Steel ingot shrinkage holes In the production process of steel ingot, after all types of refining operations are completed, it is necessary to perform some special inspections on the steel ingot. Among them, the inspection work of shrinkage holes is an important one. In actual production, if the inspection information of shrinkage holes is not satisfactory, it will affect the properties and quality of steel ingot.
Shrinkage holes are cast defects that generally occur in solidified semifinished products, and they are cylindrical metallurgical defects with little shrinkage in the ingot. Under microscopic observation, it is found that the shrinkage hole mostly has a layered configuration in the radial direction. Shrinkage holes are usually spherical, elliptical, irregularly shaped and other holes. The reason why shrinkage hole defects occur is mainly due to local segregation and gas entrapment during solidification.
The metal is intensively round-shaped objects in metal. During solidification, due to liquid metal convective flow and thermal convection within metal, metal freely moves between different parts. If semi-finished products are not completely solidified due to the local temperature does not reach the solidification point, when metal is removed from this area, shrinkage holes occur.
The appearance of shrinkage holes has a certain impact on the performance of steel ingots. It is mainly reflected in the increase of strength and plasticity. For materials with high shrinkage requirement, such as assembly parts and precision parts, the requirements for shrinkage holes are stricter. In actual production, it is also necessary to increase the container type, sand inclusion size and sulfur content of the melted steel.
In the production process of steel ingot, the occurrence of shrinkage holes must be controlled. Generally, high frequency ultrasound testing will be carried out, and regular sampling and testing will be done. In terms of the interpretation method of test results, it is necessary to ensure that parameters such as offset and load are consistent. In addition, regular inspection is also conducted and recorded in accordance with the relevant regulations in order to ensure the quality of steel ingot and prevent shrinkage holes from occurring.
