Research On Welding Performance Of High Chromium Cast Iron Type Metal Cored Wire And Abrasion Resistance Of Its Deposits

High chromium cast iron type metal-cored wire has been widely used in manufacturing and repair of many kinds of wear parts for its good welding property. In this paper, the welding performance and the deposits' property of the high chromium cast iron type metal-cored wire are analyzed and studied.The metal transfer mode and the spatter characteristics of the high chromium cast iron metal-cored wire were observed and analyzed in detail through high speed photography and welding spatter rate test. The abrasive wear resistance of the deposits of high chromium cast iron type metal-cored wire was tested using the abrasive wear tester. The microstructure of the deposits and the worn surfaces of the deposits samples were investigated with the help of optical microscope, scanning electronic microscope and energy spectrum instrument.The results of these studies are as follow:(1) The self-made high chromium cast iron type metal-cored wire shows good welding performance. Several typical characteristics are: smooth surface, no slag, relative steady globular repelled transfer and low welding spatter rate(about 1%).(2) Among those droplets, the small-sized droplets which are less than 1mm diameter take the largest proportion. They usually occur at the moments droplet leaves the end of consumable wire and droplet explodes; the medium-sized droplets which are between 1mm and 2mm diameter are far less than small-sized droplets in number, they usually occur at the early stage of the molten droplet; the large-sized droplets which are more than 2mm diameter occasionally occur and usually it is the whole droplet repelled out.(3) The main wear mechanism of the high chromium cast iron deposits are micro cutting, fracture and flaking. Beside the sand, there are M7C3 carbides, NbC and some other chromium carbides participating the abrasive wear process. The experiment data shows that the addition of Nb in the wire does not ensure the improvement of the abrasion wear resistance of the high chromium cast iron deposits, excess of Nb may even reduce its abrasion wear resistance.