最新刊期
期 5 ， 2019
- 摘要：Defects have been found on the class 1 BOSS welds in Loop 1 pressure boundary in domestic PWRs,such as,incomplete fusion,slag inclusion,blowhole and so on. an analysis is made from the aspects of the type,position and reason of the defects,two treatment solutions are formulated,one is grinding and repairing,one is cutting and replacing. Through the design and development of special tools,the technical difficulties,including the control for grinding residual wall thickness,the control for cutting to prevent foreign matters and the argon protection for weld back,have been conquered. All of these are successfully applied in Ningde,Fuqing,Fang Chenggang and Changjiang NPPs,which provide reference for the treatments of the welding defects of BOSS and other similar structures.关键词：nuclear power plant;BOSS weld;defect;treatment
- 38
- |
- 61
- |
- 1
发布时间：2022-03-15 - 摘要：The weldability of P91 and P22 steel are poor,and the dissimilar steel welding joints which are made by the two kinds of steel are very easy to harden and crack. In addition,due to the differences of the two kinds of steel in material properties,welding heat treatment requirements,and the decrease of heat treatment quality caused by the smaller product diameter which is easy influence on heater installation effect,it is difficult to ensure that the dissimilar steel welding joints achieve the comparatively ideal comprehensive mechanical properties,especially hardness index. Therefore,through analyzing material properties and the weldability of P91 and P22 small diameter pipe dissimilar steel in main steam system and according to the welding preparation,welding method,welding material,welding parameters and post-weld heat treatment steps to implement technology test. The results show that joint weld quality inspection,mechanical property test,microscopic metallographic examination,hardness test meet the design requirements and ASME specifications. Through the above implementation contents,the welding technology for on-site welding is finally determined,and the welding technology achieve good result after being applied in actual production,meet the welding construction requirements of P91 and P22 small diameter pipe dissimilar steel,and provide technical guarantee for on-site welding.关键词：P91 steel;P22 steel;post-weld heat treatment;mechanical properties;hardness
- 65
- |
- 98
- |
- 0
发布时间：2022-03-15 - 摘要：The dissimilar metal welding of seal（ASS） and penetration assemblies（Inconel 690） has been investigated by vacuum EBW in advanced PWR nuclear power plant. After visual and radiographic inspections,it is found that the main defects of dissimilar metals welding between ASS and Inconel 690 are cold shuts and nail point. Sine the fast cooling rate and samples with thick wall,metal vapor cannot escape from the weld,resulting in cold shuts. As the working distance increases, both the weld penetration and the travel of metal vapor escape reduce,so that the size and number of cold shuts in weld decease. When the working distance matches with the welding heat input appropriately,the cold shut will disappear.关键词：dissimilar metals;EBW;deep penetration welding;nail point defect
- 27
- |
- 180
- |
- 3
发布时间：2022-03-15 - 摘要：Investigation and analysis is carried out on defects detected by non-destructive testing in nuclear stabilizer nozzles welded by hot wire TIG welding,it is analyzed and found out that the main cause of these defects is lack of fusion between beads and layers,and there are some problems in matching of welding parameters and the process control. By considering the appearance of weld and the amount of overlap,the parameters are calculated and matched, like welding current,wire feed rate,etc. to optimize welding technology,which is verified by the technological test. And the results show that adopting the optimized welding parameters and improved process control measures are successfully to solve and avoid similar problems happened again. The improved technology has been applied to products, which improves the qualified rate of non-destructive testing of the hot wire TIG welding and ensures the equipment quality.关键词：hot wire TIG welding;defect;technology optimization
- 27
- |
- 73
- |
- 0
