中碳钢球化退火行为和力学性能的研究

采用常规双相区球化退火和亚温球化退火工艺研究了常规轧制（CR）和控轧控冷（CRC）的中碳钢SWRCH35K的球化退火行为和力学性能。结果表明,与传统的双相区球化退火相比,亚温球化退火时碳化物球化进程明显加快,球化率高,且碳化物比较细小,具有良好的塑性和冷成形性,采用亚温球化退火处理可明显地缩短球化退火时间。控轧控冷的中碳钢线材尽管具有比较粗大的珠光体组织,但因有相当部分的珠光体发生退化,其球化退火进程要明显快于细珠光体组织。     

热机轧制对中碳冷镦钢组织和性能的影响

采用热机轧制（TMCP）工艺技术生产中碳冷镦钢SWRCH35K M,增加了线材组织中铁素体的比例,并使珠光体组织部分粒状化,降低了线材强度和硬度,提高了塑性,且冷镦时金属流动性好、冷作硬化率低。用户可用其直接制作内六角螺栓和法兰面螺栓,免去球化退火工艺,取得明显的经济效益和环境效益。     

高强度非调质冷镦钢研究和开发现状

根据国内外高强度非调质冷镦钢的研究和开发现状,分析和讨论了800～1 200 MPa高强度非调质冷镦钢的化学成分、工艺特点、组织和力学性能。高强度非调质冷镦钢应具有高的强度和有良好的冷成形性,其热轧材的强度和硬度应控制在一个合适的范围内。采用低碳高锰及微合金化的成分系列,通过热机轧制工艺,该钢种能获得良好的组织和力学性能。     

杭钢冷镦钢生产技术发展

冷镦钢应具有高的洁净度、良好的表面质量及优异的冷变形性能，因而有一定的生产难度。杭钢冷镦钢的研发和生产，采用转炉或电弧炉加钢包精炼炉冶炼及摩根高线轧机轧制，生产了HML10、ML35、ML40和CH35ACR、CH40ACR等系列冷镦钢产品，并通过冶炼时提高钢的洁净度，轧制时优化斯太尔摩线的控制冷却，改善了钢的表面质量和冷加工性能。杭钢冷镦钢今后的发展方向是改进质量、降低成本、开发新品。     

SWRM12冷镦盘条钢试制

阐述了SWRM12冷镦盘条钢试制情况，对采用连铸坯生产的冷镦盘条进行了综合分析检验，并经用户使用证明，该产品完全满足标准件生产要求。     

Improved Cold Formability by Thermo‐Mechanical Rod Rolling

Usually, unalloyed medium carbon steels and 1% chromium steels for cold heading applications are produced by hot rolling, subsequent controlled cooling and soft annealing. It is shown that by thermomechanical rod rolling and slow air cooling at the loop cooling conveyor the tensile strength can be lowered to such an extent so that cost‐intensive soft annealing procedures are not required. The effects of the processing parameters on the microstructural evolution and final mechanical properties of steel grades 23MnB4 and 1% Cr‐steels like 32CrB4, 37Cr4 and 41 Cr4 are tested by a Gleeble machine. Using a microstructural process model, called CAROD, the entire rolling and cooling process has been optimized.     

冷轧带肋钢筋专用母材的开发

针对各冷轧带肋钢筋厂家所用原料存在的问题,通过化学成分的确定,高线轧制冷却工艺的研究,开发了冷轧带肋钢筋专用母材系列产品,提高了冷轧带肋钢筋的轧制合格率;研究了[C]、[Si]、[Mn]、[N]含量以及铁素体含量和晶粒度对冷轧带肋钢筋专用母材系列产品性能的影响,提出了提高冷扎带肋钢筋母材性能的措施.     

