Microstructure and mechanical properties of Mg-Al-Mn-Ca alloy sheet produced by twin roll casting and sequential warm rolling

Microstructural evolution and mechanical properties of twin roll cast (TRC) Mg-3.3 wt.%Al-0.8 wt.%Mn-0.2 wt.%Ca (AM31 + 0.2Ca) alloy strip during warm rolling and subsequent annealing were investigated in this paper. The as-TRC alloy strip shows columnar dendrites in surface and equiaxed dendrites in center regions, as well as finely dispersed primary Al₈Mn₅ particles on interdendritic boundaries which result in the beneficial effect on microstructural refinement of strip casting. The warm rolled sheets show intensively deformed band or shear band structures, as well as finely and homogeneously dispersed Al-Mn particles. No evident dynamic recrystallization (DRX) takes place during warm rolling process, which is more likely attributed to the finely dispersed particle and high solid solution of Al and Mn atoms in α-Mg matrix. After annealing at 350 °C for 1 h, the warm rolled TRC sheets show fine equiaxed grains around 7.8 μm in average size. It has been shown that the present TRC alloy sheet has superior tensile strength and comparative elongation compared to commercial ingot cast (IC) one, suggesting the possibility of the development of wrought magnesium alloy sheets by twin roll strip casting processing. The microstructural evolution during warm rolling and subsequent annealing as well as the resulting tensile properties were analyzed and discussed.     

基于双辊铸轧的Al-Zn-Mg-Cu系合金冷轧后的再结晶行为

将双辊铸轧运用于制造Al-Zn-Mg-Cu合金带材。研究带材减薄率及热处理温度对合金再结晶行为的影响。结果表明：在冷轧率为60％、热处理制度为500℃的条件下处理1h时,合金带材具有细晶组织（平均晶粒尺寸约为13μm,晶粒纵横比约为1．7）和高的力学性能（UTS≥360MPa,δ≥20％）。研究了微观组织对Al-Zn-Mg-Cu合金带材力学性能的影响。合适的双棍铸轧热处理及加工工艺能制造低价、高强的Al-Zn-Mg-Cu合金带材。     

双辊快速凝固AZ31镁合金薄带试验研究

在等径双辊连铸机上进行了AZ31镁合金薄带连铸的试验研究，掌握了诸如浇铸温度、铸辊转速、辊缝和侧封等合理的工艺参数，成功地铸出了AZ31镁合金薄带并对其显微组织进行了分析。     

双辊薄带连铸熔池液面波动物理模拟

设计了一个双辊薄带连铸机动态物理模拟实验装置，利用超声波浪高仪对双辊熔池液面波动进行了实验测定。重点研究了不同水口结构、拉速（转速）、熔池高度以及插入深度等参数对熔池内液面波动的影响，从而为优选出满足双辊薄带连铸布流要求的水口结构尺寸提供依据。     

Comparison of phosphor bronze metal sheet produced by twin roll casting and horizontal continuous casting

Much effort recently has been expended to study the strip casting process used to produce thin metal strip with a near final thickness. This process eliminates the need for hot rolling, consumes less energy, and offers a feasible method of producing various hard-to-shape alloys. The finer microstructure that results from the high cooling rate used during the casting process enhances mechanical properties. In this study, strips of phosphor bronzes (Cu-Sn-P) metal were produced using a twin roll strip casting process as well as a conventional horizontal continuous casting (HCC) process. The microstructures, macrosegregations, textures, and mechanical properties of the as-cast and as-rolled metal sheet produced by these two methods were examined carefully for comparative purposes. The results indicate that cast strip produced by a twin roll caster exhibit significantly less inverse segregation of tin compared to that produced by the HCC process. The mechanical properties including tensile strength, elongation, and microhardness of the products produced by the twin roll strip casting process are comparable to those of the HCC processed sheet. These properties meet specifications JIS H3110 and ASTM B 103M for commercial phosphor bronze sheet. The texture of the as-rolled sheet from these two processes, as measured from XRD pole figures, were found to be virtually the same, even though a significant difference exists between them in the as-cast condition.     