发布时间：2022-03-15 - 摘要：Aiming at the requirement of nickel-based alloy weld cutting and groove processing in nuclear power maintenance site,a portable weld cutting device is designed. The device adopts milling principle and numerical control technology to realize rapid cutting and groove processing of weld in site. The problem of tool cooling which is not allowed to use coolant in site is solved by air-cooling technology. The structure design of the device is reasonable through experiments. It can be used in the field. According to the technical requirements of nickel-based alloy weld groove,the groove processing technology was studied and two kinds of processing technology were designed. They are the processing of the groove root R1 chamfer groove and the processing of 15° angles. The process test was carried out through the reasonable setting of cutting tool materials and processing parameters. The processing accuracy,processing stability and tool wear of the two process schemes were mainly observed and determined through the test. The optimum technological scheme and process parameters were obtained.关键词：groove;nickel-based alloy;cutting device;process parameters
- 26
- |
- 46
- |
- 0
发布时间：2022-03-15 - 摘要：Steam generator transfers the heat generated by the reactor to the secondary feed water and produces saturated steam to the turbo generator. It undertakes the safety function of the nuclear power unit as an integral part of the primary loop pressure boundary.This article introduces the manufacturing process,impact test method and test results of product weld test coupon of the steam generator primary side nozzle safety end,and the unqualified cause of impact test was determined. Processing method of removing safety end and rewelding qualified safety end was used,the weld quality is qualified and the quality of steam generator product satisfied the requirements.关键词：safety end;weld test coupon;impact test;analysis;handling
- 33
- |
- 52
- |
- 0
发布时间：2022-03-15 - 摘要：Ti-Al intermetallic compound is the most potential structural materials with light weight and high temperature resistance for aircraft engine,and has the characteristics of low density,low thermal expansion rate,high heat conductivity and high heat resistance temperature.It may replace existing titanium alloy and nickel base super alloy material and become low or high temperature end components manufacturing materials for aero-engine compressor.The properties and characteristics of Ti-Al intermetallic compounds are briefly introduced.Research and application of welding technology of typical Ti-Al intermetallic compound,such as Ti3Al,Ti Al and Ti2Al Nb are summarized.Finally,the high quality welding technology and applications of Ti-Al intermetallic compounds in the field of aero-engines are summarized and expected.关键词：Ti3Al;Ti Al;Ti2AlNb;intermetallic compound;weld
- 24
- |
- 378
- |
- 3
发布时间：2022-03-15 - 摘要：70 CrMnMo martensitic steel welding materials are commonly used for surface and working face repair of tool steel. In this paper,in view of the large number of brittle fractures in 70 CrMnMo wire-drawing welding process,the material microstructure is analyzed by heat treatment principle,Ac1 phase transition point of the material was calculated and the accuracy of martensite tissue decomposition phase transition point was verified by experiments. Based on this,reasonable tempering process parameters were developed,and the ideal organization and performance were obtained quickly and efficiently by using self-made portable heat treatment equipment,which solved the problem of brittle fracture in the drawing production of 70 CrMnMo material.关键词：touch welding head;brittle fracture;martensite;portable heat treatment furnace;tempering treatment
- 28
- |
- 28
- |
- 1
发布时间：2022-03-15 - 摘要：Fe-based amorphous composite coatings were prepared on the surface of 45 steel substrate by high power fiber laser and supersonic plasma spraying equipment separately. The microstructure,microhardness and corrosion resistance of the cladding layer were analyzed by the scanning electron microscopy,microhardness tester and X-ray diffractometer. The results show that the laser cladding coating is well formed. No obvious defects,such as pores and cracks,were observed in the cladding layer. A good metallurgical bond is formed between the cladding layer and the substrate;the microstructure of cladding layer is columnar crystal,dendritic and amorphous coexisting structure. The coating by supersonic plasma spray has a high amorphous content. The mechanical bond between cladding layer and substrate is relatively weak. The defects,such as pores and microcracks,were observed in the coating. The microstructure of the laser cladding layer is dense,and Fe-Cr,（Cr Fe）7C3 compound is precipitated,which makes the hardness and corrosion resistance of the laser cladding coating much higher than that of the supersonic plasma spray coating.关键词：laser cladding;supersonic plasma spraying;microhardness;microstructure;corrosivity
