Analysis on Cracking of a Pipeline Steel Pipe during Hydraulic Burst Test

Abstract

Through macroscopic and microcosmic analysis of fracture, chemical composition analysis, fracture microscopic analysis and other methods, the causes of longitudinal and transverse fracture (only longitudinal cracking commonly through thousands of columns) in hydraulic burst test of L360M LSAW pipe were analyzed. Test results showed that the causes of transverse cracks in the steel pipe were the poor toughness of the pipe material which was related to the serious ferrite-pearlite banded structure. The serious band structure in the pipe was related to the high manganese content in the steel, which leaded to manganese segregation. We can use some measures to reduce the banded structure including controlling the element manganese content reasonably, reducing the final rolling temperature, controlling cooling rate and micro alloying.