Structure of sealed connect welding line optimizes fillet weld of hydrogenation heat exchanger

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Summary: Use finite yuan of software ABAQUS, solder in the light of heat exchanger of hydrogenation high pressure of sealed structure solder leftover stress developed coupling of an in order solder program of thermal stress computation, angle of discussion welding line and welding line dimension are leftover to soldering the influence of stress, got heat exchanger of hydrogenation high pressure solders distributinging circumstance of field of sealed structure temperature, stress field and the biggest solder the position of leftover stress and size, to prevent heat exchanger of hydrogenation high pressure to solder the invalidation of sealed structure provides reference. Keyword: The graph in leftover stress of; of experiment of orthogonality of; of dimension of welding line of; of sealed connect of; of hydrogenation heat exchanger classifies date: TG407 document mark piles up: A heat exchanger balances the indispensable crucial equipment in reclaiming with energy as unit system energy, side with as petro-chemical device large change the ceaseless development with tall parameter direction, its bulk and quality are greater and greater also. For this, the long periodic safety of equipment moves already more and more the high attention that is concerned an industry. High-pressured hydrogenation heat exchanger regards hydrogenation as one of main facility of device, loading feedstock oil and reaction to generate oily quantity of heat to exchange the task, the operation pressure as a result of equipment and temperature all taller, medium belongs to the oil gas that explodes combustibly, easily kind, because of this heat exchanger once leak is sequential very will serious. Sealed structure used the tubal case that there is much stage heat exchanger in device of some company hydrogenation flat form solders sealed structure, among them more adoption fillet weld solders sealed connect [1~3] . This characteristic that sealed structure has sealed and reliable, life to grow, but fall with the environment that face hydrogen in long-term high temperature, high pressure, structure of this welding line is easy occurrence crackle, even craze and cause leak [4] . Accordingly, research solders stress of remains of sealed connect place and its influencing factor [5] , sealed to soldering structure undertakes optimizing, life of sealed to lengthening structure and make sure hydrogenation device grows periodic safety to run the project port with be had principal. Current, domestic and international stress of remains of sealed to soldering structure is finite yuan of imitate and research of its influencing factor have not examine relevant document. Wen Zhongli is used finite yuan of software ABAQUS[6] , the fillet weld that is in charge of box flange to heat exchanger of hydrogenation high pressure solders of sealed connect solder leftover stress undertook numeric analysis, the size that discussed welding line angle and welding line measure is leftover to soldering the influence of stress, got soldering the distributinging rule of the temperature field of place and stress field. 1 computation model 1.

The flat form that heat exchanger of 1 high pressure provides box flange parameter to study the object is heat exchanger of hydrogenation high pressure to be in charge of box flange solders sealed structure. Concerned parameter is, monitor design pressure is 16.

9MPa, set thermometry to spend 272 ℃ . Material of flange tubal case, cover board all is 16Mo5. Dimension of sincere round flat is Φ 1212mm × 10mm, material is qualitative 0Cr18Ni9. Surface of flange tubal case has the 0Cr18Ni9 v layer with thick 5mm, computational model sees a picture 1. 1.

2 fillet weld solder material of hypothesis of model of sealed connect geometry is out of shape for linear aggrandizement plays plasticity model [7~9] , flange tubal case solders the detail drawing of sealed structure fillet weld sees a picture 2. From the analysis stress angle sets out, chose 2 route (BC and AD) , method BC is the welding line that is located in flange to go up (axial) , method AD is the welding line on sincere round flat (radial) . Solder use welding rod arc welding, part 3 solder way in all, solder foot height is 7mm. A302 of welding rod of path of the 1st solder, the 2nd welding rod A132 that with the 3rd solder, solder normative 1[10] seeing a table. Those who need an attention is, in the 1st solder path of path, the 2nd solder solders solder together below travel of the reentry after cooling 5min answering after the end, solder end hind should cool naturally normal temperature. Because be multi-pass welding craft, cannot be opposite the real measure of the welding line after soldering every time undertakes metrical, every solder so road measure simplifies. In the graph, MN is the solder foot height that the 1st solder, NG is the solder foot height that the 2nd solder, the solder foot height that assumes path of the 2nd solder with the 3rd solder is identical. Nextpage1.

3 board type solder sealed structure is limited yuan the model is used finite yuan of software ABAQUS6.

