Do you know what are the three methods of connecting spiral steel pipes? Let me briefly introduce them to you.
The spiral steel pipe is a strip of jointless hollow section. It can be used as a pipeline for transporting fluids such as oil, natural gas, natural gas, water, and some solid materials. The use of seamless steel pipe to manufacture ring parts can improve material utilization, simplify the manufacturing process, save materials and processing, such as rolling bearing rings, jack sets, etc., widely used in the manufacture of steel pipes.
The common connection method is welding, but in some projects, threaded connection, flange connection, socket connection, groove connection, etc. are often used.
First, welding and flange connection
Welding and flange connection belong to the traditional l-type spiral steel pipe connection method, which is far from meeting the market demand in terms of safety, sealing, cost space and repair efficiency.
Second, slotted pipe joints
The trough type pipe joint connection technology, also known as the clamp connection technology, has become the current liquid and gas pipeline connection technology. Although the technology is developed later in the country, it is rapidly favored by the domestic market due to its advanced technology. The application of the grooved pipe joint technology makes the complicated pipe connection process simple, fast and convenient. This is a major advancement in pipe joining technology. The groove connection makes the pipe connection operation simple, which is beneficial to construction safety, good system stability, convenient maintenance, time and labor saving, and therefore has good economic benefits. Use a clamped connection. Although the price of single pipe clamp fittings is higher, the overall efficiency of the entire pipe network installation is higher than that of the flange connection.
Third, the pinch joint
As an advanced pipe connection, the clamping pipe can be directly buried or buried, including steel joints and flexible joints. Therefore, it has a wide range of applications.
The above is the three methods that I want to summarize the connection of steel pipes, which can help everyone.
2019年6月19日星期三
What are the wall thicknesses of scaffolding steel pipes?
According to the "Safety Technical Specification for Building Construction Fastener Steel Pipe Scaffolding JGJ130-2011", the specification of the steel pipe of the scaffolding should be φ48.3×3.6, that is, the wall thickness is 3.6mm. Scaffolding for single gauge steel pipes. It uses only one type of steel pipe, such as fastener-type steel pipe scaffolding, and only uses 3.6mm electric welded steel pipe. Different types of construction use scaffolding and formwork brackets for different types of construction. At present, bridge support frames are mostly used for bowl buckle scaffolding, and door scaffolding is also used. Of course, this is the thickness of the more common scaffolding steel pipe, and other specifications of scaffolding can be used depending on the project.
Scaffolding steel pipes are classified according to centralized classification, and can be divided into: seamless steel pipes and seamed steel pipes, which are referred to as straight seam steel pipes, carbon pipes and alloy pipes, stainless steel pipes, and the like. The wall thickness of seamless steel tubes is: 2.146, 2.589, 2.885, 3.107, 3.477, 3.773, 3.995, 4.217, 4.476, 4.809 and so on. Scaffolding steel pipes are used not only in the manufacture of building structural grids, pillars and mechanical supports. It can be said that the steel pipe not only reduces the weight of the bracket, but also saves the building materials, and makes the construction more and more simple.
Scaffolding steel pipe wall thickness models have their own characteristics, each type of use has a standard calculation method for calculating the theoretical weight, such as the theoretical weight calculation formula of square rectangular steel pipe, weight per meter: kg / m (kg / m) & lb /ft (lbs/ft). The commonly used rectangular tube calculation formula is: (length and width) × 2 ÷ 3.14 - thickness × thickness × 0.02466 = kg / m. Therefore, in terms of purchase cost, this is also within the scope of use, based on the calculated weight to give pricing, as well as the use of scaffolding steel pipe has a certain weight comparison.
http://www.xysteelpipe.com/info/What-are-the-wall-thicknesses-of-scaffolding-steel-pipes-1436-1.htm
Scaffolding steel pipes are classified according to centralized classification, and can be divided into: seamless steel pipes and seamed steel pipes, which are referred to as straight seam steel pipes, carbon pipes and alloy pipes, stainless steel pipes, and the like. The wall thickness of seamless steel tubes is: 2.146, 2.589, 2.885, 3.107, 3.477, 3.773, 3.995, 4.217, 4.476, 4.809 and so on. Scaffolding steel pipes are used not only in the manufacture of building structural grids, pillars and mechanical supports. It can be said that the steel pipe not only reduces the weight of the bracket, but also saves the building materials, and makes the construction more and more simple.
