Ni、Zr、Mo对大热输入用自保护药芯焊丝熔敷金属组织和性能的影响

发布时间：2018-06-24 22:43

  本文选题：药芯焊丝 + 大热输入　； 参考：《郑州大学》2017年硕士论文

【摘要】：无论国内还是国外,X80管线钢用自保护药芯焊丝的焊接电压及电流较小,从而使焊接热输入较低,焊接效率低下,限制了自保护药芯焊丝的推广应用。因此,目前针对大热输入条件下自保护药芯焊丝的开发已成为焊接材料研究热点。焊接时,热输入的高低与焊接效率有直接关系,且对药芯焊丝熔敷金属组织及性能产生影响。在大热输入焊接条件下,讨论药芯焊丝中的合金化元素对焊缝熔敷金属的组织和性能的影响,可以为大热输入焊接用自保护药芯焊丝的研发,提供理论依据和数据参考,有利于药芯焊丝的推广。本文通过在大热输入(U:28V,I:350~370A,V:230mm/min)下进行焊接实验,采用OM光学显微镜、SEM扫描电镜及XRD物相分析仪等仪器,分别对不同含量的Ni、Zr、Mo焊缝熔敷金属组织和成分等进行了观察和检测。利用冲击实验机、拉伸实验机对熔敷金属的力学性能进行了测试。探究了药芯粉中Ni、Zr、Mo对大热输入用自保护药芯焊丝的焊接工艺性及焊缝熔敷金属组织和性能的影响。研究表明,Ni对焊接飞溅率和焊缝的脱渣性影响较小。Ni含量6wt.%时,焊缝熔敷金属中的针状铁素体含量较多,熔敷金属具有较高的强度和最优的低温韧性。而当Ni含量为9%时,熔敷金属组织中针状铁素体数量下降,块状铁素体含量有所增高,熔敷金属的强度达到最高,但-20℃低温抗冲击吸收功下降。随着Zr的增加,焊接飞溅率先降低后升高,焊缝脱渣率先升高后降低。当Zr含量为1wt.%时,针状铁素体的数量最多,此时熔敷金属的低温抗冲击吸收功最高。当Zr含量为2wt.%时,熔敷金属中针状铁素体数量降低,先共析铁素体的数量升高,焊缝熔敷金属的韧性出现下降,此时焊缝熔敷金属的强度最高。Mo对焊接飞溅率和焊缝脱渣性的影响较小。当Mo含量为2wt.%时,焊缝熔敷金属中析出的碳化物最多,沉淀强化最明显,焊缝熔敷金属的强度最高,但低温韧性较差。当Mo含量达到3wt.%时,焊缝熔敷金属组织中细小的针状铁素体最多,但析出物较少,此时,熔敷金属-20℃时低温抗冲击吸收功最高,但强度下降。
[Abstract]:The welding voltage and current of self-shielded flux-cored wire used in domestic and foreign pipeline steel are small, thus the welding heat input is low and the welding efficiency is low, which limits the popularization and application of self-shielded flux-cored wire. Therefore, the development of self-shielded flux-cored wire under the condition of large heat input has become a hot spot in welding materials. The heat input is directly related to the welding efficiency and has an effect on the microstructure and properties of the flux-cored wire. Under the condition of large heat input welding, the effect of alloying elements in flux-cored wire on the microstructure and properties of weld deposited metal is discussed, which can provide theoretical basis and data reference for the research and development of self-shielded flux-cored wire for large heat input welding. It is beneficial to the popularization of flux-cored wire. In this paper, the welding experiments were carried out under the input of U: 28V / I: 350,370An V: 230mm / min. OM optical microscope, SEM scanning electron microscope and XRD phase analyzer were used to observe and detect the microstructure and composition of the deposited metal in the weld of Nianzirlmo with different contents. The mechanical properties of deposited metal were tested by impact tester and tensile tester. The effect of NiAZR Mo in flux-cored powder on welding process, microstructure and properties of self-shielded flux-cored wire for large heat input was investigated. The results show that the content of acicular ferrite in weld deposited metal is more than that in weld metal, and the deposited metal has higher strength and optimum low temperature toughness when the effect of Ni on welding spatter rate and deslag property of weld seam is small. The content of acicular ferrite in weld metal deposited by Ni content is 6 wt.%. However, when Ni content is 9, the amount of acicular ferrite in the deposited metal decreases, the bulk ferrite content increases, and the strength of the deposited metal reaches the highest, but the absorption energy of low temperature impact resistance decreases at -20 鈩，

本文编号：2063305