基于CSP工艺热轧及冷轧过程3%Si钢组织和织构的演变

3%Si钢(/%:0.067C、3.09Si、0.34Mn、0.007P、0.003S、0.70Cu、≤0.005Al、0.0080～0.0120N)由50kg真空感应炉冶炼,并在实验室轧机经6道次热轧成3.5mm板,终轧温度850℃,卷取温度650℃,热轧板经常化处理后由4辊可逆轧机6道次冷轧成0.50mm薄板。分析结果表明,热轧板表面主要为随机分布较大的等轴晶,中心处由细小等轴晶和长条状晶粒组成,并出现了很强的旋转立方织构{001}〈110〉。经过冷轧,薄板表面出现了很强的α织构和γ织构组分,并且冷轧板保留了热轧的{001}〈110〉旋转立方织构。

冷轧组织对15CrMnMoV钢板断裂行为的影响

采用自制平面应力拉伸装置,通过扫描电镜,透射电子显微镜等分析测试方法对15CrMnMoV钢的淬火-回火组织和淬火-冷轧组织的断裂行为进行了研究。实验结果表明:具有冷轧组织试样的断裂阻力明显高于原始组织试样。利用复型的方法精确测定出裂纹长度,并计算得出能量释放率D-△a的关系曲线,轧制试样在△a=40μm时出现峰值,显微组织分析表明峰值产生的原因是弱界面开裂的结果。

热轧板初始组织对冷轧无取向硅钢织构演变的影响

研究了27.5 mm热轧板的初始组织(热轧态,850℃退火、950℃退火)对冷轧态和870℃退火的0.5mm冷轧无取向硅钢50W600薄板(/%:0.004C、0.33Si、0.38Mn、0.099P、0.007S、0.32Al)织构演变的影响。结果表明,经冷轧后冷轧板织构中{100}〈011〉和{112}〈110〉织构密度明显增大,末退火热轧板轧成的冷轧板织构密度较退火热轧板轧成的冷轧板强;经未退火热轧板冷轧成的薄板再结晶退火后的织构中主要为{100}〈011〉、{110}〈011〉和{111}〈112〉,退火热轧板冷轧成的薄板再结晶退火后的织构除{100}〈011〉和{110}〈011〉外还有密度较强的高斯织构。

冷轧变形量对Nb-Ti微合金化IF钢组织和性能的影响

试验研究了Nb-Ti微合金化无间隙原子(IF)钢(/%:0.006C、O.005Si、0.15Mn、0.008P、0.006S、0.039A1、0.01Nb、0.048 Ti、0.003 4N)在实验4辊冷轧机由3.98 mm热轧机冷轧至0.4mm(变形量40%～90%)过程组织和力学性能的变化。结果表明,随着冷轧变形量的增加,Nb-Ti微合金化IF钢组织中晶粒逐渐变为细小且纤维化,第二相粒子趋于沿轧制方向排列;钢的硬度、屈服强度、抗拉强度均增加,伸长率下降。变形量在75%和77%时出现低的屈强比,并可获得好的综合力学性能。

Effect of thermo-mechanical treatment on microstructure and mechanical properties of wire-arc additively manufactured Al-Cu alloy

Wire-arc additive manufacture(WAAM)has great potential for manufacturing of Al-Cu components.However,inferior mechanical properties of WAAM deposited material restrict its industrial application.Inter-layer cold rolling and thermo-mechanical heat treatment(T8)with pre-stretching deformation between solution and aging treatment were adopted in this study.Their effects on hardness,mechanical properties and microstructure were analyzed and compared to the conventional heat treatment(T6).The results show that cold rolling increases the hardness and strengths,which further increase with T8 treatment.The ultimate tensile strength(UTS)of 513 MPa and yield stress(YS)of 413 MPa can be obtained in the inter-layer cold-rolled sample with T8 treatment,which is much higher than that in the as-deposited samples.The cold-rolled samples show higher elongation than that of as-deposited ones due to significant elimination of porosity in cold rolling;while both the T6 and T8 treatments decrease the elongation.The cold rolling and pre-stretching deformation both contribute to the formation of dense and dispersive precipitatedθ′phases,which inhibits the dislocation movement and enhances the strengths;as a result,T8 treatment shows better strengthening effect than the T6 treatment.The strengthening mechanism was analyzed and it was mainly related to work hardening and precipitation strengthening.