- 29
- |
- 246
- |
- 4
发布时间：2022-03-15 - 摘要：Lifting operation plays an important role in the structure assembly and offshore installation of offshore oil platform. Once an accident causes structural damage or operation failure,it will cause serious loss of life and property. Although the hanging point is the auxiliary structure of lifting operation,it needs to bear the self-weight of the lifting structure and other additional loads. Therefore,in order to ensure the safety of offshore oil platform lifting,it is necessary to consider the welding quality of hanging points. Combining with management experience in many offshore oil platform engineering projects in resent years, the typical form of offshore oil platform is introduced, and the welding construction technique of hanging points in offshore oil platform is analyzed form the aspects of common steel and weldability,welding technology design and welding construction measures.关键词：offshore oil platform;hanging point;welding
- 32
- |
- 31
- |
- 1
发布时间：2022-03-15 - 摘要：Because of its advantages,such as optimizing arc energy distribution, stirring the welding pool and easily regulating chemical composition,a new multi-stranded wire was employed to join in the welding of high nitrogen stainless steel structures and significantly reduced the porosity in the weld,and the precipitation of second phases in the weld was suppressed,the microstructure of the heat affected zone improved with relatively low heat input. The microstructure and mechanical properties were improved by analysing and optimizing the GMAW joints of high nitrogen stainless steel,meeting the engineering technical requirements of important welded structural parts.关键词：high nitrogen stainless steel;multi-stranded wire;microstructure;mechanical property
- 27
- |
- 104
- |
- 2
发布时间：2022-03-15 - 摘要：8 mm thick 2219 aluminum alloy plates are welded by friction stir welding technology. The stress characterization and stressrelieving of 2219 aluminum alloy friction stir welded joint is studied by using a self-developed high frequency induction heating device,the test temperature is set as 90 ℃,140 ℃ and 190 ℃ respectively. Through measuring the longitudinal and transverse residual stress of weld before and after heat treatment by using X ray diffraction method,the microstructure and mechanical properties of welded joints are analyzed. The results show that peak value of longitudinal residual stress reduces significantly after high frequency induction heat treatment,which declines by 51.3% at the temperature of 190 ℃ HT,and the range of residual tensile stress narrows. As temperature of high frequency induction heating drops,the effect of stress-relieving decreases. Microstructure,microhardness and mechanical properties of welded joints do not change obviously before and after heat treatment. The high frequency induction heating technology can reduce the welding residual stress effectively,at the same time does not change the mechanical properties of welded joint.关键词：FSW;residual stress;high frequency induction heating;X ray diffraction
- 25
- |
- 113
- |
- 4
发布时间：2022-03-15 - 摘要：The formed part manufactured by rapid prototyping of arc welding has the advantages of good mechanical properties,high density and broad development prospects. In order to control the dimension of formed part and improve the limits of parameters,a double wire arc welding system is designed. The design of this system hardware is mainly introduced. A set of thin wire feeder is equipped with the conventional welding system,and an integrated double wire welding gun is designed to meet the requirement of system integration. Siemens S7-200 PLC is used as the control part,at the same time,a human-computer interface is designed to input and display parameters for the convenience of human-computer interaction. Experiments show that both coarse and thin wires can be welded well. Furthermore,the system can switch smoothly with continuous arc in welding process.关键词：arc rapid prototyping;double wire welding gun;PLC;human-computer interface
- 29
- |
- 84
- |
- 1
