高纯Cr17铁素体不锈钢热轧板退火温度对冷轧退火板成形性能的影响

研究高纯Cr17铁素体不锈钢的热轧板退火温度对最终冷轧退火板成形性能的影响。对一种铌、钛双稳定化的高纯Cr17铁素体不锈钢的热轧板进行了不同温度的退火试验,随后经相同的冷轧及退火处理,系统研究了其对组织演变、织构演变及成形性能的影响。结果表明:热轧板的退火温度是影响最终板成形性能的重要因素。随着热轧板退火温度的升高,冷轧退火板的晶粒尺寸逐渐增大甚至产生"混晶",γ纤维再结晶织构逐渐减弱,导致r-值减小,Δr值增大,使成形性能恶化。所以,在保证热轧板发生完全再结晶的前提下,退火温度应尽量低。试验钢的热轧板经900℃退火后,冷轧退火板具有最佳的成形性能:r-值高达1.80,而Δr值仅为0.15。     

高强度及超高强度双相不锈钢线材的应用

1前言 如今在许多领域中双相不锈钢被视为经久耐用的代名词。这主要是南于双相不锈钢兼具高强度、高塑性和优异的耐蚀性能。同溶条件下的双相不锈钢其强度约为奥氏体不锈钢的两倍。SAF2205是一种传统中等合金含量的双相不锈钢，具有高的耐蚀、力学性能和良好的焊接性能。SAF2205和其他2205型双相钢牌号之间的不同在于SAF2205成分控制范围更窄。     

应用铁素体区轧制工艺生产ELC钢

通过铁素体区热轧工艺生产ELC钢的工业试验,研究了一种ELC钢的热轧组织、织构及性能。结果表明,铁素体区热轧后,ELC钢大部分为变形带组织,放大1 000倍可以看到鱼骨状的晶内剪切带;热轧后,织构沿板厚方向均匀分布,织构的遗传性使得冷轧和退火后的织构沿板厚方向也均匀分布,但是退火织构中仍有{001}<110>织构存在;退火后钢板的r值在1.3左右,达到普通冲压级钢板的要求。     

终轧温度对超纯铁素体不锈钢组织、织构及成形性能的影响

研究了终轧温度对铌、钛双稳定化超纯Cr17铁素体不锈钢的组织演变、织构演变及成形性能的影响。研究结果表明,降低终轧温度能有效细化、均匀化热轧及退火组织。降低终轧温度能增强冷轧退火板的γ纤维再结晶织构、减轻偏离{111}121组分的程度。降低终轧温度是提高r值、降低Δr值、改善冷轧退火板成形性能的有效手段。     

冷轧压下率对439L铁素体不锈钢组织和性能的影响

冷轧工艺会对铁素体不锈钢的后续退火组织产生重要影响,也是铁素体不锈钢获得良好的表面质量、力学及成形性能的关键.以Nb+Ti双稳定439L铁素体不锈钢为实验材料,采用X射线衍射、微观组织表征以及性能测试等手段,研究了不同的冷轧压下率(60%～85%)对该不锈钢退火过程(1 000℃×2 min)中的微观组织和织构的演变及其力学和成形性能的影响.结果表明：随着冷轧压下率的增加,439L铁素体不锈钢退火后的γ织构不断增强,α织构逐渐消失,即在退火过程中发生了由α→γ织构的转变;同时,随着冷轧压下率的增加,退火织构的峰值强点逐渐向γ取向线靠近,此时439L冷轧退火板的平均塑性应变比(r_m)不断增加,在压下率为80%时具有最小的各向异性指数绝对值(|Δr|).     

