The influence of forging on the microstructure and properties of metal
Forging defects include surface defects and internal defects.Some forging defects will affect the processing quality of the subsequent process, while others seriously affect the performance of the forging, reduce the service life of the finished products, and even endanger the safety. Therefore, in order to improve the quality of forgings and avoid defects of forgings, corresponding technological measures should be taken and quality control of the whole production process should be strengthened.
In forging production, in order to ensure that the forgings to the required shape and size, must satisfy the performance requirements of the parts in the process of using the proposed, of which mainly includes: strength index, plasticity index, impact toughness, fatigue strength, and stress corrosion resistance, etc., for the work of high temperature parts, and high temperature tensile properties of instantaneous and durable performance, and thermal fatigue properties, etc.
The raw materials for forging are casting, rolling, extrusion and forging.In forging production, the following aspects can be adopted to improve the organization and performance of raw materials with reasonable process and process parameters:
lBreak the columnar crystal, improve the macroscopic segregation, change the as-cast structure into forged structure, and weld the internal pores under appropriate temperature and stress conditions to improve the density of the material;
lAfter forging the ingot, the fiber structure is formed, and the forgings are arranged in a reasonable direction through rolling, extrusion and die forging.
lControl the size and evenness of grain;
lImprove the distribution of the second phase;
lMake the tissue get deformation strengthening or deformation strengthening, etc.
As a result of the improvement of the above structure, the plasticity, impact toughness, fatigue strength and durability of the forging are also improved, and then through the final heat treatment of the parts can get the parts required hardness, strength and plasticity and other good comprehensive performance.
If the quality of the raw materials is poor or the forging process used is not reasonable, forging defects may occur, including surface defects, internal defects or performance disqualification. Good quality of raw materials is the prerequisite to ensure the quality of forgings. Defects in raw materials will affect the forming process of forgings and the final quality of forgings.
Influence of raw materials on forging quality