發(fā)布時間：2018-06-18 16:11

  本文選題：異種鋼焊接 + TIG-MIG復合焊�。� 參考：《太原理工大學》2017年碩士論文

【摘要】：304奧氏體不銹鋼以其良好的使用性能被廣泛應用于生產和生活中,全球鎳資源的緊張使其在使用上受到限制。443鐵素體不銹鋼含有極少量鎳,被認為是奧氏體不銹鋼的良好替代品。鐵素體奧氏體異種不銹鋼金屬的連接將發(fā)揮兩種不銹鋼金屬的各自優(yōu)勢,實現(xiàn)資源的充分利用。TIG-MIG復合焊是一種高效低熱輸入的新型焊接方法,且焊接成本低,不同于傳統(tǒng)電弧焊,TIG-MIG復合焊的電弧形態(tài)與熔滴過渡方式及其產生機制尚不明確。根據相關研究,在焊接過程中,雙層保護氣氛對于電弧穩(wěn)定性、熔滴過渡以及焊接質量等具有促進作用。氮是一種強奧氏體化形成元素,因此在奧氏體或者雙相鋼焊接中在保護氣中添加一定量的N2可以實現(xiàn)氮向被焊金屬的過渡,不僅可以提高焊縫奧氏體相含量,同時對鐵素體熱影響區(qū)的沖擊韌性的提高具有促進作用。本文首先借助高速攝像系統(tǒng)和電信號采集系統(tǒng)對焊接電流、電壓、鎢極-試板高度、鎢極-焊絲距離和保護氣氛等不同焊接參數下的TIG-MIG復合焊的電弧形態(tài)與熔滴過渡方式進行捕捉,并對其導電通道以及熔滴受力進行分析。然后根據焊接穩(wěn)定性的對比分析,實施不同保護氣氛和焊接速度下的異種鋼不開坡口對接實驗,對其接頭形貌、顯微組織和力學性能進行分析。研究結果表明,隨著焊接電流增大,熔滴過渡周期和尺寸減小,260A電流時出現(xiàn)“流水狀”噴涌過渡;電壓增大,電弧體積和亮度增加;鎢極-試板高度降低,熔滴過渡穩(wěn)定性差,雙電弧耦合性降低,鎢極-試板高度增加后熔滴過渡模式表現(xiàn)為混合過渡,熔滴指向性差,鎢極-焊絲距離增大后,焊接電弧為單電弧,熔滴過渡頻率緩慢;Ar+N2雙層保護氣氛下,電弧收縮明顯。雙電弧狀態(tài)下,焊接電流經過焊絲端一分為二流回焊接電源負極;單電弧時,電流流經熔融焊絲端與母材接觸位置后穿過GTA流向鎢極,返回焊接電源負極。與傳統(tǒng)電弧焊相比,弧根作用在熔滴上的面積增加,并增強其電磁收縮力;雙層保護氣氛提高等離子流力推動熔化的金屬向焊接熔池過渡。滴狀細顆粒過渡更有利于促進TIG-MIG復合窄間隙焊異種鋼焊接獲得良好的焊接接頭形貌。接頭形貌表明,當試板間隙為1.2mm時,正面與背面焊縫成型差。繼續(xù)增大試板間隙發(fā)現(xiàn),若試板為1.5mm和1.8mm,焊縫接頭形貌均良好。雙層保護氣氛促進焊接過程中熔池向試板間隙下方流動,促進焊縫成型。雙層保護氣氛下焊接接頭獲得更小的焊縫熔寬、余高和更寬的焊縫中部寬度。接頭顯微組織表明,304熱影響區(qū)組織未發(fā)生明顯長大,443熱影響區(qū)組織晶粒尺寸粗化嚴重;純氬氣保護氣氛下,焊縫組織為奧氏體+骨骼狀δ鐵素體構成的的雙相組織,雙層保護氣氛下,焊縫組織為奧氏體+蠕蟲狀δ鐵素體雙相組織,且奧氏體相比例增加,443熱影響區(qū)組織晶粒尺寸有一定降低。硬度測試表明,與母材硬度相比,443熱影響區(qū)顯微硬度下降,304一側變化不大;雙層保護氣氛下焊縫區(qū)硬度下降,443熱影響區(qū)顯微硬度較純氬單層氣氛下略有提高。焊接接頭的拉伸試樣斷裂位置基本位于443鐵素體不銹鋼母材上。雙層保護氣氛下所獲得的焊接接頭焊縫區(qū)和443熱影響區(qū)具有更高的沖擊吸收功,304一側熱影響區(qū)變化不大。
[Abstract]:304 austenitic stainless steel is widely used in production and life for its good performance. The tension in the global nickel resources makes it restricted to the use of.443 ferritic stainless steel with very small amounts of nickel. It is considered a good substitute for austenitic stainless steel. The connection of Ferritic Austenitic stainless steel metal will play two kinds of rust. The advantages of steel and metal and the full use of resources to make full use of.TIG-MIG composite welding is a new type of welding method with high efficiency and low heat input, and the cost of welding is low. Different from the traditional arc welding, the arc shape and droplet transition mode and its production mechanism of TIG-MIG composite welding are not yet clear. The atmosphere has a promoting effect on arc stability, droplet transition and welding quality. Nitrogen is a strong austenitizing element, so adding a certain amount of N2 in austenite or double phase steel welding can realize the transition of nitrogen to the welded metal. It can not only raise the content of austenite phase in the weld, but also heat the ferrite. The impact toughness of the affected zone is promoted. In this paper, the arc shape and droplet transition mode of TIG-MIG composite welding under different welding parameters such as welding current, voltage, tungsten pole plate height, tungsten electrode wire distance and protective atmosphere are captured with the help of high speed camera system and electrical signal acquisition system. According to the analysis of welding stability, according to the comparison and analysis of the welding stability, the joint experiment of the dissimilar steel with different protective atmosphere and welding speed is carried out. The joint morphology, microstructure and mechanical properties of the joint are analyzed. The results show that the transition period and size of the droplet decrease with the increase of the welding current, 260A The current appears "flowing water" spout transition, the voltage increases, the volume and brightness of the arc increase, the height of the tungsten pole plate decreases, the stability of the droplet transition is poor, the coupling of the double arc is reduced, and the transition mode of the droplet is mixed, the directivity of the droplet is poor, and the welding arc is the single electric arc after the tungsten electrode welding wire is increased. Arc, the transition frequency of droplet is slow; under the double arc condition, the arc contraction is obvious. Under the state of double arc, the welding current passes through the wire end of the welding wire to the negative electrode of the two flow back welding power. In the single arc, the current flows through the contact position of the molten wire end and the parent material to the tungsten pole and return to the anode of the welding power. Compared with the traditional arc welding, the arc is compared with the traditional arc welding. The area of the root effect on the droplet increases and the electromagnetic contraction force is enhanced, and the double-layer protective atmosphere increases the plasma flow force to promote the transition of molten metal to the weld pool. The transition of droplet fine particles is more conducive to the good welding joint appearance of the TIG-MIG composite narrow gap welded steel welding. The joint morphology shows that the gap of the plate is 1.. When 2mm, the front and back weld formation is poor. Continue to increase the gap between the test plate and find that if the test plate is 1.5mm and 1.8mm, the weld joint morphology is good. The double-layer protective atmosphere promotes the flow of the weld pool to the bottom gap in the welding process, and promotes the weld formation. The weld joint under double protective atmosphere obtains smaller weld width, residual height and wider welding. The microstructure of the joint shows that the microstructure of the 304 heat affected zone is not obviously grown, and the microstructure of the 443 heat affected zone is coarsely coarsely coarse-grained. Under the pure argon atmosphere, the weld structure is composed of austenite and skeletal delta ferrite, and the weld structure is austenite + vermicular delta ferrite double phase under the double protective atmosphere. Microstructure, and the proportion of austenite increased, the grain size of the 443 heat affected zone decreased to a certain extent. The hardness test showed that compared with the hardness of the parent material, the microhardness of the 443 heat affected zone decreased and the 304 side changed little. The hardness of the weld zone decreased in the double protective atmosphere, and the microhardness of the 443 heat affected zone was slightly higher than that under the pure argon monolayer atmosphere. The fracture position of the tensile specimen at the head is basically on the 443 ferrite stainless steel parent material. The weld joint zone and the 443 heat affected zone obtained in the double layer protection atmosphere have higher impact absorption work, and the 304 side heat affected zone has little change.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TG457.11