发布时间：2022-03-15 - 摘要：For the laser-MIG hybrid welding process of A7 N01 aluminium alloy,the change rules of electrical parameters under different protective atmosphere and the influence of protective gas composition on metal transfer period are studied. In the experiment,different proportions of helium-argon mixed shielded gas are used to collect the electrical parameters of A7 N01 aluminum alloy during welding process and to calculate the metal transfer period. The effects of different proportions of helium-argon mixed shielded gases on weld formation and pore defects are studied. The results show that the regularity of electrical parameters is strong and stable when the proportion of argon in mixed atmosphere is high;with the appearance of short circuit voltage,the electrical parameters of welding process are no longer periodic when the proportion of helium is more than 50%. The higher the proportion of helium,the longer the metal transfer period;when the proportion of helium exceeds 50%,the quality of weld formation decreases,and overlap and spatters occur;the addition of helium will improve the inevitable blowhole phenomenon in high purity argon atmosphere and reduce the porosity and blowhole size.关键词：A7N01 aluminum alloy;laser-MIG hybrid welding;electrical parameters
- 29
- |
- 106
- |
- 3
发布时间：2022-03-15 - 摘要：In order to verify the welding adaptability of domestic welding materials and 9 Ni steel in automatic submerged arc welding technology,domestic 9 Ni steel plates with thickness of 12 mm and 20 mm and three welding parameters（large,medium and small heat input） are selected to complete the welding technology tests of 9 Ni steel in the horizontal position of automatic submerged arc welding.By verifying, analyzing and arranging the microstructures and mechanical properties（including tension,bending,low temperature impact,CTOD and DWTT） of welded joints with different welding parameters and plate thicknesses,the performance test report of automatic submerged arc horizontal position welded joints of domestic welding materials and 9 Ni steel is obtained. Each index meets the requirements of standard specifications and verifies the welding adaptability and matching between domestic welding materials and 9 Ni steel plate.关键词：9%Ni steel;submerged arc automatic welding;mechanical property;low temperature toughness
- 29
- |
- 120
- |
- 0
发布时间：2022-03-15 - 摘要：The deformation caused by uneven heating in welding technology is always a difficult problem in industrial production. At present,for the problems of welding residual stress and deformation,ultrasonic impact technology has achieved a good results in many methods. The deformation resistance of the material reduces when the temperature is high. Based on this,a front trailing ultrasonic impact test platform is built. The front trailing ultrasonic impact test of 3 mm Q235 B sheet is carried out. The relationship between the welding deformation and grain change at the weld and the impact distance is mainly explored. When d =45 mm the deformation is reduced by 43.3% comparing with that of conventional welding, that is the effect of deformation reduction is most obvious when high temperature impact occurs. At the same time,it is found that the grain refinement of the weld is most obvious when the impact distance is short.关键词：welding deformation;front trailing ultrasonic impact;grain refinement
- 21
- |
- 96
- |
- 3
发布时间：2022-03-15 - 摘要：A group of full penetration butt weld joints are made by MAG welding of P355 NL2 normalized fine-grained steel,the microstructure and properties of welded joints are studied by tensile,bending,impact,hardness and microscopic metallographic tests.The result shows that the welded joint of P355 NL2 normalized fine-grained steel has good tensile and bending properties;the hardness value distribution of base metal is slightly low,while that of HAZ is a little high,both are within the scope of the standard;the impact energy values of the weld and HAZ both are higher than the standard requirement,and both have good impact toughness at low temperature. The central weld microstructure is distributed on the eutectoid ferrite,and the HAZ is composed of ferrite and pearlite with different grain size and strip distribution along the rolling direction.关键词：P355NL2;low temperature;microstructure and property
- 50
- |
- 35
- |
- 0
发布时间：2022-03-15 - 摘要：High frequency hybrid twin-electrode TIG welding is a new type of welding method with high quality and efficiency. In order to study its arc behavior,the arc static characteristic and dynamic characteristic tests are designed by using high-speed photography technology to photograph arc profile. The high frequency pulse currents of 0～80 kHz are introduced in the arc static characteristic test.The results show that the hybrid arc shape with high frequency pulse current is obviously different from that without high frequency pulse current,and is symmetrical triangle on the whole, and the arc outer contour is more straight,the arc diameter is smaller. When the pulse current frequency is below 50 kHz,the higher the pulse current frequency,the greater the hybrid arc compression,and the higher the energy density and stiffness of the hybrid arc. The dynamic transition behavior of hybrid arc is studied by using the method of arc step-up,the results show that the hybrid arc has strong stability and high arc stiffness with the effects of cutting-edge,non-arc-jumping and high frequency self-localization,and its mechanism is deeply analyzed.关键词：high frequency hybrid;twin electrode;argon arc welding;arc behavior;high-speed photography
