How to check the quality of forgings?

In the heat treatment of forgings, heat treatment stress is an important consideration in the process of making process, some stress is generated in the heating and cooling process, disappear with the end of these processes, this is instantaneous stress; Some stresses are equilibrium stresses that still exist in the forging after the heat treatment, and this is the residual stress.
In the process of heat treatment, if the instantaneous stress produced reaches the yield point of the material at the temperature, the forging will produce plastic deformation, so that the stress relaxation. If the instantaneous stress is greater than the breaking strength of the material, it is possible to make the forging crack, until fracture.
Even if the instantaneous stress is less than the strength limit of the material, because there are always some metallurgical defects in the large forgings, there is a great stress concentration in these defects, to make the original defects further expand, and even cause the fracture of the forgings. So it is an important problem to control the instantaneous stress of heavy forging heat treatment process.
Heat treatment residual stress has a dual effect on the workpiece, which has good and bad effects. If the residual stress is identical with the working stress symbol of the part, the strength of the part can be reduced, if the opposite, the strength of the part will be increased. For some important large forgings, the allowable participating stress should be less than 10% of the material yield point.
In order to ensure the quality of forgings and improve the performance and service life of products, in addition to the production process to check the quality of forgings at any time, the forgings must also be checked by full-time personnel before storage.
Forgings inspection includes: forgings geometry and size, surface quality, internal quality, mechanical properties and chemical composition and other aspects, and each aspect contains a number of content.
The specific inspection items and requirements for forgings shall be determined according to the importance level of forgings. The grade of forgings is divided according to the force of parts, working conditions, important degree, material type and metallurgical process, the classification of forgings grade of various industrial departments is not the same, some forgings are divided into three grades, some are divided into four or five grades.
After the production of forgings, must be inspected, so as to further ensure the quality of forgings.