Causes of Fracture Lost Wax Castings
There are thousands of types of steel used in various i […]
There are thousands of types of steel used in various industries. Each steel has a different trade name due to different properties, chemical composition or alloy type and content. Although fracture toughness values greatly facilitate the selection of each steel, these parameters are difficult to apply to all steels.
The main reasons are:
First, because a certain amount of one or more alloying elements need to be added during the smelting of the steel, different microstructures can be obtained by simple heat treatment after the material is formed, thereby changing the original properties of the steel;
Second, because the defects generated during steelmaking and pouring, especially concentrated defects (such as porosity, inclusions, etc.) are extremely sensitive during rolling, and between different furnaces of the same chemical steel, even between Different changes occur in different parts, which affects the quality of steel.
Because the toughness of steel mainly depends on the degree of microstructure and the dispersion of defects (to prevent concentrated defects), not the chemical composition. Therefore, the toughness will change greatly after heat treatment. To deeply investigate the properties of steel and the reasons for fracture, it is necessary to master the relationship between physical metallurgy and microstructure and toughness of steel.