Microstructure analysis of hardfacing layer by electrode cored with high chromium casting iron

The hardfacing electrodes cored with high chromium casting iron were developed to adequately transfer alloying elements.The transfer coefficient was calculated and the microstructure and hardness of the hardfacing layer from different coatings were investigated.The results indicated that the transfer efficiency of electrodes was more than 85%.Different compositions and microstructure in the hardfacing layer can be obtained using the same-cored wire covered with different coatings.When the cored welding-wire was covered with alkalescent low-hydrogen coating, the hardfacing layer with hypoeutectic high chromium casting iron formed and the microstructure consisted of primary austenite γ, martensite M and carbide.While covered with alkalescent graphite coating, the hardfacing layer with hypereutectic high chromium casting iron was formed and the microstructure consisted of primary carbide, martensite M, carbide Fe₇C₃ and a small amount of G.Since hard Cr₇C₃ and martensite phases existed in the hardfacing layer, the hardness of the hardfacing layer was high.The hardness of the hypoeutectic and hypereutectic high chromium casting iron hardfacing layers was 44.5-56.5 HRC and 59-67 HRC, respectively.