Using a tractor repair welding of cast iron pieces, in addition to the actual situation the appropriate choice of welding methods, but also note the following items:
First, the pre-welding welding welding welding parts of the former should be in and around all harmful impurities such as rust, oil, paint, etc. thoroughly cleaned; welding cracks if the weldment thickness less than 25 mm in diameter should be drilled only about 4 mm hole; some weldment process but also according to the requirements of selected wall thickness and groove type and so on.
Second, the choice of electrode diameter and the different types of cast iron should be used in the corresponding electrode; primarily on the basis of its diameter at the welding weldments to determine the thickness; White and death in order to prevent the generation of the fire organization, reduce the heat-affected zone , the current use of small diameter electrodes.
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Third, the polarity of the DC arc chosen, in order to avoid the penetration is too large, overheating and burn weldment, are using reverse polarity connection, that weldments - then the cathode, the anode electrode connected.
Fourth, the current intensity of choice to increase the current penetration is too large, welded metal components and impurities to the weld pool changes the diffusion properties; current is too small to affect the stability of the arc, easy slag, porosity and other defects; current intensity selection should be based on cracks or defects in the welds steric conduction, taking also into account grades and electrode diameter.
V. welding operation points in order to reduce crack welding area should be avoided overheating, long cracks should be stopped, sub-stitch welding; to reduce penetration, should choose a small current, small electrodes, and as a short arc welding; for better welding of plastic such as nickel-based welding, metallurgy and welding, welding immediately after light tapping with a hammer round weld to weld stress relaxation, clear cracks and holes; not every small solder wave across the slope while on both sides, it is a good part of freedom of contract is not welding, and arc in the groove on both sides to avoid to stay too long; the bottom solder layer should cover the bottom of annealing, change to its processing performance.
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2011年9月13日星期二
2011年9月2日星期五
Petrochemical construction and efficient welding technology and the current situation
Visit to China National Petroleum Offshore Engineering Company Zhijian Senior Engineer
As competition intensifies, the prices of petroleum, petrochemical construction cycle is short and efficient welding technology, equipment and materials applications is the trend. But efficient welding technology, equipment and materials in petroleum, chemical construction applications, there are still many problems. The following combination of specific projects to talk about the efficient application of welding technology and practical needs, necessity and importance.
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First, the offshore oil project in the construction of large marine structures. The weight of large offshore oil steel, structure and size of offshore oil development with increasing water depth, marine structures has been increasing, the volume of structures and the use of the plate thickness is increasing. With the rise in steel prices and offshore structures, offshore installation capacity requirements, the application of high strength steel is also a large area using, so that you can reduce the amount of steel. Small marine structures using materials mostly 355MPa even lower intensity level of the material, large-scale structure of 420MPa steel for offshore platforms is increasing the use of proportion. In addition, with the plate thickness increases, bringing a large number of post weld heat treatment of the workload. For example, the offshore platform jacket of a 95mm, φ3750mm ring weld, using double-sided groove (groove depth of 1 / 3, outside the groove depth of 2 / 3), weld metal weight of nearly 271kg, so the use of efficient welding technology, equipment, welding technology and high-performance materials (eliminating weld annealing treatment) is inevitable. Solve the above problem, from two aspects: First, the use of efficient submerged arc welding, the waveform control technology, dual-wire submerged arc welding system (U.S. Lincoln's products); the other hand, high strength, high toughness welding material through the evaluation of weld toughness CTOD test, the abolition of annealing after welding, thus shortening the construction cycle of marine structures.
Secondly, a large LNG storage tank construction. Large LNG storage tank for the 9Ni steel base metal. The material in the welding parameters welding requires very strict, welding heat input is small, low-temperature layer, which doomed the welding of low efficiency. Therefore, LNG girth welding using submerged arc welding in the horizontal welding, and welding and the use of both sides of the same side welding backing forming welding submerged arc process, using AC square-wave high-efficiency submerged arc welding machine and other new technologies, can effectively improve the welding efficiency.
At present, China Petroleum and Chemical efficient welding technology gap with foreign countries than not, the new welding equipment, welding and welding materials in the same starting line. Because the current structure in the marine LNG storage projects and large-scale projects using welding equipment and welding materials are mostly imported, welding technology and welding auxiliary facilities with foreign companies is not much difference. But the most crucial question is: those in the field of welding equipment and welding materials and more dependent on imports, our own production equipment and welding materials can not meet the industry's production requirements, but also our welding equipment and welding materials businesses to work together.
