本文選題：藥芯焊絲 + 大熱輸入��； 參考：《鄭州大學》2017年碩士論文

【摘要】：無論國內(nèi)還是國外,X80管線鋼用自保護藥芯焊絲的焊接電壓及電流較小,從而使焊接熱輸入較低,焊接效率低下,限制了自保護藥芯焊絲的推廣應(yīng)用。因此,目前針對大熱輸入條件下自保護藥芯焊絲的開發(fā)已成為焊接材料研究熱點。焊接時,熱輸入的高低與焊接效率有直接關(guān)系,且對藥芯焊絲熔敷金屬組織及性能產(chǎn)生影響。在大熱輸入焊接條件下,討論藥芯焊絲中的合金化元素對焊縫熔敷金屬的組織和性能的影響,可以為大熱輸入焊接用自保護藥芯焊絲的研發(fā),提供理論依據(jù)和數(shù)據(jù)參考,有利于藥芯焊絲的推廣。本文通過在大熱輸入(U:28V,I:350~370A,V:230mm/min)下進行焊接實驗,采用OM光學顯微鏡、SEM掃描電鏡及XRD物相分析儀等儀器,分別對不同含量的Ni、Zr、Mo焊縫熔敷金屬組織和成分等進行了觀察和檢測。利用沖擊實驗機、拉伸實驗機對熔敷金屬的力學性能進行了測試。探究了藥芯粉中Ni、Zr、Mo對大熱輸入用自保護藥芯焊絲的焊接工藝性及焊縫熔敷金屬組織和性能的影響。研究表明,Ni對焊接飛濺率和焊縫的脫渣性影響較小。Ni含量6wt.%時,焊縫熔敷金屬中的針狀鐵素體含量較多,熔敷金屬具有較高的強度和最優(yōu)的低溫韌性。而當Ni含量為9%時,熔敷金屬組織中針狀鐵素體數(shù)量下降,塊狀鐵素體含量有所增高,熔敷金屬的強度達到最高,但-20℃低溫抗沖擊吸收功下降。隨著Zr的增加,焊接飛濺率先降低后升高,焊縫脫渣率先升高后降低。當Zr含量為1wt.%時,針狀鐵素體的數(shù)量最多,此時熔敷金屬的低溫抗沖擊吸收功最高。當Zr含量為2wt.%時,熔敷金屬中針狀鐵素體數(shù)量降低,先共析鐵素體的數(shù)量升高,焊縫熔敷金屬的韌性出現(xiàn)下降,此時焊縫熔敷金屬的強度最高。Mo對焊接飛濺率和焊縫脫渣性的影響較小。當Mo含量為2wt.%時,焊縫熔敷金屬中析出的碳化物最多,沉淀強化最明顯,焊縫熔敷金屬的強度最高,但低溫韌性較差。當Mo含量達到3wt.%時,焊縫熔敷金屬組織中細小的針狀鐵素體最多,但析出物較少,此時,熔敷金屬-20℃時低溫抗沖擊吸收功最高,但強度下降。
[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，

本文編號：2063305