Research and development of transnormal twin roll-casting technology

1　INTRODUCTIONThedevelopmentofmodernmaterialprocessingscienceandtechnologyhasdriventhetransnormaloutfieldsmaterialprocessingtechnologytobeafavor abledevelopingandresearchdirectionoftwinrollcastingprocess[1,2 ] .Asweallknow ,theconven tionaltwinroll casting (CTRC)hasthefollowingdisadvantages :lowrollcastingspeed ;fewkindsofa luminumalloyswhichcouldbeproduced ;segregationandinhomogeneityexistingbothonthesurfaceandinsideofCTRCstrips ,andhardto producehighqualitystripsforhighgradeperforman…     

3004铝合金铸轧带坯生产实践

生产易拉罐料用的3004铝合金带坯,大多数是用热轧法生产的,用铸轧法生产的难度较大,但是热轧法的加工费是铸轧法的两倍多,因此开发铸轧法生产3004铝合金带坯的技术,具有很大的经济效益和节能效益。采用Φ1003mm×1 900 mm国产双驱动倾斜式铸轧机试生产3004铝合金带坯,通过试验性生产,摸索出了3004铝合金带坯的铸轧生产技术和工艺参数,并稳定批量地给一家生产易拉罐料的铝加工厂供给合格的3004铝合金铸轧带坯。     

Ce对铸造Al—Cu合金凝固过程影响的研究

为了探索改善高强度铸造Al-Cu合金抗热裂性能的途径,采用液淬的方法,通过测量热平衡曲线、溶质浓度分布及金相显微分析等手段,研究了0．2％,Ce对Al-4．5Cu和高强度铸造Al-Cu－Mn-Ti合金的凝固过程的影响;研究结果表明,Ce的加入,改变了试验合金的凝固特性影响了合金的枝晶生长行为,其综合作用使合金组织明显细化和均匀化,且二次晶臂发达,对提高高强度铸造Al-Cu合金抗热裂性能具有积极作用。     

双辊薄带高速铸轧机新技术

本文介绍了近年来出现的MDTRC、METRC和HPTRC等新型双辊铸轧机,对设备和工艺特点以及所得铸带的组织性能等参数进行了对比分析,指出立式TRC、铜质铸辊、无润滑、低过热度和半固态铸轧是提高铸轧速度的有效方法.     

AZ31镁合金薄带立式双辊铸轧试验研究

利用近终形双辊铸轧薄带新工艺快速凝固、动态直接成形的特点,直接制备镁合金薄带坯。研究了镁合金立式铸轧成形工艺及退火工艺,分析了不同工艺下的微观组织。结果表明:采用铸轧工艺很好的解决了坯料成形问题,同时细化晶粒,提高镁合金薄带坯的加工成形性能。经400℃,60 min退火,可以获得平均直径9～10μm分布均匀的等轴细晶组织。     

Microstructure formation mechanism and properties of a Mg-3Sn-1Mn (wt%) magnesium alloy processed by a novel semisolid continuous shearing and rolling process

A novel semisolid Continuous Shearing and Rolling (CSR) process for producing a Mg-3Sn-1Mn (wt%) alloy strip is developed, and the microstructure formation mechanism and properties of the Mg-3Sn-1Mn (wt%) alloy processed by this process are investigated. At a casting temperature of 690°C and a roll speed of 0.052 m·s^?1, a Mg-3Sn-1Mn (wt%) alloy strip with a cross section size of 4×160 mm was produced by the proposed process. Under strong cooling and shearing actions, eruptive nucleation, direct globular grain growth and dendrite arm breakage took place during the process, which caused formations of fine spherical grains. The grain size and roundness of the Mg-3Sn-1Mn (wt%) alloy strip increased with increasing increments of the casting temperature. In this perspective, roll speed obviously affects grain shape. The ultimate tensile strength and elongation of the Mg-3Sn-1Mn (wt%) alloy strip reached 205.93 MPa and 7.2%.     

镁合金的双辊板带连续铸轧技术

综述了绿色环保材料镁合金的特点、适用范围及其加工方式,分析了镁合金双辊板带连续铸轧技术是镁合金加工的未来发展方向,并指出了存在的问题和挑战.     

Fabrication of a Cu36Zr48Al8Ag8 bulk metallic glass sheet by atmosphere-controlled vertical twin roll strip casting

Large-scale fabrication of Cu₃₆Zr₄₈Al₈Ag₈ amorphous alloy sheets having with lengths above 250 mm was performed using atmosphere-controlled twin roll strip casting. By constructing a continuous cooling transformation diagram, the critical cooling rate was determined to be 212.6 K/s. The size and morphology of the crystalline phases within the amorphous matrix, which was Al-rich and Ag-depleted, were confirmed by scanning electron microscopy. The presence of a small volume fraction fine dendritic crystalline phase was necessary for the improved plasticity of the amorphous strip under tensile deformation mode.     