Our company is an offshore steel construction companies, hope that China's welding business with foreign companies to develop a very technical level, even higher level of technology of welding equipment and welding materials, welding technology reduces the high dependence on foreign .
keywords: Aluminium Welding Wire, Nickel Welding Rod, Copper Alloy Welding Wire
As competition intensifies, the prices of petroleum, petrochemical construction cycle is short and efficient welding technology, equipment and materials applications is the trend. But efficient welding technology, equipment and materials in petroleum, chemical construction applications, there are still many problems. The following combination of specific projects to talk about the efficient application of welding technology and practical needs, necessity and importance.
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First, the offshore oil project in the construction of large marine structures. The weight of large offshore oil steel, structure and size of offshore oil development with increasing water depth, marine structures has been increasing, the volume of structures and the use of the plate thickness is increasing. With the rise in steel prices and offshore structures, offshore installation capacity requirements, the application of high strength steel is also a large area using, so that you can reduce the amount of steel. Small marine structures using materials mostly 355MPa even lower intensity level of the material, large-scale structure of 420MPa steel for offshore platforms is increasing the use of proportion. In addition, with the plate thickness increases, bringing a large number of post weld heat treatment of the workload. For example, the offshore platform jacket of a 95mm, φ3750mm ring weld, using double-sided groove (groove depth of 1 / 3, outside the groove depth of 2 / 3), weld metal weight of nearly 271kg, so the use of efficient welding technology, equipment, welding technology and high-performance materials (eliminating weld annealing treatment) is inevitable. Solve the above problem, from two aspects: First, the use of efficient submerged arc welding, the waveform control technology, dual-wire submerged arc welding system (U.S. Lincoln's products); the other hand, high strength, high toughness welding material through the evaluation of weld toughness CTOD test, the abolition of annealing after welding, thus shortening the construction cycle of marine structures.
Secondly, a large LNG storage tank construction. Large LNG storage tank for the 9Ni steel base metal. The material in the welding parameters welding requires very strict, welding heat input is small, low-temperature layer, which doomed the welding of low efficiency. Therefore, LNG girth welding using submerged arc welding in the horizontal welding, and welding and the use of both sides of the same side welding backing forming welding submerged arc process, using AC square-wave high-efficiency submerged arc welding machine and other new technologies, can effectively improve the welding efficiency.
At present, China Petroleum and Chemical efficient welding technology gap with foreign countries than not, the new welding equipment, welding and welding materials in the same starting line. Because the current structure in the marine LNG storage projects and large-scale projects using welding equipment and welding materials are mostly imported, welding technology and welding auxiliary facilities with foreign companies is not much difference. But the most crucial question is: those in the field of welding equipment and welding materials and more dependent on imports, our own production equipment and welding materials can not meet the industry's production requirements, but also our welding equipment and welding materials businesses to work together.
Our company is an offshore steel construction companies, hope that China's welding business with foreign companies to develop a very technical level, even higher level of technology of welding equipment and welding materials, welding technology reduces the high dependence on foreign .
keywords: Aluminium Welding Wire, Nickel Welding Rod, Copper Alloy Welding Wire
2011年8月22日星期一
Central Asia pipeline welding technology innovation break with traditional patterns
July 20, the reporter learned from the Pipeline Bureau, in the newly completed single-Central Asia pipeline project in the main welding, pipeline Bureau of innovative construction techniques, the use of "semi-automatic welding in welding +" technology to improve the welding speed; implementation of large-scale, integrated mechanized assembly-line nature of the construction unit to play large formation combat advantage, breaking the traditional mode of construction, creating a record number of pipe welding.
As of July 20, in Uzbekistan and Kazakhstan Pipeline Bureau has completed the A-line body welding 1040 km, B body welding line has completed 460 km in total of the two countries completed the main welding more than 1500 km, and created 800 million man-hours accident-free record.
Central Asian oil pipeline project is China's biggest ever international pipeline projects. The face of cross-border multi-national construction, the effective duration of only 200 days of difficulty, the pipeline Bureau of well-organized, scientific deployment, break through the traditional mode of construction, so that the whole project as planned steadily.
