鑄造a356鋁合金的焊接模擬外文翻譯

1、<p>　　Welding Simulation of Cast Aluminium A356</p><p>　　X-T. Pham*, P. Gougeon and F-O. Gagnon</p><h4>　　Aluminium Technology Centre, National Research Council Canada Chicoutimi, Quebec, C

2、anada</h2><p><b>　　Abstract</b></p><p>　　Welding of cast aluminium hollow parts is a new promising technical trend for structural assemblies. However, big gap between components, wel

3、d porosity, large distortion and risk for hot cracking need to be dealt with. In this paper, the MIG welding of aluminium A356 cast square tubes is studied. The distortion of the welded tubes was predicted by numerical s

4、imulations. A good agreement between experimental and numerical results was obtained. </p><p>　　Introduction</p><p>　　Aluminium structures become more and more popular in industries thanks to th

5、eir light weights, especially in the automotive manufacturing industry. Moreover, welding of cast aluminium hollow parts is a new promising technical trend for structural assemblies [1-3]. However, it may be very challen

6、ging due to many problems such as big gap between components, weld porosity, large distortion and risk for hot cracking [4,5]. Due to local heating, complex thermal stresses occur during welding; residual</p><

7、p>　　Experiments</p><p>　　Experimental setup </p><p>　　Two square tubes are made of A356 by sand casting and then machined. They are assembled by four MIG welds, named W1 to W4. Their dimensio

8、ns and the welding configuration are depicted in Figure 1. Both small (inner) and large (outer) tubes are well positioned on a fixture using v-blocks as shown in Figure 2. The dimensions of the tubes make a peripheral ga

9、p of 1 mm between them. This fixture is fixed on a positioner that allows the welding process to be carried out always in the horizontal positi</p><p>　　Table 1: MIG welding parameters.</p><p>&

10、lt;b>　　a)</b></p><p><b>　　b)</b></p><p>　　Figure 1: Tube welding configuration: a) cross-section view, b) tube dimensions</p><p>　　Figure 2: Experimental setup

11、for tube welding</p><p><b>　　Testing</b></p><p>　　The porosity of welds was observed before and after welding using the X-ray technique to check the quality of these welds according

12、to the standard ASTM E155. The whole welded tubes were then tested by traction on a MTS testing machine. The final dimensions of the welded tubes are measured on a CMM machine at many points on the tubes. The distortion

13、of the welded tubes is determined by comparing the final positions with the initial positions of the tubes.</p><p>　　Numerical analysis</p><p>　　In Sysweld, a welding analysis is performed based

14、 on a weak-coupling formulation between the heat transfer and mechanical problems. Only the thermal history will affect on the mechanical properties, but not in reverse direction. Therefore, a thermal metallurgical mecha

15、nical analysis is divided into two steps. The first step is a thermal metallurgical analysis, in which the heat transferred from the welding source makes phase changes during the welding process. The results of temperatu

16、re and phas</p><h5>　　Heat source model identification</h2><p>　　Before running a welding simulation, it is necessary to determine the parameters of the heat source model. This is called heat so

17、urce fitting. Actually, it is a thermal simulation using this heat source model in the steady state, which iscombined with an optimization tool to obtain the parameters of the heat source. Figure 3 presents the form of a

18、 3D conical heat source of which the energy distribution is described in Eq (1) as follows:</p><p>　　F=Q0exp(-r²/r0²) (1) </p><p>　　in which Q0 denotes

19、 the power density; and r，r0 are defined by </p><p>　　r²=(x-x0)²+(x-x0-vt)² (2) </p><p><b>　　and </b></p><p>　　r0=re-(re-ri)

20、(ze-z+z0)/(ze-zi) (3) </p><p>　　where（x0,y0,z0)is the origin of the local coordinate system of the heat source; re and ri the radius of the heat source at the positions ze and zi,res

21、pectively;v the welding speed and t the time.</p><p>　　In this study, a metallographic cross-section has been used to identify the heat source parameters as shown in Figure 4. The use of a 3D conical heat so

