30CrMoA Round Steel, 30CrMoA Alloy Steel

30CrMo Round Steel BarHigh strength and toughness, good hardenability, critical quenching diameter in oil of 15-70mm; the steel also exhibits good thermal strength, maintaining sufficient high-temperature strength below 500℃, but its strength significantly decreases at 550℃; welding is excellent at the lower limit of alloy elements, moderate near the upper limit, and requires preheating to above 175℃ before welding; the steel has good machinability, with moderate plasticity during cold deformation; there is a first-class temper brittleness in the range of 300-350℃ during heat treatment; a tendency to form white spots. The 30CrMo round steel is typically used in tempered condition, and steel with carbon content at the lower limit can also be used as carburizing steel with high core strength. It is mainly used in medium-sized machinery manufacturing for the production of tempered parts with large cross-sections and operating under high-stress conditions, such as shafts, main shafts, high-load operating wheels, bolts, studs, gears, etc.; in the chemical industry, it is used to manufacture welded components, structures made of plates and tubes, and high-pressure conduits working in nitrogen-hydrogen media at temperatures not exceeding 250℃; in the turbine and boiler manufacturing industries, it is used to produce fasteners for work below 450℃, flanges and nuts under high pressure below 500℃, particularly suitable for conduits working at 300 atmospheres and below 400℃.

Chemical composition of 30CrMo round steel:

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

30CrMo Round Steel Mechanical Properties:

Trial blank size(mm)：25

Heat Treatment:

First quenching heating temperature (℃): 880; coolant: water, oil

Dier second quenching heating temperature(-℃): Annealing heating temperature (-℃): 540; Cooling medium: Water, Oil

Tensile strength(σb/MPa)：≥930

Yield point(σs/MPa)：≥785

Ultimate elongation(δ5/%)：≥12

Section reduction rate(ψ/%)：≥50

Impact Absorption Work(Aku2/J)：≥63

Bushing hardness(HBS100/3000) (Annealed or High Temperature Quenching Condition) ≤229