Scaffolding steel pipe wall thickness models have their own characteristics, each type of use has a standard calculation method for calculating the theoretical weight, such as the theoretical weight calculation formula of square rectangular steel pipe, weight per meter: kg / m (kg / m) & lb /ft (lbs/ft). The commonly used rectangular tube calculation formula is: (length and width) × 2 ÷ 3.14 - thickness × thickness × 0.02466 = kg / m. Therefore, in terms of purchase cost, this is also within the scope of use, based on the calculated weight to give pricing, as well as the use of scaffolding steel pipe has a certain weight comparison.
http://www.xysteelpipe.com/info/What-are-the-wall-thicknesses-of-scaffolding-steel-pipes-1436-1.htm
2019年6月18日星期二
The most conventional nondestructive testing method
The most regular NDT methods are as follows:
Penetrant Testing:4xac
Penetrant solution is applied to pipe fittings or flanges cleaned surfaces.The liquid is pulled into cracks or defects by capillary action.Excess penetrant material is carefully cleaned from the surface.A developer is applied to pull the trapped penetrant material back to the surface where it is spread out and shows an indication.This indication is much easier to find than the crack or defect.
Magnetic Particle Testing
A magnetic field is established in a pipe fitting made from ferromagnetic material.The magnetic lines of force travel through,exit and reenter the material at the poles.Defects such as crack or voids cannot support as much flux,and force some of the flux outside of the part.Magnetic particles distributed over this pipe fitting will be attracted to areas of flux leakage and shows a visible indication.
Ultrasonic Testing
When the quality checker use a transducer to send the high frequency sound waves to a pipe fitting or flange. The waves travel through the product and are received by the same transducer or another one. The amount of energy transmitted or received and the time of the energy is received are analyzed to determine the presence of flaws. Changes in material thickness and properties could be measured too.
Eddy Current Testing
The Eddy current testing is used a lot as the NDT method for seamless steel pipes. Alternating electrical current is passed through a steel pipe producing a magnetic field. When the pipe is placed closed to a conductive material, the changing magnetic field induces current flow in the pipe. These currents travel in closed loops and are called eddy currents. Eddy currents produce their own magnetic field that can be measured and used to find flaws.
Radiographic Testing
Our QC team use RT to check the quality of welded seam. They put the radiation source and detector on the two sides of the seam, and use X-ray to produce images of welded seam from film or other detector that is sensitive to radiation. The thickness and density of the welded seam that X-rays must penetrate affects the amount of radiation reaching the detector. This variation in radiation produces an image on the detector that often shows internal features of the test seam.
MT inspection in steel piping industry
Magnetic Particle Inspection (MPI) could be used to test weld seams, steel pipe fittings and forgings for surface or subsurface defects. It is a important NDT (Non-destructive testing)method, similar with PT inspection,but it can only be used on ferromagnetic metals.Magnetic Particle is also known as MPI Magnetic Particle Inspection,magnetism checking.
Magnetic Particle is a fairly quick low-cost NDT method compared to others such as Ultrasonic testing, Eddy Current and X-Ray testing.The principle of Magnetic Particle testing is quite simple,the main concern is ensuring that the pipe fittings are adequate for the application. The inexperienced workers just need short time training for the MT inspection.
Most codes require magnetism coverage in two directions to cover 100% of the part. In order to achieve this you need to understand the equipment that you are using; as well as, the direction of the magnetic field, amperage and number of turns that you are using. If you do not know and are currently performing magnetic particle you are probably missing flaws during your inspections.
In our factory, quality checkers use the MT inspection on the pipe fittings especially the tees and reducers which are likely to bring some cracks and defects on the surface. Except the forming, heat treatment and MT inspection is necessary steps in the production.
