本文選題：激光誘導(dǎo)電弧　切入點(diǎn)：低能耗高效率　出處：《大連理工大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：隨著世界各國(guó)加工制造業(yè)和工程建設(shè)的不斷發(fā)展,現(xiàn)代焊接技術(shù)正逐步向以節(jié)能、高效、優(yōu)質(zhì)為主要特征和要求的方向發(fā)展,這使得降低焊接能耗、提高焊接效率成為目前焊接領(lǐng)域亟待解決的重要問(wèn)題之一。以低能耗、高效率為主要特征的低功率激光-電弧復(fù)合熱源焊接技術(shù)在此背景下應(yīng)運(yùn)而生,本論文圍繞低功率脈沖激光誘導(dǎo)電弧復(fù)合熱、源焊接技術(shù)開展研究,總結(jié)了工藝參數(shù)與激光對(duì)電弧的誘導(dǎo)效率(相同激光功率和電弧電流參數(shù)的前提下,不同誘導(dǎo)過(guò)程中焊縫熔化深度的比值)之間的規(guī)律,通過(guò)對(duì)復(fù)合焊接過(guò)程中的現(xiàn)象進(jìn)行分析,探討了復(fù)合焊接低能耗高效率的物理本質(zhì),對(duì)比了復(fù)合焊接與其他焊接方法在能耗和效率方面的優(yōu)勢(shì),開發(fā)特殊結(jié)構(gòu)件及特殊板材的低能耗激光-電弧復(fù)合熱源焊接工藝,拓寬復(fù)合焊接的應(yīng)用范圍。本文主要研究?jī)?nèi)容和結(jié)論如下：(1)激光誘導(dǎo)電弧現(xiàn)象分析。本部分在激光輸出功率和電弧電流固定的前提下綜合考察了熱源位置和激光脈沖參數(shù)對(duì)熱源誘導(dǎo)效率的影響規(guī)律,結(jié)果表明：在L-T(激光引導(dǎo)電弧)復(fù)合焊接過(guò)程中,激光對(duì)電弧的誘導(dǎo)效率隨著Dla(激光與電弧的熱源間距)的減小而提高,激光對(duì)電弧的誘導(dǎo)作用主要是穩(wěn)定電弧,使得在高速焊接過(guò)程中依然能獲得穩(wěn)定的焊縫,適用于高速焊接；在T-L(電弧引導(dǎo)激光)復(fù)合焊接過(guò)程中,激光對(duì)電弧的誘導(dǎo)效率隨著Dla的增加呈現(xiàn)出先增加后減小的趨勢(shì),誘導(dǎo)效率最大時(shí)Dla的取值隨著電弧電流的增加而增大,激光對(duì)電弧的誘導(dǎo)作用主要是壓縮電弧,增大誘導(dǎo)效率,使得相同電弧電流和激光功率條件下可以實(shí)現(xiàn)更厚板材的全熔透焊接,適用于深熔焊接；激光誘導(dǎo)電弧中,適當(dāng)?shù)亟档图す饷}沖寬度和脈沖頻率,增大脈沖激發(fā)電流有利于誘導(dǎo)效率的提高；焊接過(guò)程中等離子體形態(tài)變化可以直觀反映出熱源誘導(dǎo)效率的變化。(2)激光誘導(dǎo)電弧機(jī)制分析。采用理論計(jì)算的方法對(duì)實(shí)現(xiàn)激光對(duì)電弧最大誘導(dǎo)效率參數(shù)條件下電弧等離子體的弧柱附加壓力、電子動(dòng)能以及等離子體弛豫時(shí)間進(jìn)行了計(jì)算,結(jié)果表明：激光脈沖作用期間,電弧弧柱附加壓力增大了5.2倍,電子動(dòng)能增加了27.5%,能量密度也獲得提高,三者的共同作用促使焊接能耗的降低和焊接效率的提高；激光脈沖作用之后,等離子體發(fā)生了弛豫現(xiàn)象,本實(shí)驗(yàn)過(guò)程中計(jì)算的弛豫時(shí)間約為7.5ms,而實(shí)際過(guò)程中弛豫時(shí)間約為8.0 ms,計(jì)算結(jié)果與實(shí)際結(jié)果比較吻合,弛豫過(guò)程在時(shí)間尺度上增強(qiáng)了激光對(duì)電弧的誘導(dǎo)作用效果；維持激光“匙孔”存在的主要作用力是蒸汽反沖壓力,激光與交流電弧波峰相匹配時(shí)電弧電場(chǎng)方向由鎢電極指向母材表面,等離子體內(nèi)能量傳遞的電子由“匙孔”中部向“匙孔”底部以及側(cè)壁方向運(yùn)動(dòng),大量的攜帶高能量的電子把自身能量傳遞給“匙孔”底部及側(cè)壁的液態(tài)金屬,從而促使母材不斷的蒸發(fā)、汽化或者電離,這相當(dāng)于延長(zhǎng)了蒸汽反沖壓力的持續(xù)時(shí)間,從而導(dǎo)致“匙孔”維持開口狀態(tài)的時(shí)間較長(zhǎng)；“匙孔”與等離子體之間存在相互促進(jìn)的作用,激光“匙孔”的開口狀態(tài)與等離子體的形成之間存在著相互促進(jìn)的作用,等離子體狀態(tài)的變化與“匙孔”行為密切相關(guān)。(3)激光誘導(dǎo)電弧作用效果分析。采用電弧焊接、激光焊接和激光誘導(dǎo)電弧復(fù)合焊接三種方法實(shí)現(xiàn)了相同尺寸板材均勻全熔透的焊接效果,計(jì)算并對(duì)比了不同焊接方法在焊接能耗和焊接效率方面的差異,結(jié)果表明：激光對(duì)電弧的誘導(dǎo)作用顯著提高了焊接效率、降低了焊接能耗；復(fù)合焊接的效率達(dá)到單獨(dú)激光焊接效率的7.14倍和單獨(dú)電弧焊接效率的4.29倍,能耗僅為激光焊接能耗的22.23%和電弧焊接能耗的63.85%,真正實(shí)現(xiàn)了低能耗、高效率的目標(biāo)。(4)激光誘導(dǎo)電弧的應(yīng)用及新工藝開發(fā)。在理論分析的指導(dǎo)下開發(fā)了低能耗激光-電弧復(fù)合焊接T形結(jié)構(gòu)件焊接工藝和平板對(duì)接單面焊雙面自由成形焊接工藝,結(jié)果表明：復(fù)合焊接實(shí)現(xiàn)了1.4 mm厚鎂合金薄板T形結(jié)構(gòu)件的優(yōu)質(zhì)連接,筋板與壁板連接的兩側(cè)焊角處均實(shí)現(xiàn)均勻的圓滑過(guò)度,焊縫余高控制在合理的尺寸范圍內(nèi),接頭剪切強(qiáng)度達(dá)到母材的89%；低能耗激光-電弧復(fù)合焊接技術(shù)對(duì)于1.4 mm厚鈦合金T形結(jié)構(gòu)件亦具有很強(qiáng)的適應(yīng)性；通過(guò)激光對(duì)電弧的誘導(dǎo)作用提高了熱源的能量密度,采用該工藝實(shí)現(xiàn)了2.5mm厚鈦合金板材的單面焊雙面自由成形,焊縫正面形成帶有均勻細(xì)密魚鱗紋的余高,沒(méi)有產(chǎn)生宏觀氣孔、咬邊等焊接缺陷,焊縫背面熔透程度適中、均勻連續(xù),接頭的性能達(dá)到或超過(guò)母材。
