低合金高强度钢Q460加工开裂原因分析

ANALYSIS ON CRACKING DURING HSLA Q460 MACHINING

针对安钢炉卷机组生产的低合金高强度中厚板Q460在后续加工时开裂进行了分析。通过化学成分分析、力学性能检测、金相分析与对比试验,分析表明:该批Q460中厚板后续加工开裂主要原因是钢中夹杂物含量过高,同时由于冷却控制不当,表层组织出现高碳粒状贝氏体和上贝氏体,双项原因复合造成。由于高碳粒状贝氏体和上贝氏体塑性差,同时夹杂物的大量存在增加了塑性变形过程中的应力集中,造成钢板在弯折过程中提前开裂,从而形成了表层细小、密集的冷弯裂纹。

The cracking in downstream machining for HSLA Q460 steel produced in the steckle mill production line in Anyang Steel is analyzed. The main cracking reasons are more inclusions and high carbon granular bainite and upper banite because of improper cooling control by means of chemical composition analysis, mechanical property detection, metallogra- phy analysis and contrast test. Because the plasticity of granular bainite and upper bainite is low and stress is concentrated during plastic deformation because of existence of inclusions ,plate cracks in advance during benting and the tiny and inten- sified cold bending cracks at the surface are formed.