PT (Penetrant testing ) inspection in steel piping industry
Penetrant testing is a very important and popular inspection method in steel pipe fittings and flanges production.
The steel pipe fittings and flanges are mostly produced by forming method which could have some cracks or defects in production.Suitable heat treatment should be done for such shape forming,but it may still have some cracks or defects.Then the PT inspection is necessary for quality checking, before the checking,QC have to do some proper cleaning and assure that surface contaminants have been removed and the surface is clean and dry.
Penetrant Testing:4xac
Penetrant solution is applied to pipe fittings or flanges cleaned surfaces.The liquid is pulled into cracks or defects by capillary action.Excess penetrant material is carefully cleaned from the surface.A developer is applied to pull the trapped penetrant material back to the surface where it is spread out and shows an indication.This indication is much easier to find than the crack or defect.
Magnetic Particle Testing
A magnetic field is established in a pipe fitting made from ferromagnetic material.The magnetic lines of force travel through,exit and reenter the material at the poles.Defects such as crack or voids cannot support as much flux,and force some of the flux outside of the part.Magnetic particles distributed over this pipe fitting will be attracted to areas of flux leakage and shows a visible indication.
Ultrasonic Testing
When the quality checker use a transducer to send the high frequency sound waves to a pipe fitting or flange. The waves travel through the product and are received by the same transducer or another one. The amount of energy transmitted or received and the time of the energy is received are analyzed to determine the presence of flaws. Changes in material thickness and properties could be measured too.
Eddy Current Testing
The Eddy current testing is used a lot as the NDT method for seamless steel pipes. Alternating electrical current is passed through a steel pipe producing a magnetic field. When the pipe is placed closed to a conductive material, the changing magnetic field induces current flow in the pipe. These currents travel in closed loops and are called eddy currents. Eddy currents produce their own magnetic field that can be measured and used to find flaws.
Radiographic Testing
Our QC team use RT to check the quality of welded seam. They put the radiation source and detector on the two sides of the seam, and use X-ray to produce images of welded seam from film or other detector that is sensitive to radiation. The thickness and density of the welded seam that X-rays must penetrate affects the amount of radiation reaching the detector. This variation in radiation produces an image on the detector that often shows internal features of the test seam.
MT inspection in steel piping industry
Magnetic Particle Inspection (MPI) could be used to test weld seams, steel pipe fittings and forgings for surface or subsurface defects. It is a important NDT (Non-destructive testing)method, similar with PT inspection,but it can only be used on ferromagnetic metals.Magnetic Particle is also known as MPI Magnetic Particle Inspection,magnetism checking.
Magnetic Particle is a fairly quick low-cost NDT method compared to others such as Ultrasonic testing, Eddy Current and X-Ray testing.The principle of Magnetic Particle testing is quite simple,the main concern is ensuring that the pipe fittings are adequate for the application. The inexperienced workers just need short time training for the MT inspection.
Most codes require magnetism coverage in two directions to cover 100% of the part. In order to achieve this you need to understand the equipment that you are using; as well as, the direction of the magnetic field, amperage and number of turns that you are using. If you do not know and are currently performing magnetic particle you are probably missing flaws during your inspections.
In our factory, quality checkers use the MT inspection on the pipe fittings especially the tees and reducers which are likely to bring some cracks and defects on the surface. Except the forming, heat treatment and MT inspection is necessary steps in the production.
PT (Penetrant testing ) inspection in steel piping industry
Penetrant testing is a very important and popular inspection method in steel pipe fittings and flanges production.
The steel pipe fittings and flanges are mostly produced by forming method which could have some cracks or defects in production.Suitable heat treatment should be done for such shape forming,but it may still have some cracks or defects.Then the PT inspection is necessary for quality checking, before the checking,QC have to do some proper cleaning and assure that surface contaminants have been removed and the surface is clean and dry.
Classification of carbon steel pipes
Classified by Production Methods
1.Seamless Steel Pipe- hot rolled seamless steel pipe, cold rolled seamless steel pipe, cold drawn seamless steel pipe
2. Welded Steel Pipe - longitudinal welded pipe, spiral welded pipe, electric resistance welded pipe
Classified by Cross-sectional Shape
1. Simple section steel pipe - round carbon steel pipe, square carbon steel pipe, rectangular carbon steel pipe, oval carbon steel pipe ect.
