤0.030
Chromium Cr: 1.50 ~ 1.80
Mo Mo: 0.45 ~ 0.55
Boron B: 0.001 ~ 0.0035
● Mechanical Properties:
Tensile strength σb (MPa):-sectional dimension of 100 to 300, 883;-sectional dimension of 300 to 500, 834;-sectional dimension of 500 to 800, 785
Yield strength σs (MPa):-sectional dimension of 100 to 300, 735; sectional dimension of> 300 to 500, 686; sectional dimension of> 500 to 800, 588
Elongation δ5 (%): 13
Reduction of ψ (%): 40
Impact toughness αkv (J / cm2): 49
Hardness:-sectional dimension of 100 to 300, 269 ~ 302HB; sectional dimension of> 300 ~ 500, 255 ~ 268HB;-sectional dimension of 500 ~ 800, 241 ~ 286HB
● Heat treatment and microstructure specifications:
Heat treatment specifications: 880 ℃ oil quenching, 500 ~ 570 ℃ tempering.