Moulds are the basic process equipment for machinery in […]
Moulds are the basic process equipment for machinery industry production and indispensable tools in the production of industrial products. The performance of molds made of mold steel needs to pass strict production process supervision, and the raw materials for the production of molds must be strictly checked Prevent defects such as heat treatment cracking caused by early failure of the mold due to material problems.
The control of the raw materials of the mold is carried out from the following aspects:
1. Macro inspection
The chemical composition is decisive for ensuring the performance of the steel, but the composition is qualified and cannot fully describe the performance of the steel. Due to the unevenness of the internal organization and composition of the steel, the macroscopic inspection largely supplements this deficiency.
Macro inspection can observe the crystallization of steel, the continuity of steel and the non-uniformity of certain components.
Standard "Structure Steel's Low-power Microstructure Defect Rating Chart" GB1979
There are 8 common defects in the macro: segregation, looseness, inclusions, shrinkage holes, bubbles, white spots, cracks, and folding.
2.1 Evaluation of annealing structure
The purpose of annealing is to reduce the hardness of the steel and facilitate machining, as well as to prepare for the subsequent heat treatment.
The annealed structure of carbon tool steel shall be evaluated according to the first grade rating chart of GB1298.
2.2, Carbide unevenness
Cr12 type of austenite steel contains a large amount of eutectic carbides in the structure. The non-uniformity of carbides has a very important effect on serviceability, so the distribution of carbides must be strictly controlled.
All in all, because the production objects of the mold production plant and workshop are relatively cumbersome, and they are more or less single pieces and small batches, which brings certain difficulties to the establishment and management of mold production quotas, plus the production methods of various factories and workshops, The equipment and technical qualities are not the same, so when formulating quotas, it is necessary to find appropriate methods according to the actual conditions of the factory and the workshop to work out advanced and reasonable quotas for working hours to improve labor productivity.
