S201奥氏体不锈钢加热工艺制定

经过对S201奥氏体不锈钢炉温制度、加热速度、炉温均匀性、炉内气氛等基本要素的研究，结合板带厂加热炉的实际情况，制定S201奥氏体不锈钢加热工艺制度，并以的生产实践验证了加热工艺的合理性。     

氮对304奥氏体不锈钢组织和力学性能的影响

在０Ｃｒ１８Ｎｉ９奥氏体不锈钢成分基础上，加入一定的氮，并使钢中的镍含量控制在标准下限含量的条件下，研究了氮对组织和力学性能的影响。结果表明：加氮后钢的强度提高，奥氏体稳定不变，固溶态组织不变，而敏化后晶界析出物类型有所不同。     

不锈钢的轧制、退火、酸洗综合生产线

将轧制、退火和酸洗工段综合在一起的一体化的主要设想可追溯到1990年在瑞典的Avesta Nyby厂增加在线轧机。自此以后，通过在J＆L Midland，然后在Ugina Isbergue，最后在AvestaPolarit RAP5生产线上取得了进展。对不同阶段的综合生产线的工艺发展进行了比较，并且对Tornio的AvestaPolarit RAP5生产线的工艺流程和设备安装进行了总结。     

304奥氏体不锈钢高温氧化行为研究

针对304热轧卷高温氧化缺陷问题,通过SEM,EPMA,XRD,EDS和XPS分析了304热轧卷氧化皮的成分和结构,研究了304的氧化行为,探讨了大生产过程中卷取温度对304氧化行为的影响.研究表明304奥氏体不锈钢热轧卷的氧化皮结构比较致密,主要成分为铁铬尖晶石(Fe3-yCryO4).304的抗氧化性较强,温度低于900℃时,氧化极为缓慢;温度高于900℃后,氧化稳步增加.适当降低卷取温度,有利于304氧化皮的去除.     

304奥氏体不锈钢带氧化铁皮直接冷轧技术的研究

结合现场生产实际,通过在试验室对奥氏体不锈钢304黑皮卷直接进行压下率分别为10%,20%,30%的冷轧然后退火酸洗的试验,证明在退火酸洗工艺相同的情况下,通过在热轧后进行一定压下率的直接轧制,可以获得与传统No.1产品相比晶粒尺寸等级相同、表面粗糙度更低、力学性能和耐蚀性相近的2E产品,并且获得更大的热轧产品厚度范围,降低冷轧一个轧程后的产品厚度.因此根据不同客户的要求,可以用2E产品替代No.1产品.     

304不锈钢带材电致塑性轧制

 在自行研制的电致塑性轧机上,对304不锈钢带材进行多道次的冷轧和电致塑性轧制,对比研究不同轧制方式下材料的变形抗力、硬度、抗拉强度及伸长率等性能变化,并对微观组织进行系统分析。结果表明,轧制过程中引入适当的高能脉冲电流,能显著降低材料的变形抗力。各道次电轧后的试样强度低于冷轧试样,伸长率则显著提高,变形能力大大改善。同时,电轧可减少或取消材料加工中的退火工序,提升生产效率。这对寻找一条清洁环保、节能高效的生产工艺道路有十分重要的工程意义。     

Metallurgical Studies of Austenitic Stainless Steel 304 under Warm Deep Drawing

Austenitic stainless steel 304 was deep drawn with different blank diameters under warm conditions using 20 t hydraulic press. A number of deep drawing experiments both at room temperature and at 150 ℃ were conducted to study the metallography. Also, tensile test experiments were conducted on a universal testing machine up to 700 ℃ and the broken specimens were used to study the fractography of the material using scanning electron microscopy in various regions. The microstructure changes were observed at limiting draw ratio （LDR） when the cup is drawn at different temperatures. In austenitic stainless steel, martensite formation takes place that is not only affected by temperature, hut also influenced by the rate at which the material is deformed. In austenitic stainless steel 304, dynamic strain regime appears above 300 ℃ and it decreases the formability of material due to brittle fracture as studied in its fractography. From the metallographic studies, the maximum LDR of the material is observed at 150 ℃ before dynamic strain regime. It is also observed that at 150 ℃, grains are coarse in the drawn cups at LDR.     

