最新刊期
期 11 ， 2022
- 摘要：With the rapid development of modern industry, conventional hard aggregate and steel brazing tools are gradually unable to meet the needs of complex extreme working environments. To solve this problem, this paper studied the influence of different brazing temperatures (860 ℃~950 ℃) on the microstructure of the vacuum brazing joint between YG6X cemented carbide and GH4169 superalloy with AgCuNiMn filler metal, and tested the tensile strength of the sample at 860~950 ℃ at room temperature and 227 ℃ the oretical working temperature, and the tensile strength of the samples (860 ℃) deep low temperature (-238 ℃) was tested. The microstructure of the brazing seam is mainly composed of Ag based solid solution and Cu based solid solution. With the increase of brazing temperature, the number of Cu based solid solution in the center of the brazing seam gradually decreases, the gap between the brazing seams gradually narrows, and the reaction layer of Cu based solid solution at the interface on both sides gradually thickens, which improves the interface bonding strength between the filler metal and the base metal to some extent, but also increases the residual stress at the brazing seam. The tensile strength of the brazed joint at room temperature shows a trend of first increasing and then decreasing. In the welding temperature range of 890 ℃~950 ℃, the tensile test temperature of 227 ℃ has little effect on the tensile strength of the joint. When the brazing temperature is 890 ℃, the average tensile strength reaches the highest value of 715.3 MPa. Under 860 ℃ welding temperature, the average tensile strength of the joint is -238 ℃ tensile strength (474.8 MPa)>room temperature tensile strength (430.2 MPa)>227 ℃ tensile strength (278 MPa). The tensile strength of the joint under deep and low temperature environment is about 10% higher than that under room temperature. As the weldly temperature at 860 ℃ is relatively low, the dissolution and diffusion of solder and base metal are relative low, the solder is softened at 227 ℃, resulting in a sharp drop in tensile strength.关键词：vacuum brazing;deep low temperature;mechanical properties;cemented carbide;superalloy
- 87
- |
- 23
- |
- 0
发布时间：2023-01-17 - 摘要：When the dissimilar metal connection components work under thermal coupling conditions, stress deformation occurs at the heterogeneous connection interface due to heat and force, which makes the connection interface location produce voids, cracks and other defects. Defects affect the material’s electrical conductivity and can be monitored for crack sprouting and expansion using resistance analysis techniques. A thermally coupled electrical detection system was designed by using the LabVIEW programming language environment, a data acquisition card and Hall current, voltage transducers, temperature and displacement sensors. The dynamic resistance and elongation during the experiment were analyzed to derive the joint failure mechanism of the composite member during operation. The system can provide technical support for basic experimental research and fieldwork monitoring of heterogeneous metal-connected components with specific examples.关键词：data acquisition;thermodynamic coupling;LabVIEW;dynamic detection
- 44
- |
- 14
- |
- 0
发布时间：2023-01-17 - 摘要：The welding temperature field of CuSi3 welding wire laser brazing of galvanized steel sheet was studied by combining welding experiment and welding numerical simulation. The combined heat source model composed of Gaussian surface heat source and rotating Gaussian body heat model was used to calculate the numerical model of the temperature field, and the effect of the welding line energy on the microstructure of the welded joint and the effect of temperature field distribution during the laser brazing process was analyzed according to the experimental and numerical calculation results. The experimental results show that the base metal BM (basic mental, BM) of the welded joint is mainly distributed as fine equiaxed grains with uniform size, while the HAZ (heat affect zone, HAZ) area is mainly distributed columnar grains that the growth direction is perpendicular to the temperature field isotherm and towards the heat source; with the increase of welding line energy, the aspect ratio of the welded joint also shows an increasing law; the temperature field distribution gradient in the center of the surface weld is small, and the welding line energy has little effect on the peak temperature of the weld center; the temperature of the weld edge close to the base metal is higher than the boiling point of the zinc coating under all parameters, which leads to the formation of holes on the surface of specimens.关键词：galvanized steel sheet;CuSi3 welding wire;laser brazing;composite heat source model;temperature field;microstructure
- 67
- |
- 14
- |
- 0
