30CrMo steel bar has high strength and toughness, the hardenability is higher, the thermal strength of 30CrMo steel bar is also good, and the strength of the ℃ under 500 is high, but the intensity of the 550 ℃ is significantly decreased. When the alloying element in the lower limit welding is good, but close to the time of welding medium, and before the welding needs to preheat to 175 ℃ above The 30CrMo steel bar machinability is good, the plasticity is medium during cold deformation, the first type of temper embrittlement is 300~350℃ in the range of heat treatment, and the tendency of forming white spots.
30crmo Chemical composition：
C：0.26～0.34
Si：0.17～0.37
Mn：0.40～0.70
Cr：0.80～1.10
Mo：0.15～0.25
P：≤0.035
S：≤0.035
Ni：≤0.030
Cu：≤0.030
Specimen blank Size (mm): 25
Heat：
First quenching heating temperature (℃): 880; coolant: water, oil
Second quenching heating temperature (℃):-
Tempering heating temperature (℃): 540; coolant: water, oil
Tensile strength (Σb/mpa): ≥930
Yield Point (Σs/mpa): ≥785
Elongation rate (δ5/%): ≥12
Sectional shrinkage Rate (ψ/%): ≥50
Impact absorbing Power (aku2/j): ≥63
Brinell hardness (hbs100/3000) (annealing or high-temperature tempering status): ≤229
Annealing annealing No. 1 "760±10℃ annealing, furnace cold to 400 ℃ air-cooled.
hb220-230
Positive fire normalize No. 4 860±10℃ is fire, the air is cold.
