A new twin-roll casting (TRC) process to produce Cu/Invar/Cu clad strips, which have greater application potential, is proposed. The symmetrical cast-rolling zone is divided into two asymmetrical parts by introducing the substrate strip in the middle. The thermal-flow coupled simulation was conducted, and it realized the coupling analysis of casting roll, molten pool, and substrate strip. The results indicate that the kissing point (KP) shape in each part is asymmetric and vortexes are more likely to occur near the KP. Besides, univariate analyses show that the influence of the cast-rolling velocity, substrate preheat temperature and casting temperature on the KP length and average outlet temperature is linear, and the influence of the substrate thickness is nonlinear. Process window prediction models were obtained, which laid the foundation of setting process parameter combinations for providing the required KP length. Furthermore, numerical simulation results indicate that the fluidity of the liquid metal ensures the continuity of production. The macro-structures evolution in the cast-rolling zone indicates that deformation below the KP ensures the quality of the product. Finally, the Cu/Invar/Cu clad strips with metallurgical bonding were fabricated. The ultimate tensile strength and maximum peeling strength are 250 MPa and 126.5 N/mm, respectively. Hence, the TRC process for trimetallic clad strips is developed successfully and stability is basically achieved through equipment design, process window prediction, experimental validation, and bonding strength characterization. These methods can be conducive to the development of other new TRC processes for multiply clad strips.

中文翻译：

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Cu/Invar/Cu复合带双辊铸造过程中流体流动、凝固和结合强度的数值与实验研究

提出了一种新的双辊铸造 (TRC) 工艺来生产具有更大应用潜力的 Cu/Invar/Cu 复合带材。通过在中间引入基体带材，将对称的铸轧区分成两个不对称的部分。进行了热流耦合仿真，实现了铸辊、熔池、基材带材的耦合分析。结果表明，每个部分的接吻点（KP）形状是不对称的，在 KP 附近更容易出现涡流。此外，单变量分析表明，铸轧速度、基体预热温度和铸造温度对KP长度和平均出口温度的影响是线性的，基体厚度的影响是非线性的。获得工艺窗口预测模型，为设置工艺参数组合以提供所需的KP长度奠定了基础。此外，数值模拟结果表明，液态金属的流动性保证了生产的连续性。铸轧区宏观组织的演变表明，低于KP的变形保证了产品的质量。最后，制造出具有冶金结合的Cu/Invar/Cu复合带。极限拉伸强度和最大剥离强度分别为 250 MPa 和 126.5 N/mm。因此，三金属复合带材的TRC工艺开发成功，通过设备设计、工艺窗口预测、实验验证和结合强度表征，基本实现了稳定性。