CSP热轧50CrV4带钢普通球化退火工艺

系统研究了球化退火温度及保温时间对CSP热轧50CrV4带钢组织与性能的影响。研究结果表明:在730~770℃的温度范围内球化退火4~18h时,随着退火温度的提高,碳化物粒径先缓慢增大后迅速降低,球化率逐渐增大;随着保温时间的延长,碳化物粒径逐渐增大,730及750℃时,球化率先增大后降低;770℃时球化率逐渐降低。当退火温度为770℃,保温时间为4h时,球化效果最佳,球化率为90.6%,碳化物平均粒径为0.29μm,硬度为202.8HV。     

ML45Mn2冷镦钢盘条的研究与开发

120 t转炉-LF-VD-350 mm x430 mm铸坯-150 mm x 150 mm轧坯-轧制流程生产的ML45Mn2钢Φ16 mm和Φ18 mm盘条采用的主要工艺为:碱度1.5-2.0精炼渣,52 t中间包,电磁搅拌,轻重压下,开轧温度1 010 ~ 1 070 °C,精轧温度820 - 850°C,卷曲温度780 - 820°C,冷速0. 15 -0.4 °C/s等工艺。检验结果显示,MI45Mn2钢盘条热轧态平均抗拉强度797 MPa,平均断面收缩率50.3% ,1/4冷镦合格,金相组织为珠光体+铁素体,断面平均硬度值为92.5HRB,带状组织1.5-2.5级,满足技术要求。     

CrMo合金冷镦钢开裂机理研究

本文研究了SCM440与SCM435冷镦开裂样品的典型特征。研究结果表明,SCM440大盘卷冷镦袁层存在大量裂纹,根据全脱碳层的厚度判断是由于控冷阶段出现问题产生的。SCM435中的大量微细裂纹是在球化退火过程中气氛存在氧化性造成的,而SCM435产生的大约7％的贯通型裂纹,是在铸坯中形成的,通过对铸坯采取扒皮处理,该类裂纹也基本消除。CrMo钢冷镦开裂存在一个共性特征：全脱碳层的形成导致其中的铁素体晶界抗氧化性降低,在CrMo冷镦钢表面形成大量沿铁索体晶界扩展的裂纹,从而导致CrMo系列冷镦钢开裂。全脱碳层的形成可能在铸坯环节,可能在热轧环节,也可能在球化退火工序。     

酒钢碳钢薄板厂冷轧机组自动打捆机多道打捆技术研究

打捆机是冷轧重要的在线设备,钢卷打捆的质量直接影响钢卷的质量,对后续罩式退火炉的生产,以及冷硬卷的包装运输都会带来很大的影响。冷轧钢卷的多道打捆技术的开发成功的解决了这个难题,为酒钢冷轧产品的质量提供了保障。     

超低碳钢空心铆钉的缺陷分析

分析了超低碳冷镦钢盘条制造空心铆钉后易出现翻边开裂、鼓肚、滑移裂纹和翻边不完全等各类缺陷的特征和产生原因。研究结果表明，晶粒过于粗大或细小均会出现不同的缺陷，盘条轧制时应控制1150～1200℃的较低钢坯加热温度，控制盘条吐丝温度910～930℃，使盘条成品具有适中的晶粒大小，以6～6．5级为宜，提高盘条表面质量也是消除各类缺陷的有效手段。     

Improvement of material properties and cladded flat product productivity with roll-bonding technology

Taking advantage of the progress of roll-bonding technology,the integrity of the material technology,and the development of the production and examination facilities of all the main carbon steels,stainless steels and specialty alloys in Baosteel,the cladded flat new products,which combined both properties of base material and clad material,have been developed and produced in large quantities.The product categories includes heavy plates with high alloy content and homogeneous distribution in thickness and carbon steel plates cladded with all kinds of stainless steels,nickel alloys,and titanium alloys.The double-sided and single-sided cladding hot rolled strips and cold rolled sheets were also commercially produced.Due to the combined properties of both the cladding material and backing material,all products show obvious improvement in properties when compared with solid material.The comparability with the existing production process and equipment laid a very solid foundation for high productivity.     

