Q355B热装连铸板坯轧制钢板裂纹分析与控制

针对Q355B热装连铸板坯轧制钢板上、下表面产生大量无规律裂纹缺陷的问题,从热装板坯加热工艺、裂纹钢板组织及不同厚度裂纹宏观、微观形貌等方面进行排查分析.结果 表明:一方面由于热装温度过高,板坯表层处于奥氏体+铁素体两相区,组织应力较大,容易产生裂纹;另一方面检修期间热装板坯在炉内加热时间过长,表层脱碳严重,且长时间处...     

大型原油储罐用B610E(08MnNiVR)高强度调质钢板研制

介绍了在宝钢分公司厚板厂产线上开发成功的大型原油储罐用B610E（08MnNiVR）高强度钢板的成分和性能特点、生产工艺,列举了典型厚度钢板的实物性能,试验和分析了其大热输入焊接的适应性。研究结果表明,宝钢分公司厚板厂产线工业批量生产的B610E（08MnNiVR）钢板性能稳定。完全满足10万m。大型原油储罐用大热输入焊接高强度钢板技术要求,已成功地用于建造10万m。原油浮顶储罐。     

Q345B中厚钢板表面裂纹原因分析

通过板坯表面酸洗、钢板表面抛丸、氮氧分析、扫描电镜能谱仪和金相显微镜等手段,对唐钢所生产Q345B中厚钢板的表面裂纹处进行观察、检测,研究了热装板坯在轧制过程中产生表面裂纹的原因和机理.同时还进行了板坯热装、温装、冷装对比试验.结果表明,含铝低合金钢板由于板坯热装温度处于第三低温脆性区域,冷却过程中奥氏体向铁素体的转变不完全,AIN在奥氏体晶界析出,削弱晶界能,体积膨胀加剧了晶界强度的减弱,在轧制时扩展形成表面裂纹.     

连铸板坯毛刺去除机的研制

为适应济钢一炼钢厂4#热装热送的需要,研制开发了连铸板坯在线毛刺去除机。该设备结构简单,动作可靠,刀刃使用寿命长,去除毛刺效率高,解决了热装热送板坯轧制后产生的钢板表面夹层、结疤等问题,提高钢板成材率0.1%以上。     

板坯表面纵裂纹的原因分析

依据提钒炼钢二厂1~#、2~#板坯连铸机生产Q235B、Q345B钢板坯表面纵裂的实际,分析了钢中C含量、Mn/S比、连铸保护渣的性能、浇注过程钢水过热度、拉速、结晶器冷却以及结晶器参数等对板坯表面纵裂的影响,提出了相应的控制措施。     

韶钢连铸板坯热装红送获得成功

韶钢连铸板坯热装红送获得成功最近，韶钢连铸板坯热装红送获得成功。连铸板坯热装红送是指电炉冶炼出来的供轧制钢板使用的钢坯，在保持高温红坯的状态下，直接送到轧钢系统轧制成钢板。跟以前冶炼出钢坯，冷却后才送到轧钢系统，再经过加热成红坯轧制钢板比较，不仅减少...     

Q235B钢板坯表面纵裂纹的原因分析

结合唐山不锈钢有限责任公司2#板坯连铸机生产Q235B钢板坯表面纵裂的实际,分析了钢中C含量、S含量、连铸保护渣的性能、浇注过程钢水过热度及拉速的稳定控制等对板坯表面纵裂的影响,提出了相应的控制措施。     

AH32船板低Ti/N比导致表面裂纹的研究

根据典型的钢板裂纹实例,通过对铸坯、钢板试样进行研究,用对比分析的方法得出低Ti/N比导致板坯热送轧制钢板产生表面裂纹的结论。并据此采取一系列措施,取得了良好的效果。     

电磁搅拌对管线钢板坯质量和钢板性能的影响

详细对比了使用电磁搅拌(S-EMS)和未使用S-EMS的管线钢板坯质量和轧制后钢板性能,研究S-EMS对管线钢板坯质量和钢板性能的影响。对比结果显示:使用S-EMS后,板坯的中心偏析和疏松显著改善,板坯中心等轴晶率由12%提高到26%。管线钢的冲击性能(-20℃)和落锤性能(-15℃)得到了显著改善,钢板的中心组织以均匀细小的针状铁素体为主,基本消除了中心条带状偏析带、粗大魏氏体和颗粒状贝氏体组织。轧制后钢板的常规冲击KV2≥350 J所占比例为100%;落锤剪切面积比SA样本合格率提高了2.65%,达到了100%。     

低合金高强度中厚板生产技术

Q345B中厚板生产中，提高板坯表面及内在质量要注重化学成分设计．合理制定加热、轧制规范，轧制厚规格钢板时还应进行正此处理．以满足性能要求。     

Q345B连铸坯内部质量对钢板力学性能的影响

文章研究了Q345B连铸坯低倍组织、碳偏析和钢板常规力学性能,从而找出Q345B连铸坯低倍组织对钢板常规性能的影响,为中厚板连铸坯轧制成的钢板力学性能预测提供依据。     

贮罐和压力容器用高性能厚板的开发

为了满足能源领域的需求,JFE公司开发了高性能即韧性、强度和焊接性都优良的610MPa级高强度系列钢板,包括高焊接性的JFE—HITEN610U2、低温贮罐用JFE—HITEN610U2L和大输入热量焊接用JFE—HITEN610E。这些产品的特点是低C、低Pcm（焊接裂纹敏感性成分）和不加入B。由于采用了微合金化技术和超级在线快速冷却（Super—OLAC）的直接淬火—回火工艺,从而获得了优良的母材及焊缝性能。另外,针对市场对高可靠性超厚钢板的需求,开发了采用锻造、轧制工艺和高质量连铸板坯生产超厚钢板的技术,在压力容器用SQV2B板和200mm厚度级别的超厚板生产中,实现了优良的内部质量;且这些产品都有了较多的应用实绩。     

