钒氮合金钢延伸不合分析及预防

Analysis and prevention of elongation failure in vanadium-nitrogen microalloyed steel

钒氮微合金钢轧后延伸性能不稳定,经常出现批次伸长率不合,特别是轧制40-50mm等厚规格,更易出现延伸不合现象。通过对延伸不合试样进行金相、电镜分析,认为铸坯中间裂纹是造成该缺陷的主要原因,进而在连铸过程采取有效手段减少拉矫阻力、应变阻力,从而减弱铸坯受力,达到消减中间裂纹、提升轧后延伸率目的。

The elongation performance of vanadium and nitrogen microalloy steel is unstable after rolling, and the batch qualification rate in terms of elongation is often inconsistent, especially for the rolled productl of 40~50mm thickness.Through the metallographic and electric mirror analysis of the unqualified sample, it is found that the intermediate crack of the cast billet is the main cause of the defect. Effective measures were taken to reduce the tensile resistance and strain resistance,so the force of the cast billet can be weaken, and the aim of reducing intermediate crack and improving elongation after rolling was achieved.