Q355XG钢冷轧板屈服强度较低的原因

Cause for Lower Yield Strength of Cold-rolled Q355XG Steel Plate

连续退火后的冷轧Q355XG钢板的屈服强度常常低于国标要求。为此,检测了屈服强度不合格的冷轧板的化学成分和力学性能符合和不符合要求的冷轧板的显微组织,并通过退火处理进行试验验证。结果表明:Q355XG钢冷轧板屈服强度偏低主要是退火温度过高所致。为确保Q355XG钢冷轧板的力学性能符合要求,其退火温度应高于Ac120~30℃。

The yield strength of cold-rolled Q355XG steel plate after continuous annealing is often lower than the requirement of national standard.For this reason,the chemical composition of the cold-rolled plate exhibiting unqualified yield strength and the microstructure of the cold-rolled plates exhibiting desirable and undesirable mechanical properties were measured,and the test results were verified by annealing treatment.The results indicated that the excessively high annealing temperature is responsible for the cold-rolled Q355XG steel plate exhibiting lower yield strength.The cold-rolled Q355XG steel plate should be annealed at 20 to 30℃above Ac1 temperature to ensure that its mechanical properties meet the requirements.