Bunina L. Increasing the constructive strength of low-alloy steel for forgings

Object of research - the processes of structure formation and nonmetallic inclusions in result of complex deoxidation and hot working by pressure (forging) of low-alloy steels. Subject of research - the conformities of nonmetallic inclusions influence on high-temperature resistance, defect of ingots and forgings, mechanical and service properties of forging steel. Purpose of work - the rise of high-temperature resistance and constructive strength of forging steels by lowering of nitride aluminium quantity and globular of sulphide inclusions in the result of complex deoxidation by aluminium and ferrocerium. Method of research - method of metallographic analysis and mechanical tests by room temperature and high temperature, scanning microscope, local spectrum analysis, the test of fracture toughness, cyclic cracking resistance, low-cycle endurance and wear-resistance of steels. As a result of steel complex deoxidation by aluminium and ferrocerium the high temperature cracking resistance and mechanical properties of chrome steel for forgings have been improved. The influence of final deoxidation and the type of nonmetallic inclusions which appear after two types of deoxidation - by aluminium and aluminium and ferrocerium, on the defect of ready-made details of metallurgical equipment and the constructive strength of forged manganese steels were studied. It is proved that deoxidation by aluminium and ferrocerium allows to decrease the quantity of aluminium nitride on the boundaries of austenitic grains and to get globular nonmetallic inclusions, which do not form during forging, that allows to decrease the defect of details, to increase the constructive strength and decrease the anisotropy of steel properties for forgings. Implemented of JSC "Tokmac forging plant". Area of application - repair- mechanical departmens of metallurgical plants.