22、urce fits very well the weld cross-section. The mesh size in the cross-section is around 0.5 mm for this case. The finer is the mesh, the more accurate is the shape of the melting pool, but the longer is the simulation.&

23、lt;/p><p>　　Figure 3: 3D conical heat source (Sysweld).</p><p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　Figure 4: (a) Metallographic cross-section,

24、(b) Melting pool cross-section.</p><p>　　Analysis model</p><p>　　The mesh of the tubes was created in Hypermesh 7.0. Sysweld 2007 has been used as solver and pre/post processor. A full 3D therma

25、l metallurgical mechanical analysis with brick and prism elements. Two welding sequences have been done such as W1/W2/W3/W4 and W1/W3/W2/W4. The tubes are clamped using four v-blocks during the welding, two for each tube

26、. In the simulations, the positions where the tubes are in contact against the surfaces of the v-blocks are considered as fixed conditions (i.e. Ux = U</p><p><b>　　Results</b></p><p>

27、;　　The distortion of the welded tube is measured when it is released from the constraints. The distortion is determined by measuring the displacement of the small tube on the top and lateral surfaces along the centre lin

28、e of the tube. These measures are relative to the large tube. Figures 5a-b depict the distortion predicted by the numerical simulations of the sequence W1/W2/W3/W4 and W1/W3/2/W4, respectively. Good agreements between ex

29、perimental and numerical results were obtained in the two weldi</p><p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　Figure 5: Tube distortion (Norm U): (a) Sequen

30、ce W1/W2/W3/W4, (b) Sequence W1/W3/W2/W4.</p><p>　　Table 2: Distortion result comparison (welding sequence W1/W2/W3/W4)</p><p>　　Table 3: Distortion result comparison (welding sequence W1/W3/W2/

31、W4)</p><p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　Figure 7: State of stresses Sxy (a) Clamped, (b) Released. (Red = positive, Blue = negative)</p>&l

32、t;p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　Figure 8: State of stresses Sxz (a) Clamped, (b) Released. (Red = positive, Blue = negative)</p><p>　　Figures

33、6-8 shows the state of the stresses of the welded tubes at room temperature for the sequence W1/W2/W3/W4 after welding when clampled and released from constraints (x is the direction along the axe of the welded tube). To

34、 show how the welded tube is distorted, positive-negative values are used instead of the true values of stresses. The distortion of the welded tube can be explained as the new equilibrium position due to the residual str

35、esses when there is no external load. It is remarked</p><p>　　Conclusions</p><p>　　The MIG welding is very good for assembling aluminium cast tubes (hollow parts) in the presence of large gaps.

36、</p><p>　　The 3D thermal metallurgical mechanical simulation of the cast tube welding using Sysweld has been validated. A very good agreement between numerical and experimental results was obtained for both

37、the distortion tendency and distortion range. </p><p>　　The welding sequence has a major influence on the distortion of the welded structure. It turns out that the optimization of the welding sequences for a

38、 reasonable distortion of a welded structure with a large number of welds becomes very important. </p><p>　　Acknowledgments</p><p>　　The authors would like to thank gratefully Rio Tinto Alcan an

39、d General Motor for financial and technical supports, particularly Martin Fortier and Pei-Chung Wang. Also, the authors are grateful to Welding Team at ATC (Audrey Boily, Martin Larouche, François Nadeau and Mario P

40、atry) for experimental works.</p><p>　　References</p><p>　　1. K-H. Von Zengen, Aluminium in future cars – A challenge for materials science, Materials Science Forum, 519-521 (Part 2), 1201-1208

41、(2006). </p><p>　　2. S. Wiesner S., M. Rethmeier and H. Wohlfart, MIG and laser welding of aluminium alloy pressure die cast parts with wrought profiles, Welding International, 19 (2), 130-133 (2005). </p

42、><p>　　3. R. Akhter, L. Ivanchev, C.V.Rooyen, P. Kazadi and H.P. Burger, Laser welding of SSM Cast A356 aluminium alloy processed with CSIR-Rheo technology, Solid State Phenomena, 116-117, 173-176 (2006). </

43、p><p>　　4. J.F. Lancaster, Metallurgy of welding, Abington Publishing (1999). </p><p>　　5. Φ. Grong, Metallurgical modelling of welding, The institute of materials (1997). </p><p>　　6.