中厚板中间坯冷却过程中晶粒长大及控制方法

为控制中厚板中间坯长时间待温导致的晶粒长大,研究了中间强制水冷却对奥氏体组织的影响.通过对Q345B钢和含Nb-Ti钢采用1050℃变形后快冷至1050~950℃预定温度保温的热模拟方法,确定了中间坯冷却过程中的晶粒尺寸变化规律,提出了中厚板冷却过程中晶粒长大的控制方法,建立了Q345B钢和含Nb-Ti钢在中间冷却过程中的晶粒长大模型.在中间冷却过程中,Q345B钢晶粒稳定性较差,而含Nb-Ti钢晶粒稳定性良好,归因于以铌为主的析出相对奥氏体晶界的钉扎作用.中间坯的强制冷却可控制奥氏体晶粒长大,63mm厚中间坯强制冷却可有效减小平均晶粒尺寸约20μm.在实际生产中,经中间强制冷却后16 mm厚度Q345B钢板的冲击韧性提高25%~70%.      

Industrial practice of clad-rolling in heavy steel plate production

In this paper,a brief introduction on clad-rolling heavy steel plates of 90 mm and 140 mm thick is presented.The steel plates were hot rolled by 265mm slabs that are cladded by double 135mm continuous casting slabs of Q235 steel.After hot rolling,interface of the cladding slabs completely disappeared, revealing uniform grains similar to the rest of the materials.Ultrasonic tests were carried out on both steel plates,demonstrating excellent results.Through thickness tensile tests were also implemented on ...     

Development of microalloyed steel for pipeline applications

Abstract

An experimental HSLA steel was produced by the electric arc furnace, vacuum degassing, ladle treatment and continuous casting route. The experimental steel was then rolled in a laboratory using a hot rolling schedule to simulate an industrial controlled hot rolling procedure for the production of plates as closely as possible to investigate the effect of a thermomechanical processing schedule plus the use of water quench, accelerated cooling followed by forced nitrogen gas or air as cooling media, on the mechanical properties of plates. The results showed that the controlled thermomechanical hot rolling schedule of slabs followed by the cooling of plates in either forced nitrogen gas or by accelerated cooling exhibited target properties equivalent to a steel grade API X-80.     

Study on the surface cracking in hot-rolled plates of Fe-23Mn-2Al-V austenitic steel

The study introduces the chemical composition,mechanical properties,physical properties and production processes of the Fe-23Mn-2Al-V austenitic steel.Investigations were made into the formation of cracks in the hot-rolled Fe-23Mn-2Al-V steel plates,with optical microscopy(OM),scanning electron microscopy(SEM)and energy dispersive spectrum(EDS).The results have shown that intergranular oxidation in the reheating fumace is the main cause of the cracks on the surface of the hot-rolled steel plates.The surface cracking can be largely avoided by controlling the remaining oxygen content in the reheating furnace and improving continuous casting(CC)processes to increase the thickness of fine equiaxed grain layer of the steel slabs.     

X80管线钢板探伤不合原因分析

通过超声波扫描显微镜、金相显微镜、扫描电子显微镜、EPMA电子探针等检测手段,详细分析了X80管线钢板材超声探伤不合的原因。分析结果表明,X80管线钢连铸坯和轧材内部均没有明显的裂纹缺陷;铸坯和轧材探伤不合位置处明显存在的Al-O-Ni型复合夹杂物偏聚缺陷是造成钢板探伤不合的直接原因,且夹杂物偏聚行为并不是元素偏析所致。优化生产工艺后,X80管线钢板探伤合格率提高到98.5%。     

Q345A 中板控轧控冷工艺试验

采用外购Q345A连铸板坯,在韶钢2500mm轧机上进行了以“再结晶区 未再结晶区”两阶段控轧及轧后空冷或水冷工艺为主体的中板控轧控冷试验,主要研究了轧制温度、终冷温度对钢板组织和性能的影响,为韶钢“大转炉一中板轧机”生产高强度低合金钢板进行了控轧控冷工艺的技术储备．     

连铸板坯热装炉对材性能的影响

分析比较了Ｑ２３５－Ａ碳结钢及Ｂ级一般强度船板钢连铸板坯红坯“裸送”热装炉与冷装炉轧制成材的板材工艺与力学性能，热装炉工艺成材的冷弯及冲击性能明显低于后者。     

Types of Continuous Casters and the Quality of Continuous-Cast Slabs for Obtaining Rolled Products for Crucial Applications

This article examines the production of continuous-cast slabs for the production of thick (thicker than 20 mm) plates used in critical applications. It is shown that the melt needs to be carefully prepared for casting on a continuous caster. When the steel is made in a converter, the pig iron must be desulfurized beforehand and the steel tapped from the furnace must subsequently be treated on ladle-furnace and vacuum-degassing units. It was established that production of high-quality slabs suitable for obtaining critical rolled products can be consistently achieved only through the use of a vertical continuous caster. The bending and unbending which slabs undergo on curvilinear casters and the curved axis of such casters make it very difficult or even impossible to obtain slabs and thick plates that do not have asymmetrically distributed nonmetallic inclusions, axial segregation, and internal and external cracks. The article analyzes the success that the company Severstal' had in rebuilding its vertical slab caster. The project, carried out by TsNIIchermet and the companies ORMET-YuUMZ and Korad, shows that Russian metallurgical science, the metallurgical industry, and the machine-building sector have competitive engineering solutions to offer.