- 25
- |
- 102
- |
- 2
发布时间：2022-03-15 - 摘要：On the CRH5 A EMU,the chutes of the underframe side beams are inevitably defective due to manufacturing anomalies. This paper introduces several different repairing schemes for chute repair. Detailed strength calculation and comparative analysis were carried out for the single-side chute repair,the overall chute repair,and the overall replacement of the underframe beam. The structural design and strength theory calculation in the repair process can provide an important reference for the subsequent repair of the side frame beam.关键词：underframe side beam;welding repair;strength calculation
- 26
- |
- 37
- |
- 1
发布时间：2022-03-15 - 摘要：In the repair of tail erosion sealing surface of cylinder of cracking gas compressor in petroleum refining and chemical enterprises. In the past,there were some disadvantages such as poor bonding,easy to crack and undercut,and secondary damage of sealing surface in the methods such as gluing and arc welding. Exploring the composite welding technology of gas brazing and fusion welding. After selecting welding materials,adjusting welding specifications,and using special tools created by ourselves,the welding seam was repaired with high quality,which reduced the difficulty of the operation and improved the repair quality and efficiency.关键词：cracking gas compressor;turbine cylinder;sealing surface;acetylene welding;repair welding
- 42
- |
- 18
- |
- 1
发布时间：2022-03-15 - 摘要：Orthogonal test is used to optimize the resistance spot welding parameters of Q345 D carbon steel. Through single factor analysis of welding current,welding time and electrode pressure which have great influence on spot welding strength,the rule of influence of welding parameters on tensile strength of spot welding is obtained,and the procedure window of spot welding parameters is gained. On the basis of single factor analysis, three factors and three levels orthogonal test parameters are determined to conduct spot welding experiments. The range and variance analysis of the orthogonal test results are carried out by using the tensile strength of spot welding as the evaluation index. The optimum parameters of Q345 D spot welding are gained as follows: welding time of 25 CYC,welding current of 12 kA and electrode pressure of 7.5 kN.关键词：carbon steel;spot welding;orthogonal test;rail vehicle
- 72
- |
- 100
- |
- 1
发布时间：2022-03-15 - 摘要：In order to verify the qualification of the transverse bending test of 9 Ni steel welding specimen,SMAW is adopted for multilayer and multi-pass welding of 26 mm thick 9 Ni steel. The microstructures and mechanical properties of welded joints are analyzed by Vickers microhardness tester and universal tester. The results show that there are four good transverse bending test specimens,the microstructures of HAZ are martensite and grains are easy to grow. According to the results,the causes and prevention methods of cracks in the transverse bending HAZ are analyzed,which has certain guiding significance to the implementation of welder certification examination standard in classification society.关键词：9Ni steel;heat affected zone;microstructure;crack
- 26
- |
- 79
- |
- 1
发布时间：2022-03-15 - 摘要：In this paper,0.6 mm stainless steel sheet and 8 mm carbon steel thick plate are used for overlapping MAG arc spot welding test. The test results of MAG spot welding parameters and equivalent nugget diameter of overlapping surface are analyzed. It is proposed that the nugget equivalent diameter of overlap surface which is larger than the requirement of product drawings and stable in size can be formed by using welding parameters in the "core" range. Suggestions on practical application of MAG arc spot welding process for stainless steel sheet lapping are put forward.关键词：stainless steel;MAG;arc spot welding;welding experiment
- 41
- |
- 72
- |
- 1