2. Complex section steel pipe - hexagonal carbon steel pipe with unequal edge, five plum shaped carbon steel pipe, double convex carbon stee pipe, double concave carbon steel pipe ect.
Classified by Wall Thickness
1. Thin walled carbon steel pipe
2. Thick walled carbon steel pipe
Classified by the Application
Carbon steel pipe can be used for thermal equipment, machinery industrial pipe, oil line pipe, geological drilling steel pipe, container steel pipe, chemical industry steel pipe, and other special purpose steel pipe.
1.Seamless Steel Pipe- hot rolled seamless steel pipe, cold rolled seamless steel pipe, cold drawn seamless steel pipe
2. Welded Steel Pipe - longitudinal welded pipe, spiral welded pipe, electric resistance welded pipe
Classified by Cross-sectional Shape
1. Simple section steel pipe - round carbon steel pipe, square carbon steel pipe, rectangular carbon steel pipe, oval carbon steel pipe ect.
2. Complex section steel pipe - hexagonal carbon steel pipe with unequal edge, five plum shaped carbon steel pipe, double convex carbon stee pipe, double concave carbon steel pipe ect.
Classified by Wall Thickness
1. Thin walled carbon steel pipe
2. Thick walled carbon steel pipe
Classified by the Application
Carbon steel pipe can be used for thermal equipment, machinery industrial pipe, oil line pipe, geological drilling steel pipe, container steel pipe, chemical industry steel pipe, and other special purpose steel pipe.
Carbon Steel Alloy-ASTM A53
ASTM A53 is a carbon steel alloy,used as structural steel or for low-pressure plumbing.The alloy specifications are set by ASTM international,in specifications ASTM A53/A53M.
A53 pipe comes in three types and two grades,A53 Type F,which is longitudinally furnace butt welded or continuous welded(Grade A only),A53 Type E，which is longitudinally electric resistance welded(Grades A and B)，and A53 Type S,which is seamless pipe,produced by hot working,and possibly cold finishing,the steel(Grade A and B).ASTM A53 pipe is sized according to the nominal pipe size(NPS)system.It is commonly available with national pipe thread ends or with plain cut ends.It can be used for steam,water,and air conveyance.It is also weldable and can be used in structural application,although ASTM A500 tube,which is available in the same NPS
Sizes,is sometime preferred.
This is a standard set by the standards organization ASTM international,a voluntary standards development organizations that sets technical standards for materials,products,systems,and service.
A53 pipe comes in three types and two grades,A53 Type F,which is longitudinally furnace butt welded or continuous welded(Grade A only),A53 Type E，which is longitudinally electric resistance welded(Grades A and B)，and A53 Type S,which is seamless pipe,produced by hot working,and possibly cold finishing,the steel(Grade A and B).ASTM A53 pipe is sized according to the nominal pipe size(NPS)system.It is commonly available with national pipe thread ends or with plain cut ends.It can be used for steam,water,and air conveyance.It is also weldable and can be used in structural application,although ASTM A500 tube,which is available in the same NPS
Sizes,is sometime preferred.
This is a standard set by the standards organization ASTM international,a voluntary standards development organizations that sets technical standards for materials,products,systems,and service.
2019年6月10日星期一
Characteristics of straight seam and spiral seam welding of large diameter steel pipe
Straight seam welding of large diameter steel pipes is produced from steel plates, while spiral welding of large diameter steel pipes is produced by hot rolled coils. The rolling process of the hot strip mill has a series of advantages, and has the metallurgical process capability for producing high quality pipeline steel. For example, a water cooling system is installed on the output gantry to accelerate cooling, which allows the use of low alloying compositions to achieve special strength levels and low temperature toughness, thereby improving the weldability of the steel. However, this system is basically not available in steel plate production plants.
