First, the characteristics of high chromium cast iron
High chromium cast iron is a kind of cast iron with high chromium content. Due to the addition of chromium, high chromium cast iron has excellent wear resistance, corrosion resistance and high temperature properties, and is widely used in machinery manufacturing, pump manufacturing, mining machinery and other fields.
2. Heat treatment method of high chromium cast iron
For the heat treatment method of high chromium cast iron, different ways such as normalizing, quenching and tempering are usually used to optimize the hardness and strength of the material.
1. Normalize
The positive heat treatment method is to repeatedly heat high chromium cast iron at a high temperature of about 500℃ to achieve the quenching effect of the material. Normalizing can improve the strength and hardness of high chromium cast iron, but also lead to increased brittleness of the material.
Step 2 Quench
Quenching is the treatment of high chromium cast iron in a tank containing coolant to achieve the hardness and strength of the material. The quenching temperature is generally between 800 and 980 ° C, and too fast cooling should be avoided to avoid cracks in the material.
3. Temper
Tempering is after quenching treatment, and then the high chromium cast iron is again placed at a certain temperature for heat treatment, in order to reduce the hardness of the material, while improving its toughness and ductility. The general temperature of tempering treatment is 280 ~ 520℃, and the time is about 1 ~ 3 hours.
Third, the influence of different heat treatment methods on high chromium cast iron
Different heat treatment methods have different effects. Due to the high chromium content, high chromium cast iron is prone to chromization in the treatment process, which affects the properties of the material. Therefore, before heat treatment, the appropriate treatment temperature and time should be selected to minimize the impact of chromatization on material properties.
Normalizing treatment can improve the hardness and strength of the material, but it will also affect its toughness and ductility, and it is easy to crack and other problems. Quenching treatment can improve the hardness and strength of the material, and maintain its excellent wear resistance and corrosion resistance; After tempering, the hardness of the material is reduced, the toughness and ductility are improved, but at the same time, the wear resistance and corrosion resistance of the material are also reduced.
Iv. Summary
The characteristics of high chromium cast iron determine that it needs to pay attention to the occurrence of chromic phenomenon in the heat treatment process, and choose the appropriate heat treatment method. Different treatments, such as normalizing, quenching and tempering, determine the hardness, toughness, ductility, wear resistance and corrosion resistance of the material. In the process of use, it is necessary to choose the appropriate heat treatment method according to the specific application scenario to ensure the excellent performance of high chromium cast iron materials.