5, the program of thermal stress computation that develops coupling of an in order comes imitate board type solders of sealed structure solder leftover stress. Is computational process as follows: ? Pai  raw meat or fish treats Gu of  of ＝ of an ancient wine vessel made of horn to closely question lot shows be lame truly > collect attacks Bao of Su of Jing Mao  irrigates Ψ of  of Chi of  of Mao  collect to treat? of Gui of ㄒ of Bao head ざ to be analysed in force in justice field is being booked from now on in the process, read take each node temperature, undertake interpolation is calculated. ② is passed bring to bear on inside of electric arc of heat build-up imitate heat action, use unit activation technology (the case of Modelchangeremoveoradd) imitate multi-pass welding. ③ heats up analysis and force analysis to use same unit and node. Considering the symmetry of the model, the 1/2 that takes a model undertakes an analysis. Build a model for symmetrical face with the median plane, use structural sex reseau, generate 1521 node, 1422 unit. The hot imitate of ABAQUS chooses DCAX4 of unit of 4 node semmetry, leftover stress imitate chooses CAX4 unit, reseau differentiates see a picture 4, the density of the reseau in the graph states temperature change is minor near welding line respectively reach very big. 2 orthogonality experiment expresses a design to be in numeric imitate, to reduce imitate number, the orthogonality that arranges a group of L9(33) tries proved recipe case, undertake to test result orthogonality is analysed at the same time, find a group of fillet weld to solder the welding line angle with sealed best connect and dimension, to consider to solder further the craze of sealed connect is offerred draw lessons from. To reduce imitate number as far as possible, inspect α of welding line angle, MN and NG the influence of leftover to soldering stress, appropriate chooses orthogonal experiment magic art [11] . Considering 4 afore-mentioned welder art there is interact between parameter, because this serves as factor with them, every factor takes 3 values to serve as a level, have 9 groups of tests in all, the L9(33) orthogonality watch of such design sees a table 2. Result of Nextpage3 numeric imitate and orthogonality are analysed 3.

Result of 1 numeric imitate is expressed according to orthogonal experiment, through finite the computation of yuan of software ABAQUS is ordinal reached method BC is in what structure of every groups of welding line falls to solder leftover stress is worth. Watch 2 in serial number 1~9 falls in structure of diverse welding line, method BC solders the comparison of result of imitate of leftover stress numerical value sees a picture 5. Method BC and method AD are in same solder below the structure solder the comparison of leftover stress sees a picture 6, ° of its corresponding =45 of α of angle of welding line structure, MN=3mm, NG=4mm. By the graph 5 can see, ① falls in different welding line structure, the metabolic trend that method BC each spot welding accepts leftover stress is identical, solder leftover stress extreme value distributings in be apart from welding line 0~5mm inside, distance welding line is further solder leftover stress is less. Of ② graph 5a solder the least value of leftover stress extreme value appears in the 2nd group, numerical value is 256MPa. The least value of the leftover stress extreme value of ③ graph 5b appears in the 5th group, numerical value is 257MPa. The least value of the leftover stress extreme value of ④ graph 5c appears in the 7th group, numerical value is 248MPa. Of ⑤ graph 5c solder leftover stress and other two graphs photograph is compared, stress is centered and stress change gradient is bigger, appeared the maximum of stress of the welding line in group of serial number 1~9 and the least value. By the graph 6 can see, connective of ① welding line 2 components, its solder the change of leftover stress is likeness inside 0~30mm. ② is near welding line and welding line, method BC and method AD have likewise big solder leftover stress extreme value, its numerical value all is 257MPa. But method BC extreme value is located in be apart from welding line 0~5mm, method AD extreme value is located in be apart from welding line 0~11.

6mm. Of ③ method BC solder leftover stress is jumped over as distance welding line far, solder leftover stress decreases successively gradually, appear around 3mm 35MPa of the least value. Of ④ method AD solder leftover stress appears in place of 20mm of distance welding line 66MPa of the least value. Analyse by above knowable, of spacer of sincere round flat solder limits of leftover stress extreme value wants than flange big. In be far from welding line place, of spacer of sincere round flat solder leftover stress is worth those who compare flange position to solder leftover stress value wants big, and of spacer of sincere round flat solder leftover stress distributings to go up than flange solder leftover stress distributings complex much. Nextpage3.

2 orthogonality analysis serves as with extreme value of the stress in result of every groups of imitate inspect a target, according to method of orthogonal experiment data processing, the size that can analyse MN of A of welding line angle, dimension and NG is leftover to soldering the influence of stress, orthogonal analysis sees a table as a result 3. In the watch, ki(i=1, 2, the sum of Mises stress extreme value that 3) is every factor to go up in every level, ki(i=1, 2, 3) is the average of Ki, Δ I is extreme difference, Δ I=maxki-minki, MPa. In order to express 3 in every factor is exemple, next type establish: ? ? listed the stress extreme value in result of every groups of imitate is calculated Ki and Δ I, can see from which, α of Δ NG> Δ > Δ MN. Explain from this in 3 factor, NG is leftover to soldering the impact of stress is the biggest, the influence of angle α next, MN impact is the least. The stress value of the correspondence of the 3rd level of element NG is the least, namely the 3rd level is best. Get the 2 levels of element angle α with manage, the 2 levels of element MN are best. Accordingly, get the structure of optimal welding line that makes leftover stress extreme value the least, namely NG=4mm, MN=2mm, α =45 ° . Fillet weld of heat exchanger of high pressure of 4 epilogue hydrogenation solders sealed connect solders in what the welding line structure of different combination falls in the welding stress of process and cooling process, the area is affected in welding line and welding line heat inside solder leftover stress is the greatest. And these place get power complex and get power inhomogenous, produce crackle extremely easily. When the design, the heat treatment after should adopting necessary solder solders with reducing leftover stress, prevent to produce leak invalidation. Result of this computation analysis can solder to fillet weld of heat exchanger of hydrogenation high pressure the structure of actual welding line of sealed connect chooses to provide reference, also solder to study further and analyse this kinds of heat exchanger the craze invalidation of sealed connect provided certain basis. CNC Milling CNC Machining