Study On High Temperature Friction Performance Of Nickel Base Layer On Cast Steel Surface

Study On High Temperature Friction Performance Of Nickel Base Layer On Cast Steel Surface

Large Steel Castings Manufacturers shares that the surface wear of mud pump body and conveying pipe is the main form of failure in petroleum, chemical industry and other industries. There are two ways to improve the wear resistance of materials. One is to strengthen the material as a whole. Second, surface strengthening is used to improve the surface properties of materials. Common surface technologies include surfacing welding technology, welding technology, electroplating brush plating technology and chemical plating technology, etc. This method can not only save costs, but also meet the comprehensive requirements for the external hardness and internal toughness of materials in some working conditions. Cast-penetrated method is a new kind of surface modification methods developed in the late 20th century, it on the surface, at the same time, the performance of castings with high strength, high toughness can be obtained, compared with other surface technology, casting infiltration method does not need special processing equipment, surface treatment layer thickness, short production cycle, low cost and parts deformation, etc. In this paper, the nickel base layer was prepared on the surface of cast steel with good wear resistance of nickel base alloy and good toughness and impact resistance of ZG45.

The infiltrating agent of the Alloy Steel Pipeline Valves surface was 150 ~ 300 commercially available nickel-based alloy powders. The chemical composition (mass fraction, %) was 0.6 ~ 0.8c, 4.0 ~ 5.0si, 16 ~ 18Cr, 5Fe, and the rest was Ni. The matrix is made of 45 steel with better toughness, and the adhesive is made of NJB with less gas emission. A certain amount of nickel-based self-fluxing powder is mixed with an appropriate amount of adhesive to make a slurry, which is coated on the specific surface of the baked and dried sand mold (the inner wall of the mold cavity corresponding to the surface of the casting to be modified). And then dried at 300 ℃ x 2 h, the preset layer can withstand high temperature liquid steel erosion, pouring temperature is 1650 ℃, keep the degree of negative pressure in 0.7 ~ 0.4 MPa, alcan deoxidization. In the process of infiltration layer formation, the casting was removed after cooling to room temperature, and the sample was processed after sand removal.

By negative pressure casting infiltration method, a layer of 2 ~ 5mm nickel-based infiltration layer with good matrix bonding can be prepared on the surface of cast steel. The permeation layer is mainly composed of ni-cr-fe, FeNi matrix phase, FeB and NiB hard phase. The friction coefficients of cast steel and nickel base layer decrease with the increase of temperature. At the same temperature, the friction coefficient of nickel base layer is lower than that of cast steel. The wear volume of the matrix and the permeable layer does not increase with the increase of temperature. Compared with the wear volume of the matrix at the same temperature, the wear volume of the permeable layer decreases to different degrees, especially at room temperature, which is 1/3 of the wear volume of the matrix.