发布时间：2023-01-17 - 摘要：The mixed welding of U26Mn A-B rails and U75V pearlite rails is studied by gas pressure welding methods,and the metallurgical bonding characteristics and mechanical properties of the weld interface of the gas pressure welding joints of dissimilar rails are explored through OM, SEM, impact, tensile, and hardness tests. The results show that there is element diffusion behavior on both sides of the weld interface of the gas pressure welded joint.The metal at the weld interface has undergone mutual crystallization and recrystallization under the action of heat-mechanical cycles,and the metallurgical combination is good (except rail feet). The average strength of welded joints reaches 86% of the base material of bainite rail, and the average strength of normalized joints reaches 90% of the base material of bainite rail. The average hardness of the rail top surface and the softened zone, as well as the width of the softened zone of the welded joint meet the standard requirements of TB/T1632 "Rail Welding". The presence of sulfide in the joint has a great influence on the impact toughness of the joint.关键词：bainite + pearlite;rail;gas pressure welding;element diffusion behavior;mechanical properties
- 46
- |
- 14
- |
- 0
发布时间：2023-01-17 - 摘要：In order to meet the performance requirements of copper/stainless steel direct-connected permanent cathode plate, laser welding without filler wire is used to study the morphology and microstructure of copper/stainless steel fillet welded joint under different laser power and preheating conditions. The nominal tensile strength, conductivity and corrosion resistance of the joint are also measured. The results show that the weld forming quality of copper/stainless steel joints increases and then decreases with the laser power increases. After preheating with laser power of 3 000 W, the quality of welded joint is optimal, the joint is well formed and no welding cracks. Spherical and dendritic ε-Cu particle phase in fusion zone uniformly distribute in (γ+ε) dual-phase solid solution organization dominated by γ-phase. The mechanical properties and conductivity of joint with different laser power are as follows: preheating with 3 000 W>3 000 W>2 000 W>4 000 W. The copper side area of the joint is more prone to corrosion failure, the steel side area has good corrosion resistance, and the ε-Cu phase in fusion zone is easily corroded and dissolved.关键词：copper/stainless steel welding;laser welding;mechanical properties;electrical conductivity;corrosion properties
- 41
- |
- 12
- |
- 0
发布时间：2023-01-17 - 摘要：The plasma transfer arc (PTA) was used to hardfacing self-developed wear-resistant alloy powder on Q235 steel, with w(Cr)/w(C) at 5∶1, the influence of Fe/C ratio on the microstructure and mechanical properties of the deposited metal was studied. The metallographic microscope, spectrometer (OES), wear-resistance experiment and hardness detection were used in this study. The results show that the Fe elements play an effective melting role in the melting process, when no Fe powder is added, the bead can not be formed; while the Fe/C ratio is 4∶1, the bead is well formed, M7C3 carbide grain is small size and well distributed on the surface of the martenite matrix; with the increase of the Fe/C ratio, the melting aid of Fe element will reduce the burning proportion of the hardfacing alloy, however, the reduced weight percentage of C elements leads to the increased size of the hard phase grains in microstructure, when the Fe/C ratio is 10∶1, the M23C6 carbides are formed, and the wear resistance deteriorates.关键词：plasma hardfacing;hardfacing alloy;Fe/C ratio;bead formation;hard phase
- 32
- |
- 12
- |
- 0
发布时间：2023-01-17
Important Issuse
- 摘要：With the extension of operation time of nuclear power units, the probability of degradation of nuclear materials and failures of nuclear components increase. As an on-line repair technology without removing defects, Weld Overlay (WOL) has been widely used in corrective maintenance or mitigation maintenance of nuclear equipments and pipelines at home and abroad. Technical principle was analyzed and residual stress was verified by finite element simulation to study the standard specifications of WOL applied in nuclear field, and the key principles for the selection of welding materials and welding methods of WOL were put forward. The typical applications of WOL on CRDM Ω welds and dissimilar metal welds were summarized, the key technical requirements of welding structure and process parameters of WOL were analyzed, the conclusions of residual stress and structural integrity evaluation were studied, and some research suggestions on WOL were proposed. The results show that WOL can strengthen the structure and improve the state and distribution of residual stress, and the structure after WOL can meet the requirements of service safety in a long operating period.关键词：Weld Overlay (WOL);residual stress optimization;structural reinforcement;CRDM Ω weld;dissimilar metal weld
- 46
- |
- 13
- |
- 0
发布时间：2023-01-17 - 摘要：In order to solve the problems of the various weld forms, low welding efficiency and difficult to achieve welding automation of 5A06 aluminum alloy thin-walled fuel tank, four GMAW welding processes AC-CMT, CMT, P-MIG and CMT+P were studied. The difference in weld forming characteristics, pore distribution, microstructure, and joint properties of the four processes were compared and studied. The results show that the front reinforcement of the joint, the energy input required for penetration, and the number of pores in longitudinal and transverse section with P-MIG is the lowest. The microstructure of the weld zone of four process joints consisted of α-Al matrix and β-Al3Mg2, compared with AC-CMT and CMT processes, the grain size in the weld zone of P-MIG and CMT+P joints is larger and the width of heat affected zone is wider. The mechanical property test shows that the tensile strength of P-MIG joint is the highest (318 MPa), which is 89.1% of the base metal, and the joint still does not crack when the bending angle is 180° with P-MIG. SEM observation show that the tensile fracture surfaces does not exist pore with P-MIG and AC-CMT, and more pores could be observed on the tensile and bending fracture surfaces of CMT and CMT+P joints. By comprehensive comparison, the P-MIG process has the least pores, the highest tensile strength and better bending performance, which is more suitable for the robot automatic welding of 5A06 aluminum alloy thin-walled fuel tank.关键词：5A06 aluminum alloy;welding process;microstructure;pore;bending properties;Robot welding
