Sn对SUS304HC奥氏体不锈钢的有害影响

研究了 Sn在 SUS30 4 HC含铜奥氏体不锈钢生产中的有害影响。结果表明 :Sn原子易在钢锭激冷层产生偏析 ,通常聚集在晶界上 ,削弱了晶界结合力 ,使热塑性下降。锡含量高的 SUS30 4 HC含铜奥氏体不锈钢初轧开坯时容易出现开裂现象。 SUS30 4 HC含铜奥氏体不锈钢中锡含量在 0 .0 11%以下 ,铅当量 1.1× 10 - 6以下 ,一般不会对热塑性产生不良影响。通过改变加入的 Cu合金种类 ,并对含 Sn废钢加入量进行控制 ,解决了 SUS30 4 HC中锡含量高的问题。     

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。     

Sn含量对粉末冶金304不锈钢组织和性能的影响

采用真空烧结制备了304奥氏体粉末冶金不锈钢,研究了不同Sn含量对粉末冶金304不锈钢材料显微组织、密度、抗拉强度和耐腐蚀性能的影响。结果表明：在烧结温度1 300℃的条件下,随着Sn的添加量增加,组织中的孔隙数量减少,孔隙尺寸减小且分布均匀,不规则的大孔隙逐渐变为球形的小孔隙,试样具有最大的密度7.308 g/cm³。当Sn的添加量为2%时,烧结试样断口的韧窝分布均匀,孔隙发生球化,孔隙较小且尺寸均匀,韧窝之间以网状相连,此时力学性能达到最优,硬度和抗拉强度分别达到62.23HRB和363.34 MPa。继续增大Sn的添加量,由于密度下降,力学性能也随之下降,断口中韧窝尺寸增大且出现不规则的形状。电化学实验表明,随着Sn含量增加到2%,304不锈钢的耐蚀性先增大后减小。     

201不锈钢与304不锈钢耐腐蚀性能的研究

本文用动电位极化法及浸泡法比较了304不锈钢及201不锈钢的耐蚀性，结果发现，201不锈钢的耐晶间腐蚀性能优于304不锈钢，且其耐醋酸的腐蚀性也明显地优于304不锈钢，但其耐硝酸的腐蚀性能却不如304不锈钢，因此，我们认为经济型的201不锈钢具有良好的应用前景。     

形变马氏体对304L奥氏体不锈钢显微组织和力学性能的影响

非稳态奥氏体不锈钢在经过变形后,极容易产生形变马氏体组织。本实验分析了固溶处理后304L奥氏体不锈钢在5%～50%轧制变形下马氏体显微组织的变化情况,测量了不同变形量下形变马氏体含量。同时分析不同形变马氏体含量对304L奥氏体不锈钢拉伸力学性能,得到形变马氏体含量对材料拉伸力学性能的影响关系。     

Sn对含铜奥氏体不锈钢热塑性的影响

本文主要分析讨论了Sn对含铜奥氏体不锈钢线材生产及应用的影响。Sn原于易在钢锭激冷层偏析，通常聚集在晶界上，形成低熔点共晶体，削弱了晶界结合力，使钢的热塑性下降。Sn含量高的含铜奥氏体不锈钢线材进一步加工时会发生的脆断现象。含铜奥氏体不锈钢中Sn含量控制在某一范围内，铅当量小于某一值时，一般不会对热塑性造成影响。     

铜对奥氏体抗菌不锈钢性能的影响

 研究了不同铜含量的奥氏体抗菌不锈钢的抗菌性能、腐蚀性能和力学性能。样品经过热轧、抗菌热处理、冷轧、退火处理后,进行了抗菌试验、腐蚀试验等。试验结果表明,随着铜含量的增加,抗菌性逐渐提高;其耐点蚀性随着铜含量的增加呈提高的趋势;强度随着铜含量的增加先减后增,塑性先增后减。     

Cu对304奥氏体不锈钢应变诱发马氏体相变的影响

借助 X-射线衍射分析法研究了 0.45% ~1.44%Cu 对(%)：0.068 ~ 0.072C 18.72~19.06Cr 、9.40~ 9.46Ni的304不锈钢-196 ℃低温拉伸应变诱发马氏体相变的影响。结果表明,Cu对304不锈钢-196 ℃应变诱 发e马氏体相变有明显的抑制作用;当Cu含量增至1.44%时,在经低温变形的钢中未检测到ε马氏体相变。随钢中Cu含量增加,-196℃ 应变诱发α'马氏体相变倾向降低,致使应变累积到一定程度后,流变应力低于低Cu钢。     

高铝304奥氏体不锈钢温轧态的组织和性能研究

采用高铝304不锈钢为对象,对其进行温轧处理,研究铝含量和温轧变形量对微观组织和性能的影响规律,利用光学显微镜(OM)、电子探针(EPMA)和扫描电子显微镜(SEM)分析了合金的表面形貌和表面成分。结果表明:组织主要由灰色的奥氏体相和浅黑色的铁素体相组成,黑色析出物是由氮化铝和其他碳化物所组成的富集相,随铝含量增大,铁素体的含量增高。铝含量为1%的试样三种轧制变形量下的屈服强度分别是285、266、273 MPa,而含铝量为1.5%的试样屈服强度分别是350、365、322 MPa;合金的断口都是由大的等轴韧窝(5～30μm)和旁边排布的较小韧窝(≤5μm)所构成,不同变形量下的断裂方式均是韧性断裂;含铝量为1%的试样具有较高的抗拉强度,而铝含量为1.5%的试样具有较高的屈服强度,高铝不锈钢各项性能指标有很大改善,对工业生产具有重要意义。     

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.     

