Factors affecting heat treatment processing of forgings

Factors affecting heat treatment processing of forgings

In forging production, in addition to ensuring the required shape and size of the forging, it is also necessary to meet the performance requirements of the parts during use. By adopting reasonable forging processes and process parameters, the microstructure and properties of the workpiece can be improved through heat treatment technology

The influence of forging structure on the structure and properties after heat treatment processing is mainly manifested in the following aspects: (1) Unmodifiable structural defects: materials such as austenitic and ferritic heat-resistant stainless steel, high-temperature alloys, aluminum alloys, magnesium alloys, etc. that do not undergo allosteric transformation during heating and cooling, as well as some copper alloys and titanium alloys, etc., whose structural defects generated during forging cannot be improved by heat treatment processing. (2) Organizational defects that can be improved: coarse grains and Weibull structure in generally overheated structural steel forgings, slight network carbides caused by improper cooling in hypereutectoid steel and bearing steel, etc. can still achieve satisfactory organization and properties after forging heat treatment processing. (3) Organizational defects that are difficult to eliminate through normal heat treatment processing, such as low magnification coarse grains, 9Cr18 stainless steel, H13 twin carbides, etc., require measures such as high-temperature normalizing, repeated normalizing, low-temperature decomposition, and high-temperature diffusion annealing to be improved.

(4) Organizational defects that cannot be eliminated by general heat treatment processing techniques: severe stone like and angular fractures, overburning, ferrite bands in stainless steel, carbide mesh and bands in martensitic alloy tool steel, etc., which result in a decrease in the performance of forged parts after heat treatment processing, and even unqualified. (5) Organizational defects that will further develop during heat treatment processing: for example, the coarse grain structure in alloy structural steel forgings, if not improved during post forging heat treatment processing, often leads to coarse martensite needles and poor performance after carbon and nitrogen co diffusion and quenching; The coarse banded carbides in high-speed steel often cause cracking during quenching.

(6) If heated improperly, such as at too high a temperature or for too long, it can cause defects such as decarburization, overheating, and overburning.

(7) During the cooling process after forging, improper processing may cause cooling cracks, white spots, etc., which may crack during the heat treatment process.

The above is the factors that affect the heat treatment processing of forgings shared by Forever Electromechanical Factory based on years of practical experience in the production of heat treatment equipment. If you want to learn more about induction heat treatment equipment, please follow Forever Electromechanical Factory's website for detailed information.