【摘要】：汽輪機在電廠設(shè)備中起著無可替代的作用，它是電力工業(yè)的心臟。隔板是核電機組通流主要部件之一，起到固定靜葉和阻止級間漏氣的作用，能保證機組的經(jīng)濟型和安全性�？紤]到隔板的運行環(huán)境，為提高隔板外環(huán)的抗水蝕能力，，工藝設(shè)計上要求在外環(huán)的進汽側(cè)、出汽側(cè)汽封處堆焊不銹鋼耐蝕層。哈爾濱汽輪機廠針對隔板堆焊時的典型結(jié)構(gòu)形式，制作了能夠表征隔板外環(huán)結(jié)構(gòu)的小型物理實驗件并進行堆焊。本文運用有限元分析軟件MARC，首先對實驗件進行數(shù)值模擬，通過調(diào)整參數(shù)縮小與實驗結(jié)果之間的差距，然后應(yīng)用調(diào)整后的參數(shù)對隔板外環(huán)的堆焊過程進行模擬。 實驗件焊接變形數(shù)值模擬結(jié)果表明：焊后母材處的位移小，襯板處的位移大且存在明顯的梯度分布；襯板上隨著與焊縫之間距離的增加，位移逐漸增大，最大位移位于收弧端的襯板外邊緣處且主要由Y向位移體現(xiàn)，其值為17.1mm。將實驗數(shù)據(jù)和數(shù)值模擬結(jié)果對比發(fā)現(xiàn)：兩者在焊接角變形具體數(shù)值方面存在一定的偏差，但是這個偏差是在允許的范圍之內(nèi)的（10%以下）。另外，文中還設(shè)計采用從兩端向中間的焊接順序進行實驗件的堆焊，發(fā)現(xiàn)此時最大位移位于實驗件的中部，其值為12.8mm。相比從頭到尾的焊接順序，最大位移減小25.1%。這是由于從兩端向中間焊接時，溫度場相互重疊，溫度梯度小，進而焊接變形得到減小。對比兩種焊接順序下實驗件首端和末端的角度數(shù)據(jù)發(fā)現(xiàn)，采用從兩端向中間的焊接順序只影響實驗件末端的角變形，而對首端的角變形沒有影響。 隔板外環(huán)焊接變形的數(shù)值模擬結(jié)果表明：采用先焊內(nèi)圓再焊外圓的順序時，總的節(jié)點位移為7.8mm，總的等效殘余塑性應(yīng)變?yōu)?3.3%。采用內(nèi)圓外圓同時焊接的順序時，總的節(jié)點位移為3.8mm，總的等效殘余塑性應(yīng)變?yōu)?.6%，位移和等效殘余塑性應(yīng)變分別減小了51.3%和35.3%，這是由于內(nèi)圓外圓同時焊接時焊接變形相互抑制。另外，內(nèi)圓外圓同時分段退焊時，總的節(jié)點位移和總的等效殘余塑性應(yīng)變分別為3.7mm和8.2%，與內(nèi)圓外圓同時焊接時差別不大，這可能是由分段長度過大所導(dǎo)致的。
[Abstract]:Steam turbine plays an irreplaceable role in power plant equipment, it is the heart of power industry. The separator is one of the main components of the flow passage of nuclear power unit. It can fix the static blade and prevent the leakage between stages, which can ensure the economic and safety of the unit. Considering the running environment of the separator, in order to improve the water corrosion resistance of the outer ring, the process design requires the inlet side of the outer ring and the surfacing of the steam seal on the exit side of the outer ring to weld the stainless steel corrosion resistant layer. Aiming at the typical structure of clapboard surfacing in Harbin Steam Turbine Factory, a small physical experiment piece which can characterize the structure of outer ring of partition plate was made and surfacing welding was carried out. In this paper, the finite element analysis software Marc is used to simulate the experimental specimen, and the gap between the parameters and the experimental results is reduced by adjusting the parameters, and then the surfacing process of the outer ring of the diaphragm is simulated by the adjusted parameters. The numerical simulation results of welding deformation show that the displacement of the base metal is small, the displacement of the liner is large and there is obvious gradient distribution after welding, and the displacement increases gradually with the increase of the distance between the liner and the weld. The maximum displacement is located at the outer edge of the liner at the end of the arc and is mainly reflected by Y direction displacement with a value of 17.1 mm. By comparing the experimental data with the numerical simulation results, it is found that there is a certain deviation in the specific values of welding angle deformation, but this deviation is within the allowable range (less than 10%). In addition, the welding sequence from two ends to the middle is used for the surfacing welding of the experimental piece. It is found that the maximum displacement is in the middle of the experimental piece at this time, and its value is 12.8 mm. The maximum displacement is reduced by 25. 1% compared with the first-to-end welding sequence. This is because the temperature field overlaps and the temperature gradient is small when welding from both ends to the middle, and then the welding deformation is reduced. Comparing the angle data of the first and the end of the test piece in two welding sequences, it is found that the welding sequence from the two ends to the middle only affects the angle deformation of the end of the test piece, but has no effect on the angle deformation of the first end. The numerical simulation results show that the total joint displacement is 7.8 mm and the equivalent residual plastic strain is 13.3 mm when welding the inner circle first and then the outer circle. The total joint displacement is 3.8 mm and the total equivalent residual plastic strain is 8.6 mm. The displacement and equivalent residual plastic strain are reduced by 51.3% and 35.3% respectively, which is due to the mutual inhibition of the welding deformation of the inner circle and the outer circle. In addition, the total joint displacement and the total equivalent residual plastic strain are 3.7mm and 8.2 respectively when the inner circle and outer circle are welded simultaneously, which may be caused by the excessive segment length.
【學(xué)位授予單位】：哈爾濱理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG404

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