Microstructure and properties of domestic free-cutting ferritic stainless steel containing Bi for ball point pen were studied by means of scanning electron microscope(SEM), electron probe(EPMA) and tensile test. The results were also compared with those of the free cutting ferritic stainless steel containing Pb in order to discuss the possibility of replacing harmful element Pb with Bi. The results show that the ferrite grain sizes of the two kinds of free-cutting ferritic stainless steel are very fine, and the free-cutting phases are mainly MnS and Bi or Pb. In which the distribution state of the MnS free-cutting phase is very similar, and is distributed on the ferrite matrix in a chain-like form in the form of spindle-like or short rod-like, and the Bi or Pb are very fine and dispersed in the matrix. This microstructure is very beneficial to the cutting performance. The tensile test results show that the mechanical properties of the free-cutting ferritic stainless steel containing Bi for ball point pen are similar to those of the free-cutting ferritic stainless steel containing Pb for ball point pen. The results show that the element Bi is expected to replace the harmful element Pb.
修改评论