44、 Sysweld, Sysweld reference manual, ESI Group (2005). </p><p><b>　　譯文</b></p><p>　　鑄造A356鋁合金的焊接模擬</p><p>　　X-T. Pham*, P. Gougeon and F-O. Gagnon </p><h4>　

45、　Aluminium Technology Centre, National Research Council Canada Chicoutimi, Quebec, Canada</h2><p><b>　　摘要：</b></p><p>　　空心鋁鑄造件的焊接是一個(gè)很有前途的新結(jié)構(gòu)組件技術(shù)的趨勢(shì)。然而，組件之間的差距較大，焊接孔隙度，大變形和熱裂需要處理的風(fēng)險(xiǎn)。在

46、這篇文章中，對(duì)鑄造A356鋁合金的方管的MIG焊接進(jìn)行了研究。并對(duì)焊接管彎曲變形進(jìn)行了數(shù)值模擬預(yù)測(cè)。實(shí)驗(yàn)結(jié)果和數(shù)值模擬結(jié)果的相似度很高。</p><p><b>　　1前言：</b></p><p>　　由于鋁合金結(jié)構(gòu)自身的重量輕，所以它變得越來(lái)越流行，尤其是在汽車制造業(yè)。此外，空心鋁鑄造件的焊接是一種新的有前途的結(jié)構(gòu)組件技術(shù)的趨勢(shì)[1-3]。但是它可能有很大的挑戰(zhàn)，

47、由于大的差距，例如組件之間，焊接孔隙度，大變形和熱裂的危險(xiǎn)等很多問(wèn)題[4,5]。由于局部加熱，復(fù)雜的熱應(yīng)力發(fā)生在焊接中；焊后會(huì)出現(xiàn)殘余應(yīng)力和變形的結(jié)果。在這篇文章中，關(guān)于鑄造A356鋁合金的方管的MIG焊接進(jìn)行了研究。Sysweld軟件[6]被用于焊接模擬。其目的是驗(yàn)證這個(gè)軟件在大差距的焊接管扭曲變形的預(yù)測(cè)中的能力。在這項(xiàng)工作中，在焊接后利用X射線技術(shù)來(lái)檢查焊縫的孔隙率。在熱源參數(shù)的基礎(chǔ)上，確定了焊縫截面和焊接參數(shù)。冶金力學(xué)的3D熱量模

48、擬已經(jīng)被使用。用數(shù)值模擬所預(yù)測(cè)出來(lái)的扭曲值與焊后用CCM機(jī)器所測(cè)量的實(shí)驗(yàn)結(jié)果進(jìn)行了比較。</p><p><b>　　2實(shí)驗(yàn)：</b></p><p><b>　　2.1實(shí)驗(yàn)方案</b></p><p>　　兩個(gè)成直角的管子是用A356通過(guò)砂型鑄造然后在加工形成的。他們是由四個(gè)管MIG焊接組裝而成 ，命名為W1至W4。他們

49、的尺寸和焊接配置描繪如圖1.不論小還是大的管子都很好的定位在一個(gè)采用V形塊的夾具上，如圖2所示。管子的規(guī)模使它們之間產(chǎn)生了一個(gè)1毫米厚的不主要的縫隙。這個(gè)夾具固定在一個(gè)定位上，使焊接過(guò)程中總是保持水平位置。每個(gè)焊縫的長(zhǎng)度是35毫米。被安裝在Motoman機(jī)器人上的Fronius焊頭是用于MIG焊過(guò)程中的。表1表明了這個(gè)焊接結(jié)構(gòu)的焊接工藝參數(shù)。</p><p>　　表1：MIG焊接參數(shù)</p><

50、;p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　圖1：鋼管焊接配置:a）截面圖 b）鋼管尺寸</p><p>　　圖2：管焊接實(shí)驗(yàn)裝置</p><p><b>　　2.2測(cè)試</b></p><p>　

