Study On The Properties Of Stainless Steel Sheets For The Carriages Of High-speed Trains

As the light weight material for high-speed train, stainless steel is widely used; The five different strength grades of301L metastable austenitic stainless steel is fit to the different parts of high-speed trains. At present, the traditional production process of301L carriage sheet is skin-pass rolling, but the process for DLT、MT and HT is not mature.This paper developed a new process to produce different strength grades301L carriage sheets:It used different annealing temperature treatment for301L cold rolled sheets to get the different strength ranks. Also we analysis the sensitive tendency of301L in780℃, and get a result that annealing treatment in780℃is not harmed to the ability to resist intergranular corrosion of301L stainless steel.Compared with the traditional process, use flexibility annealing process to produce different strength grades301L carriage sheets can gained better mechanical properties, the yield ratio and elongation rate are higher than the skin-pass rolling sheets. Otherwise, consideration from shape control, Flexibility annealing process can reduce the residual stress of the cold rolled sheet,so can get better shape than skin-pass rolling process.Another task of the subject is the development of the304N austenitic stainless steel carriage sheets. Based on the304stainless steel alloy, we add some nitrogen alloys to get304N stainless steels, and through research the effection of nitrogen content to the thermal deformation and intergranular corrosion of304N stainless steel, got the best nitrogen content of304N stainless steel.Studies show that, with the increase of nitrogen content, the strength of304N stainless steel is significantly increased. The nitrogen content increased0.05%can result the strength of304N stainless steel increased40-50MPa; With the increase of nitrogen content, the elongation rate of304N stainless steel increased firstly, then decreased. The yield ratio304N stainless steel is increased with the increase of the nitrogen content. It is important to the carriage plate that can reduce rebound after cold-forming. The research of the intergranular corrosion of304N stainless steel shows that the appropriate nitrogen content is benefit to the resistance ability to the corrosion of304N stainless steel. When the nitrogen content less than0.184%, the resistance ability to intergranular corrosion of304N stainless steel is improved with the increased of nitrogen content, and this ability is decreased with the increase of nitrogen content when the nitrogen content over0.184%.Considering the mechanical properties and the corrosion resistance of304N stainless steel, the best nitrogen content of304N stainless steel is0.184%.