August 29, 2019
After adopting this heat treatment method, the casing pipe can effectively improve the impact toughness, tensile strength and anti-destructive performance of the casing pipe, and ensure the good value in use. Casing is a common pipe for drilling oil and natural gas, and it needs to have good performance in use. The casing pipe is controlled by different temperature in different temperature zones. The heating needs to be produced according to a certain temperature. The AC1=736 °C of the K55 oil casing material steel, AC3=810 °C, and the tempering temperature after quenching is 630 ° C. The heating temperature of the fire is 50 min. The heating temperature is selected between 740-810°C during quenching. The sub-temperature quenching selects the heating temperature of 780°C, and the holding time of the quenching heating is 15 min. The sub-temperature quenching is heated in the α + γ two-phase region, and the local undissolved ferrite is quenched in the state, and the toughness is also maintained while maintaining the high strength. improve.
In order to improve the mechanical properties of the casing pipe rail and the wear resistance of the rail head, the full-length quenching of the rail head is beneficial to water quenching of the rail head after the rail rolling, and then by CH fire. After the rail is cooled, the end of the rail is rapidly heated to 880-920X by off-line high frequency, and then water quenched. After 50-480tc, the waste heat is self-tempered; after printing variable frequency induction heating, the rail end is rapidly heated to 880-920x by high frequency induction.
The heat treatment of the API 5ct casing pipe needs to be strictly enforced to ensure that the produced oil casing has good product quality and performance, exhibits good use value and performance in use, adheres to high strength and toughness, and performs heat treatment in different ways.
At the same time, the low temperature quenching is lower than the conventional temperature, which reduces the quenching stress, thereby reducing the quenching deformation, thus ensuring the smooth operation of the oil casing heat treatment production, and providing a good raw material for the subsequent wire processing and the like. .
The quality assurance data shows that the tensile strength of the oil casing after heat treatment Rm910-940MPa yield strength Rt0.6820-860MPa is 100% qualified, and the impact toughness Akv65-85J data It is indicated that the K55 casing pipe is a high-quality steel casing with relatively good quality. On the other hand, it also shows that the sub-temperature quenching process is an effective method to avoid high-temperature brittleness in the production of steel products.