51、　焊接前后利用X射線技術(shù)觀察焊縫氣孔，按ASTM E155標(biāo)準(zhǔn)檢查這些焊縫質(zhì)量。然后整個(gè)焊接管子通過(guò)一個(gè)MTS試驗(yàn)機(jī)上的牽引來(lái)測(cè)試。焊接管最終的尺寸被定位在管子上的多個(gè)點(diǎn)的CMM機(jī)器所測(cè)量。扭曲的焊接管的最終位置與初始位置的管子進(jìn)行比較。 </p><p><b>　　3數(shù)值分析</b></p><p>　　在Sysweld軟件中，焊接分析是基于熱傳導(dǎo)和力學(xué)問(wèn)題之間的

52、微弱鏈接而制定的。只有熱學(xué)經(jīng)歷在相同方向上才將影響力學(xué)性能 。因此，熱學(xué)冶金力學(xué)分析分為兩個(gè)步驟。第一步是一種熱學(xué)冶金分析，其中在焊接過(guò)程的相變過(guò)程中從焊接電源的熱量被轉(zhuǎn)移。第一步溫度和相變的結(jié)果將作為第二次的分析。它是一個(gè)純熱彈塑性模擬[6]。</p><p><b>　　4熱源模型的鑒定</b></p><p>　　焊接模擬運(yùn)行之前，有必要確定熱源模型的參數(shù)。這就

53、是所謂的熱源配件。實(shí)際上，它是一種熱模擬中的穩(wěn)定狀態(tài)，在這種穩(wěn)定狀態(tài)中用一種優(yōu)化工具來(lái)獲得的熱量來(lái)源的參數(shù)。圖3給出了一個(gè)三維錐形熱源形式，它的能量分布在方程中描述：舉例如下:</p><p>　　F=Q0exp(-r²/r0²) (1) </p><p>　　其中Q0 表示功率密度; r，r0 被定義為：

54、</p><p>　　r²=(x-x0)²+(x-x0-vt)² (2) </p><p><b>　　和 </b></p><p>　　r0=re-(re-ri)(ze-z+z0)/(ze-zi) (3) &

55、lt;/p><p>　　其中（x0,y0,z0)是局部坐標(biāo)系原點(diǎn)熱源，re和 ri 在位置ze 和zi,分別為半徑熱源；v為焊接速度，t為時(shí)間。</p><p>　　在這項(xiàng)研究中，金相截面已被用來(lái)確定熱源，如圖4所示的參數(shù)。一個(gè)三維錐形熱源使用非常適合的焊接橫截面。在橫截面的網(wǎng)狀尺寸是這種情況下約為0.5毫米。越細(xì)的網(wǎng)狀，越是更準(zhǔn)確的熔池形狀，但不再是模擬。</p><p&

56、gt;　　圖3:三維錐形熱源 (Sysweld).</p><p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　圖4: (a) 金相截面(b) 熔池截面</p><p><b>　　5模型分析</b></p><p

57、>　　在Hypermesh7.0上創(chuàng)建了管網(wǎng)。Sysweld2007已被用來(lái)作為求解器和前后處理器。一個(gè)完整的三維熱學(xué)冶金力學(xué)分析用磚和棱鏡為元素。兩種焊接序列已完成，如W1/W2/W3/W4和W1/W3/W2/W4。在焊接過(guò)程中，夾住管子的過(guò)程中使用四個(gè)V形塊，每個(gè)管子兩個(gè)。在模擬中，管子的立場(chǎng)是反對(duì)接觸的V形塊的表面被認(rèn)為是固定的條件（如Ux = Uy = Uz = 0）。在釋放階段，管子在V形塊中是不受力的。</p&g

58、t;<p><b>　　6結(jié)果</b></p><p>　　當(dāng)焊接管子從束縛狀態(tài)被釋放時(shí)，它的變形被控制。失真是通過(guò)測(cè)量沿管子的中心線從頂部到兩側(cè)面的小管的位移。這些措施是相對(duì)于大管的。圖5a,b的描述失真通過(guò)數(shù)值模擬預(yù)測(cè)序列為W1/W2/W3/W4和W1/W3/W2/W4。在數(shù)值計(jì)算結(jié)果和實(shí)驗(yàn)中獲得了良好的協(xié)議的兩種焊接順序如表2-3所示，在這兩種傾向的扭曲和變形的過(guò)程中變化

