Manufacturing method for steel forging used for critical component of deep sea Christmas tree

Abstract

The invention discloses a manufacturing method for a steel forging used for a critical component of a deep sea Christmas tree. The manufacturing method comprises the following steps that 1, F22 alloy steel and Fe-Ga intermediate alloy serve as the raw materials and are smelted to be high-quality molten steel in a medium frequency electric furnace; 2, liquid die forging is conducted on a hydraulic press, demolding is conducted at the temperature of about 1200 DEG C, a blank is forged through the forging mode that free forging and restrained forging are composited, and thus a secondary forging blank is obtained; 3, quenching heat treatment is conducted on the secondary forging blank through the mode that water cooling and air cooling are cycled and alternated for two times; and 4, secondary tempering treatment is conducted on the quenched secondary forging blank through the steps of tempering, water cooling, re-tempering and re-water-cooling, so that the steel forging used for the critical component of the deep sea Christmas tree is obtained. According to the manufacturing method for the steel forging used for the critical component of the deep sea Christmas tree, quenching cracks of the complex-shaped large forging is effectively prevented by combining the forging process with the heat treatment process; in addition, the comprehensive mechanical property, especially the low-temperature toughness of the manufactured steel forging used for the critical component of the deep sea Christmas tree is substantially improved, and the steel forging can be well applied to a deep sea low-temperature working condition environment.

Description

technical field [0001] The invention relates to a method for manufacturing a steel forging for key parts of a deep-sea oil tree, belonging to the field of metal forging and heat treatment. Background technique [0002] The development capability of offshore oil and gas resources is determined by the advanced nature of offshore oil and gas development equipment. The development of offshore oil and gas exploration and development equipment with my country's independent intellectual property rights is an effective way to promote technological development and ensure my country's energy security. my country's oil drilling and production equipment manufacturing enterprises have accumulated rich experience in the development of land equipment for decades, which has laid a foundation for the design and manufacture of offshore oil and water equipment, and has realized the localization of some equipment. However, at present, the localization and use of some offshore oil drilling and p...

AI Technical Summary

Problems solved by technology

However, when F22 is processed by conventional forging methods, it will be difficult to forge through. Some as-cast metallurgical defects, such as segregation, porosity, and shrinkage cavities, will remain in the forging to varying degrees, which will cause greater stress in the forging during heat treatment. Concentration often leads to cracking of forgings during heat treatment or during placement after heat treatment, or reduces the effective life of parts in service due to the existence of internal stress

In addition, in terms of performance, it is also difficult to meet the low-temperature toughness and high-low temperature fatigue strength required for deep-sea oil tree steel.

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