Development of High-Performance Steel Plates with Excellent Weldability

摘要

POSCO has continuously striven to lead the way in steel productionrnand then stand ready to surpass the 30 million tons mark in annualrnproduction over 3 decades since the start of a mass production with arnscale of 1.03 million tons of crude steel in 1973. And POSCO isrnannually manufacturing 3.3 million tons of various steel plates forrnshipbuilding, offshore structure, pipeline, construction and pressurernvessel, etc. at Pohang work. As well as the quantity, POSCO is makingrnefforts to supply high performance steel plates to customers throughrnintensive R&D activities. In the present paper, three representativernplate products whose welding performances are very important arernbriefly introduced. In the first place, an innovative technology forrnincreasing HAZ toughness in high heat input is described. Thermallyrnstabilized TiN particles can effectively suppress the abnormal growthrnof austenite in HAZ through the modification of Ti/N ratio. In addition, the performances of weld joints of API 2W Gr. 50 / 60 class and APIX80 grade plates developed in POSCO are reported.