(1. 青島四方機(jī)車(chē)車(chē)輛股份有限公司，青島 266111；
2. 中國(guó)科學(xué)院金屬研究所 中國(guó)科學(xué)院核用材料與安全評(píng)價(jià)重點(diǎn)實(shí)驗(yàn)室，沈陽(yáng) 110016)
摘 要: 為了準(zhǔn)確預(yù)測(cè)異種不等厚鋁合金電阻點(diǎn)焊熔核尺寸及表面形貌，本文綜合考慮電阻點(diǎn)焊過(guò)程中電極與工件、工件與工件間接觸面積的動(dòng)態(tài)變化以及材料力學(xué)性能對(duì)接觸電阻的影響，建立了較為完善的電阻點(diǎn)焊有限元模型，研究異種不等厚鋁合金電阻點(diǎn)焊熔核形成機(jī)理以及電極圓角半徑對(duì)接頭形貌的影響規(guī)律。結(jié)果表明：熔核最先在焊點(diǎn)邊緣形成，然后向中心擴(kuò)展，隨著焊接時(shí)間的延長(zhǎng)，熔核截面由橢圓形向方形轉(zhuǎn)變；電極圓角半徑增大，點(diǎn)焊熔核尺寸、壓痕深度和凸起高度增加。模型計(jì)算得到的熔核尺寸和焊點(diǎn)表面形貌與實(shí)驗(yàn)結(jié)果符合較好，驗(yàn)證了模型的有效性。
關(guān)鍵字: 鋁合金；電阻點(diǎn)焊；數(shù)值模擬；熔核形狀；表面形貌
（1. CRRC Qingdao Sifang Co., Ltd., Qingdao 266111, China;
2. CAS Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:In order to accurately predict the nugget size and surface morphology of the resistance spot welded dissimilar unequal thickness aluminum alloy joint, a finite element model was established. The dynamic contact between the electrode and the workpieces and the influence of mechanical behavior of the workpieces on the contact resistivity were considered in the model. The nugget formation mechanism of the aluminum alloy during resistance spot welding and the influence of corner radius of the electrode on the joint were analyzed. The calculated results show that the initial nugget forms at the edge of the weld point, then propagates to the center. With the welding time increasing, the cross section of the nugget changes from generally elliptical to square. Besides, the nugget size, the indentation depth and pile-up height increase with the corner radius of the electrode increasing. The effectiveness of the numerical model was verified by comparing the calculated result with experimental result.
Key words: aluminum alloy; resistance spot welding; numerical simulation; nugget shape; surface morphology
