When the hydraulic test of the erw steel pipe is carried out, it is often found that the bursting opening is cracked from the weld of the erw steel pipe, which indicates that the strength of the welded portion is lower than that of the base metal. Through experimental analysis, it is found that if an internal scraping groove is formed on the inner surface of the steel pipe during the removal of the burr in the weld, the wall thickness of the sample at the weld bead is reduced, and the sample is easily broken from the tensile test.
The water pressure test of the water supply pipeline is the means for the final quality assessment of the erw steel pipe laying. Generally, there are two main requirements for the hydraulic pressure test: one is that it can correctly reflect the leakage of the pipeline; the other is the pressure test. No problem, nor can the interface be damaged due to pressure test, but it will affect the quality of the project, or retry the work, resulting in waste, and can not cause personal safety accidents.
In addition, when the weld tensile test is carried out in accordance with APISPEC 5L, it is often the case that the remaining height of the weld is removed or retained, and the weld is often broken. This indicates that the strength of the weld of the erw steel pipe is lower than that of the base metal. There are two reasons for the analysis: one is that the strength of the weld portion of the erw steel pipe is lower than that of the base material; the other is the scraping on the inner surface of the steel pipe when the burr in the weld is removed.
The groove or the residual burr causes the transition of the weld portion and the base material to be unreasonable, resulting in stress concentration, so that the overall structural strength of the weld portion is lower than that of the base material portion. Therefore, the transition shape of the weld portion of the ERW welded pipe and the base metal should be optimized to ensure the overall quality of the steel pipe. The hydraulic pressure test is not necessarily 1.5 times of the design pressure. For details, please refer to GB50235-2011 Industrial Metal Pipeline Construction Specification or TSG-D0001 Pressure Pipe Safety Technology Supervision Regulations - Pressure Pipeline Standard.
http://www.xysteelpipe.com/info/Precautions-for-ERW-steel-pipe-when-testing-water-pressure-1229-1.htm
2018年7月24日星期二
Pipeline insulation joint welding technology
Pipe insulation at the interface should be preceded by repair welding mouth, gouging, bevel angle pipe end to end face, blunt edge, gap, should meet the following requirements;clip can not help strip welding or heating counterparts gap narrowing gap welding.
Counterpart pipe insulation should be flush with the inner wall, 300mm long straightedge should be used in order around the inner wall abutting the interface, the wrong port of tolerance should be 0.2 times the wall thickness, and no greater than 2mm.
When the counterpart of the weld location should meet the following requirements: a straight pipe from the upper section of the center plane between the two butt weld, nominal diameter greater than or equal to 150mm, not less than 150mm, when the nominal diameter less than 150mm, should not be smaller than the outer tube path. The pipe should;be measured from the interface center counterparts at 200mm flatness, when the pipe when the nominal diameter of less than 100mm, tolerance of 1mm, when nominal pipe diameter greater than or equal to 100mm, tolerance is 2mm. But the full-length to allow deviation 10mm.
On opening pipe insulation should meet the following requirements: Do not dry tube longitudinal weld ring opening to; any position on the pipeline shall prescribe hole; the pipe,section or may not be on the tube openings; straight pipe length should not be used less than 800mm short section of stitching.
Check www.tjxysteel.com for more info
Counterpart pipe insulation should be flush with the inner wall, 300mm long straightedge should be used in order around the inner wall abutting the interface, the wrong port of tolerance should be 0.2 times the wall thickness, and no greater than 2mm.
When the counterpart of the weld location should meet the following requirements: a straight pipe from the upper section of the center plane between the two butt weld, nominal diameter greater than or equal to 150mm, not less than 150mm, when the nominal diameter less than 150mm, should not be smaller than the outer tube path. The pipe should;be measured from the interface center counterparts at 200mm flatness, when the pipe when the nominal diameter of less than 100mm, tolerance of 1mm, when nominal pipe diameter greater than or equal to 100mm, tolerance is 2mm. But the full-length to allow deviation 10mm.
On opening pipe insulation should meet the following requirements: Do not dry tube longitudinal weld ring opening to; any position on the pipeline shall prescribe hole; the pipe,section or may not be on the tube openings; straight pipe length should not be used less than 800mm short section of stitching.
