Study on Unqualified Mechanism of Extrusion Performance of Hot Rolled Q345D Plate

Abstract

In this paper, a systematic analysis of the failure performance of the slab after continuous hot rolling is carried out. The results show that the microstructure of Q345D steel plate is F + P, individual Class A inclusions exceeding standard, specifications for 15-25um. The results show that elongation of unqualified specimens is common in inclusions exceeding the standard or banded tissue level. The phenomenon of stratification is common in cold fracture test specimen. The inclusions are predominantly Class A sulfides and Class C silicates. By comparing the rolling temperature and other parameters, it is found that the dendritic segregation is the main factor affecting the performance when the ribbon and billet are cast.