Cause Analysis of Surface Crack Defect of 30Mn2 Hot Rolled Bar
XU Zhigang
LIU Yong
ZHANG Yingtao
MA Xingtao
GAO Wenjuan
Abstract：Aiming at the surface crack defects of 30Mn2 hot rolled bar, the sample was taken in defect position and the composition, properties, microstructure and energy spectrum were analyzed. The results showed that the material composition and performance met the design requirements, large bubbles and inclusions existed in crack inside, matrix existed in banded structure caused by phosphorus segregation (the ghost line structure), and inclusions contained slag composition. Crystallizer slag entrapment is the main cause resulted in appearing longitudinal crack in rolled bar. Through replacing protection slag and optimizing adding way, the emergence of the rolled 30Mn2 steel surface defects again such as cracks and ghost line structure was avoided.
Keywords：hot rolled bar30Mn2surface crackghost line structureinclusionslag entrapment
Publication Date：2013-09-01
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：3( 37-39 )