腐蚀对高性能钢Q550E力学指标影响的试验研究

Experimental Study on Influence of Corrosion on Mechanical Index of High Performance Steel Q550E

为深入研究腐蚀对高性能钢Q550E力学指标的影响,分为5组,共制作了30个钢材试件,目标质量锈蚀率分别为0,5%,10%,15%和20%,在实验室对钢材试件进行了不同程度的加速锈蚀试验,开展了拉伸试验以及使用FARO 3D激光扫描仪扫描锈蚀试件。建立了腐蚀影响下高性能钢Q550E的本构关系模型。对比分析了在相同锈蚀率下高性能钢Q550E和普通钢Q235B力学指标的退化程度。试验研究表明:(1)随着质量锈蚀率的增加,Q550E高性能钢材的屈服强度、抗拉强度、伸长率、弹性模量逐渐下降,锈蚀过程中试件表面蚀坑深度增长明显,蚀坑呈椭球型和马鞍型,随着锈蚀率增加到20%,蚀坑逐渐增长为局部大蚀坑;(2)在腐蚀试件的应力-应变曲线中,随着腐蚀率增加,钢材的延性性能减小,逐渐由延性破坏转变为脆性破坏,屈服平台逐渐缩短甚至消失,得到了Q550E高性能钢材的屈服平台消失时的临界质量锈蚀率。(3)在锈蚀率变化相同时,高性能钢比普通钢有更强的抵抗腐蚀退化和变形的能力。

To study the influence of corrosion on the mechanical index of high performance steel Q550 E,30 high-performance steel specimens are fabricated and divided into 5 groups with a designed mass corrosion rate of 0,5%,10%,15% and 20%. The accelerated corrosion test with different degrees and the tensile test on these steel specimens are conducted,and the corroded specimens are scanned by FARO 3 D laser scanner in the laboratory. The constitutive relation model is established considering the influence of corrosion. The degradation degrees of the mechanical index of high performance steel Q550 E and ordinary steel Q235 B is compared and analyzed at same corrosion rate. It is concluded that（ 1） The yield strength,the tensile strength,the percentage elongation and the elastic modulus of high performance steel Q550 E gradually decrease as corrosion rate increases,the depth of corrosion pits at surface of corroded specimens increases and appears ellipsoidal type and saddleback type,and the corrosion pits develop into local large pit when the corrosion rate increases up to 20%;（ 2） the ductility of the steel specimens reduces and the failure modevaries from ductile to brittle as the corrosion rate increases in the stress-strain curve of corrosion specimen,the yielding plateau of Q550 E steel material shortens gradually to disappear,and the critical mass corrosion rate is obtained while the yielding plateau disappeared;（ 3） the high performance steel has greater ability to resist corrosion degradation and distortion than ordinary steel when at same corrosion rate.