In Situ Observation of Solidification Process of AISI 304 Austenitic Stainless Steel

The solidification process of AISI 304 stainless steel during cooling at a rate of 0.05 K/s has been observed in situ using a confocal scanning laser microscope （CSLM）. The results show that the 8 phase appeared first in liquid steel, as the temperature decreased, the γ phase precipitated prior at δ-grain boundary at 1452. 2 ℃, the liquid steel disappeared at 1 431.3 ℃, and then the γ phase precipitated on the δ ferrite. Based on the Scheil-Gulliver solidification model, the solidification processes of AISI 304 stainless steel are simulated using the Scheil model in Thermo Calc, and the simulation results agree well with the results observed in the experiment.     

Tribological Investigation of Effect of Grain Size in 304 Austenitic Stainless Steel

Stainless steels are widely used in a variety of engineering applications such as food appliances, surgical instruments, nuclear reactors and cryogenic applications. The properties of stainless steel are greatly affected by the grain size. The present study investigates the effect of grain size on sliding wear behavior of AISI 304 stainless steel. The sliding wear properties are measured using a Pin-on-Disc machine. Annealing heat treatment process varies the grain size of steel at 1100 °C. The wear test is performed on different grain sizes of AISI 304 steel at various sliding speeds under dry condition. The wear rate of the steels at different sliding distances is plotted as a function of grain size. The maximum wear rate is obtained at an intermediate grain size. It is noted that frictional force and temperature initially increases and then reaches the saturation plateau. The results are used to establish a correlation between the grain size and sliding wear properties of stainless steel. The present study is useful in enhancing the life of various components made of the stainless steel.     

304L不锈钢轧制边裂缺陷研究

钢厂采用立式连铸生产304L不锈钢,但在轧制过程中易出现边裂现象。本文采用化学成分分析、微观组织观察、能谱分析及高温力学性能检测等手段,对钢材组织、边裂部位的断裂形貌以及断裂部位存在的夹杂物进行了研究。结果表明304L热轧板的组织为奥氏体和铁素体。裂纹穿过两相组织并导致组织的压缩变形。裂纹内含有CaO-SiO₂-Al₂0₃-MgO复合型夹杂物,夹杂物含有Na元素和K元素。最终确定在生产过程中卷进的保护渣是导致钢材产生轧制边裂的原因。     

Advances in the Optimization of Thin Strip Cast Austenitic 304 Stainless Steel

This study is about the latest advances in the optimization of the microstructure and properties of thin strip cast austenitic stainless steel (AISI 304, 1.4301). Concerning the processing steps the relevance of different thin strip casting parameters, in‐line forming operations, and heat treatments for optimizing microstructure and properties have been studied. The microstructures obtained from the different processing strategies were analysed with respect to phase and grain structures including the grain boundary character distributions via EBSD microtexture measurements, the evolution of deformation‐induced martensite, the relationship between delta ferrite and martensite formation in austenite, and the texture evolution during in‐line deformation. It is observed that different process parameters lead to markedly different microstructures and profound differences in strip homogeneity. It is demonstrated that the properties of strip cast and in‐line hot rolled austenitic stainless steels are competitive to those obtained by conventional continuous casting and hot rolling. This means that the thin strip casting technique is not only competitive to conventional routes with respect to the properties of the material but also represents the most environmentally friendly, flexible, energy‐saving, and modern industrial technique to produce stainless steel strips.     

铸态304L奥氏体不锈钢等径角挤压变形研究

 研究了铸态304L奥氏体不锈钢在等径角挤压(ECAP)变形过程中显微组织的演变过程。结果表明,经4道次剪切变形后树枝晶破碎、原始粗大晶粒碎化。显微组织的变化过程可归纳为：原始粗晶粒→晶粒被滑移带分割→位错发展形成高密度位错墙,与滑移带共同作用形成胞块结构→应变增加形成层片状界面→形成大角度晶界的细小晶粒。表明铸态304L奥氏体不锈钢经ECAP变形后塑性变形机制主要由滑移完成。