不锈钢的市场现状及发展趋势

介绍了世界不锈钢的市场现状，以及我国不锈钢的生产及消费情况；说明了我国不锈钢生产及市场前景看好，以及铁素体不锈钢是未来不锈钢的重要发展趋势。     

喷丸与沉积稀土薄膜对TP304H钢在SO2-O2气氛中高温腐蚀的影响

采用喷丸与电泳沉积稀土薄膜复合处理工艺对TP304H钢表面进行处理，在管式高温腐蚀试验装置中，以650℃通入1％SO2 14％O2 85％Ar混合气体腐蚀150h评价其抗腐蚀性能。结果表明，虽然单一沉积稀土氧化物薄膜和喷丸均能不同程度地提高抗腐蚀性能，但以复合处理效果最好。该处理方法可使试验周期内腐蚀增重量减少近50％，生成的腐蚀产物膜连续致密。X-ray衍射分析证明复合处理改变了腐蚀产物的物相构成，主要相成分由未处理样品的Fe2O3／Fe1-xS／Ni1-xS转变为Cr2O3／FeCr2S4／Ni3-xS2。最后讨论了喷丸与电泳沉积稀土薄膜复合处理提高抗腐蚀性能的机理，认为复合处理效果在于喷丸处理有效促进表层附近区域合金元素Cr向表层富集，稀土氧化物则促进了Cr的选择性氧化。     

304不锈钢冷轧卷连续钝化工艺参数的正交试验

用CIE1976L^*a^*b^*色空间中的白度HW^*作为不锈钢冷轧卷钝化后表面质量的评价指标，对304(18-8)奥氏体不锈钢板材的钝化工艺参数(HNO3 10％～20％，HF 0．8％～2．5％、钝化温度40～70℃、钝化时间1．0～3．0min)进行了正交试验和方差分析。试验和分析结果得出，不同炉批304不锈钢冷轧卷材，因成分和工艺差异，使板材最佳钝化工艺参数稍有不同，但从整体来看，304不锈钢卷材钝化的最佳工艺参数为：HNO3 10％～12％，HF 2．0％～2．5％，钝化温度40～50℃，钝化时间2．0～2．5min。     

不锈冷轧带钢表面光洁度的控制

在生产中，不锈冷轧带钢的表面光洁度一般用粗糙度进行控制，其粗糙度越低，光洁度越高。应使用低粗糙度和低微小缺陷面积率的不锈热轧带钢，高的总压下量，低粘度轧制油和平整率达到1％的工艺轧制可获得较高光洁度的不锈冷轧带钢。高速钢轧辊轧制的不锈冷轧带钢的光洁度优于模具钢轧辊。     

Surface Alloying of Nitrogen to Improve Corrosion Resistance of Steels and Stainless Steels

It is well known that the addition of nitrogen to steels and stainless steels enhances the passivity and localized corrosion resistance, in addition to improving the mechanical properties. Selective alloying of surfaces of steels and stainless steels with nitrogen could also enhance the corrosion resistance and improve the mechanical properties without affecting the bulk properties. Techniques like ion implantation, laser alloying, nitriding, etc. can be effectively used to introduce very high levels of nitrogen. In addition, these techniques can also produce modified surfaces with novel microstructures to further improve the properties. The surface alloying methods also provide an opportunity to selectively nitrogenate the surface of finished components in order to obtain better properties. The review highlights the techniques, modifications and the properties obtained further.     

板坯连铸中间包钢液洁净度的水力学模拟和应用

为改善太钢 10 4 0mm× 16 0mm连铸不锈钢板坯质量 ,通过水力学模拟研究了中间包内钢液的流动 ,并用直径 0 .5～ 1.0mm ,密度 0 .99mg/mm3 的聚苯乙烯塑料粒子模拟钢中直径 5 0～ 10 0 μm夹杂物的排除情况 ,确定了在中间包内设置挡渣墙和坝流控制方案 ,并进行 4 0 9不锈钢 10 4 0mm× 16 0mm连铸板的工业试验 ,结果表明 :中间包设置挡渣墙和坝后 ,铸坯夹杂物总量比中间包无控流装置生产的铸坯降低 6 6 %。     

奥氏体不锈钢化学抛光工艺的研究

通过试验对奥氏体不锈钢化学抛光工艺进行优选,研制了环保、经济的不锈钢抛光工艺。     

On R ratio dependence of threshold stress intensity factor range for fatigue crack growth in type 316(N) stainless steel weld

Abstract

The influence of R ratio in the range 0·05–0·4 on the ambient temperature fatigue crack growth behaviour of an austenitic stainless steel weld, SS 316(N), has been studied. Results indicate that the cyclic threshold stress intensity factor ΔK_th increases with decreasing R ratio. The data are compared with those for SS 316, SS 316L and SS 316L(N) base materials from the literature, and various approaches dealing with the R ratio effects are examined. Zhang’s model considering the contribution of the crack tip plasticity to the fundamental fatigue crack propagation process does provide a consistent interpretation for the data.