The alloy content (carbon equivalent) of the coiled sheet is often lower than that of similar grades, which also improves the weldability of the spiral weld of large diameter steel pipes. Since the rolling direction of the spiral welded coil is not the direction of the vertical steel pipe axis (the pinching depends on the helix angle of the steel pipe), and the rolling direction of the straight seam welded steel plate is perpendicular to the axial direction of the steel pipe, the crack resistance of the spiral welded material Better than straight seam welding.
The magnetic flaw detection of straight seam welding can only find the defects of the surface and near surface of the magnetic Q235B straight seam submerged arc welded pipe, and only the quantitative analysis can be done for the defect. The nature and depth of the defect can only be estimated based on experience. The magnetic test is to find the defects by magnetic flux magnetization of the ferromagnetic Q235B straight seam welded pipe. According to the method of measuring magnetic flux leakage, it can be divided into magnetic powder method, magnetic induction method and magnetic recording method, among which magnetic powder method is the most widely used. The penetration test of spiral welding is to discover and display defects by using physical properties such as permeability of certain liquids, including coloring test and fluorescent flaw detection, which can be used to check defects on the surface of ferromagnetic and non-ferromagnetic materials.
The alloy content (carbon equivalent) of the coiled sheet is often lower than that of similar grades, which also improves the weldability of the spiral weld of large diameter steel pipes. Since the rolling direction of the spiral welded coil is not the direction of the vertical steel pipe axis (the pinching depends on the helix angle of the steel pipe), and the rolling direction of the straight seam welded steel plate is perpendicular to the axial direction of the steel pipe, the crack resistance of the spiral welded material Better than straight seam welding.
The magnetic flaw detection of straight seam welding can only find the defects of the surface and near surface of the magnetic Q235B straight seam submerged arc welded pipe, and only the quantitative analysis can be done for the defect. The nature and depth of the defect can only be estimated based on experience. The magnetic test is to find the defects by magnetic flux magnetization of the ferromagnetic Q235B straight seam welded pipe. According to the method of measuring magnetic flux leakage, it can be divided into magnetic powder method, magnetic induction method and magnetic recording method, among which magnetic powder method is the most widely used. The penetration test of spiral welding is to discover and display defects by using physical properties such as permeability of certain liquids, including coloring test and fluorescent flaw detection, which can be used to check defects on the surface of ferromagnetic and non-ferromagnetic materials.
Hot dip galvanized pipe and cold galvanized pipe
The hot-dip galvanized steel tube is obtained by reacting a molten metal with an iron matrix to produce an alloy layer, thereby combining the substrate and the plating layer. Hot-dip galvanizing is the first step of pickling the steel pipe in order to remove the iron oxide on the surface of the steel pipe. After pickling, it is washed by an aqueous solution of ammonium chloride or zinc chloride or a mixed aqueous solution of ammonium chloride and zinc chloride, and then sent to a hot dip plating bath. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life. The hot-dip galvanized steel pipe base and the molten plating solution are complex physical and chemical anti-galvanized steel pipes, and a corrosion-resistant structure of zinc-iron alloy layer is formed. The alloy layer is integrated with the pure zinc layer and the steel pipe base. Therefore, its corrosion resistance is strong.
The cold-galvanized steel pipe is electro-galvanized, with a small amount of galvanizing, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip galvanized pipe. In order to ensure quality, most of the regular galvanized pipe manufacturers do not use electro-galvanizing (cold plating). Only small companies with small equipment and old equipment use electro-galvanized steel, of course, their prices are relatively cheaper. At present, the Ministry of Construction has officially laid down the cold-galvanized pipe with backward technology, and the cold-galvanized pipe is not allowed to be used as water and gas pipe in the future. The galvanized layer of the cold-galvanized steel pipe is an electroplated layer, and the zinc layer and the steel pipe base are separately layered. The zinc layer is thin, and the zinc layer is simply attached to the steel pipe base and is easy to fall off. Therefore, its corrosion resistance is poor. In new homes, the use of cold-galvanized steel pipes as water supply pipes is prohibited.
