高质绿色化发展趋势下轧制技术的创新实践

高质化、绿色化已成为钢铁行业发展的必然趋势.以热轧钢铁材料组织性能调控工艺与技术、板带高精度尺寸控制技术、薄带铸轧短流程技术为例,介绍了相关工艺技术的自主创新与应用实践进展,具体包括热轧板带新一代控轧控冷技术在实现目标组织调控、解决板形问题方面的研发应用及进展;3 mm厚薄规格高强钢板带离线淬火工艺技术的发展应用;热、...     

基于铁素体轧制工艺低碳铝镇静钢板r值降低原因分析

某钢厂试开发基于铁素体轧制工艺的SPCC板,经热轧-冷轧-罩式退火工序后对样品进行性能检测,发现与传统奥氏体轧制工艺相比,该工艺路径下的产品各项力学性能指标均有不同程度下降,且r值有明显降低。对两种工艺路径的热轧板和冷轧退火成品板进行了组织和织构的对比分析,且提出了改进措施。结果表明:铁素体轧制工艺中热轧精轧温度过高,形成两相区轧制,得到粗大F+纤维状F的不均匀室温组织,从而导致冷轧退火板中存在较高强度{001}<110>织构组分,是导致最终产品r值降低的主要原因。     

热轧工艺对65Mn钢显微组织及力学性能的影响

研究了热轧工艺对65Mn钢组织与性能的影响。采用电子探针显微分析仪(EPMA)和透射电镜(TEM)对热轧组织进行了表征。结果表明:通过控制热轧工艺,可获得珠光体和贝氏体两种初始组织。随着终轧温度和终冷温度的降低,先共析铁素体含量和珠光体体片层间距逐渐减小,强度、硬度逐渐升高。相比珠光体组织,热轧贝氏体组织具有更高的强度,抗拉和屈服强度分别为943 MPa 和648 MPa。     

汽车结构用热轧双相钢的生产现状及发展趋势

介绍了热轧双相钢在汽车板“以热代冷”进程中的发展情况、国内外主要热轧双相钢产品的化学成分和性能,及其在车身结构及车轮上的应用情况,同时指出,依托短流程薄规格生产工艺技术优势,进一步提高热轧双相钢的生产稳顺性、组织性能稳定性、成品的板形和表面质量,将是实现汽车结构用低成本热轧双相钢开发生产的重要研发方向.     

热轧组织对冷轧无取向硅钢退火织构及组织的影响

对不同加热温度处理的热轧低硅钢带进行了冷轧及退火实验,分析了热轧钢带的组织对冷轧无取向硅钢再结晶退火过程中的组织及织构的影响。结果表明:热轧组织对冷轧无取向电工钢冷轧板再结晶组织及织构演变有重要影响;等轴晶粒组织的热轧钢带比混晶组织的热轧钢带冷轧后再结晶退火快,且退火后晶粒尺寸均匀;随着等轴晶粒尺寸增加,冷轧退火后形成的冷轧硅钢{110}类型的织构增强,{100}类型的织构减弱;表明热轧组织为等轴晶粒时,不利于冷轧无取向硅钢磁性能的改善。     

Microstructure and Mechanical Properties of 1,000 MPa Ultra-High Strength Hot-Rolled Plate Steel for Coal Mine Refuge Chamber

The 1,000 MPa ultra-high strength hot-rolled plate steel with low-carbon bainitic microstructure was developed in the laboratory for coal mine refuge chamber. The static recrystallization behavior, microstructure evolution, and mechanical properties of this hot-rolled plate steel were investigated by the hot compression, continuous cooling transformation, and tensile deformation test. The results show that the developed steel has excellent mechanical properties at both room and elevated temperature, and its microstructure mainly consists of lath bainite, granular bainite, and ferrite after thermal–mechanical control process(TMCP). The ultra-high strength plate steel is obtained by the TMCP process in hot rolling, strengthened by bainitic transformation, microstructure refinement, and precipitation of alloying elements such as Nb, Ti, Mo, and Cu. The experimental steel has relatively low welding crack sensitivity index and high atmospheric corrosion resistance index. Therefore, the developed steel has a good balance of strength and ductility both at room and elevated temperature, weldability and corrosion resistance, and it can suffice for the basic demands for materials in the manufacture of coal mine refuge chamber.     

