Process design of check valves

(1) The quality control of the main blank: All parts of this valve are forgings, and forging is strictly carried out in accordance with the forging process specifications and process cards. The starting and ending forging temperatures, deformation degree, and deformation speed are strictly controlled, and cooling is carried out according to the cooling method specified in the process specifications. Chemical composition analysis, mechanical performance testing, intergranular corrosion testing, and metallographic structure analysis were conducted on forged products, and after analysis, testing, and measurement, they all met the corresponding standards.

The quality of forgings is ensured through ultrasonic inspection and liquid penetrant inspection. According to the requirements of RCC-M, 100% ultrasonic testing and evaluation are carried out on forgings, and liquid penetrant inspection and evaluation are carried out on all surfaces of forgings.

(2) In order to improve the welding quality, plasma argon arc welding technology is used for the welding of the sealing surfaces of the valve disc and valve seat. At the same time, to ensure welding quality, the welding processes used in production have been re evaluated.

(3) Assembly testing of high-quality products not only requires high-precision components, but more importantly, how to assemble these high-precision components into high-performance products. CNNC Suvalve has organized an experienced and technically proficient assembly and debugging team composed of multiple technicians and senior technicians, responsible for the assembly, debugging, and testing of valves. They have formulated cleaning and assembly processes for components, strictly control and strive for excellence in assembly and debugging, ensuring the successful assembly and debugging of valves. Various performance tests have been conducted, and all indicators meet the requirements of the design task book.

(4) Process inspection has developed a quality plan for valves to ensure quality control from raw materials, raw material input, machining, welding, heat treatment, non-destructive testing, cleaning, assembly, factory testing, and various type tests, and has been recognized and witnessed on site by the Second Research and Design Institute of the Nuclear Industry.