Structure and properties of steel coatings deposited by activated arc metallising

This work analyses and compares the structure and properties of coatings of 20Kh13 and 40Kh13 steels deposited by the EAM and AAM methods. Conclusions are as follows. The structure of the metallized coating of Kh13 type steels consists of tempered martensite and includes type Fe sub 3 O sub 4 oxides, retained austenite and carbides. The microhardness of the coating of Kh13 type steels is in the range 4.5-6.8 GPa and increases with increasing carbon content in the initial material. The microhardness of the oxide is slightly higher than that of the areas of pure metal. The steel particles which form the layer are reheated to approx200 deg C in contact with the melted particles. The use of a reducing atmosphere in activated metallizing decreases the number of oxides, and the number and size of the pores, and the increase of dispersion of the structure is also associated with this. The most favorable conditions were obtained at an oxidation degree of the atmosphere of 0.8. Operation of the coatings under impact-abrasive wear at a contact load of < =100 MPa takes place by the internal friction mechanism through oxide interlayers. The degree of oxidation of the coating of approx3% is optimum as regards the effect of the oxides. At the given loads, these coatings are more efficient than all-steel surfaces.