40 MNB physical properties
Chemical composition
Carbon C: 0.37 ~ 0.44
Silicon Si: 0.17 ~ 0.37
Manganese Mn: 1.10 ~ 1.40
Sulfur S: allow residual content of 0.35 or less
P P: allow residual content of 0.35 or less
Chrome Cr: allow residual content of 0.30 or less
Nickel Ni: allow residual content of 0.30 or less
Copper Cu: allow residual content of 0.30 or less
Boron B: 0.0005 ~ 0.0035
Mechanical properties
Sample blank dimensions (mm) : 25
Heat treatment:
The first quenching heating temperature (℃) : 850; Cooling agent: oil
The second quenching heating temperature (℃) : -
Tempering heating temperature (℃) : 500; Cooling agent: water, oil
Tensile strength σ b (MPa) : 980 (100) or
Yield strength σ s (MPa) : 785 (80) or
Elongation δ 5 (%) : 10 or more
Reduction of area ψ (%) : was 45
Impact work Akv (J) : 47 was
Impact toughness value α kv (J/cm2) : 59 (6) or
Brinell hardness (HBS100/3000) (annealing or high temperature tempering state) : 207 or less
【 characteristics 】
This is a kind of replace 40 cr steel relatively successful new steel grade, it has high strength, hardness, wear resistance and good toughness, its h a 40 cr is a little bit higher, in oil critical multiplying diameter of 18 ~ 33 mm; After normalizing machinability is good, cold drawn, thread rolling, tapping and forging, heat treatment process and all performance is good, high temperature grain growth, oxidation and decarbonization tendency and quenching distortion dip
Smaller to all; But there are temper brittleness, tempering stability than 40 cr steel is a bit poor.
The examples of application 】
The steel in general quenched and tempered state use, use temperature range in - 20 ~ 425 ℃, the main instead of 40 cr steel production, small cross section of quenched and tempered parts, such as automobile axle, steering shaft, worm, spline shaft and machine tool spindle, gear, etc. In addition also instead of 40 cr steel production Φ 250 ~ 320 mm hoist intermediate shaft and large cross section parts. When making the smaller sizes when parts of this steel can be used instead of 40 crni steel.
|
|
