I. General requirements for materials used in forging.
1. The chemical composition meets the requirements.
2. Smelting, casting, rolling, forging, cleaning and other production processes meet the requirements.
3. The surface quality meets the requirements, and there are no scratches, scales, folds, cracks and other defects (or the degree of defects is within the allowable range). The defects shall be removed. Sometimes it is necessary to peel the surface completely.
4. The structured state meets the requirements, and there is no uneven structure, overheated structure, slag inclusion, porosity, white spots and other internal defects.
II. Test of materials used in forging
Materials used in forging before leaving the factory, the forging parts manufacturer shall generally carry out an inspection to supply qualified products, but the forging factory as the user shall also carry out necessary inspection. The inspection may be carried out by means of a general survey or spot check. The inspection items can be determined according to the types of materials used in forging and the use requirements of forging.
1. Check the chemical composition by sampling. Spark identification, magnetic induction and spectral analysis were used to check whether the materials were mixed.
2. Visual inspection to determine whether there are defects on the surface, the degree of defects and decarburization.
3. Check whether materials used in forming meet the requirements of dimension and shape tolerance.
4. Check the shrinkage and white spots in materials used in forging by fracture test; check the thermal brittleness of materials used in forging by thermal fracture test.