Low-chromium-content stainless steel with excellent corrosion resistance of weld

• Main Authors: TERAOKA SHINICHI, SAKAMOTO SHUNJI, FUKAYA MASUHIRO
• Format: Patent
• Language: English
• Published: 01.07.2015
• Subjects: ALLOYS; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MACHINE TOOLS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; SOLDERING OR UNSOLDERING; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WELDING; WORKING BY LASER BEAM

The present invention provides an optimum low-chromium stainless steel which prevents corrosion resistance degradation of a weld in the case of welding a low-chromium stainless steel utilizing martensite transformation in multiple passes (multipass), is excellent in weld intergranular corrosion resistance even in a severe corrosion environment, simultaneously avoids occurrence of preferential corrosion at the bond-bordering region of the weld heat-affected zone, and is also excellent in productivity, which low-chromium stainless steel comprises, in mass %, C: 0.015 to 0.025%, N: 0.008 to 0.014%, Si: 0.2 to 1.0%, Mn: 1.0 to 1.5%, P: 0.04% or less, S: 0.03% or less, Cr: 10 to 13%, Ni 0.2 to 1.5%, and Al: 0.005 to 0.1% or less, and further comprises Ti: 6×(C %+N %) or greater and 0.25% or less, the balance being Fe and unavoidable impurities, and the contents of the elements satisfy specified expressions.