发布时间：2022-03-15 - 摘要：The numerical control system for energy storage single side projection welding is designed to realize the welding of automobile brake shoes and steel mesh. The structure of the numerical control system for energy storage single side projection welding is introduced. According to the energy storage single side numerical control welding process,a human-computer interaction interface based on touch screen is designed. The communication between the touch screen and main control board can conveniently realize the real-time monitoring of welding status,manual operation control,multiple sets of parameter storage and recall,and fault detection of welding process.关键词：brake shoe;energy storage projection welding;touch screen;HMI
- 24
- |
- 87
- |
- 0
发布时间：2022-03-15 - 摘要：The effect of stud welding principle and parameters on welding quality is described in detail. Through statistical analysis of stud welding defects of front floor sheet,it is found that magnetic blow is the main cause of stud removal welding. The reasons of welding magnetic blow are analyzed and discussed from the aspects of stud size,part shape,ground connection method and fixture design. By increasing the fixture support,adjusting the grounding line and optimizing the lifting height,the welding defects caused by magnetic blow in the stud welding process of sheet are solved,and the stud welding quality is improved.关键词：stud welding;magnetic blow;sheet;support structure
- 22
- |
- 155
- |
- 4
发布时间：2022-03-15 - 摘要：In order to study the trace characteristics of multi-strand copper-clad aluminum conductor under the fault of over-current,copper-clad aluminum conductor conforming to the national standard was selected. By changing the preset current value,melting marks of copper-clad aluminum conductor at different degrees of over-current were prepared to observe the heating phenomenon and macroscopic trace characteristics of the conductor after heating. The analysis shows that the phenomenon of wire heating deformation is related to the current value,Only when the over-current multiple is between 2 and 4 times,the insulation can be burned in a large range,which can cause fire;in addition,the copper clad aluminum conductor with excessive current has and only produces molten beads at the first breakpoint. Since molten beads do not appear in the burn mark,short circuit or over-current fault will occur once molten beads are found in the fire.关键词：identification of physical evidence;copper clad aluminum conductor;fever phenomenon;macroscopic trace feature
- 23
- |
- 70
- |
- 1
发布时间：2022-03-15 - 摘要：The welding difficulties,heat treatment technology and selection of matching welding materials of 9 Ni steel are analyzed. The welding technology test of 9 Ni electrode arc welding is carried out. Through nondestructive test and mechanical property test of the postweld material,the welding parameters corresponding to the optimum mechanical properties of welds are obtained. It provides technical reference for welding construction of liquid cargo storage tank.关键词：LNG;welding;crater crack;mechanical properties;heat crack
- 30
- |
- 95
- |
- 0
发布时间：2022-03-15 - 摘要：Pipeline emergency maintenance construction has the characteristics of tight time,heavy task,often affected by sudden factors,and very difficult construction operation. The welding operation is the most important link in pipeline emergency maintenance construction. Whether the quality monitoring is scientific or not is one of the key procedures to ensure the welding quality in pipeline emergency maintenance construction. If the monitoring is inadequate,it will increase the consumption of manpower and cost for repairing the welded joints,even will directly affect the safe operation of pipelines and cause accidents. Combining with the shortcomings of the current welding quality monitoring mode commonly used in emergency maintenance construction,it is analyzed the specific significance of employing welding inspectors as quality monitoring personnel in emergency maintenance construction operation to monitor the welding quality. It is proposed that welding inspectors should take on some new responsibilities under the special environment of emergency maintenance construction,so as to promote the effective improvement of the overall quality management level of emergency maintenance construction.关键词：welding inspector;pipeline emergency maintenance construction;welding quality monitoring mode
- 24
- |
- 35
- |
- 0
发布时间：2022-03-15
- Postal code：610051
- Tel：028-83289008
- Technical support is provided by Beijing Founder electronics co., LTD 蜀ICP备07004068号-2
公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0