冷轧无取向硅钢的实验研究

采用正交实验法进行了模拟实验,研究冷轧及退火工艺参数对无取向硅钢的晶粒度及显微硬度的影响,得到了无取向硅钢最佳冷轧及退火工艺．     

磁场退火对冷轧无取向硅钢微观组织的影响

在正交实验基础上,研究磁场退火工艺对0.5 mm厚的0.3%Si冷轧无取向硅钢微观组织的影响.分析了磁场强度、退火温度和保温时间对无取向硅钢微观组织的影响.实验结果表明,退火温度是影响无取向硅钢晶粒尺寸的最主要因素,其次是保温时间与磁场强度.磁场强度一定时,随着退火温度的升高、保温时间的延长,晶粒尺寸有长大的趋势,并且晶粒均匀性有所提高.在实验条件下,当施加的磁场强度为1 T、退火温度为800℃、保温时间为60 min时,晶粒尺寸最大.     

无取向硅钢晶粒与晶界特征的EBSD分析

借助电子背散射衍射（EBSD）技术测量和计算了无取向硅钢再结晶退火后再结晶百分比、晶粒尺寸、取向差分布等参数,分析了再结晶退火温度对无取向硅钢晶粒大小、微观取向和耐蚀性的影响。结果表明,3个温度（810、840、880℃）下退火3 min后,再结晶均充分完成。随着退火温度的升高,再结晶晶粒尺寸长大。拥有{100}面织构的晶粒比其他取向晶粒具有更好的耐蚀性,侵蚀后晶粒凸出于试样表面。880℃退火后的小尺寸晶粒周围多为小角度晶界,不易迁移,不易被侵蚀。     

表面机械研磨/异步轧制无取向硅钢薄带的渗硅行为

对w（Si）=3%无取向硅钢进行表面机械研磨处理（SMAT）和异步轧制（CSR）,获得表面纳米结构,再进行550～650℃、4 h固体粉末渗硅处理,用透射电镜（TEM）、扫描电镜（SEM）和X射线衍射仪（XRD）研究表层组织演变。结果表明：经过SMAT后,w（Si）=3%无取向硅钢表面形成了等轴状、取向呈随机分布的、晶粒尺寸为10 nm的纳米晶组织;异步轧制后,表面纳米晶组织保持不变;550～650℃、4 h渗硅处理后,SMAT＋CSR样品表面形成化合物层,其厚度随着温度的升高由17μm增加到52μm;化合物层由Fe3Si和FeSi相组成.     

再结晶退火温度对无取向硅钢织构和磁性能的影响

对冷轧及退火后无取向硅钢织构及磁性能的变化进行研究。借助电子背散射衍射（EBSD）技术测量退火试样的极图,计算取向分布函数（ODF）和织构组分的体积分数,并利用TYU-2000M磁性能测量仪测量试样的磁性能。结果表明,810、840、880℃下退火3min后,试样的再结晶均充分完成,且晶粒随着退火温度的升高而长大;退火后,试样中首先显现{111}〈112）织构组分,且随退火温度的升高呈增强趋势;退火温度继续升高时,{111}〈110〉织构组分增强,一次再结晶后材料中出现{111}面织构,导致试样的磁感应强度B50降低,同时由于晶粒的长大使得试样的铁损P15减小。     

常化与退火工艺对50W470H无取向硅钢磁性能的影响

研究了常化温度和退火温度对冷轧无取向硅钢的显微组织和磁性能的影响。结果表明,常化温度升高,铁损呈先降低后升高的趋势,磁感应强度波动程度小。退火温度升高,铁损逐步降低,磁感应强度同样波动程度小。在常化1000℃-1050℃+退火925℃-1025℃下能获得最佳磁性能,最佳磁性能P1.5/50=2.5W/kg-2.9W/kg、磁感B50=1.74-1.76T。     

基于CSP流程的冷轧无取向电工钢生产工艺开发

以马钢CSP流程开发冷轧无取向电工钢实践为基础，介绍了CSP流程生产无取向电工钢的特点，重点讨论了CSP流程生产无取向电工钢的关键环节：精炼、热轧和退火工艺等工艺路线的设计和优化过程。     

3%无取向硅钢薄板的表面纳米化结构与性能

为了探索金属薄板表面纳米化制备方法,本工作选取3%无取向硅钢热轧板进行表面机械研磨处理（SMAT）和异步轧制（CSR）,研究深度方向结构和硬度的变化.结果表明：SMAT过程中,3%无取向硅钢通过位错的演变,在表面形成了等轴状、尺寸约为10 nm的、取向呈随机分布的纳米晶,纳米晶层厚度约为20μm;SMAT样品经过CSR后,表面的显微组织基本不变,但纳米晶层的厚度明显减小;SMAT和CSR处理使表面硬度显著提高（约为85%）.本工作表明,SMAT与CSR复合工艺可以制备大尺寸的、具有纳米结构表层的金属薄板.     

