Ⅰ. The reason why the carbon content of stainless steel castings is too high
In the process of producing stainless steel castings, the control of carbon content is difficult to master, because too much carbon content will have a certain impact on product quality. This article will analyze the reasons for the high carbon content of stainless steel castings. , let's find out together.
1. Unreasonable pouring conditions for stainless steel castings
If the setting of the pouring and filling process is too long, the temperature of the molten steel during the pouring process is low, especially for the position where the wall thickness of the stainless steel casting increases, the solidification rate of the molten steel is slow, resulting in a long liquid-solid residence time, prompting The action time of the molten steel and the thermal decomposition products of the pattern increases, and the carburization and carbon deposition of the stainless steel castings are increased.
2. The carbon content of stainless steel castings is strictly controlled
The carbon content in the production smelting ingredients is not strictly controlled, especially the carbon content in various scrap steels and whether there are other alloying materials in various scrap steels are unknown.
3. The setting of the gating system for stainless steel castings is unreasonable
In particular, the unreasonable configuration of the vacuum pumping system and the casting sand box or the casting process of the stainless steel castings causes the vacuum degree in the casting sand box to vary, the deviation is too large, or the actual vacuum degree is insufficient during the pouring process of the stainless steel castings. The pressure gauge shows an incorrect value that meets the requirements of the technical parameters, so that the thermal decomposition products of the pattern cannot be quickly and quickly discharged from the casting cavity, resulting in carburization or carbon deposition of the casting components.
The reasons for the high carbon content of stainless steel castings have been analyzed above. Therefore, we should pay attention to controlling these three aspects in the future production process to improve product quality.
Ⅱ. Selection formula for surface cleaning of stainless steel castings
What kinds of formulas are used for surface cleaning of stainless steel castings? How to choose? The cleaning of stainless steel 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, cleaning agents include solvent-based cleaning solutions (there are two types of petroleum solvents and organic solvents, which are not widely used) and water-based cleaning solutions (there are alkaline cleaning agents). and surface active agent, etc.), in the actual cleaning process of heat-treated stainless steel castings, the most used are: 3%-10% sodium carbonate or sodium hydroxide cleaning solution, the temperature is controlled at 80-100 ℃, mostly used for quenching Degreasing and salt slag finishing of post-stainless steel castings.