Effects of cold rolling and heat treatment on microstructure and mechanical properties of AA 5052 aluminum alloy

The microstructures and mechanical properties of homogenized-rolled AA5052 aluminum alloys with different rolling reductions and following annealing treatments were investigated by optical microscope, scanning electron microscope, X-ray diffractometer, micro-hardness and tensile tests. The results show that with increasing rolling reduction, the equiaxed grains are elongated along the rolling direction obviously, and accumulation of rolling reduction increases the work hardening effect, which results in the enhanced strength and degraded plasticity. When rolling reduction is 87%, the ultimate tensile strength reaches 325 MPa but elongation is only 2.5%. There are much more secondary phase precipitates after annealing treatment. With an increase of annealing temperature, the amount of precipitates increases and work hardening diminishes continuously. The elongation is improved to ~23% but the tensile strength is decreased to 212 MPa after annealing at 300 °C for 4 h, which are comparable to those of as-homogenized alloy.

Microstructure and mechanical properties of cold-rolled Ti_(50)Ni_(47)Fe_3 shape memory alloy

Mechanical and shape memory properties of a Ti50Ni47Fe3 alloy annealed at 450-750 °C for 1 h after a cold-rolled reduction of 25% were investigated by phase transformation analysis and microstructure characterization using tensile tests, Vickers hardness tests, electrical resistivity-temperature tests, SEM and TEM. From the results of the tensile, it can be inferred that the fracture stress and yield stress decreased and the fracture elongation increased as the annealing temperature increased for the rolled Ti50Ni47Fe3 alloy. They reached stead values when the temperature was above 650 °C. The change in Vickers hardness corresponded to the change in the fracture stress and yield stress. The electrical resistivity-temperature curves suggest that a two- stage martensitic transformation（B2-R-B19′） occurred during cooling and heating. The transformation temperatures decreased to lower temperatures when the annealing temperature was increased and maintained the same after the annealing temperature reached 650 °C. TEM revealed the distinct processes occurring at elevated temperatures： recovery, polygonization, and recrystallization.

Superplastic extensibility deformation of Al-3%Mn alloy with submicrometer grain size

Submicrometer-grained （SMG） Al-3%Mn （mass fraction） alloy specimens with initial grain size of -0.3 μm were produced by ball milling for 3 h. The Al-3%Mn specimens which were cold rolled with a strain rate of 1×10^-3- 1×10^-2 s-1 at room temperature show high extensibility to failure more than 2500%. Microstructures of pure Al and Al-3%Mn alloy at as-milled and cold-rolled state were examined using X-ray diffraction and transmission electron microscopy （TEM）. Based on the microstructure analysis, it is established that the mechanism of the continued plastic deformation in SMG Al-3%Mn alloy consists of dislocation slip, grain boundary sliding companied by dynamic recovery and recrystallization, and dynamic recrystallization is a main control factor of the large plastic deformation.

Effects of stress state on texture and microstructure in cold drawing-bulging of CP-Ti sheet

Three different stress states of the combination of tensile（t） stress and compressive（c） stress,t t,t c and t c c,exist in the deformed commercially pure titanium（CP-Ti） sheet during cold drawing-bulging.The textures and microstructures in the different stress state regions were investigated by means of XRD and TEM analysis.Similar development of texture and microstructure is achieved with less thickness strain under multiaxial stresses in drawing-bulging than in cold rolling.The results show that texture and microstructure are much sensitive to multiaxial stresses.Twinning is more easily activated under compressive stress than tensile stress.Prism a slip is heavily affected by tensile stress,resulting in a remarkable change of the intensity of（0°,35°,0°） texture,while pyramidal c＋a slip,forming（20°,35°,30°） texture,weakens with the increase of thickness strain in spite of stress state.

Effect of thermomechanical processing on microstructure and mechanical properties of CoCrFeNiMn high entropy alloy

The CoCrFeNiMn high entropy alloy was produced by homogenization, cold rolling and recrystallization. The effects of thermomechanical processing on microstructures and tensile properties at different temperatures were investigated using X-ray diffractometry（XRD）, optical microscopy（OM）, scanning electron microscopy（SEM） and multi-functional testing machine. The results show that dendritic structures in cast alloy evolve into equiaxed grains after being recrystallized, with single face-centered cubic（FCC） phase detected. The most refined alloys, stemming from the highest rolling ratio（40%）, exhibit the highest strength due to the grain boundary strengthening, while the variation of elongation with temperature shows a concave feature. For the coarse-grained alloys, both the ductility and work hardening ability decrease monotonically with increasing temperature. Serrated flow observed at intermediate temperatures is attributed to the effective pinning of dislocations, which manifests the occurrence of dynamic strain hardening and results in the deterioration in ductility. Besides, dimples on the fracture surfaces indicate the typical ductile rupture mode.