- 67
- |
- 10
- |
- 0
发布时间：2023-01-17 - 摘要：The repair welding quality is directly related to the mechanical properties and service life of ZTA15 titanium alloy castings. Therefore, TIG welding experiments of ZTA15 titanium alloy were carried out by using TC4 welding wire. The microstructures, tensile test at room temperature and at 400 ℃, and impact toughness at room temperature of the welded joints were analyzed. The results show that the TIG welded joint is of good quality, without defects such as pores, cracks, and lack of fusion. The microstructures of weld metal and heat affected zone are composed of acicular martensite α' phase+flaky α phase+β matrix. The tensile strength of the welded joints is 1033.7 MPa at room temperature and 675.0 MPa at 400 ℃ respectively, and the corresponding elongation is 41.8% and 37.2% of the base metal respectively. However, the impact toughness of the welded joints reaches 95.5% of the base metal at room temperature. All of the tensile samples monotonously fractured at the base metal zone, with quasi-cleavage fracture mode.关键词：ZTA15 titanium alloy;TC4 welding wire;TIG welding;microstructure;mechanical properties
- 69
- |
- 11
- |
- 0
发布时间：2023-01-17 - 摘要：The HS13/5L martensitic stainless steel welding wire is used for MAG welding between the upper crown, blade and lower ring of the runner of Baihetan million kilowatt hydropower unit. Because HS13/5L belongs to 13Cr type super martensitic stainless steel, the toughness of its MAG welding deposited metal is lower than that of the base metal, which directly affects the performance of the runner. Therefore the microstructure and mechanical properties of the deposited metal were studied. The welded microstructure of the deposited metal is quenched martensite, interdendritic delta ferrite and tempered martensite in some reheat zone, and the tempered microstructure is tempered martensite, reversed austenite. 590 ℃×8 h tempering treatment significantly improves the toughness of deposited metal, the reversed austenite formed by tempering at a temperature near the Ac1 is an important toughening phase. The normalizing+tempering heat treatment process can improve the toughness of the deposited metal to a certain extent, and the impact toughness is basically stable above 100 J, which is 10~20 J higher than the existing heat treatment process of 590 ℃×8 h. HS13/5L deposited metal has excellent mechanical properties, meeting the welding requirements of turbine runner in Baihetan power station.关键词：supermartensitic stainless steel;reversed austenite;deposited metal;impact toughness;normalizing treatment
- 70
- |
- 13
- |
- 0
发布时间：2023-01-17 - 摘要：In order to obtain aluminum alloy welded joints that meet the requirements of China Classification Society, this paper selects ER5356 aluminum alloy welding wire for 5083 aluminum alloy MIG welding butt test. The welding gap and misalignment adaptability of 6 mm thick welded joints were studied by means of microscopic metallographic observation and mechanical property test. The gap and misalignment adaptation window area of 5083 aluminum alloy MIG welding to base metal were obtained, and the mechanical properties and microstructure of welded joints were analyzed. The results show that the tolerance of the butt gap of aluminum alloy MIG welding is strong, reaching 66.6 % of the thickness of the base metal, and the tolerance of the butt error variable of the base metal can reach 50 % of the thickness of the base metal. The microstructure of the weld zone is uniform and fine, mainly composed of α-Al phase and β-Al3Mg2 phase, and the microstructure of the heat affected zone is coarser than that of the weld zone. The average tensile strength of the welded joint is 263.5 MPa, reaching 94.1 % of the base metal, and has good bending resistance. The hardness value of the fusion line of the welded joint is the lowest, which is 70 HV, meet the requirement of China Classfication Society.关键词：5083 aluminum alloy;MIG welding;microscopic structure;mechanical property
- 53
- |
- 15
- |
- 0
发布时间：2023-01-17 - 摘要：In order to repair the BOSS welds which can not be isolated even shutting down the operating nuclear power plant, a overlay repair scheme with pre-existed defects not been removed was proposed, which was carried out using manual GTAW procedure for BOSS welds on thin-walled stainless steel pipes with and without coolant and pressure inside. The scheme, procedure and the quality of the repair welds was evaluated by mechanical properties tests, micro and macro examination, simulation and verified test of phased array ultrasonic examination. Results shows that the proposed repairing scheme is feasible, which can be completed in the 20 hours limited time windows of the plant, the leaking risk of the coolant can be avoid by controlling the welding fusion depth with the specific welding procedure developed, and the microstructure and mechanical properties of the welds can be satisfied. Then a new selection could be in place for the in-service repairing of the thin-walled pipe to guarantee the safety and the economy of the nuclear power plant.关键词：nuclear power plant;thin-walled stainless steel;BOSS welds;in-service repairing