冷轧变形量对304不锈钢力学性能的影响

 研究304奥氏体不锈钢薄板的硬度随冷轧变形量的变化规律,为奥氏体不锈钢薄板工业生产提供指导。同时,采用金相显微镜、维氏硬度测量、X-射线衍射仪和透射电镜研究了不同变形量冷轧对304不锈钢显微组织和机械性能的影响。在室温对0.5mm厚退火板材进行冷轧,使冷轧变形量从10%增加到52%。结果表明,形变诱发马氏体相变是导致304不锈钢冷轧时产生加工硬化的主要原因,冷轧可以显著提高钢的强度和硬度。当冷轧变形至40%时,304不锈钢的维氏硬度是未变形时的2.2倍,屈服强度、抗拉强度分别增大到未变形时的4.2倍（880MPa）和1.8倍（1312MPa）。     

铸态304L奥氏体不锈钢等径角挤压变形的力学性能

 研究了经1~4道次等径角挤压变形(ECAP)后,铸态304L奥氏体不锈钢微观结构的演变,同时测定了ECAP变形后的力学性能。结果表明,经4道次变形后,铸态粗大晶粒破碎形成细小的大角度晶粒,平均晶粒尺寸约202 nm;抗拉强度和屈服强度大大提高(Rp02=1 002 MPa,Rm=1 100 MPa),但均匀塑性变形能力(A＜3%)和加工硬化指数(n=0060)却显著下降。     

奥氏体不锈钢302和304的轧制

由于奥氏体不锈钢加Ｔｉ后污染钢液,在钢中形成ＴｉＮ和Ｔｉ(ＣＮ)夹杂,国外含Ｔｉ奥氏体不锈钢的生产量很小(只占0.5%),所以不含Ｔｉ的302和304奥氏体不锈钢得到了广泛应用。302钢号相当于1Ｃｒ18Ｎｉ9,304钢号相当于0Ｃｒ18Ｎｉ9。1　302和304不锈钢的轧制特点(1)钢的导热性差,导热系数相当于低碳钢的27%,加热速度较慢,一般为130℃ｈ。(2)在900～1250℃时有良好的塑性,但热变形抗力很大,随着加工过程中温度的下降,变形抗力急剧增高,因而要控制终轧温度和变形程度,通常轧制时为使终轧温度不低于950℃,轧辊表面不浇冷却水,并控制最大相对压…     

Characteristics of Mechanical Properties and Microstructure for 316L Austenitic Stainless Steel

 A comparative study on mechanical properties and microstructure of 316L austenitic stainless steel between solution treated specimen and hot rolled specimen was conducted. After a specimen was subjected to solution treatment at 1050 ℃ for 6 min, its mechanical properties were determined through tensile and hardness tests. Based on the true stress vs true strain and engineering stress vs engineering strain flow curves, the work hardening rate has been explored. The results show that the solution treated specimen has an excellent combination of strength and elongation, and that this steel is easy to work-hardening during deformation. Optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffraction examinations were conducted, these reveal that twins in 316L austenitic stainless steel can be divided into suspended twin and transgranular twin which have different formation mechanisms in growth, and that the deformation induced martensite nucleated and grown in the shear band intersections can be observed, and that the fracture surfaces are mainly composed of dimples and exhibit a tough fracture character.     

Influence of Pre-Transformed Martensite on Work-Hardening Behavior of SUS 304 Metastable Austenitic Stainless Steel

The metastable austenite was transformed to martensite by prestrain tension of SUS304 stainless steel to study the influence of transformed martensite on its subsequent work-hardening behavior under the uniaxial tensile condition. The X-ray diffractometer (XRD) was employed to detect the transformed martensite. Results showed that the volume fraction of transformed martensite increases with increasing prestrain. The pre-transformed martensite in the microstructure remarkably affects the deformation behavior of the steel, and the strength increases and the elongation decreases. The work-hardening curve of prestrained specimens observably changes with true strain. The work-hardening exponent n of stainless steel decreases with the increase of pre-transformed martensite. The achievement is a significant contribution to the process design during pressing.     

Influence of PreTransformed Martensite on WorkHardening Behavior of SUS 304 Metastable Austenitic Stainless Steel

 The metastable austenite was transformed to martensite by prestrain tension of SUS304 stainless steel to study the influence of transformed martensite on its subsequent work hardening behavior under the uniaxial tensile condition. The X ray diffractometer (XRD) was employed to detect the transformed martensite. Results showed that the volume fraction of transformed martensite increases with increasing prestrain. The pre transformed martensite in the microstructure remarkably affects the deformation behavior of the steel, and the strength increases and the elongation decreases. The work hardening curve of prestrained specimens observably changes with true strain. The work hardening exponent n of stainless steel decreases with the increase of pre transformed martensite. The achievement is a significant contribution to the process design during pressing.