Investigation of Causes for Surface Cracking of Piercer Plug made in 3Cr2W8V Steel

Before being operated, surface cracking is developed with some of the piercer plugs which are made of 3Cr2W8V steel with processes, namely forging, machining and heat treatment.Based on analyses of both macromorphology and micromorphology of the crack, it is identified that it is the local eutectic carbide segregation formed during the metallurgy process of the raw material for the plug that causes the cracking developed along with the increase of deformation amount during forging of the plug.Accordingly, measures are proposed, including properly controlling of carbide inhomogeneity and adequately forging, etc., when making the plug with 3Cr2W8V steel.