Influence of Texture on Magnetic Aging of Cold Rolling Non‐oriented Silicon Steel Sheets

The relationship between magnetic aging and texture of 50W800 non‐oriented silicon steel (0.002~0.003 % C) was investigated. The Young's modulus of cementite is very close to that of {100} planes in ferrite and obviously lower than those of other crystallographic planes in ferrite. Therefore, cementite particles would precipitate in the form of disks along the {100} planes of the ferrite matrix during aging. The magnetic properties after aging at 200°C for 24 hours showed that the aging precipitation of cementite particles increased the core loss. The driving force for the wall movement of 180° stripe domains depends on the sheet texture. The texture, in which the <100> direction is parallel to the magnetizing field, is the most favourable texture component to reduce the core loss increment induced by aging.     

卷取温度对深冲DP钢组织性能及织构的影响

为研究深冲织构的演变规律,利用OM、TEM和XRD等技术研究了热轧卷取温度对微碳深冲DP钢组织、性能与织构的影响。结果表明,热轧板主要由铁素体＋珠光体构成,随卷取温度升高,铁素体晶粒略增大,伸长率逐渐上升;热轧板中钼基碳化物的最佳析出温度为700℃;与650和750℃相比,700℃卷取后的退火板能获得较高体积分数（4.0%）马氏体与较细（11.7μm）铁素体的组织特征,同时拥有最强的〈111〉//ND纤维织构和最弱的{001}〈110〉织构,使得其抗拉强度达到455 MPa,塑性应变比r值达1.5。     

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。     

Textures and Properties of Hot Rolled High Strength Ti-IF Steels

The texture evolution in a high strength Ti-IF steel during the processing of hot rolling, cold rolling, and annealing is studied. For comparison, both ferrite rolling and austenite rolling are employed. It is found that the texture type is the. same after ferrite rolling and austenite rolling, but the texture intensity is much higher in the ferrite rolled sample. Furthermore, texture characteristics at the surface are absolutely different from those at the mid sec tion in both ferrite rolled and austenite rolled samples, as well as under the cold rolled and annealed conditions. The shear texture { 110 } 〈001 〉 disappears and orientation rotates along { 110 } 〈001 〉→ { 554 } 〈 225 〉→ { 111 } 〈 112 〉→{111}〈110〉→{223}〈110〉 during cold rolling. Compared to the austenite rolled sample, the properties of the cold rolled and annealed sheet which is subjected to ferrite rolling are higher.     

裂解连杆用高强度非调质钢的研制

设计了用于裂解连杆的高强度非调质钢及其生产工艺,通过金相显微镜、扫描电镜等方法,分析了钢的显微组织、析出相及其对力学性能的影响。结果表明:组织由铁素体和珠光体组成,向钢中添加高的V和N元素,有利于增加更多的弥散析出相,提高其强度。轧后加速冷却,有利于铁素体晶粒细化、珠光体球团尺寸和珠光体片层间距减少、析出相增多,使其抗拉强度和屈服强度分别达到1 000 MPa和750 MPa以上。     

铁素体钢中白点缺陷的检验分析

 通过金相显微镜、扫描电镜等分析方法对铁素体钢低倍检验后发现的疑似白点缺陷进行了分析判断,发现疑似白点缺陷在金相显微镜下呈锯齿状裂纹,为白点裂纹形貌特征。通过对低倍试样上断口的检验发现,低碳铁素体钢宏观断口处分布有银灰色圆形斑点,为白点缺陷特征,铁素体不锈钢宏观断口无明显白点特征,但铁素体不锈钢的疑似白点显微断口有沿晶断裂和以夹杂物为裂纹源的解理断裂两种,都具有氢脆断口特征,由此判断,两种铁素体钢中缺陷均为白点缺陷。铁素体不锈钢中的白点缺陷与常见白点断口上的浮云状、波纹状、解理羽毛、显微疏松等形貌特征有所不同,而且不同铁素体不锈钢试样上的白点缺陷断口形貌也不同,一处为沿晶断裂,一处为以夹杂物为裂纹源的解理断裂。     

Structure of IF steel in continuous annealing

The recovery and recrystallization kinetics of IF titanium steel is studied by investigating the microstructure, measuring the coercive force, and analyzing the residual stress. The results are familiar, except for the initial and final temperatures of these processes, which are specific to the steel employed. We assume that, on heating cold-rolled IF steel in the range 550?C650°C, the dislocation density is unchanged on account of retardation by small TiC particles. Formulas are derived for the coercive force as a function of the grain size and may be used for monitoring purposes.     