- 49
- |
- 14
- |
- 0
发布时间：2023-01-17 - 摘要：Aiming at the problems of high labor intensity, unstable welding quality, low production efficiency and high cost in manual arc welding of hollow blade of autonomous nuclear power plant, an automatic welding method of laser vision welding seam tracking is adopted. The laser vision model of weld tracking was revised, the welding procedure and process parameters were optimized, and the structure and equipment of laser fixing bracket were deepened by studying the factors of unstable weld tracking, inaccurate locating and large deformation of blade welding. The results show that the automatic welding laser vision tracking system operates stably and the production efficiency of welding hollow blade is increased by 44.5%. The weld seam is formed beautifully and reliably, which better ensures the product quality and has broad market application value.关键词：hollow blade;weld tracking;laser teaching;deformation of weld;automatic welding
- 44
- |
- 15
- |
- 0
发布时间：2023-01-17 - 摘要：A main steam isolation valve has a penetrating crack on the cobalt-based surfacing sealing surface of the valve gate plate during the manufacturing. Through analyzing the mechanism of cobalt base alloy surfacing crack formation, the influence of stress on welded joints and other related factors, it is concluded that the main reason is that the validation of process qualification is insufficient, and the influence factors such as the asymmetry of valve gate plate welding structure and the thickness of surfacing are not fully considered. The treatment before surfacing, welding structure, welding parameters, heat treatment process, process control and other aspects are optimized and improved. The measure is as follows: leave 10 mm ring strip in the original lap area, reduce the stress concentration at the lap of two kinds of processes, and optimize the number of surfacing layers to two layers; On the premise of ensuring the surfacing quality, select small welding current and welding speed as far as possible; Increase the preheating temperature and carry out the postweld heat treatment. The primary pass rate of gate surfacing weld reaches 100%. This measure provides some references for the subsequent treatments of the sealing surface cracks on the same kind of main steam isolation valve in nuclear island in domestic nuclear power plants.关键词：main steam isolation valve;cobalt base alloy;surfacing;penetrating crack
- 48
- |
- 10
- |
- 0
发布时间：2023-01-17 - 摘要：Based on the automatic TT welding system for the girth weld of LNG storage tank, this paper conducted TT automatic welding test of 9Ni steel plates with different wall thicknesses, observe the weld formation, analyze the weld quality in combination with nondestructive testing and physical and chemical performance tests, and summarize the automatic TT welding process for the girth weld of 9Ni steel. According to the experimental research, this TT automatic welding process is fully applicable to the girth weld of 9Ni steel plate, and the weld formation is good, the joint performance is excellent, and each index is higher than the standard requirements. It can effectively improve the welding quality of LNG tank, greatly reduce the consumption of welding materials, and reduce the workload, so as to save costs and control quality.关键词：LNG tank;9Ni steel;girth welding;TT welding;automatic GTAW
- 59
- |
- 18
- |
- 0
发布时间：2023-01-17
Welding Technology
- 摘要：The product is developed for users who have no re baking conditions before use or are unwilling to re bake and directly use acid stainless steel electrodes. The addition of appropriate fluoride and arc stabilizer is very beneficial to improve the arc stability and porosity sensitivity; the addition of marble in the coating can improve the anti porosity sensitivity of the weld and the vertical welding process performance; dewatering treatment of rutile and feldspar is conducive to improving the anti porosity sensitivity of weld. After 3 to 6 days and 50%~80% humidity accelerated moisture absorption, the developed electrode has better anti porosity sensitivity than the conventional acid stainless steel electrode. By comparing the arc stability, slag removal, arc re ignition, spatter rate, electrode coating anti redness, cracking and vertical welding process of the two kinds of electrodes, the welding process performance of the electrode without re drying is equivalent to that of the electrode requiring re drying. Through the contrast test of physical and chemical properties, the mechanical properties are close, the chemical composition is equivalent, and the results are excellent, which fully meet the requirements of standards and users.关键词：acid stainless steel electrode;no bake;porosity sensitivity;processability
- 58
- |
- 15
- |
- 0
发布时间：2023-01-17
Welding Material
- 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