热处理对不同碳含量3.5Ni钢力学性能和低温韧性的影响

利用光学显微镜及SEM进行组织观察,通过拉伸和低温冲击试验研究了热处理对两种不同碳含量3.5Ni钢的力学性能和低温韧性的影响。两种3.5Ni钢热轧板分别经860 ℃×1 h空冷的正火处理和860 ℃×1 h水淬+(580, 610, 640)×1 h回火的调质处理。结果表明:含碳量较高的3.5Ni钢热轧态强度低塑性高,但－100 ℃冲击吸收能量低,经正火处理后试验钢的整体性能降低,而调质处理后强度和低温冲击吸收能量均明显提升,塑性略有降低;含碳量较低的3.5Ni钢热轧态已经具有优异的拉伸性能和低温冲击性能,经热处理后拉伸性能和低温韧性没有得到明显提升。     

Special features of the formation of microstructure of heat-treated low-alloy steel

The strength and the operational properties of low-alloy thick-sheet steels is increased by heat treatment in the line of the mill with the use of the rolling or furnace heat. The present work concerns the special features of structure formation and the mechanical properties of rolled stock from sheet structural steel 09G2S with a strength level C345 (σ_y=325-345 MPa) in a hot-rolled and a normalized state after accelerated cooling from the normalizing furnace and after rolling behind the finishing stand. As a result of the rapid cooling in the line of the mill the sheet acquires properties corresponding to steels with a C390–C440 strength level (σ_y=390-440 MPa). Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 9–11, August, 1998.     

热轧和冷轧工艺对MGH754合金板材组织及性能的影响

通过光学显微镜、扫描电镜和透射电镜对热轧和冷轧后的MGH754合金板材的显微组织和断口形貌进行了分析,研究了冷轧与热轧工艺对其组织以及力学性能的影响。结果表明,MGH754合金热轧板材的终态组织是发生了二次再结晶的粗晶组织,而冷轧板材只发生了一次再结晶。热轧板材的高温抗拉强度要优于冷轧板材,但其高温伸长率却低于冷轧板材。     

新一代热轧板带材表面氧化铁皮控制技术的现状与进展

热轧板带材作为海洋、交通、能源等行业的支柱性原材料,力学性能与尺寸精度一直是衡量其质量的最重要指标。然而随着相关行业的转型升级,对其表面质量也提出了严苛的要求,导致大量钢材产品由于表面不过关被降级或判废。由于钢材的氧化在热轧过程中贯穿始终,并受到合金元素及诸多工艺参数的交互影响,很难实现结构、厚度、均匀性的精准控制。尽管前期围绕着“黑皮钢”,已经开发出了一些氧化铁皮的控制方法,但仅局限于强度较低、厚度较薄的汽车结构钢。为此,东北大学轧制技术及连轧自动化国家重点实验室开发了新一代热轧板带材表面氧化铁皮控制技术,其研发与应用全面提升了我国热轧钢材产品的表面质量。目前,所生产的系列高表面质量产品已达到了国外企业对钢材表面质量的苛刻要求,成功助力我国钢铁行业产品结构的转型升级。     

夹层钢板冲压的成形机理与缺陷分析

介绍了夹层钢板的材料结构、夹层钢板的冲压成形性及在成形过程中容易产生的缺陷,总结了影响夹层钢板成形性能的因素。介绍了夹层钢板在汽车行业中的应用情况及国内外的研究现状,并指出了当前车用夹层钢板研究的热点难点,对夹层钢板在此行业中应用发展做了展望。     

薄带铸轧产品特性及应用进展

薄带铸轧工艺是将快速凝固与轧制变形融为一体的短流程、近终型生产工艺,具有流程短、工序少、能耗低、排放少的优势。通过对薄带铸轧产品进行组织分析及力学性能研究,结果表明,在薄带铸轧的快速凝固、快速冷却、小压下量轧制条件下,产品组织与传统热连轧工艺产品在晶粒形态、晶粒尺寸上具有显著区别。薄带铸轧产品性能波动小、各向同性好、利于焊接、尺寸公差精确、表面质量好,易于生产高强度薄规格产品,在轻量化及“以热代冷”趋势下具有广阔的应用空间。     

�������߲����Ƶķ���

 主要对Q235B热轧卷板出现边部裂纹的原因以及裂纹形成过程进行了研究。通过成分分析、宏观裂纹检验、光学显微镜下的裂纹组织以及扫描电镜和能谱的分析,对Q235B热轧卷板出现边部裂纹的原因进行了分析,并对裂纹形成过程进行了数值模拟。结果表明：导致裂纹形成的主要原因是钢坯中存在低熔点夹杂物及夹渣,其在轧制过程中没有被轧合,形成裂纹。通过对夹杂物和硫含量的控制及铸坯的均热模式的改进,可减少或避免裂纹的产生。     

Influence of Finish Rolling Temperature on Microstructure and Mechanical Properties of a 19Cr1.5Mo0.5W Ferritic Stainless Steel

A 444-type heat-resistant ferritic stainless steel containing 0.05 wt% Ce(rare earth element) and 2 wt%(Mo+W) was adopted as an experimental material to study the effect of finish rolling temperature on microstructure and texture evolution as well as on mechanical properties and formability.The rolling processes contain hot rolling at two different finish rolling temperatures(860℃ and 770℃) and annealing,cold rolling and subsequent annealing.It was found that the microstructures after hot rolling and annealing could be refined by lowering finish rolling temperature.The resultant microstructures after cold rolling and annealing were hereditarily refined.Lowering finish rolling temperature can weaken α-fiber texture in hotrolled or cold-rolled ferritic stainless steel strip,while γ-fiber texture in the final product was homogeneously strengthened.Additionally,enhanced mechanical property and formability in terms of strength and average plastic strain ratio could be obtained via decreasing finish rolling temperature.     