In the welding process, the pipe line construction on the Council in addition to the use of CRC automatic welding, the technical staff of the CRC also the world's fastest root welding technology and pipeline Bureau of the most skilled, semi-automatic welding technologies, in the traditional "cellulosic electrode + semi-automatic welding "process, based on the development of" semi-automatic welding in welding + "technology, welding is 1.5 times the original schedule, while reducing the labor intensity of 1.5 times and construction costs.
In project management, pipeline Bureau emphasized that the design, procurement and construction (EPC) closely co-ordinate arrangements, enhance communication, resource sharing, giving priority to efficiency, the three parties to the relative coordinate, implement EPC minimize costs, maximize efficiency; full use of pipeline Bureau construction advantages, the implementation of large-scale, comprehensive mechanization of assembly-line construction crew to play large formation combat advantage. From the measurement of pay, transport piping, welded topography detected by the recovery process 22 single integrated unit to complete the construction, reducing the working interface, improved work efficiency. Kazakh segment CRC Ma Jingyong automatic welding group, semi-automatic welding in welding + MA Wu welding units were created on 32 km and 28 km of pipeline welding a new record.
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In quality control, pipeline Bureau pioneered the domestic non-destructive testing team lead Ruha Wu countries, the power to make up for the lack of local sub. NDT speed up construction to ensure the smooth progress. March 24, Kazakh Pipeline Bureau, to obtain a non-destructive testing qualification, Kazakh Pipeline Bureau since its independence in non-destructive testing work legally, which is in the Kazakh foreign companies to obtain this qualification the first time in history.
Currently, A-line natural gas pipeline in Central Asia after the completion of the main welding, pipe work focused Bureau field station installation, plumbing and landscape restoration under the ditch, while efforts to accelerate the B line construction is scheduled to be completed end of September, Kazakhstan, the main section of Line B welding, ensure that this year November 15 and single production line through the end of next year.
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As of July 20, in Uzbekistan and Kazakhstan Pipeline Bureau has completed the A-line body welding 1040 km, B body welding line has completed 460 km in total of the two countries completed the main welding more than 1500 km, and created 800 million man-hours accident-free record.
Central Asian oil pipeline project is China's biggest ever international pipeline projects. The face of cross-border multi-national construction, the effective duration of only 200 days of difficulty, the pipeline Bureau of well-organized, scientific deployment, break through the traditional mode of construction, so that the whole project as planned steadily.
In the welding process, the pipe line construction on the Council in addition to the use of CRC automatic welding, the technical staff of the CRC also the world's fastest root welding technology and pipeline Bureau of the most skilled, semi-automatic welding technologies, in the traditional "cellulosic electrode + semi-automatic welding "process, based on the development of" semi-automatic welding in welding + "technology, welding is 1.5 times the original schedule, while reducing the labor intensity of 1.5 times and construction costs.
In project management, pipeline Bureau emphasized that the design, procurement and construction (EPC) closely co-ordinate arrangements, enhance communication, resource sharing, giving priority to efficiency, the three parties to the relative coordinate, implement EPC minimize costs, maximize efficiency; full use of pipeline Bureau construction advantages, the implementation of large-scale, comprehensive mechanization of assembly-line construction crew to play large formation combat advantage. From the measurement of pay, transport piping, welded topography detected by the recovery process 22 single integrated unit to complete the construction, reducing the working interface, improved work efficiency. Kazakh segment CRC Ma Jingyong automatic welding group, semi-automatic welding in welding + MA Wu welding units were created on 32 km and 28 km of pipeline welding a new record.
cast steel ball valves, industrial ball valve, ball valve manufacturers
In quality control, pipeline Bureau pioneered the domestic non-destructive testing team lead Ruha Wu countries, the power to make up for the lack of local sub. NDT speed up construction to ensure the smooth progress. March 24, Kazakh Pipeline Bureau, to obtain a non-destructive testing qualification, Kazakh Pipeline Bureau since its independence in non-destructive testing work legally, which is in the Kazakh foreign companies to obtain this qualification the first time in history.
Currently, A-line natural gas pipeline in Central Asia after the completion of the main welding, pipe work focused Bureau field station installation, plumbing and landscape restoration under the ditch, while efforts to accelerate the B line construction is scheduled to be completed end of September, Kazakhstan, the main section of Line B welding, ensure that this year November 15 and single production line through the end of next year.
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