鞍钢先进高强汽车用钢的研制开发

介绍了鞍钢先进高强汽车用钢开发研制情况,包括以980 MPa级DP钢、TRIP钢、TWIP钢和QP钢为代表的热轧、冷轧和热镀锌先进高强钢系列产品,以及鞍钢开发的先进高强钢热镀锌生产技术,并对鞍钢先进高强汽车钢未来的发展方向进行了展望。     

The Effect of Hot‐ and Cold‐Rolling on the Electropulse‐Induced Microstructure and Property Changes in Medium Carbon Low Alloy Steels

The application of electropulse to hot‐rolled and cold‐rolled, medium carbon low alloy steels has generated completely different effects. For cold‐rolled steel samples, electropulsing treatment causes microstructure refinement and, hence, increments in tensile strength, yield strength, and elongation. For hot‐rolled steels, the effect of electropulsing is found to be negligible. This proves the importance of dislocations in the micromechanism of electropulse‐induced microstructure transformation in solids. The optimal electropulse parameters for the improvement of cold‐rolled steels are observed. The experimental observations are explained within the frameworks of thermodynamics and kinetics of microstructure transformation.     

临界区等温球化退火对低密度轴承钢组织和硬度的影响

摘要：临界区等温球化退火是实现高碳轴承钢中片状珠光体球化的主要热处理方式,其将片状珠光体转变为粒状珠光体,改善轴承件的可加工性及组织均匀性。研究了临界区等温球化退火工艺对低密度含Al轴承钢微观组织演化及硬度的影响。研究结果表明,轴承钢钢中高含量Al的添加可以提高临界区等温球化退火温度,缩短球化时间,将珠光体的硬度降低至300HV以下。但是,临界区等温球化保温过程中有石墨颗粒形成,石墨颗粒的产生虽然能够有效地降低球化后钢材硬度,但是部分石墨颗粒在最终的奥氏体化过程中难以溶解进入钢材基体,未溶解的石墨颗粒不仅增加了组织的不均匀性,而且降低了轴承钢硬度。所以,较长时间退火保温的临界区球化退火方式并不适用于低密度高碳高Al轴承钢。     

CSP工艺冷轧薄板盐浴退火再结晶实验

 研究了以CSP工艺热轧板卷为原料的冷轧薄板在盐浴退火过程中的再结晶行为,通过显微组织、显微硬度及电子背散射衍射技术观察、分析揭示了再结晶的规律,结果表明,CSP工艺冷轧薄板经盐浴退火后的再结晶组织为等轴状晶粒;在相同温度下盐浴退火,冷轧压下率较大时,完成再结晶所需的保温时间较短,再结晶晶粒细小。     

SPHC钢热轧板卷破边成因及防治措施

针对安钢热连轧SPHC钢在轧后出现的严重破边现象,对热轧板卷破边的成因及防治措施进行了研究.从机制认识出发,结合金相检验、扫描电镜分析、成分分析等方法,对破边缺陷的特征及成因进行了分析.结果表明,热轧板卷破边可能与板坯角部表观质量没有直接关联,钢中Mn/S比偏低及加热温度偏高也将导致热轧板卷破边缺陷严重.据此,从生产工...     

Twin roll strip casting of low carbon steels

Abstract

Strip casting of low carbon steels has been investigated using a laboratory twin roll machine with copper rolls. The following grades have been studied: a deep drawing low carbon (LC) steel, a LC steel with titanium addition, and a high strength low alloy (HSLA) grade. The casting behaviour of these steels has been examined, and the observed surface defects classified. Defects are most pronounced for the LC grade and significantly less for the HSLA steel and the LC steel with titanium addition. The as cast structure has been analysed. It can be modified by post-cast treatment, e.g. by normalisation or in line rolling. The mechanical properties of cold rolled and annealed strip materials and their textures are presented. Satisfactory sheet properties can be achieved both as hot band and as cold rolled sheet when adequate treatment steps are applied. Consequences for strip casting applications and future research are discussed.     

410S热轧卷直接冷轧工艺探索

通过对410S冶炼成分的合理设计、铸态组织的控制、热轧工艺的探索,获得了优良的热轧边部质量及良好的整卷性能均匀性,为热轧卷直接冷轧后获得高光洁度的表面及良好的深冲加工性能提供了保障.