Research and Development > Technical Report > No.12 Special Issue on “Steel Pipes and Tubes” and “Stainless Steel” > Development of API X80 Grade Electric Resistance Welding Line Pipe with Excellent Low Temperature Toughness

No.12 Special Issue on “Steel Pipes and Tubes” and “Stainless Steel”

Development of API X80 Grade Electric Resistance Welding Line Pipe with Excellent Low Temperature Toughness

NAKATA Hiroshi     KAMI Chikara     MATHUO Nobuyuki

Abstract

This paper introduces nature and characteristics of the X80 electric resistance welding (ERW) line pipe. Thick-walled high strength line pipes are to be increasingly used for high pressure pipeline operation to improve the transport efficiency for natural gas and oil. To improve the material properties of hot coil for X80, the effects of microstructure, chemical composition on strength and toughness were investigated. Based on the result, JFE Steel has developed ultra low carbon bainitic ferrite steel with fine precipitates and no coarse pearlite or martensite by applying JFE Steel’s thermomechanical controlled process (TMCP) technologies. Good balance of material properties of base material and seam weld suitable for low temperature use was obtained.

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