發(fā)布時間：2019-05-12 11:44

【摘要】：針對目前大型氣墊登陸艇1561高強度鋁合金及配套焊材熔化極惰性氣體保護焊MIG橫焊氣孔率高、接頭軟化程度大、工藝不過關等問題,開展MIG橫焊技術(shù)的工藝適應性研究。研究MIG橫焊位置的氣孔敏感性,分析氣孔形成原因,探索焊縫中氣孔的控制措施,與此同時,研究MIG橫焊焊縫氣孔敏感性與力學性能之間的關系,優(yōu)化焊接工藝,以獲得良好的組織與力學性能。首先從基材內(nèi)部原因即基材氫含量角度進行試驗,為研究基材氫含量對橫焊氣孔敏感性的影響,分別對1561、5083鋁鎂合金以及1561、ER5183鋁合金焊絲進行氫含量測定,使用美國力可公司RHEN602氫分析儀,利用脈沖加熱-石墨電極爐-熱導法進行檢測,根據(jù)檢測結(jié)果進行試驗,試驗結(jié)果表明高氫含量的母材與焊絲對氣孔敏感性的影響顯著,并且焊絲的影響程度要大于母材的影響程度。對基材進行高溫預熱去氫,試圖降低基材表面氫含量,試驗結(jié)果表明在預熱爐300℃下預熱5h后隨爐冷卻的基材橫焊氣孔敏感性明顯降低。然后從外部原因即焊前清理、焊槍角度、保護氣體種類及成分、焊接電流、焊接電壓、焊接速度等角度進行控制變量試驗,焊前清理分為基材的機械清理和化學清理,在基材的機械清理的基礎上進行化學清理可以明顯降低氣孔敏感性;焊槍角度分為上傾5°、水平、下傾5°,焊槍角度上傾5°的焊縫氣孔敏感性最低;保護氣體種類分為純氬氣和氬氣與氦氣的混合氣,25%氦氣+75%氬氣的氣孔敏感性最低;焊接電流分為103A、108A、113A,隨著焊接電流的增加,焊縫氣孔敏感性明顯增加;焊接電壓分為18V、21V、24V,隨著焊接電壓的增加,焊縫氣孔敏感性逐漸減少;焊接速度分為350mm/min、450mm/min、550mm/min,隨著焊接速度的增加,焊縫氣孔敏感性逐漸減少。最后對焊接工藝進行優(yōu)化,試圖得到氣孔敏感性最低的焊縫,在上述焊前清理、焊槍角度、保護氣體等最優(yōu)焊接條件情況下,摸索最優(yōu)的焊接參數(shù),對焊接電流、焊接電壓、焊接速度三個因素進行正交試驗,試驗結(jié)果表明焊接電壓對氣孔敏感性的影響程度最大,最優(yōu)的焊接參數(shù)為:焊接電流108A,焊接電壓24V,焊接速度450mm/min,并發(fā)現(xiàn)此焊接工藝參數(shù)下的焊縫力學性能最好。為了進一步降低氣孔敏感性,利用涂抹活化劑進行焊接,試驗結(jié)果表明活化劑可以有效地降低氣孔的敏感性,并明顯提高了焊縫的拉伸強度。
[Abstract]:In order to solve the problems of large air cushion landing boat 1561 high strength aluminum alloy and matching welding material melting pole inertia gas shielded welding MIG transverse welding, the process adaptability of MIG transverse welding technology is studied in view of the problems such as high porosity, high soften degree of joint and failure of process. The porosity sensitivity of MIG transverse welding position is studied, the causes of porosity formation are analyzed, and the control measures of porosity in weld are explored. At the same time, the relationship between porosity sensitivity and mechanical properties of MIG transverse welding seam is studied, and the welding process is optimized. In order to obtain good microstructure and mechanical properties. Firstly, the hydrogen content of 1561, 5083 Al-mg alloy and 1561, ER5183 aluminum alloy welding wire was determined in order to study the effect of substrate hydrogen content on porosity sensitivity of transverse welding. The RHEN602 hydrogen analyzer of American Like Company was used to detect the stomatal sensitivity by pulse heating-graphite electrode furnace-thermal conductivity method. According to the test results, the test results show that the base metal and welding wire with high hydrogen content have a significant effect on stomatal sensitivity. And the influence degree of welding wire is greater than that of base metal. The substrate was preheated and dehydrogenated at high temperature in an attempt to reduce the hydrogen content on the surface of the substrate. The experimental results show that the porosity sensitivity of the substrate cooled with the furnace is obviously reduced after preheating at 300 鈩，

本文編號：2475365