Check www.tjxysteel.com for more info
Thick-walled Spiral Pipe Steel Grades
In the pipeline pressure ratio is also gradually reduced.Optimized calculation, comparison and selection of diameter, pressure and pressure ratio requirements.When determining the amount of input, determine the diameter, pressure, pressure ratio by optimizing the future, such as selecting a higher pressure steel strength grade is too low, it will cause excessive wall thickness, which gives the pipe, site welding and transportation links with many other be difficult, or even difficult to achieve.
Now more choice of fluid pipes thick-walled spiral pipe, pipeline delivery pressure medium is gradually increased in recent years, especially in the gas pipeline online. This is because in a certain range to improve the delivery pressure will increase economic efficiency, to pipe gas pipeline, for example, in the same amount of input conditions, increases the density of the gas delivery pressure and increase the flow rate is reduced, so that the friction resistance decreased.
Production needs to promote the improvement of the steel grade. The so-called pressure ratio refers to the ratio of inbound and outbound pressure pressure, the pressure ratio across the board reduction means are operating at a higher pressure, so that power consumption can also be reduced. Early pressure is more than 1.6, and later fell to 1.4 in recent years, some foreign gas pipeline to take pressure ratio was 1.25. Of course, the pressure ratio decreases, the number of compressor stations to increase, so that investment will increase.
Now more choice of fluid pipes thick-walled spiral pipe, pipeline delivery pressure medium is gradually increased in recent years, especially in the gas pipeline online. This is because in a certain range to improve the delivery pressure will increase economic efficiency, to pipe gas pipeline, for example, in the same amount of input conditions, increases the density of the gas delivery pressure and increase the flow rate is reduced, so that the friction resistance decreased.
Production needs to promote the improvement of the steel grade. The so-called pressure ratio refers to the ratio of inbound and outbound pressure pressure, the pressure ratio across the board reduction means are operating at a higher pressure, so that power consumption can also be reduced. Early pressure is more than 1.6, and later fell to 1.4 in recent years, some foreign gas pipeline to take pressure ratio was 1.25. Of course, the pressure ratio decreases, the number of compressor stations to increase, so that investment will increase.
How to polish seamless steel tubes
Polishing methods of seamless steel tubes are as follows:
1. Mechanical polishing
The advantage is that the parts are smooth and the brightness is high after processing. The disadvantage is that the intensity of labor is too great, resulting in serious pollution, and can not process complex parts, the gloss can not be consistent, the holding time is not long, mechanical polishing is suitable for processing simple parts, and small and medium parts.
2. Chemical polishing
A little bit is investment equipment, complex parts can be polished, fast, high efficiency, good corrosion resistance, the disadvantage is poor light, need ventilation equipment, heating difficulties. Suitable for small batches of complex parts and small parts that do not require high brightness.
3. Electrochemical polishing
The advantage is that the specular gloss is kept long, the process is stable, the cost is low, and the anti-corrosion is disadvantaged. The disadvantage is that the equipment has a large investment at one time, the complicated parts have to be tooled, and the auxiliary electrode is mass-produced, and the cooling device is needed. Suitable for mass production, mainly used in high-grade products, export products, tolerance products, stable processing technology and simple operation.
http://www.xysteelpipe.com/info/How-to-polish-seamless-steel-tubes-1224-1.htm
1. Mechanical polishing
The advantage is that the parts are smooth and the brightness is high after processing. The disadvantage is that the intensity of labor is too great, resulting in serious pollution, and can not process complex parts, the gloss can not be consistent, the holding time is not long, mechanical polishing is suitable for processing simple parts, and small and medium parts.
2. Chemical polishing
A little bit is investment equipment, complex parts can be polished, fast, high efficiency, good corrosion resistance, the disadvantage is poor light, need ventilation equipment, heating difficulties. Suitable for small batches of complex parts and small parts that do not require high brightness.
3. Electrochemical polishing
The advantage is that the specular gloss is kept long, the process is stable, the cost is low, and the anti-corrosion is disadvantaged. The disadvantage is that the equipment has a large investment at one time, the complicated parts have to be tooled, and the auxiliary electrode is mass-produced, and the cooling device is needed. Suitable for mass production, mainly used in high-grade products, export products, tolerance products, stable processing technology and simple operation.
http://www.xysteelpipe.com/info/How-to-polish-seamless-steel-tubes-1224-1.htm
2018年7月12日星期四
Specification and welding point of high frequency welded pipe
The welding of high-frequency welded pipes is a new welding process that uses the skin effect and adjacent effect generated by high-frequency current to connect steel plates with other metal materials.