核电站设备制造中双相不锈钢的应用

奥氏体-铁素体双相不锈钢中稳定存在奥氏体相和铁素体相,该钢具有较高的机械性能和优异的耐点蚀、晶间腐蚀和应力腐蚀性能,在核电站设备制备中被广泛应用。一般双相不锈钢铸件中铁素体相的体积分数≤20%,服役温度≤425℃,双相不锈钢锻件中铁素体相约占50%,服役温度≤250℃。文中介绍了核电站设备中应用的双相不锈钢铸、锻件的化学成分、制造和焊接工艺要求及组织和性能。     

固溶温度对2205双相不锈钢氢脆敏感性的影响

采用光学显微镜、慢应变速率拉伸、扫描电镜研究了2205双相不锈钢固溶温度与氢脆敏感性的关系。结果表明:随着固溶温度的升高,2205双相不锈钢中铁素体含量升高,奥氏体含量降低。奥氏体含量为48.8%时,2205双相不锈钢具有最低的氢脆敏感性,随着铁素体含量的上升,其氢脆敏感性逐渐升高。二次裂纹的产生和发展过程表明2205双相不锈钢氢脆敏感性是由奥氏体相的含量和晶粒尺寸所决定的。     

JSP-双机可逆冷轧条件下IF钢织构研究

针对济钢现场工艺条件下生产的Ti-IF钢,利用X’Pert ProxX射线衍射宏观织构分析方法,研究了中薄板坯热连轧轧制及随后的冷轧、退火工艺过程中织构的变化规律。IF钢冷硬板主要织构类型为{111}〈110〉、{111}〈112〉和{001}〈110〉,其中{111}〈110〉织构强度达到12;再结晶退火后的IF钢退火板,主要织构类型为{111}〈110〉和{111}〈112〉,{111}〈110〉织构强度提高到15.37。济钢生产的Ti-IF钢获得了对板材成形最有利的{111}//ND织构。     

精轧温度对超纯21%Cr铁素体不锈钢织构演变和成形性能的影响

研究了超纯21%Cr铁素体不锈钢精轧温度对织构演变规律和成形性能的影响。将粗轧板坯切块并在900~750℃范围内进行精轧,随后经相同的热轧退火、酸洗、冷轧及退火处理,系统研究了试样的宏观织构、显微织构和成形性能的变化规律。结果表明:精轧温度对铁素体不锈钢的织构演变有重要影响,降低热轧精轧温度有利于增加热轧退火板中{111}再结晶织构组分;冷轧及冷轧退火板的织构分布具有明显的遗传性,热轧板中较高的{111}再结晶织构组分,促进了冷轧退火板中{111}再结晶织构的生成,从而提高了铁素体不锈钢的成形性能。     

低碳钢板冷轧织构的不均匀性

用X射线衍射法测量了冷轧低碳钢板的表层和心部织构.实验结果表明,钢板表层主要包含{112}〈110〉和{001}〈110〉织构组分,心部主要包含{112}〈110〉和{111}〈110〉织构组分,说明低碳钢板冷轧织构具有不均匀性.用改进的Sachs模型模拟了体心立方金属冷轧织构的演化过程,与实验结果有较好的一致性.     

轧制方式对SUS430铁素体不锈钢组织和性能的影响

 采用X射线衍射技术和光学显微分析等方法,研究了同步和异步冷轧方式对SUS430铁素体不锈钢微观组织、织构演变以及力学和成形性能的影响。结果表明,与同步冷轧相比,由于异步轧制剪切变形的引入,可使异步冷轧板材的平均晶粒尺寸减小。在同步冷轧过程中,其二次冷轧再结晶织构为完整的γ纤维织构,导致铁素体不锈钢的最终性能优于同步一次冷轧;而在异步冷轧过程中,异步一次冷轧再结晶织构为强点{111}<[1][1]2>的γ纤维织构,异步二次冷轧再结晶织构属于随机取向织构,其结果是异步一次冷轧板材的性能优于异步二次冷轧。综合分析表明,与异步二次冷轧方式相比,同步二次冷轧方式有利于铁素体不锈钢性能的提高。     