59、的范圍。</p><p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　圖5：電子管失真（標(biāo)準(zhǔn)U）：（a）序列W1/W2/W3/W4，（b）序列W1/W3/W2/W4</p><p>　　表2：扭曲結(jié)果的比較（焊接順序W1/W2/W3/W4）</p&g

60、t;<p>　　表2：畸變結(jié)果比較（焊接順序W1/W2/W3/W4）</p><p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　圖6：規(guī)定壓力 Sxx （a）夾緊（b）放松（紅=正，藍(lán)=負(fù)）</p><p><b>　　a)<

61、;/b></p><p><b>　　b)</b></p><p>　　圖7：規(guī)定壓力 Sxy （a）夾緊（b）放松（紅=正，藍(lán)=負(fù)）</p><p><b>　　a)</b></p><p><b>　　b)</b></p><p>　　圖8：規(guī)

62、定壓力 Sxz （a）夾緊（b）放松（紅=正，藍(lán)=負(fù)）</p><p>　　圖6-8顯示了在夾緊和放松后的焊接在室溫的規(guī)定壓力下焊接序列W1/W2/W3/W4的狀態(tài)（x是沿焊接管斧頭方向）。以展示焊管失真，正負(fù)值來(lái)代替真實(shí)的應(yīng)力值。該焊管失真可以解釋為新的平衡位置，由于殘余應(yīng)力在沒(méi)有外部負(fù)載的情況下。這就是說(shuō)，在存在較大的差距時(shí)，在很大程度上對(duì)焊管失真是圍繞當(dāng)?shù)氐暮缚p旋轉(zhuǎn)模式進(jìn)行的。</p><

63、;p><b>　　7結(jié)論</b></p><p>　　MIG焊接很好的解決了鋁鑄造管（中空部分）存在非常大的差距的問(wèn)題。</p><p>　　三維熱學(xué)冶金鑄造力學(xué)焊接管采用Sysweld模擬已驗(yàn)證。模擬值與實(shí)驗(yàn)結(jié)果在扭曲趨勢(shì)和變形范圍內(nèi)非常吻合。</p><p>　　焊接的序列對(duì)焊接結(jié)構(gòu)變形產(chǎn)生重大影響。事實(shí)證明，優(yōu)化的焊接順序?qū)σ粋€(gè)具有

64、大量的焊縫的扭曲焊接結(jié)構(gòu)的合理性非常重要。</p><p><b>　　致 謝</b></p><p>　　The authors would like to thank gratefully Rio Tinto Alcan and General Motor for financial and technical supports, particularly Ma

65、rtin Fortier and Pei-Chung Wang. Also, the authors are grateful to Welding Team at ATC (Audrey Boily, Martin Larouche, François Nadeau and Mario Patry) for experimental works.</p><p><b>　　參考文獻(xiàn)<

66、/b></p><p>　　[1] K-H. Von Zengen, Aluminium in future cars – A challenge for materials science, Materials Science Forum, 519-521 (Part 2), 1201-1208 (2006). </p><p>　　[2] S. Wiesner S., M. Re

67、thmeier and H. Wohlfart, MIG and laser welding of aluminium alloy pressure die cast parts with wrought profiles, Welding International, 19 (2), 130-133 (2005). </p><p>　　[3] R. Akhter, L. Ivanchev, C.V.Rooy

68、en, P. Kazadi and H.P. Burger, Laser welding of SSM Cast A356 aluminium alloy processed with CSIR-Rheo technology, Solid State Phenomena, 116-117, 173-176 (2006). </p><p>　　[4] J.F. Lancaster, Metallurgy of

69、 welding, Abington Publishing (1999). </p><p>　　[5] Φ. Grong, Metallurgical modelling of welding, The institute of materials (1997). </p><p>　　[6] Sysweld, Sysweld reference manual, ESI Group