[Abstract]:With the continuous development of the construction industry and the world manufacturing processing, modern welding technology is gradually to energy saving, high efficiency, high quality as the main characteristics and requirements of the direction of development, which makes the welding to reduce energy consumption, improve the efficiency of welding has become one of important questions to be solved in the field of welding current. With low energy consumption, high efficiency and low power came into being the main feature of the laser arc hybrid welding technology under this background, this paper focuses on laser induced arc composite heat source welding low power pulse technology research, summarizes the induction efficiency of process parameters and laser on the arc weld depth ratio (melting process of different induction condition of the same laser power and arc current parameters, the) between the rules, based on the hybrid welding phenomenon in the process of analysis, discusses the physical hybrid welding with low energy consumption and high efficiency of this matter, comparison Composite welding and other welding methods in terms of energy consumption and efficiency advantages of low energy laser welding technology development special structure and special plate arc composite heat source, broaden the application scope of composite welding. In this paper, the main research contents and conclusions are as follows: (1) analysis of laser induced electric arc phenomenon. In this part of the laser output power and the arc current is fixed under the premise of a comprehensive investigation of the position of heat source and the laser pulse parameters on heat induced efficiency were investigated, the results showed that: in the L-T (laser guided arc) hybrid welding process, the laser induced efficiency of arc with Dla (heat source distance between laser and arc) decreases with the increase of arc induced by laser is mainly in high speed welding arc stability, which can still obtain a stable welding process, suitable for high speed welding; T-L (arc guided laser) in hybrid welding process, The induction efficiency between laser and arc with the increase of Dla, showing a trend of first increase and then decrease the maximum value, the induction efficiency of Dla increases with the increase of arc current, induced by laser on the arc is mainly compression arc, increase efficiency and achieve a more thick plate full penetration welding makes the same arc current and laser power conditions, suitable for deep penetration welding; laser induced arc, appropriate to reduce the laser pulse width and pulse frequency, pulse excitation current increase is conducive to improving the efficiency of induction; changes of plasma shape in the welding process can directly reflect the change of heat induced efficiency. (2) analysis of laser induced arc mechanism. The theoretical calculation of the arc column pressure arc plasma laser on arc induced maximum efficiency parameters under the condition of electron kinetic energy and plasma relaxation The relaxation time was calculated, the result showed that the laser pulses, the arc column added pressure increases by 5.2 times, the kinetic energy of the electrons is increased by 27.5%, the energy density is also improved, the three together to reduce energy consumption and improve the efficiency of welding welding; after the laser pulse, the relaxation of plasma in this experiment, in the process of calculation of the