CuCl2处理对木榫焊接性能的影响

摘要

Chinese larch was selected as the welding substrate and birch dowels were immersed in CuCl2 solution.The influence of CuCl2 treatment on rotation welding performance was studied.Test results showed that 1) The average pullout resistance of the CuCl2 treated group was higher than that of the untreated group,which was 4 988 N and 4 027 N,respectively,indicating that the CuCl2 treated dowels may effectively improve the pullout resistance.2) The distribution of lignin and other molten materials on the welding interface was observed and analyzed.It was found that molten materials were homogeneous distributed on the welding interface of the CuCl2 treated group.While for the untreated group,the blank and accumulated regions of molten materials were found.3) Wood dowel and welding interface of the untreated and the CuCl2 treated groups were detected by FTIR,respectively.Lignin and hemicellulose were pyrolyzed during the welding process.The side chains of the lignin were pyrolyzed for both of the untreated and the CuCl2 treated groups.The lignin aromatic rings of the CuCl2 treated group were slightly pyrolyzed,while the lignin aromatic rings of the untreated group were relatively stable and the condensation occurred through-CH2-between lignin units.4) The CuCl2 treatment and welding process may improve the degree of crystallinity.The degree of crystallinity of untreated wood dowel was 19.2 ％.And the degree of crystallinity of the CuCl2 treated dowel,untreated interface and the CuCl2 treated interface was 12.5％,75％ and 51％ higher than that of the untreated wood dowel.%选取国产落叶松作为木榫旋转焊接基材,采用CuCl2浸渍桦木木榫,分析浸渍处理对焊接性能.结果表明,1)CuCl2处理组试件和未处理组试件平均抗拉拔力分别为4 988 N和4 027 N,说明浸渍木榫能够有效提高焊接试件抗拉拔力;2)对木质素等熔融物质在焊接界面的分布情况进行观测分析,发现在CuCl2处理试件界面分布较均匀,而在未处理试件界面有熔融物质缺失和富积区域;3)采用FTIR对未处理木榫与界面、CuCl2处理木榫与界面的对比分析,发现木质素、半纤维素等在焊接过程中均发生了热解,CuCl2处理试件的木质素芳香环发生了少量热解,而未处理试件木质素侧链发生热解后,芳香环相对比较稳定并通过-CH2—发生了单元间缩合;4)CuCl2处理和焊接过程均能提升相对结晶度,未处理木榫相对结晶度为19.2％,CuCl2处理木榫、未处理界面和CuCl2处理界面的相对结晶度分别高于未处理木榫12.5％、75％和51％.