Strengthening and Heat Treatment of ERW Casing

The use of normal austenite quenching process to produce 27MnCrV after the existence of significant high temperature temper brittleness, resulting in low impact toughness and instability. To solve such problems are usually handled in two ways: First, the use of rapid cooling after tempering method to avoid high temperature brittleness, access to toughness. And second, sub-temperature quenching method through the steel is not fully austenitized to effectively improve the harmful elements and impurities, improve toughness. The first method, the heat treatment equipment requirements are relatively strict, need to add additional costs.

27MnCrV steel AC1 = 736 , AC3 = 810 , sub-temperature quenching heating temperature between 740-810  selected. Sub-temperature quenching selection heating temperature 780 , quenching and heating time of 15min; quenching after tempering selection temperature 630 , tempering heating holding time 50min. As the sub-temperature quenching in the α + γ two-phase zone heating, in the part of the undissolved ferrite state to be quenched, while maintaining a high strength, the toughness is improved.

At the same time, low temperature quenching is lower than conventional temperature, which reduces the stress of quenching, thus reducing the deformation of quenching, which ensures the smooth operation of heat treatment production, and provides a good raw material for subsequent wire processing.

At present, the process has been applied in the tube processing plant. The quality assurance data show that the yield strength of the steel pipe after heat treatment Rt0.6 is 820-860MPa, the tensile strength Rm is 910-940MPa, the impact toughness Akv is between 65-85J, 100% qualified. Data show that 27MnCrV steel pipe is a very high quality high-grade steel erw casing, on the other hand also shows that the sub-temperature quenching process is the production of steel products to avoid high temperature brittleness when an excellent way. The erw casing is a large diameter pipe that acts as a fixed oil and gas well wall or wellbore. The casing is inserted into the wellbore and fixed with cement to prevent the wellbore from separating the formation and the borehole from collapsing and ensuring that the drilling mud circulates in order to facilitate drilling. The different types of bushings used in the oil extraction process are to protect the casing from the shallow and shallow layers and to support the wellhead and maintain the other layers of the casing. The technical erw casing divides the pressure at different levels so that the drilling fluid is normally circulated and protects the production casing and installs the anti-bursting device, the leak-proof device and the tail pipe in the drilling.