http://www.xysteelpipe.com/info/Hot-dip-galvanized-pipe-and-cold-galvanized-pipe-1426-1.htm
The cold-galvanized steel pipe is electro-galvanized, with a small amount of galvanizing, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip galvanized pipe. In order to ensure quality, most of the regular galvanized pipe manufacturers do not use electro-galvanizing (cold plating). Only small companies with small equipment and old equipment use electro-galvanized steel, of course, their prices are relatively cheaper. At present, the Ministry of Construction has officially laid down the cold-galvanized pipe with backward technology, and the cold-galvanized pipe is not allowed to be used as water and gas pipe in the future. The galvanized layer of the cold-galvanized steel pipe is an electroplated layer, and the zinc layer and the steel pipe base are separately layered. The zinc layer is thin, and the zinc layer is simply attached to the steel pipe base and is easy to fall off. Therefore, its corrosion resistance is poor. In new homes, the use of cold-galvanized steel pipes as water supply pipes is prohibited.
http://www.xysteelpipe.com/info/Hot-dip-galvanized-pipe-and-cold-galvanized-pipe-1426-1.htm
2019年6月6日星期四
Weld hole prevention measures
It is well known that there are many types of welded steel pipes. There are always seamless steel pipes and straight seam steel pipes(LSAW), while straight seam steel pipes have weld seams, and weld seams will produce pores under certain conditions. Generally the factors causing the pores in the weld are: moisture, dirt, scale and iron filings in the flux, welding composition and thickness, steel surface quality and steel edge treatment, welding process and steel tube forming process. The weld hole of the welded pipe not only affects the tightness of the pipe weld, but also causes the pipe to leak, and it will become the induction point of corrosion, which seriously reduces the weld strength and toughness.
Steel surface treatment: in order to avoid the inclusion of iron oxide and other impurities in the unwinding and unwinding, a plate cleaning device should be provided.
Steel sheet edge treatment: rust and burr removal devices should be installed on the side of the steel plate to reduce the possibility of generating air holes. The position of the cleaning device is preferably installed after the edge milling machine and the disc cutter. The structure of the device is a movable wire wheel with two adjustable positions on one side, and the upper and lower sides of the plate are pressed.
Weld appearance: the forming coefficient of the weld is too small, the shape of the weld is narrow and deep, and the gas and inclusions do not easily float out, and the pores and slag are easily formed. Generally, the weld bead forming coefficient is controlled at 1.3-1.5, the thick-walled welded pipe takes the maximum value, and the thin-walled pipe takes the minimum value.
Reduce the secondary magnetic field: in order to reduce the influence of magnetic partial blow, the connection position of the welding cable on the workpiece should be kept away from the welding terminal only, and the partial welding magnetic cable can be prevented from generating a secondary magnetic field on the workpiece.
Process aspect: the welding speed or current should be appropriately reduced to delay the crystallization rate of the weld pool metal to facilitate gas escape. At the same time, if the strip delivery position is unstable, adjustment should be made in time to prevent fine adjustment of the front axle or rear. The bridge remains shaped, causing gas to escape.
Flux composition: when the solder contains an appropriate amount of CaF2 and SiO2, it absorbs a large amount of H2 and generates HF which is highly stable and insoluble in the liquid metal, thereby preventing the formation of hydrogen pores. The deposition thickness of the flux is generally 25-45mm, the flux particle size is large, the density is small, the stacking thickness takes the maximum value, and the minimum value is taken; the large current, the low welding speed stacking thickness takes the maximum value, and the minimum value, in addition, the summer or the air When the humidity is high, the recovered flux should be dried before use.
http://www.xysteelpipe.com/info/Weld-hole-prevention-measures-1425-1.htm
Steel surface treatment: in order to avoid the inclusion of iron oxide and other impurities in the unwinding and unwinding, a plate cleaning device should be provided.
Steel sheet edge treatment: rust and burr removal devices should be installed on the side of the steel plate to reduce the possibility of generating air holes. The position of the cleaning device is preferably installed after the edge milling machine and the disc cutter. The structure of the device is a movable wire wheel with two adjustable positions on one side, and the upper and lower sides of the plate are pressed.
