Weld Formation Characteristics in Resistance Spot Welding of Ultra-Thin Steel
Weld Formation Characteristics in Resistance Spot Welding of Ultra-Thin Steel
复制标题
超薄钢电阻点焊焊缝成形特征
作者：
YangYang Zhao;Yansong Zhang;Pei-Chung Wang
最近的趋势是在保证结构性能的同时经济地制造轻量化车辆，这使得薄钢（例如< 0.5 mm）在汽车工业中越来越有吸引力。研究了0.35 mm厚600 MPa级双相钢电阻点焊过程中焊缝的形成过程。结果表明：焊缝形成较早，焊接时间为40ms，焊缝尺寸达到最大2.8 mm，此后焊缝尺寸基本保持不变，并逐渐呈现出独特的“双层”特征；从温度演化的角度对焊缝分层的形成机理进行了模拟。模拟结果表明，在剩余的焊接过程中，焊缝温度区先是升高，然后惊人地降低，最终形成“双层”焊缝。结果表明，焊缝强度随焊缝尺寸的增大而增大，但随焊缝分层的发生而增加的幅度不大。因此，采用大的焊接电流和短的焊接时间来连接超薄钢是可取的。
Recent trends toward economically fabricating lightweight vehicles while ensuring structural performance makes thin (e.g., < 0.5 mm) steels increasingly attractive in the automotive industry. In the present study, the formation of the weld during resistance spot welding (RSW) of a 0.35-mm-thick 600 MPa grade dual-phase steel was investigated. The results indicated the weld initiated early and grew to reach a maximum size of 2.8 mm within a welding time of 40 ms, and then its size remained virtually unchanged, and gradually exhibited a unique “double-layer” feature. Furthermore, the mechanism for the formation of weld layering was modeled from the perspective of temperature evolution. Modeling results indicated the temperature weld zone increased initially but then surprisingly decreased for the remaining welding process, and eventually resulted in a “double-layer” weld. It was found that the strength of the weld increased with the weld size and was improved little with the occurrence of the weld layering. Therefore, the use of high welding current and short welding time is preferable to join ultra-thin steel.