汽轮机隔板外环多层多道焊焊接变形数值模拟
发布时间：2018-08-18 11:17
【摘要】：汽轮机在电厂设备中起着无可替代的作用，它是电力工业的心脏。隔板是核电机组通流主要部件之一，起到固定静叶和阻止级间漏气的作用，能保证机组的经济型和安全性。考虑到隔板的运行环境，为提高隔板外环的抗水蚀能力，，工艺设计上要求在外环的进汽侧、出汽侧汽封处堆焊不锈钢耐蚀层。哈尔滨汽轮机厂针对隔板堆焊时的典型结构形式，制作了能够表征隔板外环结构的小型物理实验件并进行堆焊。本文运用有限元分析软件MARC，首先对实验件进行数值模拟，通过调整参数缩小与实验结果之间的差距，然后应用调整后的参数对隔板外环的堆焊过程进行模拟。 实验件焊接变形数值模拟结果表明：焊后母材处的位移小，衬板处的位移大且存在明显的梯度分布；衬板上随着与焊缝之间距离的增加，位移逐渐增大，最大位移位于收弧端的衬板外边缘处且主要由Y向位移体现，其值为17.1mm。将实验数据和数值模拟结果对比发现：两者在焊接角变形具体数值方面存在一定的偏差，但是这个偏差是在允许的范围之内的（10%以下）。另外，文中还设计采用从两端向中间的焊接顺序进行实验件的堆焊，发现此时最大位移位于实验件的中部，其值为12.8mm。相比从头到尾的焊接顺序，最大位移减小25.1%。这是由于从两端向中间焊接时，温度场相互重叠，温度梯度小，进而焊接变形得到减小。对比两种焊接顺序下实验件首端和末端的角度数据发现，采用从两端向中间的焊接顺序只影响实验件末端的角变形，而对首端的角变形没有影响。 隔板外环焊接变形的数值模拟结果表明：采用先焊内圆再焊外圆的顺序时，总的节点位移为7.8mm，总的等效残余塑性应变为13.3%。采用内圆外圆同时焊接的顺序时，总的节点位移为3.8mm，总的等效残余塑性应变为8.6%，位移和等效残余塑性应变分别减小了51.3%和35.3%，这是由于内圆外圆同时焊接时焊接变形相互抑制。另外，内圆外圆同时分段退焊时，总的节点位移和总的等效残余塑性应变分别为3.7mm和8.2%，与内圆外圆同时焊接时差别不大，这可能是由分段长度过大所导致的。
[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.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG404
本文编号：2189303
[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.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG404
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本文编号：2189303
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