Bending analysis and control of rolled plate during snake hot rolling

In order to study the bending behavior of aluminum alloy 7050 thick plate during snake hot rolling, several coupled thermo-mechanical finite element(FE) models were established. Effects of different initial thicknesses, pass reductions, speed ratios and offset distances on the bending value of the plate were analyzed. ‘Quasi smooth plate' and optimum offset distance were defined and quasi smooth plate could be acquired by adjusting offset distance, and then bending control equation was fitted. The results show that bending value of the plate as well as the extent of the increase grows with the increase of pass reduction and decrease of initial thickness; the bending value firstly increases and then keeps steady with the ascending speed ratio; the bending value can be reduced by enlarging the offset distance. The optimum offset distance varies for different rolling parameters and it is augmented with the increase of pass reduction and speed ratio and the decrease of initial thickness. A proper offset distance for different rolling parameters can be calculated by the bending control equation and this equation can be a guidance to acquire a quasi smooth plate. The FEM results agree well with experimental results.     

Influence of hot rolling conditions on the mechanical properties of hot rolled TRIP steel

Influence of hot rolling conditions on the mechanical properties of hot rolled TRIP steel was investigated. Thermomechanical control processing （TMCP） was conducted by using a laboratory hot rolling mill, in which three different kinds of finish rolling temperatures were applied. The results show that polygonal ferrite, granular bainite and larger amount of stabilized retained austenite can be obtained by controlled rolling processes. The finer ferrite grain size is produced through the deformation induced transformation during deformation rather than after deformation, which affects the mechanical properties of hot rolled TRIP steel. Mechanical properties increase with decreasing finish rolling temperature due to the stabilization of retained austenite. Ultimate tensile strength （UTS）, total elongation （TEL） and the product of ultimate tensile strength and total elongation （UTS×TEL） reaches optimal values （791 MPa, 36% and 28 476 MPa%, respectively） when the specimen was hot rolled for 50% reduction at finish rolling temperature of 700 ℃.     

建筑用热轧奥氏体304不锈钢管力学性能

为了解热轧无缝不锈钢管材料性能,分别对取材自奥氏体304 Φ216×16 mm热轧不锈钢管的光滑和缺口圆棒试件进行单调和循环加载两类试验,获取了应力-应变关系及基本材料参数,得到滞回和骨架曲线,标定钢材循环强化参数,并观察了断面微观破坏特征．研究表明:国产热轧不锈钢管加工工艺对中厚管材性影响不大;奥氏体304不锈钢在循环荷载作用下具有良好强化效应和耗能性能;宜采用随动-等向混合强化材料模型描述其行为,所标定循环强化参数可用于复杂应力状态下的数值模拟;不锈钢材微观破坏特征异于普通低合金或低碳钢．     

高强度冷轧双相钢应变硬化行为

为了研究双相钢在变形过程中的应变硬化特性,采用Hollomon法与修正的Crussard Jaoul法分析了试验钢的应变硬化曲线,并利用力学测试与显微组织观察等手段研究了组织结构对应变硬化行为的影响机制.结果表明：三种试验钢,均表现出较高的初始加工硬化能力.具有岛状马氏体与类针状马氏体的双相钢表现出两个阶段的应变硬化特征,具有粗大块状马氏体的双相钢则表现出三个阶段的硬化特征.与类针状和粗大块状马氏体相比,含有岛状马氏体的双相钢表现出较强的加工硬化能力和强度与塑性的良好配合.块状马氏体较早的进入塑性变形,导致双相钢变形协调难度加大并在晶界周围产生孔洞而使塑性恶化.     

Numerical simulation of circular jet impinging on hot steel plate

Flow structure and heat transfer characteristics of an axisymmetric circular jet impinging on a hot 1Crl8Ni9Ti medium plate have been simulated numerically using computational fluid dynamic (CFD) code. The relation between flow field of jet impingement and its heat transfer capability is analyzed, and the phenomenon that heat transfer at stagnation point is smaller than that of points directly around is discussed. The simulation result provides boundary conditions for thermal analysis of medium plate quenching.     

Analysis of the factors affecting thermal evolution of hot rolled steel during coil cooling

1. IntroductionPrecipitation is the most important metallurgicalprocess during coil cooling in a hot rolling mill. Beingone of the strengthening approaches, precipitationhardening contributes to the strength of steel products[1-5]. It is well known that p…     

铌钒成分热轧H型钢翼缘落锤冲击性能与断口形貌分析

通过落锤低温冲击试验,研究了两种不同铌钒成分的热轧H型钢翼缘-60℃-20℃的低温冲击韧性,同时,采用扫描电镜对落锤冲击断口进行观察和分析。结果表明,随着冲击试验温度的降低,热轧H型钢的翼缘冲击韧性不断降低,其中高钒低铌成分在-20℃冲击韧性明显降低;低钒高铌成分在-40℃冲击韧性明显降低。     

卷取温度对热轧TRIP钢残奥及力学性能的影响

为了研究卷取温度对热轧TRIP钢的残余奥氏体和力学性能的影响,使用金相显微镜、扫描电镜、x-射线衍射、拉伸实验等方法对三种卷取温度下制备的热轧TRIP钢进行分析.结果显示,随着卷取温度的降低,残余奥氏体晶粒尺寸变小,残奥体积分数和碳的质量分数也变小.450 ℃和400 ℃卷取温度下制备的热轧TRIP钢的残奥形貌的圆整性相差不大,而350 ℃卷取温度下制备的热轧TRIP钢的残奥形貌较圆整.热轧TRIP钢的力学性能随着卷取温度的降低表现为高的屈服强度和低伸长率,450 ℃卷取温度下制备的热轧TRIP钢的综合力学性能最优.