Weld appearance: the forming coefficient of the weld is too small, the shape of the weld is narrow and deep, and the gas and inclusions do not easily float out, and the pores and slag are easily formed. Generally, the weld bead forming coefficient is controlled at 1.3-1.5, the thick-walled welded pipe takes the maximum value, and the thin-walled pipe takes the minimum value.
Reduce the secondary magnetic field: in order to reduce the influence of magnetic partial blow, the connection position of the welding cable on the workpiece should be kept away from the welding terminal only, and the partial welding magnetic cable can be prevented from generating a secondary magnetic field on the workpiece.
Process aspect: the welding speed or current should be appropriately reduced to delay the crystallization rate of the weld pool metal to facilitate gas escape. At the same time, if the strip delivery position is unstable, adjustment should be made in time to prevent fine adjustment of the front axle or rear. The bridge remains shaped, causing gas to escape.
Flux composition: when the solder contains an appropriate amount of CaF2 and SiO2, it absorbs a large amount of H2 and generates HF which is highly stable and insoluble in the liquid metal, thereby preventing the formation of hydrogen pores. The deposition thickness of the flux is generally 25-45mm, the flux particle size is large, the density is small, the stacking thickness takes the maximum value, and the minimum value is taken; the large current, the low welding speed stacking thickness takes the maximum value, and the minimum value, in addition, the summer or the air When the humidity is high, the recovered flux should be dried before use.
http://www.xysteelpipe.com/info/Weld-hole-prevention-measures-1425-1.htm
2019年6月4日星期二
Welded steel pipe defect
Welded steel pipe production process is a steel sheet,strip,and other various molding methods using the straight press roll helical direction curling into a desired cross-sectional shape,and then by means of heart,prssure,different methods of welding weld weld together to obtain steel.Therefore,defects in the welded steel pipe is divided into two parts:the steel base material defects and weld defects.
1.Steel base material defect
The sheet material defects after rolling and other processes,most of planar,parallel to the surface;their main weakness delamination,cracks,folds,etc.,which is the most common layered internal defects.Stratification will produce a variety of cracks when the tensile stress perpendicular to the surface of the sheet by the hierarchical will seriously affect the strength of the steel pipe,it is not allowed defects.
2.Weld defects
Weld defects refers to defect during welding or after welding resulting in the weld is divided into cracks,proes,slag,incomplete penetration,incomplete fusion,undercut weld defects.Intensive weld porosity,slag,etc.a dense three-dimensional defects,cracks,lack of fusion and other defects in the case of the flat,great harm.Strip slag.
1.Steel base material defect
The sheet material defects after rolling and other processes,most of planar,parallel to the surface;their main weakness delamination,cracks,folds,etc.,which is the most common layered internal defects.Stratification will produce a variety of cracks when the tensile stress perpendicular to the surface of the sheet by the hierarchical will seriously affect the strength of the steel pipe,it is not allowed defects.
2.Weld defects
Weld defects refers to defect during welding or after welding resulting in the weld is divided into cracks,proes,slag,incomplete penetration,incomplete fusion,undercut weld defects.Intensive weld porosity,slag,etc.a dense three-dimensional defects,cracks,lack of fusion and other defects in the case of the flat,great harm.Strip slag.
Belt And Road impact on steel industry
Shinestar Steel Research Institute believes that China's era of rapid economic growth has gone for ever, which makes the steel industry has experienced the middle adjustment pains low growth in the past five years, and future growth continued to slow down will become an indisputable fact.Therefore, the hope of the future development lies in the discovery of new growth momentum of China's economy, growth support points.
The layout of the new strategic space needs to be realized through specific economic activities.The infrastructure Belt and Road in the background are beyond the borders, has a broad space for regional infrastructure, China international, along the way will undoubtedly open the human history one of the most magnificent level intercontinental infrastructure construction stage, so large-scale construction will bring a variety of new demand.In Southeast Asia and even greater Eurasian space, China's infrastructure is beginning to show a new development context.If the infrastructure in China's iron and steel, with China's high-speed development, the layout, it needs to how much demand for iron and steel?If China cannot meet the demand for steel who can fill the gap?Does this mean for China's iron and steel, a huge new demand.Shinestar Steel Research Institute believes that the infrastructure is just a part of it, we must rely on infrastructure integration production capacity and transfer, there must be more to promote trade exchanges, including a solid pace of internationalization of the RMB, along the way of opening a new era, brought far beyond our imagination.
