After the oil casing adopts this heat treatment method, the impact toughness, tensile strength, and anti-destruction performance of the oil casing can be effectively improved, and the good value in use can be guaranteed. Oil casing is a necessary pipe for drilling oil and natural gas, and it needs to have good performance in use. Different temperature controls are used for oil casing in different temperature sections. The heating needs to be produced according to a certain temperature. AC1=736℃, AC3=810℃ of 27MnCrV steel. After quenching, the tempering temperature should be 630℃, and tempering heating The holding time is 50 minutes; the heating temperature is selected between 740 and 810 °C during sub-temperature quenching. The sub-temperature quenching selects the heating temperature of 780 °C, and the quenching heating holding time is 15 minutes. Because the sub-temperature quenching is heated in the α+γ two-phase region, the quenching is carried out in the state of local undissolved ferrite, and while maintaining high strength, the toughness is obtained. improve.
The heat treatment of oil casing must be strictly implemented to ensure that the produced oil casing has excellent product quality and performance, and can show good use value and performance in use. Adhere to high strength and toughness, heat treatment in different ways. At the same time, the low-temperature quenching is lower than the conventional temperature, which reduces the stress of quenching and reduces the deformation of quenching, which ensures the smooth operation of the production of oil casing heat treatment and provides a good solution for subsequent wire processing. raw material.
At present, this process has been applied in the pipe processing plants of different steel pipes. The quality assurance data shows that the tensile strength of the steel pipe after heat treatment is Rm910-940MPa, the yield strength Rt0.6820-860MPa is 100% qualified, and the impact toughness Akv65-85J data indicates that 27MnCrV steel pipe is already a very high-quality high-grade steel oil casing. On the other hand, it also shows that the sub-temperature quenching process is an excellent method to avoid high-temperature brittleness in the production of steel products.