铁素体不锈钢铸轧薄带凝固组织对冷轧退火带晶粒簇的影响

 研究了Cr17铁素体不锈钢铸轧薄带凝固组织对其冷轧退火带晶粒簇、成形性和皱折特性的影响。利用电子背散射衍射技术对Cr17铁素体不锈钢铸轧薄带及相应的冷轧退火带进行了显微织构分析。结果表明：①Cr17铁素体不锈钢铸轧薄带冷轧退火带的晶粒簇依赖于初始铸轧薄带的凝固组织类型;②柱状晶组织的铸轧薄带具有显著的{001}∥ND晶体取向特征,而等轴晶组织的铸轧薄带晶体取向随机、分散;③等轴晶组织铸轧薄带比柱状晶组织铸轧薄带的冷轧退火带具有更少的{001}<110>晶粒簇和更多的{111}<112>、{111}<110>晶粒簇;④铸轧薄带的等轴晶组织比柱状晶组织有利于提高冷轧退火带的成形和抗皱性能。     

薄带连铸与常规生产流程条件下 Cr17铁素体不锈钢的织构及成形性能

研究了薄带连铸条件下Cr17铁素体不锈钢薄带坯的初始组织及织构,并重点对常规连铸坯和等轴晶薄带坯在轧制及退火过程中的织构演变进行了对比研究.研究结果表明:在薄带连铸条件下,通过调整熔池内钢水的过热度可以实现对薄带坯初始组织、织构的有效控制.在较低的过热度(20～40℃)条件下,可以获得具有全等轴晶组织和随机织构的薄带坯...     

Effect of Hot Band Annealing Processes on Microstructure,Texture and r-Value of Ferritic Stainless Steel

The effect of hot band annealing processes,namely simulating batch annealing and continuous annealing,on microstructure,texture,grain boundary character and r-value of ferritic stainless steel was investigated.The hot band displayed a highly elongated ribbon-like structure and a pronounced deformation texture.The fully recrystallized grains were observed after continuous annealing while the "typical" hot rolled structure was remained after batch annealing.Also,the α-fibre texture formed during hot rolling almost disappeared after continuous annealing and a weak γ-fibre texture was obtained.By contract,the α-fibre texture remained very stable after batch annealing.After cold rolling and recrystallization annealing,the favorable γ-fibre texture was achieved in the continuous annealed steel.Instead of forming the γ-fibre texture,the recrystallization texture was notably shifted toward {223}582 in the batch annealed steel.Finally,the improvement in drawability with high r-value and low Δr-value were also displayed in sheet through the initial continuous annealing process.     

Effect of Processing Condition on Texture and Drawability of a Ferritic Rolled and Annealed Interstitial-Free Steel

The processing conditions of the texture formation and deep drawability of a Ti-IF steel strip hot-rolled in ferritic region and subsequently annealed were investigated. The r-value increases with the decrease of reheating temperature, and finish rolling temperature and the increase of reductions in ferritic region. For lubricated ferritic rolling and annealing, the r-value is raised up to 1.75, and elongation rate is over 50% at the finish rolling temperature of 650 ℃, which is suitable for DDQ grade products. However, the r-value is below 1.0 in the case of unlubricated rolling. The X-ray diffraction was used to analyze the textural characteristic of samples. For samples subjected to lubricated rolling and annealing, the strong { 111 }//ND recrystallization texture is distributed homogeneously along the thickness direction, and the intensity of { 110} recrystallization texture is very low even in surface. However, for unlubricated samples, the {111} texture is distributed inhomogeneously and is weak along the thickness direction, and （110}//ND recrystallization texture is strong, which deteriorates the formability.     

双辊铸轧Cr12钢的热处理工艺对深冲性和抗皱性的影响

将双辊铸轧Cr12钢薄板于1 000℃固溶,再采用炉冷和水淬两种方式冷却至室温,分别获得了多边形铁素体和板条马氏体两种组织,再经过相同冷轧和退火工艺,得到了两种成品板.经拉伸试验测定,水淬板的深冲性和抗皱性均强于炉冷板.组织分析发现:热处理后,水淬板内马氏体板块明显细小于炉冷板内铁素体晶粒;冷轧后,水淬板内板块间界演变...     

