| The liquid boronizing of stainless steel to improve its wear resistance has been studied by means of the measurement of the boronized depth and the microhardness, the observation of the microstructure and the test of wear resistance. Liquid boronizing was carried out in molten borax containing various proportion of SiC. The boronized depth and the microhardness at the surface layer were increased with increasing the SiC content, boronizing time and temperature, but boronized depth increased little due to the rapid deterioration of fluidity of molten bath when the amount of SiC in the molten borax exceeded 40%. The boronized depth of the stainless steel was about half that of low carbon steel which was boronized at the same condition, and the boronized depth of 430 stainless steel was larger by 20-30% than that of 304 stainless steel. The wear resistance of the boronized specimen was increased remarkably (about 100 times) than that of the non-boronized specimen, and the wear resistance was improved when tempered the pre-boronized specimen and tested the boronized specimen at elevated temperature. The optimum condition for the best wear resistance was found to be as follows: 1) Bath composition was 25-35% SiC/Na₂B₄O_7. 2) Boronizing temperature was in the vicinity of 950℃. 3) Boronizing time was about 9 hrs. |
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