Mechanical Properties and Weldability of High Strength Stainless Steel Bearing 0.03% or Less Carbon for Railroad Vehicles

Abstract

The effects of alloying elements, volume fraction of deformation-induced martensite and rolling reduction on the mechanical properties of Type 301 stainless steels bearing 0.03% or less carbon have been investigated, and product properties of this Type 301L are also shown.
1) Tensile strength strongly depended on the volume fraction of deformation-induced martensite and tensile strength decreased with increasing Ni_eq., where Ni_eq.=Ni(%) +0.35Si(%) +0.5Mn(%) +0.65Cr (%) +12.6(C+N)(%). Steels having a constant Ni_eq. showed higher tensile strength by increasing N.
2) Proof stress of as-annealed and 20%-rolled materials was little affected by Ni_eq. and increased with increasing N content.
3) Elongation was little affected by N content, and it strongly depended on Ni_eq. As N is one of the factors in Ni_eq., N has an influence on elongation through Ni_eq.
4) The mechanical properties of all the products, from LT to HT tempered ones, were confirmed to meet the typical specification for the railroad vehicles.
5) Mechanical properties of Type 301L welded joints were equal to those of Type 301M bearing 0.06% carbon.
6) In the case that metastable austenite stainless steels were cold-rolled, welding current required to form the nugget where diameter was 4 mm decreased, because specific resistance increased with increment of deformation-induced martensite by cold-rolling.
7) Resistance of Type 301L to intergranular stress corrosion cracking and intergranular corrosion was superior to that of Type 301M.