00Cr12Ti铁素体不锈钢的再结晶退火与成形性研究

 研究了1.0 mm厚 00Cr12Ti冷轧板在再结晶退火工艺条件下力学性能的变化规律。研究结果表明,随着退火温度的升高,维氏硬度、屈服强度、抗拉强度和屈强比均呈快速下降趋势,在超过800 ℃之后变化不大。再结晶退火后,00Cr12Ti钢拥有较多的{111}取向的晶粒,塑性应变比值r0、r45、r90和r-在退火温度超过780 ℃以后都有较大升高,并且r90>r0>r45。在700～800 ℃之间,平面各向异性Δr值变化不大,随后Δr值随温度上升急剧升高,因而成形时易产生严重的制耳现象。通过杯突试验发现,杯突值IE与r-值的变化相一致,表明00Cr12Ti冷轧板在高温再结晶退火后,可获得良好的成形性能。     

摩擦对IF钢铁素体区热轧和退火织构的影响

采用X射线衍射仪分析IF钢铁素体区热轧织构以及退火织构的演化,在实验室热轧机上进行了IF钢的铁素体区热轧,研究了摩擦对IF钢铁素体区热轧、退火织构的影响。结果表明：无润滑轧制时,钢板表层形成强高斯织构组分{110}〈001〉,弱γ纤维织构,导致再结晶织构中高斯组分强度高,γ纤维织构强度低;润滑轧制时,钢板表层高斯织构组分强度降低,{100}〈011〉、γ纤维织构强度提高,退火后γ纤维织构强度提高。钢板中心受摩擦作用影响较小,轧制过程中发展为较强的α和γ纤维织构,退火后γ纤维织构成为主要织构组分。     

Microstructure, Texture, and Formability of Nb+Ti Stabilized High-Purity Ferritic Stainless Steel

 The microstructure, texture and formability of Nb+Ti stabilized high-purity ferritic stainless steel were investigated. The interstitial elements C and N could be fully stabilized with Nb and Ti, and the precipitates were mainly composed of TiN and NbC. By analyzing texture at the various thermomechanical processes, the intensity of α-fiber obtained during hot rolling was reduced greatly after annealing and a non-uniform γ-fiber was achieved. The favorable γ-fiber was displayed in cold rolled and annealed sheet, whereas the texture maximum located at (554)<225>. The formation of this shifted texture mainly attributed to the influence of “Zener” drag and selective growth. Finally, the obtained mean r-value was notably higher, mean r=1.70, compared with traditional ferritic stainless steels.     

Evolution of Through-Thickness Texture in Ultra Purified 17%Cr Ferritic Stainless Steels

 Texture inhomogeneity usually takes place in ferritic stainless steels due to the lack of phase transformation and recrystallization during hot strip rolling, which can deteriorate the formability of final sheets. In order to work out the way of weakening texture inhomogeneity, conventional hot rolling and warm rolling processes have been carried out with an ultra purified ferritic stainless steel. The results showed that the evolution of through-thickness texture is closely dependent on rolling process, especially for the texture in the center layer. For both conventional and warm rolling processes, shear texture components were formed in the surface layers after hot rolling and annealing; sharp α-fiber and weak γ-fiber with the major component at {111}<110> were developed in both cold rolled sheet surfaces, leading to the formation of inhomogeneous γ-fiber dominated by {111}<112> after recrystallization annealing. In the center layer of conventional rolled and annealed bands, strong α-fiber and weak γ-fiber textures were formed; the cold rolled textures were comprised of sharp α-fiber and weak γ-fiber with the major component at {111}<110>, and inhomogeneous γ-fiber dominated by {111}<112> was formed after recrystallization annealing. By contrast, in the centre layer of warm rolled bands, the texture was comprised of weak α-fiber and sharp γ-fiber, and γ-fiber became the only component after annealing. The cold rolled texture displayed a sharp γ-fiber with the major component at {111}<112> and the intensity of γ-fiber close to that of α-fiber, resulting in the formation of a nearly homogeneous γ-fiber recrystallization texture in the center layer of the final sheet.