X80管线钢管全自动焊环焊接头力学性能研究OA

To investigate the distribution law of strength and toughness of automatic gas metal arc welding(GMAW)girth welded joints of X80 pipelines,mechanical property test data of 20 automatic GMAW girth welded joints of X80 with specification Φ1219 mm×22 mm from a certain pipeline project were collected.Statistical analyses were conducted on the test data of transverse tensile of girth welds,longitudinal tensile of full welds,and Charpy V-notch(CVN)impact tests at weld centers and fusion lines.The distribution characteristics and dispersion of strength and toughness of girth welded joints were studied,and comparisons were made on the tensile properties and impact toughness at different circumferential positions,as well as the changing rules in impact toughness between inner and outer surfaces.Results show that the automatic GMAW girth welded joints of X80 achieve high-strength matching,with the average value of the tensile strength matching coefficient of girth welds greater than 1.13.The longitudinal tensile properties of full welds have large dispersion,among which the fluctuation of tensile strength is significantly larger than that of the transverse direction of girth welds,and the yield ratio is high.The differences in tensile properties at different circumferential positions of girth welded joints are very small.The impact toughness of automatic GMAW girth welded joints of X80 is favorable;the dispersion of impact absorption energy at fusion lines is greater than that at weld centers,with occasional low values data.The impact absorption energy at vertical welding position is slightly lower than that at flat and overhead welding positions,and the impact absorption energy at the inner surface is slightly higher than that at the outer surface.