【相似文獻】

相關期刊論文 前10條

1 盧鳳喜;退火保護氣氛的氫含量對無取向電磁鋼板的影響[J];鋼鐵研究;2001年03期

2 潘惠泉,朱保華,唐開福;工業(yè)氮作保護氣氛在熱處理上的應用[J];鐵道學報;1982年04期

3 賴春林,孫長波,張琦,郭崇文;保護氣氛在銅材退火中的選擇及應用[J];應用能源技術;2001年01期

4 ;“乙醇轉化法”制取氮基保護氣氛工藝及裝置研究成功并推廣應用[J];上海金屬(鋼鐵分冊);1983年02期

5 ;乙醇轉化法氮基保護氣氛制取工藝及裝置[J];上海鋼研;1985年05期

6 王冶;江華鋒;趙云波;宮本勝;趙連成;;滴注式保護氣氛加熱及其實際應用[J];機械工程師;1985年01期

7 唐華生;;燒結時爐內保護氣氛化學成分的作用[J];粉末冶金技術;1986年03期

8 何葆祥;;帶有高效率保護氣氛循環(huán)的真空回火爐[J];鑄鍛熱;1990年01期

9 芮桂秋;;氮——甲醇保護氣氛的應用研究[J];湖南冶金;1991年01期

10 宋曉天;王真珍;;用凈化發(fā)生爐煤氣制備氮基保護氣氛[J];金屬熱處理;1992年10期

相關會議論文 前4條

1 楊明華;李鵬輝;;催化除氧在氮基保護氣氛中的試驗研究[A];江蘇省機械工程學會第六次會員代表大會論文集[C];2002年

2 梁國培;;65Mn鋼板氮基保護氣氛潔凈淬火工藝的應用[A];中國電子學會生產技術分會第五屆金屬材料及熱處理年會論文集（三）[C];1994年

3 梁國培;;65M_n鋼板氮基保護氣氛潔凈淬火工藝的應用[A];中國電子學會生產技術分會金屬材料及熱處理專業(yè)委員會北京學組第三屆年會論文集（上冊）[C];1993年

4 陳德利;王海江;徐朋;孫利軍;張麗娜;;撫鋼保護氣氛電渣爐冶煉1Cr21Ni5Ti不銹鋼生產實踐[A];第十七屆（2013年）全國煉鋼學術會議論文集（B卷）[C];2013年

相關碩士學位論文 前1條

1 魏瀟瀟;保護氣氛電渣爐控制系統(tǒng)設計及自動引弧控制方法研究[D];東北大學;2012年

，

本文編號：2036066