Effect of rolling reduction and annealing process on microstructure and corrosion behavior of LZ91 alloy sheet

The effect of rolling reduction and annealing process on the microstructure and corrosion behavior of Mg-9Li-1Zn(LZ91) alloy was investigated. The test alloy sheets were cold rolled with the reduction of 50% and 75%, respectively, and then were annealed at 200 ℃ for 1 h. The microstructure of test alloys was observed by OM and SEM while the phase composition was determined by XRD. The corrosion property was evaluated by electrochemical measurements and immersion tests. The results show that LZ91 alloy sheet consists of α-Mg, β-Li and precipitated Mg-Li-Zn compounds(MgLi2Zn and MgLiZn phases). Dynamic recrystallization grains appear in β-Li phase during annealing process, leading to grain refinement. The results indicate that the increasing rolling reduction and performing the annealing process can enhance the corrosion resistance of LZ91 alloy. The 75% cold-rolled and annealed LZ91 alloy shows the best corrosion resistance.

Grain structure and tensile property of Al-Li alloy sheet caused by different cold rolling reduction

The effect of cold rolling reduction(50%-90%)on the grain structures of solutionized 1445 Al-Li alloy sheet at525-575 ℃ was investigated through electron backscatter diffraction(EBSD).Although the solutionization temperature is elevated to 575 ℃,the sheet is not completely recrystallized.The main recrystallization model is subgrain coalescence and growth,and the non-recrystallization is due to the formed nano-sized Al3(Sc,Zr)dispersoids,which pin the grain boundaries,subgrain boundaries and dislocations.With increasing the cold rolling reduction,the fraction and size of the recrystallized grains in the sheet solutionized at525 ℃ are decreased,but the fraction of the subgrains is increased,leading to a decrease in the fraction of the deformed structures.Meanwhile,the number fraction of high-angle boundaries(HABs)is increased.Due to the decreased fraction of the deformed structures and increased fraction of the HABs,the T8-aged 1445 Al-Li alloy sheet displays a decrease trend in the strength and heterogeneity with increasing the cold rolling reduction.At higher solutionization temperature of 575 ℃,the fraction of the recrystallized grains and their size are obviously increased.

关于MES系统的冷轧生产组织模式探究

冷轧生产是钢铁生产过程中的重要一环,冷轧钢在现在汽车、家电和其他产业设备、建筑材料中起着重要的作用,在我国现在的钢铁市场上占据着重要的位置。冷轧钢在生产的过程中一般要经过生产合同的执行、材料的申报等步骤和流程,各种环节带来的时间延迟是非常大的,因此在现在钢铁企业冷轧钢的生产效率不高。为了能够提高冷轧钢的生产效率,为我国市场上对刚才的需求提供保证,同时节省企业生产过程中的成本,我们希望能够建立一个一体化生产执行系统。因此MES系统在钢铁企业冷轧钢的生产中得到了应用,它能够利用现在的信息通信技术,将生产过程中的各个环节统一,提高生产过程中的时效性。但是在现在的冷轧MES系统中,还存在着一些问题,比如合同主制程确认效率较低、合同归并不合理等,这些问题给冷轧生产带来了诸多的影响。本文针对这些问题进行了分析,并且给出了一些解决建议。

Microstructure Evolution of Zr_(50)Cu_(18)Ni_(17)Al_(10)Ti_5 Bulk Metallic Glass during Cold-rolling

Zr5018Nil1AlTi10Ti5 bulk metallic glass has been rolled at room temperature up to 95% in thickness reduction, and the dependence of microstructure on the strain was investigated. With increasing thickness reduction, the full width at half maximum （FWHM） and crystallization enthalpy decrease gradually till 80%, and then increase evidently at 95%. It is revealed that the reversible transition between the ordered and disordered atomic configurations was found in the metallic glass as the deformation proceeds, which is further verified by the high-resolution transmission electron microscopy images. The final microstructure in metallic glass during cold-rolling is the net result of two competing processes between shear-induced disordering and diffusion controlled reordering.