After the oil casing
adopts this heat treatment method, it can effectively improve the impact toughness, tensile strength, and anti-destruction performance of the oil casing, ensuring a good value in use. Oil casing is a necessary pipe for drilling oil and natural gas, and it must have good performance in use. Different temperature controls are used for oil casing in different temperature ranges. The heating needs to be produced according to a certain temperature. The AC1=736°C and AC3=810°C of 27MnCrV steel should be selected for tempering after quenching. The holding time is 50 minutes; the heating temperature is selected between 740 and 810°C during sub-temperature quenching. The heating temperature for sub-temperature quenching is 780°C, and the holding time for quenching and heating is 15 minutes. Since sub-temperature quenching is heated in the α+γ two-phase region, the quenching is carried out under the condition of keeping local undissolved ferrite. While maintaining high strength, the toughness is improved. 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, and conduct heat treatment in different ways . At the same time, low-temperature quenching is lower than the conventional temperature, which reduces the stress of quenching and the deformation of quenching. This ensures the smooth operation of the production of oil casing heat treatment and provides a good foundation for subsequent wire processing. raw material.
At present, this process has been applied in different steel pipe processing plants. 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.