API petroleum casing, is a kind of pipeline to transport oil and other raw materials, for API petroleum casing technical requirements are also quite strict, which is the most stringent requirements of the temperature, the requirements of each processing stage has the corresponding temperature, such as 27MnCrV steel AC1 corresponding to the temperature of 736 degrees Celsius, sub-temperature quenching heating temperature should be controlled at 740 - 810 degrees Celsius, to ensure that sub-temperature quenching temperature at 780 degrees, to ensure that the heating time is more than 15 minutes; API petroleum casing after quenching temperature should be controlled at 630 degrees volatility. 810 degrees Celsius, to ensure that the sub-temperature quenching temperature of 780 degrees, to ensure that the heating time of more than 15 minutes; API petroleum casing in the quenching after the volatile temperature should be controlled at 630 degrees, control the tempering time should be more than 50 minutes. If you want to improve the toughness of API petroleum casing, then the heating temperature should be controlled between α + γ, the requirement of retaining part of the dissolved ferrite state of API petroleum casing quenching treatment. Therefore, API petroleum casing heat treatment using sub-temperature quenching can better API petroleum casing tensile strength, and improve the API petroleum casing impact toughness and resistance to destruction performance.
In the process of heat treatment of API casing should be strictly controlled, so as to ensure the quality of API casing, to ensure that in the use of the process of super toughness and other performance.API casing using low-temperature quenching processing method can reduce the quenching of the stress changes, usually this low-temperature quenching temperature than the room temperature is low, so in the quenching is not easy to lead to API casing. Usually this low-temperature quenching temperature is lower than the normal temperature, so it is not easy to cause deformation of API petroleum casing during quenching, and this processing method not only ensures the normal production, but also provides raw materials for the future wire turning process.
