Microstructure and properties at bonding interface of AA4045/AA3003 aluminum alloy cladding billet prepared by semi-continuous casting

AA4045/AA3003 cladding billet was prepared by direct chill semi-continuous casting process. The macrostructures, microstructures, temperature distribution, compositions distribution and the mechanical properties at the bonding interface were investigated in detail. The results show that the cladding billet with few defects could be obtained by semi-continuous casting process. At the interface, diffusion layer of about 10μm on average formed between the two alloys due to the diffusion of alloy elements in the temperature range from 596 to 632 °C. From the side of AA4045 to the side of AA3003, the Si content has a trend to decrease, while the Mn content has a trend to increase gradually. Tensile strength of the cladding billet reaches 103.7 MPa, the fractured position is located on the AA3003 side, and the shearing strength is 91.1 MPa, revealing that the two alloys were combined metallurgically by mutual diffusion of alloy elements.

Effect of clad ratio on interfacial microstructure and properties of cladding billets via direct-chill casting process

Numerical simulation and experiments were introduced to develop AA4045/AA3003 cladding billets with different clad-ratios. The temperature fields, microstructures and mechanical properties near interface were investigated in detail. The results show that cladding billets with different clad-ratios were fabricated successfully. Si and Mn elements diffused across the bonding interface and formed diffusion layer. With the increase of clad-layer thickness, the interfacial region transforms from semisolid-solid state to liquid-solid state and the diffusion layer increased from 10 to 25 μm. The hardness at interface is higher than that of AA3003 side but lower than that of the other side. The bonding strength increased with the clad-layer thickness, attributing to solution strengthening due to elements diffusion. The cladding billets were extruded into clad pipe by indirect extrusion process after homogenization. The clad pipe remained the interfacial characteristics of as-cast cladding billet and the heredity of clad-ratio during deformation was testified.

制坯工艺对热轧不锈钢/碳钢复合板复合效果的影响

采用真空电子束焊接、界面四周焊合抽真空和界面四周焊合3种工艺制备不锈钢/碳钢复合板坯并热轧,研究了不同制坯工艺下复合板复合界面的组织结构及其性能。结果表明,利用真空电子束焊接和界面四周焊合抽真空两种方式制备的复合板坯经热轧后能100%复合,而通过界面四周焊合方式制备的复合板坯在热轧后界面结合率较低。对3种工艺下成功复合的部位,其复合界面形貌相似,即界面都较平直,且都存在不锈钢、碳钢和复合层3个区域以及近复合层碳钢内的脱碳区,靠近不锈钢侧也都间断分布着Si-Mn等的氧化物。真空电子束焊接和界面四周焊合抽真空两种方式制备的坯料在热轧后碳钢与不锈钢之间都实现了较高强度的复合,并且真空电子束焊接坯料热轧复合板的强度值都略高于界面四周焊合抽真空复合板的。

双金属层状复合铸锭热处理研究

以复合铸造技术制备的4045/3003铝合金复合铸锭为研究对象,研究了均匀化温度和时间对界面处组织性能的影响。结果表明,经过均匀化退火后,共晶相熔断并球化,且在一定范围内,随着温度升高、时间增加,球化更完全,分布更均匀,但不能改变整体上共晶相的树枝状分布。均匀化后复合铸锭硬度和界面抗拉强度整体均略有提高。4045/3003铝合金复合铸锭最佳均匀化制度为560℃+12h。

非对称热轧单面不锈钢-碳钢复合板生产工艺研究

采用"电子束真空焊接制坯+热轧"的工艺在钢厂热连轧生产线上进行了"316L不锈钢+Q345C碳钢"的单面不锈钢复合板热轧生产。采用非对称制坯及异步轧制的手段生产出了高品质单面不锈钢复合板,所生产的不锈钢复合板界面剪切强度大于320 MPa、屈服强度大于370 MPa、抗拉强度大于520 MPa、断后伸长率大于30%,各项指标均达到GB/T8165-2008的要求。不锈钢层和碳钢层结合度良好,复合界面平直,无明显缺陷,不锈钢与碳钢之间实现了良好的冶金结合,结合率达100%。

一种不锈钢复层钢带热轧法的实验研究

完成了由连铸钢坯通过爆炸复合不锈钢,对包复坯采用单根轧制和迭合轧制2种方法生产不锈钢复层钢带的试验﹒在上述试验的基础上,提出了1种新的不锈钢复合带热轧方法,并进行了实验研究﹒结果表明,新的热轧法比传统热轧法装配工艺简单,在普通的热轧机上也可以实施热轧﹒样品分析结果表明,复合带界面结合质量良好﹒提出的热轧法新工艺,可望试验推广在大规模轧机上生产不锈钢复合带卷﹒

DC铸造法制备包覆铸锭研究（英文）

首先建立了一个数学模型,用来模拟包覆(direct chill, DC)铸造过程和工艺参数(包括铸造速度、铸造温度、冷却水量)对包覆铸锭的影响规律。以模拟结果为依据,通过优化工艺参数成功制备了尺寸为Φ140 mm/Φ110 mm的AA4045/AA3003包覆铸锭,并通过实验测温对模型进行了验证。采用多种手段对界面的组织性能进行了检测。结果表明,测温结果与模拟结果相互吻合,模型可靠。优化后的包覆铸造工艺参数为:铸造速度100 mm/min,冷却水量35 L/min,铸造温度1020 K(AA4045)、1000 K(AA3003)。包覆铸锭界面处无气孔、夹杂等缺陷,通过元素扩散形成了约15μm的扩散层。界面抗拉强度为107.3MPa,大于AA3003合金基体强度,说明2种合金实现冶金结合。

水平连续铸造工艺对3003/4045复层管界面特征的影响

采用水平连续铸造技术制备3003/4045铝合金复层管坯,探讨了铸造速度、外层合金浇注温度和气体保护对复层管界面结合质量的影响,并对结合界面的形貌、元素分布和结合强度进行分析。结果表明,当铸造速度为180 mm/min、外层合金浇注温度为700℃并对内层管坯施加气体保护时,可成功制备出界面实现连续均匀冶金结合的复层管。拉伸剪切实验中变形与断裂发生在界面附近强度较低的3003合金侧,表明界面剪切强度大于3003合金的剪切强度。