Effect Of The Nitrogen On Strength Of 20MnSi Steel

20MnSi steel rebar can be made available to steel structure, construction and machine parts. The main drawback of 20MnSiâ…¡grade rebar which is used widely is the low intensity, only 335MPa.Therefore,steel consumption is greatly in the building engineering. Nitrogen alloying can make the adhesion of segregation of metal atoms and grain boundaries strengthened, nitrogen still play important role in obstructing grain growth and organization coarsening. 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 to observe the organization and tensile fracture surface of 20MnSi experimental steel,using OM to 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 testing machine for impact test and Gleeble-1500D thermal simulation machine and other methods to analyze the microstructure and property of 20MnSi experimental steel.The analysis on the hot ductility shows that nitrogen plays a role in improving the tensile strength at the same plasticity of 20MnSi experimental steels. There is a big increase in the peak stress and reduction of area of when the nitrogen content of 0.4%⁰.6%. But no significant change when the nitrogen content reach to between 0.6% and 0.8%.It is seen from high temperature deformation behavior of 20MnSi experimental steels containing different N contents, under the same deformation conditions, the deformation resistance of the 20MnSi experimental steel containing 0.6% N is generally greater than that of 20MnSi experimental steels containing 0.4% and 0.8% N; the addition of N can put dynamic recrystallization off.Before the N content reach up to 0.6%, the increasing of impact energy is big; continue to increase the nitrogen content, the change of impact energy is not clear. As the temperature decreases, the impact energy decreased gradually.