Heat Treatment Technology for Industrial Oil Casing

This heat treatment method effectively improves the impact toughness, tensile strength, and rupture resistance of oil casing, ensuring its excellent performance in use. Oil casing is an essential material for drilling oil and natural gas, requiring good performance during use. Different temperature controls are used for different temperature ranges in oil casing production. For 27MnCrV steel, AC1=736℃, AC3=810℃. The tempering temperature after quenching should be 630℃, with a holding time of 50 minutes. For sub-critical quenching, the heating temperature is selected between 740 and 810℃. The sub-critical quenching temperature is 780℃, with a holding time of 15 minutes. Because sub-critical quenching is performed in the α+γ two-phase region, preserving the undissolved ferrite state, it maintains high strength while improving toughness.

Strict adherence to heat treatment procedures is essential to ensure the produced oil casing possesses excellent product quality and performance, exhibiting good value and performance during use. Maintaining high strength and toughness is crucial, and different heat treatment methods are employed. Simultaneously, low-temperature quenching, performed at lower temperatures than conventional methods, reduces quenching stress and deformation, ensuring smooth operation of the oil casing heat treatment process and providing excellent raw materials for subsequent machining processes such as threading.

Currently, this process has been applied in various steel pipe processing plants. Quality assurance data shows that the heat-treated steel pipes exhibit tensile strength Rm910-940MPa, yield strength Rt0.6820-860MPa, and 100% compliance with rupture resistance standards. Impact toughness Akv65-85J data indicate that 27MnCrV steel pipe is a high-quality, high-grade oil casing. This also demonstrates that sub-temperature quenching is an excellent method for preventing high-temperature brittleness in steel product manufacturing.