钢中非金属夹杂物对显微组织的影响

使用金相法对碳素结构钢Q235B钢板的拉伸试样非正常断口进行分析,研究了钢中夹杂物类型和形态以及钢的显微组织。结果表明,Q235B钢板拉伸试样非正常断口及附近部位夹杂物严重,且存在粗大的带状组织,带状铁素体中有明显的非金属夹杂物。粗大带状组织的形成原因是由于铁素体以非金属夹杂物为结晶核心并沿着非金属夹杂物的变形方向生长而形成的。     

Texture and Microstructural Evolution in Pearlitic Steel During Triaxial Compression

This article presents the deformation behavior of high-strength pearlitic steel deformed by triaxial compression to achieve ultra-fine ferrite grain size with fragmented cementite. The consequent evolution of microstructure and texture has been studied using scanning electron microscopy, electron back-scatter diffraction, and X-ray diffraction. The synergistic effect of diffusion and deformation leads to the uniform dissolution of cementite at higher temperature. At lower temperature, significant grain refinement of ferrite phase occurs by deformation and exhibits a characteristic deformation texture. In contrast, the high-temperature deformed sample shows a weaker texture with cube component for the ferrite phase, indicating the occurrence of recrystallization. The different mechanisms responsible for the refinement of ferrite as well as the fragmentation of cementite and their interaction with each other have been analyzed. Viscoplastic self-consistent simulation was employed to understand deformation texture in the ferrite phase during triaxial compression.     

72A帘线钢线材冷拔笔尖状断裂分析和改进工艺措施

72A帘线钢线材拉丝笔尖状断裂的推动力,为拉拔时的不均匀变形。心部粗大的先共析铁素体和粗片状渗碳体易形成粗拉时的裂纹源;中心偏析产生的裂纹多出现在中拉工序。控制连铸坯中心碳偏析指数≤1.1,采用相变前≥15℃/s快冷,相变区600～620℃近似等温的控冷策略,获得先共析铁素体含量≤0.8%,索氏体率达90%的均匀组织,基本杜绝了72A线材直拉时笔尖断裂的产生。     

多边铁素体对X70管线钢DWTT性能影响分析

借助光学显微镜和扫描电子显微镜研究分析了多边铁素体对X70管线钢DWTT剪切面积百分比SA%的影响。分析认为：含有15%左右细小的多边铁素体在X70管线钢中可导致裂纹尖端产生较大的塑性变形,并使裂纹尖端的应力得到松弛,阻止裂纹扩展,从而提高剪切面积百分比。     

Effect of Tempering on the Structure and Coercive Force in the AISI D3 (217H12WF) Ledeburite Chromium Steel

The main purpose of the studies was to establish the effect of the tempering temperature on the changes of carbide and retained austenite contents. It has been found that the course of changes of the coercive force of hardened steel after austenitizing is qualitatively similar to the hardness changes. That means in practice it is possible to determine the 217H12WF steel hardness based on the measurement of the coercive force.     

焊接钢管压扁试验开裂原因的分析与对策

压扁试验是检验钢管质量的方法之一,通过分析压扁试验开裂原因来采取相应手段可解决焊接钢管压扁试验开裂问题。实验采用扫描电子显微镜(SEM)、能谱仪(EDS)和金相显微镜(OM)等设备对焊接钢管压扁试验开裂的原因主要进行两方面分析:金相分析和断口分析。金相分析可得出主要结论,断口分析验证金相分析得出最终结论。结果表明:焊接钢管压扁试验开裂的主要原因为焊接钢管内存在大量的硅酸盐类夹杂物,此类夹杂物属于高温塑性夹杂物,容易破坏基体的横向连续性,在压扁试验中可引起应力集中,促使裂纹的形成,导致钢管开裂。焊接钢管开裂的次要原因为试样存在带状组织且铁素体晶界处还分布着网状三次渗碳体,三次渗碳体塑性差,压扁时会进一步加剧裂纹的扩展。通过分析开裂的原因进而对焊接钢管生产工艺进行优化,经过钢包精炼炉(LF)精炼与控轧控冷技术可减少钢中夹杂物,进而改善焊接钢管压扁开裂问题,使钢管失效率下降,提高焊接钢管的质量。     

Erratum to: Effect of Tempering on the Structure and Coercive Force in the AISI D3 (217H12WF) Ledeburite Chromium Steel

The main purpose of the studies was to establish the effect of the tempering temperature on the changes of carbide and retained austenite contents. It has been found that the course of changes of the coercive force of hardened steel after austenitizing is qualitatively similar to the hardness changes. That means in practice it is possible to determine the 217H12WF steel hardness based on the measurement of the coercive force.     

