The raw materials of the mold are controlled from the following aspects:
1. Macro inspection
The chemical composition is decisive to ensure the performance of the steel, but the qualified composition cannot fully explain the performance of the steel. Due to the inhomogeneity of the internal structure and composition of the steel, the macro inspection has largely supplemented this deficiency.
Macroscopic inspection can observe the crystallization of steel, the destruction of steel continuity and the inhomogeneity of certain components.
Standard “Defect Rating Chart of Low Power Structure of Structural Steel” GB1979
There are 8 common macroscopic defects: segregation, porosity, inclusion, shrinkage, bubbles, white spots, cracks, and folds.
2.1 Evaluation of annealing organization
The purpose of annealing is to reduce the hardness of steel, facilitate machining, and also prepare the organization for subsequent heat treatment.
The annealing structure of carbon tool steel is evaluated according to the first grade rating chart of GB1298.
2.2. Inhomogeneity of carbides
Cr12 ledeburite steel contains a large number of eutectic carbides in its structure. The unevenness of carbides has a very important impact on performance, so the distribution of carbides must be strictly controlled.
All in all, because the production objects of mold production plants and workshops are relatively cumbersome and are more or less single-piece and small batches, it brings certain difficulties to the formulation and management of mold production quotas. In addition, the production methods of various factories and workshops, The equipment and technical qualities are not the same. Therefore, when formulating the quota, it is necessary to find an appropriate method to formulate an advanced and reasonable working-hour quota according to the actual conditions of the factory and the workshop in order to increase labor productivity.