Structure and mechanical properties of the nitrogen-containing austenitic plate steel 04Kh20N6G11AM2BF

Structure and mechanical properties of the nitrogen-containing austenitic plate steel 04Kh20N6G11AM2BF with a thickness of 20 and 40 mm after hot rolling, quenching from different temperatures, and final strengthening by cold or warm deformation have been studied. For these large-section plates, sufficiently high mechanical properties were obtained, namely, the yield stress σ_0.2 ≥ 690 MPa, the relative elongation δ ≥ 20%, the relative reduction ? ≥ 50%, and the impact toughness KCV ⁺²⁰ ≥ 100 J/cm². This complex of strength and plastic properties of hot-rolled steel was produced after the quenching of the plates from 1150°C and subsequent strengthening warm (600°C) or cold (20°C) rolling with a reduction of up to 15%. These properties of steel were due to several causes, namely, the presence of nitrogen in the fcc solid solution, an increased density of dislocations (≈ 10¹⁰ cm^?2), the precipitation of nanocrystalline vanadium nitrides with sizes of 2–4 nm, and the absence of large amounts of coarse near-boundary particles.     

CSP卷取温度对冷轧深冲钢板的影响

研究了热轧卷取温度对CSP(compact strip production)冷轧深冲板的性能、组织和织构的影响。CSP热轧板组织主要为多边形铁素体,随卷取温度降低,晶粒尺寸略有减小。660℃和680℃卷取的成品冷轧板组织为等轴晶粒,卷取温度不超过600℃时则以"饼型"晶粒为主。力学性能测试表明,低于600℃卷取的成品板屈服强度和抗拉强度较低,其加权平均塑性应变比(rm)可达到1.80以上,伸长率超过49%。随卷取温度升高,成品板的{001}〈110〉和{110}〈110〉织构的取向分布密度逐渐升高,{111}织构取向分布密度先升高后降低,{111}〈110〉和{111}〈112〉织构取向分布密度差值也是先升后降。     

热轧酸洗搪瓷钢板STC330R的组织与性能

简要介绍了首钢热轧酸洗搪瓷钢板STC330R的生产工艺流程、成分设计,研究了两种不同热轧工艺方案下产品力学性能、金相组织及析出相形态,分析了不同热轧工艺下析出相尺寸、分布等对产品氢渗透时间的影响。实验结果表明,以低碳低锰成分体系为基础、添加少量Ti元素进行微合金强化,并采用合适的热轧工艺制度生产的热轧酸洗搪瓷钢板STC330R的基体组织为铁素体+少量珠光体,存在细小且弥散分布的析出相Ti C,其力学性能满足标准要求,氢渗透时间长于国内同级别产品,抗鳞爆性能优异。     

304不锈钢免退火直接冷轧工艺研究

分析了热轧304板卷的金相组织及力学性能,结果表明304热轧板卷可以不退火直接进行冷轧。对304热轧板卷进行了免退火直接冷轧试验,轧后冷板经固溶退火,其晶粒度、力学性能及耐晶间腐蚀性能与退火后再冷轧的产品差别不大,符合生产标准要求。因此,实际生产中可以通过优化生产工艺,实现节能降本。     

控冷工艺对热轧双相钢组织与性能的影响

基于合金减量化原则,通过热轧+超快冷技术得到了强韧性较好的600 MPa级热轧双相钢,研究了控冷工艺对其组织与性能的影响。结果表明,随着弛豫时间的减少和卷取温度的降低,钢中铁素体体积分数逐渐减少,铁素体晶粒尺寸逐渐减小,抗拉强度由602 MPa 增加至637 MPa,伸长率由31.0%减小至24.0%,屈强比为0.53~0.59,n值为0.17~0.21。综合考虑板形风险和力学性能,试验钢合适的卷取温度为150 ℃,合适的弛豫时间为7 s。     

Variations in the microstructure and mechanical properties of the oxide layer on high speed steel hot rolling work rolls

This paper is part of a larger study to understand the wear of hot rolling rolls. A significant cost of the hot rolling process is associated with the consumption of rolls, which is why a comprehensive understanding of the wear of the roll material is important. Given that the surface of the rolls is covered by an oxide layer, it is important to know the tribological and mechanical properties of the oxides. Research in this area concentrates mainly on the morphologies and microstructures of the oxide layers. Previously published works give very little, if any, information of the mechanical properties of the layers on high speed steel. This paper presents a methodology to study the mechanical properties of the oxide layer formed on the surface of a high speed steel roll using combined nanoindentation tests and finite element simulations. Mechanical properties such as the elastic modulus (E), hardness (H), yield strength (σ_y), and Poisson's ratio (ν), have been determined, and the work has revealed a variation of microstructure, porosity (f), and mechanical properties of the oxide layer across its thickness. The outer sub-layer has a higher E and H than the inner sub-layer. This variation of mechanical properties in the oxide layer was consistent with variations in the porosity and grain sizes in the two sub-layers.