Study Of Effect Of Arsenic And Lanthanum On Properties Of High Carbon Steel

Oxidation potential of the residual elements Arsenic?As?is lower than iron,and it is difficult to remove the residual elements in the current smelting process.The residual elements affect the hot workability,temper brittleness and mechanical properties of the steel,because of segregation during the solidification process,grain boundary segregation and oxidation enrichment.At present,the method of reducing and controlling residual elements in steel has high overall cost,complicated operation and large energy consumption,and is not suitable for industrial production.Rare earth elements can not only react with the residual elements As,Sn,Pb in the steel,but also can reduce the content of sulfur?S?and oxygen?O?to purify the molten steel.Therefore,in this paper,in order to control the effect of As on the mechanical properties and high temperature oxidation properties of high carbon steels,the occurrence of As,the influence of As on the mechanical properties and high temperature oxidation properties of high carbon steel and comprehensive treatment effect of rare earth La were studied.As affected the mechanical properties of the high carbon steel by affecting the microstructure.When the content of As in the range of 0.008-0.115 %,the tensile strength and yield strength of high carbon steel all increased first and then decreased,and when As content was 0.060 %,the two reached the maximum.The trend of mechanical properties was consistent with the effect of As on spacing of sorbite and the original austenite grain size.When the content of As was higher than 0.030 %,the plasticity and toughness of high carbon steel were significantly reduced.In the absence of O,segregation of As wasn't affected by As content and oxidation temperature of high carbon steel.O had a significant effect on the aggregation of As at the grain boundaries of the steel surface when As content is greater than 0.030 %,both of which was in the grain boundary.Rare earth La significantly affected the formation of inclusions in As-containing high carbon steel.The study on the addition of rare earth La showed that the La-O-As inclusions was the main form of high carbon steel,and the inclusions are formed in the solid phase.La₂O₃ and La₂O₂ S were used as hetero-nucleation cores of La-O-As inclusions to produce composite inclusions.La-O-As inclusions could be present in the form of single-particle inclusions.To avoid the deterioration of mechanical properties of high carbon steel,La content should be controlled in the appropriate range.The oxidation temperature and As content significantly affected the high temperature oxidation of high carbon steel.The studies showed that the enrichment degree of As and oxide thickness reached the maximum when the oxidation temperature is 1080?.When As content is 0.090 %,the enrichment of As in the oxide-matrix interface was the most serious.La had no significant effect on the oxide structure of As-containing high carbon steel.When La content was increased to 0.089 %,it could ensure that As was not enriched at the interface of oxide layer.