relaxation time is about 7.5ms, and the actual process of relaxation time is about 8 ms, the calculation results are consistent with the actual results, the relaxation process to enhance the effect of laser induced by arc in time scale; the main force to maintain the laser "keyhole" there is steam recoil pressure, laser and AC arc wave matching electric field direction by tungsten electrode to the surface of base material, electron plasma energy transfer from the central to the "keyhole" and "keyhole" bottom The side wall of the direction of movement, a large number of high energy electrons carry their own energy transfer to the liquid metal keyhole bottom and side wall, so as to promote the continuous evaporation of the parent material, which is equivalent to the vaporization or ionization, prolong the duration of the vapor recoil pressure, resulting in the "keyhole" to maintain the state opening time "there are long; promote the interaction between keyhole and plasma, there is mutual promotion between laser" keyhole "opening state and plasma formation is closely related to changes in plasma state and" keyhole "behavior. (3) analysis of laser induced by arc welding. The effect of arc, arc composite three kinds of welding method to achieve the same effect of uniform size of sheet metal welding full penetration laser welding and laser induced, calculated and compared the different welding method in welding welding efficiency and energy consumption The differences, the results showed that the induction effect of the laser on the arc significantly improve the welding efficiency, reducing welding energy consumption; 4.29 times the efficiency of hybrid welding to separate laser welding efficiency 7.14 times and single arc welding efficiency, energy consumption is only 22.23% of the energy of laser welding and arc welding energy consumption 63.85%, realizing a low energy consumption high efficiency, objective. (4) the application and development of new process of laser induced arc. Under the guidance of the theoretical analysis of low energy laser arc hybrid welding side welding free forming welding process, welding and butt T shaped structure developed the results show that the composite welding realized the high quality connection of 1.4 mm thick magnesium alloy thin T shaped structure, both sides are welded stiffened plate and shell connection angle are uniform smooth, the weld height control in the size of a reasonable range of joint shear strength reached The 89% parent material; low energy laser arc hybrid welding technology has strong adaptability for 1.4 mm thick titanium alloy T structure; through the induction effect of the laser on the arc heat source improves the energy density, the process of implementation of welding of 2.5mm thick titanium alloy double surface free forming, welding seam with the formation of uniform fine scales more than high, no macro porosity, undercut welding defects such as weld penetration of moderate, uniform and continuous, joint performance reach or exceed the base material.

【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG403

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本文編號(hào)：1599458