Progress of Research on Seamless Steel Tube Piercing Plug

Summarized here in the paper is the present situation concerning the research on the material of and the surface treatment process for the seamless steel tube piercing plug.Also analyzed are the advantages and shortcomings of the piercing plugs as made with different materials and the surface treatment processes for them.Accordingly the direction for further research on the plug is proposed.The analysis result leads to the conclusion as follows.The alloy steel is the most commonly used material for the piercing plug.And the Mo alloy is mainly employed to produce the plug for piercing hi-NiCr stainless steel tubes.Besides the surface functional coating process and surface nitridizing process are also widelyapplied methods for piercing plug surface treatment.Both the material and surface treatment process as properly selected for the piercing plug are the key to enhance the service life thereof.Finally it is proposed that the way for piercing plug processing should be gradually switched to the direction of shortening the surface treatment cycle,obtaining homogeneous and compact protective coating,keeping low energy consumption and ensuring green economy,etc.