Mining Equipment Castings And Forgings High Chromium Cast Iron

Mining equipment Castings And Forgings with High Chromium Cast Iron

1. Introduction of high chromium cast iron Castings And Forgings

High chromium cast iron (chromium > 12%) is an excellent wear resistant material. In the study of high chromium cast iron, generally concentrated on Cr15, Cr20 and other high chromium cast iron. This paper analyzes the influence of ultra high chromium cast iron (chromium content > 20%), an important component of high chromium cast iron, on the changing properties of the studied microstructure with the increase of Cr content and the addition of various alloying elements.

2. Different types of high chromium cast iron each component content is different:

3. Heat treatment process of high chromium cast iron Castings And Forgings

(1) The commonly used heat treatment process of high chromium cast iron is heated to 950~1000℃, and then quenched after heat preservation and air cooling 200~260℃ low temperature tempering.

(2) High temperature pelletizing treatment 1140~1180℃ for 16h air cooling, can significantly improve the impact toughness and wear resistance. The high temperature pelletizing treatment can make all carbides spheroid, which can eliminate or reduce the separation effect of large bulk and continuous network carbides on the matrix. The carbides spheroidized by the pelletizing are supported by more uniform matrix, especially by a certain amount of austenite. If the holding time is properly reduced, the effect can also be achieved on thin section parts. The disadvantage of this process is that it consumes more heat energy.

(3) The mature process is: softening annealing after casting, easy to process, air cooling quenching and low temperature stress tempering after processing. The hardness is generally required to be HRC58-62, which is mostly used for wear-resistant and wearing parts such as slag slurry pump parts.

(4) We here is a high chromium production base, generally provide Cr24, Cr26, Cr28, Cr15Mo3, Cr26

Do high chromium grinding ball, Cr%=10.2~10.5%, C%=2.2~2.7%, Si, S double zero below, required hardness HRC> 58 We are using the quenching liquid to quench. The quenching process parameters are: 650 ℃ for 2 hours, rising to 960℃ for 3.5 hours; Tempering temperature 380~400℃, holding for 4~6 hours. Grinding ball specifications φ40-φ80. The process is 1050℃, quenching 250~350℃ tempering.

4. Anti-wear performance and application of high chromium cast iron Castings And Forgings

High chromium cast iron has high chromium content, good hardness, corrosion resistance and oxidation resistance, and has higher toughness than ordinary white iron, so it is widely used in various abrasive wear occasions and various high temperature wear and corrosion wear conditions. At present, high chromium cast iron grinding ball has been widely used in dry ball mill of electric power and building materials industry. In wet ball mill of metallurgical mine, high chromium cast iron grinding ball also has good wear resistance.

It is hoped that the material has high wear resistance and excellent heat resistance under high temperature wear condition, and the high wear resistance comes from the high hard strength phase in the tissue, such as eutectic carbide, etc. The superior heat resistance depends on the high hardness hard phase, the matrix and the oxidation resistance of the interface between the matrix and the hard phase. If the understanding of high temperature abrasive wear mechanism and working conditions is insufficient, attention will not be paid to the high temperature wear resistance of materials when selecting materials, resulting in the very short service life of many high temperature anti-wear parts. Early studies emphasized the adhesion mechanism in high temperature wear. Later, it was found that in high temperature wear, the temperature of the interface would lead to the adsorption, oxidation of the friction surface, and the change of the mechanical properties of the material, so it is a very complex failure form. In a pair of friction pairs, there is usually not only one form of friction loss, but usually several mechanisms (such as fatigue spalling, abrasive wear, oxidative wear and adhesion, etc.) coexist, or the transformation from one form to another occurs under certain conditions.