Oil casing is used not only for oil extraction but also as a pipeline for transporting raw materials. To improve the quality of oil casing, temperature control during production must be strictly adhered to. Typically, sub-critical quenching is used instead of conventional quenching. Conventional quenching leaves residual stress inside the workpiece, increasing brittleness and hindering subsequent processing. Sub-critical quenching prevents excessive brittleness from affecting subsequent processes. The main procedure involves first selecting a sub-critical quenching temperature, typically between 740-810℃, for about 15 minutes. After quenching, tempering is performed for 50 minutes at 630℃. Of course, different steels have their own specific heating temperatures and times for heat treatment; as long as the performance of the workpiece is improved, the purpose of heat treatment is achieved.
Heat treatment is the most crucial step in the processing of oil casing. The performance and quality of the finished product largely depend on the results of heat treatment. Therefore, manufacturers maintain extremely strict requirements for the heat treatment process, leaving no room for negligence. Sometimes, low-temperature quenching can be used. Low-temperature quenching effectively removes residual stress from the oil casing, reducing post-quenching deformation and shaping the casing into a more suitable raw material for subsequent processes. Therefore, the current achievements in oil casing are inseparable from heat treatment. Since the introduction of this processing step, the impact toughness, rupture resistance, and tensile strength of oil casing have all been significantly improved.
Post time: Jan-05-2026