Effect of Phosphorus on Hot Ductility of High Manganese Austenitic Steel

Abstract

The forging technical performances of austenitic high manganese steel are very poor, which has been a technical problem difficult to be resolved in engineering.The thermoplasticity of the high manganese steels with different content of impurity is tested by using Gleeble-3500 hot simulation testing machine in order to investigate the effects of phosphorus on the thermoplasticity of the high manganese steel.The alloying and impurity elements distribution of high manganese steel sample is analyzed by using a KYKY-2800 type scanning electron microscope.At the same time, the conventional mechanical properties of the forging high manganese steel are studied and compared with those of casting high manganese steel.The results show that the zero ductility temperature and the plastic temperature range of high manganese steel are reduced significantly by phosphorus.Furthermore, the relationship between the zero ductility temperature of high manganese steel and the content of phosphorus is expressed by the equation:T=1 220-1 520?w P%.Thus phosphorus is the main factor causing the poor forging technical performance of the high manganese steel.The reason is that the phosphorus segregated at the austenite grain boundary forms Fe-(Fe Mn)3P type low melting point eutectic structure.The mechanical properties of forging high manganese steel are obviously superior to casting high manganese steel.Therefore, the forging treatment will further expand the application areas of high manganese steel.