Causes of fracture failure defects and their preventive measures about the heat treatment of the plunger pump head by high-frequency induction quenching equipment

The plunger pump head body has to withstand huge friction during operation, so it needs to be quenched to improve its wear resistance. For the quenching of workpieces, high-frequency induction quenching equipment is commonly used nowadays. During the quenching process, the workpiece is affected by many factors and will produce quenching defects, among which fracture failure is one of the common defects. Today, we will analyze the causes of this defect and what are the preventive measures?

The reasons for the fracture and failure of the plunger pump head body are as follows:

(1) The pump head body is made of 42CrMo steel, which is large in size and is a large forging. In smelting and steel ingot forming, component segregation is prone to occur. In forging, the forging ratio is insufficient and component segregation cannot be eliminated, resulting in the initiation and expansion of cracks in weak areas with poor performance.

(2) The heat treatment quality is low and does not meet the technical requirements. The strength, toughness and plasticity of the parts are low, and induction quenching cracks appear in the defective areas, which causes cracks to initiate and extend preferentially in the weakest areas.

(3) The surface processing quality of the pump head body is poor, with rough knife marks, rough processing on the arc transition surface, and shallow groove-like transition wiring. These all cause stress concentration and accelerate the generation and expansion of cracks.

(4) Improper forging ratio, the combined effects of high-temperature heating by induction quenching and component segregation result in uneven grains, mixed crystals, and coarse grains that are highly brittle and prone to crack initiation and expansion.

In order to prevent cracks and fracture defects in the pump head body, the improved processes and methods are proposed as follows:

(1) The pump head body is large in size, has complex stresses, and has poor heat treatment performance. Therefore, the material performance and quality can be improved by optimizing the steel material.

(2) Improve cutting quality, reduce stress concentration, and help reduce fatigue crack initiation and back extension.

(3) Strict heat treatment process to prevent overheating. Improve the quenching process, such as using isothermal induction quenching, to prevent quenching cracks caused by large thermal stress and structural stress during carburizing and quenching, and quenching cracks turn black due to high-temperature oxidation. There is a corrosion expansion morphology in the main crack area. Qualified heat treatment can help improve the strength and toughness of parts and prevent the occurrence and development of quenching cracks.

(4) Increase the forging ratio, improve the quality of forgings, and eliminate component segregation remaining in metallurgy. Add homogenization annealing and normalizing treatment to eliminate structural segregation and mixed crystal phenomena.

(5) Severe segregation occurs during forging, and homogenization annealing and normalizing treatments should be added to eliminate structural segregation and mixed crystal phenomena.

Zhengzhou Gou's is a manufacturer specializing in the production and sales of high-frequency induction annealing equipment. The equipment it produces has complete functions, simple operation, and is popular at home and abroad. With many years of experience in the industry, we have a good understanding of the heat treatment of workpieces. If you want to know more about workpiece quenching, please call us for consultation.