世界镁及镁合金板带轧制回眸与展望(2)

介绍了世界镁及其合金板带轧制的发展历史,镁合金板带的常规轧制方法,典型镁合金板带的力学性能。这里详述了镁合金板带的双辊铸轧技术进展情况,概述了镁合金板带的其他生产工艺。     

Microstructure formation mechanism and properties of AZ61 alloy processed by melt treatment with vibrating cooling slope and semisolid rolling

A melt treatment with a vibrating cooling slope and a semisolid rolling process to produce an AZ61 alloy strip was proposed. The microstructure formation mechanism and the properties of the AZ61 alloy produced by the proposed process were investigated. Due to the high cooling rate and stirring action caused by the vibration cooling slope, the nucleation rate was greatly improved, which caused the formation of fine spherical or rosette primary grains. During the rolling process, the solid fraction increased from the entrance to the exit of the roll gap, and under the shearing action of the roller, the distribution of solute in the melt was homogenous, and the primary grains grew further. When the casting temperature was 680 °C, a strip with a cross section of 4 mm×160 mm was produced and a homogeneous microstructure was obtained. The ultimate tensile strength of the AZ61 alloy strip produced by the proposed method reached 242 MPa, and the corresponding elongation to failure was 4%, which were better than those achieved in previous similar studies.     

SIMULATION OF THE TWIN ROLL STAINLESS STRIP CASTING PROCESS

1. IntroductionTwin roll stainless strip casting' process which can directly cast a thin strip with thickness less than 10mm from a molten metal pool is being researched by industrious workersall over the world. Compared with the conventional continuous casting, this process caneliminate the expansive and complex hot-rolling facilities, and can reduce both the capitalinvestmellt and the cost of production. Among various processes under development, thetwin-roll strip casting is revealed as the…     

双辊薄带钢铸轧熔池电磁侧封模拟试验

报道双辊薄带钢持轧熔池电磁侧封低熔点合金模拟试验研究结果。在额定功率60kW、频率2500Hz的电源下，成功实现对高10cm金属熔池的例向电磁约束与封堵。     

铸轧镁合金薄带组织演变实验研究与模拟

以镁合金薄带双辊铸轧新技术为背景,开展了铸轧成形过程中组织性能的模拟研究。镁合金薄带双辊铸轧是以液态镁合金为原料,用两个反向转动的水冷铸辊为结晶器,直接制备1．5～3．0mm镁合金薄带的短流程新工艺。对双辊铸轧轻合金薄带的凝固组织演化过程进行数值模拟,用以优化和指导制备技术,具有重要的理论意义和应用前景。项目研究组通过对双辊铸轧过程动态凝固成形的有限元数值模拟研究、镁合金薄带铸轧实验研究以及后续加工过程中的组织演变规律研究,得到了主要工艺参数对铸轧工艺稳定性及组织性能的影响规律。     

工艺参数对连续流变轧制成形Mg-3Sn-1Mn合金板材组织和力学性能的影响

开发了Mg-3Sn-1Mn合金板材倾斜板连续流变轧制成形工艺,并研究工艺参数对合金板材微观组织和力学性能的影响.结果表明:随着轧辊转速的增加,板材的初生晶粒平均直径增大;随着倾斜板振动频率增加,板材的初生晶粒平均直径先减小后增大,板材的抗拉强度和伸长率先增加后降低.随着浇注温度的升高,板材的初生晶粒平均直径逐渐增大,板材的抗拉强度和伸长率逐渐降低.当浇注温度为670℃、轧辊转速为52mm/s、倾斜板振动频率为60 Hz时,制备了组织性能较好的Mg-3 Sn-1Mn合金板材,其力学性能优于添加0.87％Ce(质量分数)的Mg-3Sn-1Mn合金热轧板材的力学性能.     

双辊薄带连铸技术的研究与发展

双辊连铸技术是一种新型近终形连铸技术,近年来受到普遍关注。本文综述了该项技术在国内外的研究与发展,介绍了侧封、轧辊运行状况和工艺参数等双辊连铸技术中的关键问题及研究热点。双辊连铸技术将广泛应用于不铸钢薄带的连续铸造生产、其它高合金特种钢双辊连铸技术的研究与应用也指日可待。