9.6 million km of land in China,the adjustment of regional economic structure is also in the rapid advance of the steel industry in the study of the market structure of the need to pay attention to this point.Among them, in particular is the integration of the beijing-tianjin-hebei region development.As a key sector of regional development,
integration of the beijing-tianjin-hebei region is currently building in Beijing as the starting point of the radial transport system.Such a structure up, how much need to build, how much of the iron and steel, how much investment, will get the number of growth, are obvious.Shinestar steel group last year to put into operation in Tianjin production base, is based in Tianjin, radiation global manufacturing platform, high frequency ERW pipe's production of LSAW pipe, SSAW steel pipe, seamless steel pipe and other quality products, is constantly to meet customer demand.
Infrastructure of the formation of the region to accelerate the development of the region's capacity to re layout.Now, we can see the layout of coastal heavy chemical industries include iron and steel, is rapidly formed a pattern in Tangshan, Tianjin as the representative of the heavy, especially the rise of manufacturing industry circle, and Beijing to the two wings extending in the modern industry.These changes in the development of Beijing, Tianjin and Hebei, it means that a non limited prospects, it will undoubtedly bring great demand, these are worth the steel industry to think.
The future, shinestar will grasp the macro economic development opportunities, innovative production technology, continue to produce high frequency ERW pipe, LSAW pipe, SSAW steel pipe, seamless steel pipe and other high-quality products, to enhance the market competitiveness of continuous efforts.
The layout of the new strategic space needs to be realized through specific economic activities.The infrastructure Belt and Road in the background are beyond the borders, has a broad space for regional infrastructure, China international, along the way will undoubtedly open the human history one of the most magnificent level intercontinental infrastructure construction stage, so large-scale construction will bring a variety of new demand.In Southeast Asia and even greater Eurasian space, China's infrastructure is beginning to show a new development context.If the infrastructure in China's iron and steel, with China's high-speed development, the layout, it needs to how much demand for iron and steel?If China cannot meet the demand for steel who can fill the gap?Does this mean for China's iron and steel, a huge new demand.Shinestar Steel Research Institute believes that the infrastructure is just a part of it, we must rely on infrastructure integration production capacity and transfer, there must be more to promote trade exchanges, including a solid pace of internationalization of the RMB, along the way of opening a new era, brought far beyond our imagination.
9.6 million km of land in China,the adjustment of regional economic structure is also in the rapid advance of the steel industry in the study of the market structure of the need to pay attention to this point.Among them, in particular is the integration of the beijing-tianjin-hebei region development.As a key sector of regional development,
integration of the beijing-tianjin-hebei region is currently building in Beijing as the starting point of the radial transport system.Such a structure up, how much need to build, how much of the iron and steel, how much investment, will get the number of growth, are obvious.Shinestar steel group last year to put into operation in Tianjin production base, is based in Tianjin, radiation global manufacturing platform, high frequency ERW pipe's production of LSAW pipe, SSAW steel pipe, seamless steel pipe and other quality products, is constantly to meet customer demand.
Infrastructure of the formation of the region to accelerate the development of the region's capacity to re layout.Now, we can see the layout of coastal heavy chemical industries include iron and steel, is rapidly formed a pattern in Tangshan, Tianjin as the representative of the heavy, especially the rise of manufacturing industry circle, and Beijing to the two wings extending in the modern industry.These changes in the development of Beijing, Tianjin and Hebei, it means that a non limited prospects, it will undoubtedly bring great demand, these are worth the steel industry to think.
The future, shinestar will grasp the macro economic development opportunities, innovative production technology, continue to produce high frequency ERW pipe, LSAW pipe, SSAW steel pipe, seamless steel pipe and other high-quality products, to enhance the market competitiveness of continuous efforts.
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