Oil casing pipe preparation and heat treatment technology

Petroleum casing pipe preparation and heat treatment technology:

27MnCrV is a new steel grade for the production of TP110T steel grade oil pipe casings. The conventional steel grades for the production of TP110T steel grade oil pipe casings are 29CrMo44 and 26CrMo4. Compared with the latter two, 27MnCrV contains less Mo element, which can greatly reduce production costs. However, after using the normal austenitizing quenching process to produce 27MnCrV, there is obvious high-temperature temper brittleness, resulting in low impact toughness and instability.

Two methods are usually used to solve such problems: one is to use rapid cooling after tempering to avoid high-temperature brittleness and obtain toughness. The second is the sub-temperature quenching method, which effectively improves harmful elements and impurities and improves toughness through incomplete austenitization of steel. The first method has relatively strict requirements on heat treatment equipment and requires additional costs.

After the oil casing adopts this heat treatment method, it can effectively improve the impact toughness, tensile strength, damage resistance, etc. of the oil casing, ensuring good value in use.

Oil casing is a necessary pipe material for drilling oil and natural gas, and it must have good performance during use. Petroleum casing uses different temperature controls in different temperature sections. Heating needs to be produced according to a certain temperature. AC1=736℃, AC3=810℃ for 27MnCrV steel. After quenching, the temperature selected for tempering is 630℃, and the tempering heating holding time is The heating temperature during 50min sub-temperature quenching is selected between 740-810℃. The heating temperature for sub-temperature quenching is 780°C, and the holding time for quenching heating is 15 minutes. Since sub-temperature quenching is heated in the α + γ two-phase region, quenching is performed while preserving partially undissolved ferrite. This maintains high strength and improves toughness. .

At the same time, low-temperature quenching is lower than the conventional temperature, which reduces the quenching stress and thereby reduces the quenching deformation. This ensures the smooth operation of the production of oil casing heat treatment and provides good raw materials for subsequent wire processing. 

At present, this process has been applied in pipe processing plants of different steel pipes. The quality assurance data shows that the tensile strength of the heat-treated steel pipe is Rm910-940MPa, the yield strength is Rt0.6820-860MPa, and the damage resistance is 100% qualified. The impact toughness Akv65-85J data indicates that, 27MnCrV steel pipe is already a very high-quality high-grade petroleum 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.

The heat treatment of oil casing needs to be strictly implemented to ensure that the produced oil casing has good product quality and performance, shows good use value and performance during use, and maintains high strength and toughness.

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