Q355B钢厚板表面裂纹原因分析及改进措施  

Cause Analysis and Improvement Measures of Surface Crack of Q355B Steel Thick Plate

作　　者：郭鹏 Peng Guo(Xinjiang Bayi Iron and Steel Co.,Ltd.,Urumqi,Xinjiang 830022)

机构地区：[1]新疆八一钢铁有限公司,新疆乌鲁木齐830022

出　　处：《新疆钢铁》2024年第1期80-82,共3页Xinjiang Iron and Steel

摘　　要：本文针对某钢厂Q355B钢板表面裂纹问题,通过对裂纹缺陷位置取样做金相检测和对铸坯扒皮检查,分析造成Q355B钢板表面裂纹的主要原因是Nb强化铸坯第Ⅲ脆性温度区间较Ti的高,加之浇注速度降低了0.2 m/min,铸坯矫直时表面温度正好在第Ⅲ脆性温度区容易产生裂纹。铸坯直接热送热装到加热炉,于奥氏体晶界的先共析铁素体和析出的第二相粒子,在加热过程不能充分回溶且轧制过程易产生裂纹。本文采取优化合金、改善铸坯冷却强度、适当提高浇注速度和铸坯下线缓冷等措施降低铸坯表面裂纹发生的概率。Aiming at the surface crack problem of q355b steel plate in a steel plant,this paper analyzes the main reason for the surface crack of q355b steel plate by taking samples from the crack defect location for metallographic inspection and peeling inspection of the slab,and analyzes that the main reason for the surface crack of q355b steel plate is that the third brittleness temperature range of Nb strengthened slab is higher than that of Ti,and the pouring speed is reduced by 0.2 mgmin.When the slab is straightened,the surface temperature is just in the third brittleness temperature range,which is prone to crack.The bil⁃lets are directly heated and charged to the heating furnace.The precipitated ferrite and the precipitated second phase particles at the austenite grain boundary can not be fully re dissolved during the heating process,and cracks are easy to occur during the rolling process.In this paper,some measures are taken to reduce the probability of slab surface crack,such as optimizing the alloy,improving the cooling intensity of slab,appropriately increasing the pouring speed and slow cooling of slab.

关 键 词：Q355B 钢板 表面裂纹 

分 类 号：TF777[冶金工程—钢铁冶金]