常规热连轧线Ti-IF钢铁素体轧制工艺研究与应用

 介绍了铁素体区轧制技术的优势、特点以及其在国内外钢铁企业的发展情况,重点阐述了Ti-IF钢铁素体轧制工艺在常规热连轧生产线上的成功开发与应用,结合常规热轧产线的装备特点进行工艺制度与成分体系的分析与设计,掌握了铁素体轧制板材产品的工艺控制过程和方法,同时针对生产Ti-IF钢铁素体轧制的润滑条件对{111}织构强度的影响进行了对比分析和改进,实现了1 100 ℃的低温轧制技术,达到了提高轧线成材率、节能降耗的目的,并从产品开发及用户使用角度出发,为铁素体轧制高性能产品推广提供了技术保证。     

Mechanical Properties and Retained Austenite Transformation Mechanism of TRIP-Aided Polygonal Ferrite Matrix Seamless Steel Tube

 Through the comparison of microstructure for polygonal ferrite (PF) matrix transformation induced plasticity (TRIP) seamless steel tube at different positions before and after tensile rupture, the transformation behavior of retained austenite (RA) was studied. The results showed that there were no yield points in tensile process and the splendid elongation and tensile strength were contributed by the uniform ferrite/bainite grains and the transformation of RA. The stability of RA was to some extent in inverse proportion with the ability of transformation induced plasticity. The coarse retained austenite located in ferrite and ferrite/bainite laths were all transformed into martensite during the tensile process.     

裂解连杆用高强度非调质易切削钢的研制

 设计了用于裂解连杆的高强度非调质易切削钢及其生产工艺,通过金相显微镜、扫描电镜等方法,分析了研制钢的显微组织、析出相及对力学性能的影响。结果表明：研制钢是由铁素体和珠光体组成,向钢中添加高的V和N元素,有利于增加更多的弥散析出相,提高其强度。轧后加速冷却,有利于铁素体晶粒细化、珠光体球团尺寸和珠光体片层间距减少、析出相增多,使其抗拉强度和屈服强度分别达到1000MPa和750MPa以上。     

B对含P高强度无间隙原子钢{111}面织构的影响

借助光学显微镜(OM)、X射线衍射(XRD)技术及电子背散射衍射(EBSD)技术,分析了2种含P高强度无间隙原子(IF)钢的热轧组织和热轧、冷轧及退火织构,结果表明:不含B与含B的高强IF钢热轧后,均得到多边形铁素体,但不含B热轧板晶粒尺寸较大。2种钢热轧板织构均比较散漫,γ纤维织构强度较弱,而不含B的IF钢经过80%大变形量冷轧以后,获得强的γ纤维织构,{111}面织构的体积分数达到41.41%,而含B的IF钢冷轧后{111}面织构的体积分数为33.83%。含B的IF钢冷轧后{112}110织构组分的体积分数比不含B的IF钢要高。2种实验钢在810℃退火60~180s以后,{111}面织构强度进一步增强,不含B的IF钢退火120s后{111}面织构的体积分数最大达到72.8%,而含B的IF钢退火120s后{111}面织构的体积分数最大达到66.6%。     

Micromechanical Behavior and Failure Mechanism of F/B Multi-phase High Performance Steel

The deformation and micro-voids formation mechanisms in ferrite / bainite( F / B) multi-phase steel with the volume fraction of bainite less than 50% were studied by numerical simulation and experimental observation. The results show that the micro-strain concentrates at the soft / hard phase( F / B) interface in the multi-phase steel,which should be correlated with the mechanism of incoordinate deformation. During the necking of the steel,the micro-voids initially form around the F / B interface,which also form in ferrite and bainite with the severe strain. The micro-voids in bainite are more dense and finer than those in ferrite. The failure mechanism of bainite is the coalescence of micro-voids,and the failure mechanism of ferrite is the growth and tearing of micro-voids. Due to the different failure mechanisms of ferrite and bainite,a suitable part of soft phase would be beneficial to the capability of anti-failure of F / B multi-phase steel during the ductile fracture.     

Measurements by SKPFM and Finite-Element Modeling of Hydrogen Atom Diffusion and Distribution in Ferrite and Bainite Contained in X80 Steel

Herein, the diffusion and distribution of hydrogen (H) atoms in ferrite and bainite contained in an X80 pipeline steel is studied by both scanning Kelvin probe force microscopy and finite-element modeling. The effect of metallurgical microphases on H-atom accumulation in the steel is analyzed. The results show that H-charging elevates the electrochemical dissolution activity of both ferrite and bainite contained in the steel, as indicated by the increased Volta potential and thus the decreased work function. The H atoms tend to accumulate at ferrite, making the local H-atom concentration much greater than the concentration at bainite. The results imply that, compared with bainite, ferrite is the location to accumulate more H atoms initiating hydrogen-induced cracks once the local H-atom concentration reaches a threshold value.