本文以304不锈钢与316不锈钢为研究对象,通过动态腐蚀试验研究了pH值对两种不锈钢材料在高温高压水环境中腐蚀行为的影响规律。SEM-EDS分析证实两种不锈钢材料表面均形成了Fe、Cr、Ni为主的颗粒氧化物,然后采用XPS获得了不锈钢表面氧化...本文以304不锈钢与316不锈钢为研究对象,通过动态腐蚀试验研究了pH值对两种不锈钢材料在高温高压水环境中腐蚀行为的影响规律。SEM-EDS分析证实两种不锈钢材料表面均形成了Fe、Cr、Ni为主的颗粒氧化物,然后采用XPS获得了不锈钢表面氧化膜中主要元素的化学形态与质量占比。腐蚀动力学分析结果表明两种不锈钢材料的腐蚀速率与释放速率均随浸泡时间呈现先增加后趋于平缓的趋势,此外,6.8~7.4范围内的pH值变化对两种不锈钢材料的腐蚀释放行为影响较小。The effect of pH value on the corrosion behavior for 304 and 316 stainless steels in high-temperature and high pressurized water was investigated through corrosion experiment. The SEM-EDS results confirm the existence of metal oxide particles (Ni, Fe, Cr) on 304 and 316 stainless steel surfaces. The chemical component and speciation in oxide film were obtained by means of XPS analysis. The corrosion kinetics curves reveal that the corrosion rate and release rate firstly increase over exposing time, then tend to moderate. Furthermore, the corrosion release behaviors of 304 and 316 stainless steels are little influenced by the pH varied between 6.8 and 7.4.展开更多
本文介绍了304不锈钢冷轧卷边鳞缺陷的形貌与产生原因,针对产生原因及结合公司生产实际对边鳞缺陷进行分析,发现冶炼化学成分、板坯加热工艺参数是影响304边鳞缺陷的主要因素。因此,通过调整S质量分数、N质量分数及均热温度等措施,缺陷...本文介绍了304不锈钢冷轧卷边鳞缺陷的形貌与产生原因,针对产生原因及结合公司生产实际对边鳞缺陷进行分析,发现冶炼化学成分、板坯加热工艺参数是影响304边鳞缺陷的主要因素。因此,通过调整S质量分数、N质量分数及均热温度等措施,缺陷率由3.68%降至0.42%以下,边鳞缺陷改善明显,产品质量得到了显著的提升。This article introduces the morphology and causes of edge scale defects in 304 stainless steel cold rolled coils. Based on the analysis of the causes and the actual production of the company, it is found that the smelting chemical composition and slab heating process parameters are the main factors affecting the edge scale defects in 304 stainless steel. Therefore, by adjusting the S mass fraction, N mass fraction, and soaking temperature, the defect rate decreased from 3.68% to below 0.42%, and the edge scale defects were significantly improved, resulting in a significant improvement in product quality.展开更多
文摘【目的】水下局部干法焊接是实现水下高质高效焊接的有效手段,但局部干燥区的水分很难保证完全排净,针对残留水分会导致焊缝成形变差这一问题,对残留水分的影响机理和排水不净情况下的焊接温度场进行研究。【方法】以6 mm厚304L不锈钢为试验材料,开展局部干燥区不同水分残留情况(有/无水膜)下的非熔化极惰性气体保护(Tungsten inert gas welding,TIG)焊搭接试验,焊后观察焊缝宏观形貌并制作金相试样,通过显微镜观察焊缝截面成形及其微观组织;建立有限元模型、温度场模型和不同环境湿度下的对流换热模型,对焊接过程进行温度场模拟,验证温度场准确性,并对温度场计算结果进行分析。【结果】结果表明,在合适的焊接参数下,局部干燥区有/无水膜均能获得表面质量良好、内部缺陷较少的焊缝。不同的是,有水膜的焊缝截面尺寸略小于无水膜的;模拟温度场的峰值温度位于合理的电弧焊峰值温度区间(1700~2300℃),焊缝截面的最大模拟误差为7.5%,表明模拟温度场具有较高的可靠性;观测点温度变化曲线表明,无水膜时焊缝中心温度峰值比有水膜时高121.68℃,冷却速度比有水膜时慢13.63℃/s,这是因为干燥区的残留水分在焊接热输入的作用下沸腾、蒸发,使焊接过程中能量损耗加大、能量利用率降低,同时蒸发产生的水汽增大了空气湿度,从而增强了焊接过程的对流换热,进一步增大了焊接能量损失,最终导致焊缝截面的熔宽、熔深减小。【结论】局部干燥区排水不净时,较少的残留水分仍对焊接过程和焊接结果有很大影响,文中仅就其对焊缝成形的影响机理做了相关工作,以期对排水不净的深入研究提供数据参考和理论支持。
文摘本文以304不锈钢与316不锈钢为研究对象,通过动态腐蚀试验研究了pH值对两种不锈钢材料在高温高压水环境中腐蚀行为的影响规律。SEM-EDS分析证实两种不锈钢材料表面均形成了Fe、Cr、Ni为主的颗粒氧化物,然后采用XPS获得了不锈钢表面氧化膜中主要元素的化学形态与质量占比。腐蚀动力学分析结果表明两种不锈钢材料的腐蚀速率与释放速率均随浸泡时间呈现先增加后趋于平缓的趋势,此外,6.8~7.4范围内的pH值变化对两种不锈钢材料的腐蚀释放行为影响较小。The effect of pH value on the corrosion behavior for 304 and 316 stainless steels in high-temperature and high pressurized water was investigated through corrosion experiment. The SEM-EDS results confirm the existence of metal oxide particles (Ni, Fe, Cr) on 304 and 316 stainless steel surfaces. The chemical component and speciation in oxide film were obtained by means of XPS analysis. The corrosion kinetics curves reveal that the corrosion rate and release rate firstly increase over exposing time, then tend to moderate. Furthermore, the corrosion release behaviors of 304 and 316 stainless steels are little influenced by the pH varied between 6.8 and 7.4.
文摘本文介绍了304不锈钢冷轧卷边鳞缺陷的形貌与产生原因,针对产生原因及结合公司生产实际对边鳞缺陷进行分析,发现冶炼化学成分、板坯加热工艺参数是影响304边鳞缺陷的主要因素。因此,通过调整S质量分数、N质量分数及均热温度等措施,缺陷率由3.68%降至0.42%以下,边鳞缺陷改善明显,产品质量得到了显著的提升。This article introduces the morphology and causes of edge scale defects in 304 stainless steel cold rolled coils. Based on the analysis of the causes and the actual production of the company, it is found that the smelting chemical composition and slab heating process parameters are the main factors affecting the edge scale defects in 304 stainless steel. Therefore, by adjusting the S mass fraction, N mass fraction, and soaking temperature, the defect rate decreased from 3.68% to below 0.42%, and the edge scale defects were significantly improved, resulting in a significant improvement in product quality.
