Abstract：In order to solve the problem of the disqualification of the flaw detection for the low alloy Q345B plate produced by the 250 mm×1 650 mm section continuous caster in Nanyang Hanye Special Steel Co., the unqualified steel was sampled and detected by the electron microscope. It can be concluded that the main reasons for the disqualification of the flaw detection was the center segregation of manganese, the manganese sulfide inclusions and the aluminium oxide inclusions. Through optimizing the component to reduce the manganese mass fraction in the steel, improving the purity in the molten steel, reducing the sulfur mass fraction in the molten steel, optimizing the second cooling system and strictly controlling the opening degree of the caster, the center segregation of the slab was improved, and the quality qualification rate of the steel plate flaw detection after rolling was increased.
2017, Vol. 27 
