IMPROVING OF HOT WORKABILITY AND EXPANDING THE TEMPERATURE RANGE OF SAFE HOT WORKING FOR M35 HIGH-SPEED STEEL

摘要

Increasing the hot workability and expanding the temperature working range for M35 high-speed steel (HSS) by industrial hot rolling as well as by hot compression tests have been studied and achieved. The types of carbides for as-cast as well as for wrought states were revealed by EBSD and the optimal soaking temperatures for both microstructural states were assessed. The soaking temperature had a decisive influence on the characteristics of carbides that lead to improving the intrinsic hot workability as well as to considerably expanding the temperature range of safe hot working down to 850 degrees C. The apparent activation energy for hot working which amounts 639 kJ/mol as well as constants of the hyperbolic sine constitutive equation for extended temperature range have been calculated. Industrial practice confirms the laboratory results.