Effect Of The Nitrogen On Strength Of20MnSi Steel

20MnSi steel rebar can be made available to steel structure, construction and machineparts. The main drawback of20MnSi Ⅱ grade rebar which is used widely is the low intensity,only335MPa.Therefore,steel consumption is greatly in the building engineering. Nitrogenalloying can make the adhesion of segregation of metal atoms and grain boundariesstrengthened, nitrogen still play important role in obstructing grain growth and organizationcoarsening. The current study of high nitrogen steel limited mainly to austenitic steel,martensite steel and two-way stainless steel. Actually the role of nitrogen is far more than that.This paper put nitrogen element into experiment steel in the form of Si3N4.Using SEM toobserve the organization and tensile fracture surface of20MnSi experimental steel，using OMto observe the organization and organization near the fracture after high-temperature tensile,using TEM to observe the forged steel organization and EDX, JB-30B-type impact testingmachine for impact test and Gleeble-1500D thermal simulation machine and other methods toanalyze the microstructure and property of20MnSi experimental steel.The analysis on the hot ductility shows that nitrogen plays a role in improving the tensilestrength at the same plasticity of20MnSi experimental steels. There is a big increase in thepeak stress and reduction of area of when the nitrogen content of0.4%~0.6%. But nosignificant change when the nitrogen content reach to between0.6%and0.8%.It is seen from high temperature deformation behavior of20MnSi experimental steelscontaining different N contents, under the same deformation conditions, the deformationresistance of the20MnSi experimental steel containing0.6%N is generally greater than that of20MnSi experimental steels containing0.4%and0.8%N; the addition of N can put dynamicrecrystallization off.Before the N content reach up to0.6%, the increasing of impact energy is big; continue toincrease the nitrogen content, the change of impact energy is not clear. As the temperaturedecreases, the impact energy decreased gradually.