The effect of quenching at 890 ~ 780 °C on transverse impact energy of steel 27MnCrV (% : 0. 24C - 0. 30C

0. 50 ~0. 70Cr

0. 06 ~0. 10V) for petroleum casing pipe tempered at 630 °C has been tested and studied. Results show that with decreasing the quenching temperature

the transverse*V- notch impact energy increases obviously ； with insuring non-decreasing tensile strength of steel

the minimum transverse impact energy increases to 66 J by quenching at 820 °C + tempering at 630 °C from 35 J by quenching at 890 °C+ tempering at 630 °C. The optimum heat treatment process of steel 27MnCrV is water quenching at 830 °C ± 10°C + tempering at 630 °C air cooling

its tensile strength is 847 〜860 MPa

Yield strength is 922 -930 MPa and impact energy is 57 ~66 J to meet the requirement of standard.