Heat-resistant steel precision castings should be stacked reasonably according to the layout characteristics during heat treatment to prevent deformation as much as possible. When the segregation of the as-cast arrangement of the casting is serious, in order to eliminate the influence on the function of the end of the casting, a unified treatment method needs to be adopted. In the as-cast arrangement, there are often coarse dendrites and segregation. During heat treatment, the heating temperature should be slightly higher than that of forgings with the same composition, and the austenitizing holding time should be appropriately extended. For steel castings with messy shapes and large wall thicknesses, section effects and casting need to be considered during heat treatment.
The main elements of high temperature oxidation and high temperature corrosion resistance in heat-resistant steel precision castings can improve the thermal strength of heat-resistant steel. The high temperature corrosion resistance of heat-resistant steel has a certain relationship with its chromium content. Therefore, the chromium content of commonly used heat-resistant steels should not be lower than nickel, which is one of the important alloying elements in heat-resistant steels. In order to obtain the pure austenite structure of the steel at normal temperature, the nickel content is not less than 25%. However, when the steel contains other alloying elements, in order to obtain a pure austenite structure, the nickel content can be appropriately reduced.
How to clean heat-resistant steel precision castings
Heat-resistant steel precision castings are one of the castings. The cleaning of heat-resistant steel precision castings is divided into general cleaning, ultrasonic cleaning, degreasing cleaning and vacuum cleaning. They have their own characteristics, and the formulations of the cleaning solutions used are different. Generally, there are solvent-based cleaning solutions and water-based cleaning solutions.
In the actual cleaning process of heat-resistant steel precision castings, the most used ones are:
1. Metal cleaner
It is mostly used for cleaning before heat treatment and chemical heat treatment of heat-resistant steel precision castings
2.3%-10% sodium carbonate or sodium hydride cleaning solution, the temperature is controlled at 80-100°C, it is mostly used for degreasing and salt slag finishing of heat-resistant steel precision castings after quenching.
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