The emergence and maturity of high-frequency welding technology has directly promoted the tremendous development of the straight seam welded pipe industry. It is a key process for the production of straight seam welded pipe.
The quality of high-frequency welding directly affects the overall strength, quality grade and production speed of welded pipe products. High-frequency welded pipe generally refers to high-frequency straight-slit electric resistance welded steel pipe (ERW). After the hot-rolled coil is formed by the forming machine, the skin effect and the proximity effect of the high-frequency current are used to heat and melt the edge of the tube blank under the action of the squeeze roller. Pressure welding is used to achieve production.
The high-frequency resistance welded steel pipe is different from the ordinary welded pipe welding process. The weld is formed by melting the base material of the steel strip body, and the mechanical strength is better than that of the general welded pipe.
The high-frequency welded pipe has smooth appearance, high precision, low cost and low weld seam height, which is beneficial to the coating of 3PE anti-corrosion coating. The welding method of high-frequency welded steel pipe and submerged arc welded pipe is significantly different. Since the welding is completed instantaneously at high speed, the difficulty in ensuring the welding quality is much higher than that in the submerged arc welding method.
http://www.xysteelpipe.com/info/Specification-and-welding-point-of-high-frequency-welded-pipe-1199-1.htm
The emergence and maturity of high-frequency welding technology has directly promoted the tremendous development of the straight seam welded pipe industry. It is a key process for the production of straight seam welded pipe.
The quality of high-frequency welding directly affects the overall strength, quality grade and production speed of welded pipe products. High-frequency welded pipe generally refers to high-frequency straight-slit electric resistance welded steel pipe (ERW). After the hot-rolled coil is formed by the forming machine, the skin effect and the proximity effect of the high-frequency current are used to heat and melt the edge of the tube blank under the action of the squeeze roller. Pressure welding is used to achieve production.
The high-frequency resistance welded steel pipe is different from the ordinary welded pipe welding process. The weld is formed by melting the base material of the steel strip body, and the mechanical strength is better than that of the general welded pipe.
The high-frequency welded pipe has smooth appearance, high precision, low cost and low weld seam height, which is beneficial to the coating of 3PE anti-corrosion coating. The welding method of high-frequency welded steel pipe and submerged arc welded pipe is significantly different. Since the welding is completed instantaneously at high speed, the difficulty in ensuring the welding quality is much higher than that in the submerged arc welding method.
http://www.xysteelpipe.com/info/Specification-and-welding-point-of-high-frequency-welded-pipe-1199-1.htm
Different temperature service with different seamless steel pipe
We, seamless steel pipe, are born for your service. No matter you need which kind of temperature service, we are here for you. Today, we will show our ability here and thus you know which one is in your order.
The situation can be classified into low temperature service and medium temperature service as well as high temperature service. Today, we can take a look at them one by one.
Low temperature: Low temperature service seamless pipes are application for low-temperature pressure container piping by the main standard GB/T18984-2003, ASTM/ASME A/SA333 with steel grade 16MnDG, 10MnDG, A333 Gr.1, A333 Gr.6, A333, Gr.3. and so on.
High Pressure and Temperature: High Pressure and Temperature Service Seamless Pipes are application for heating-pipelines, containers, coal-saving devices super-heaters and re-heaters of high temperature and high press boiler by the main standard GB5310-2008, GB9948-2006, GB6479-2000, ASTM/ASME A/SA213, ASTM/ASME A/SA335, EN10216-2, ASTM/ASME A/SA312.
http://www.xysteelpipe.com/info/Different-temperature-service-with-different-seamless-steel-pipe-1200-1.htm
The situation can be classified into low temperature service and medium temperature service as well as high temperature service. Today, we can take a look at them one by one.
Low temperature: Low temperature service seamless pipes are application for low-temperature pressure container piping by the main standard GB/T18984-2003, ASTM/ASME A/SA333 with steel grade 16MnDG, 10MnDG, A333 Gr.1, A333 Gr.6, A333, Gr.3. and so on.
High Pressure and Temperature: High Pressure and Temperature Service Seamless Pipes are application for heating-pipelines, containers, coal-saving devices super-heaters and re-heaters of high temperature and high press boiler by the main standard GB5310-2008, GB9948-2006, GB6479-2000, ASTM/ASME A/SA213, ASTM/ASME A/SA335, EN10216-2, ASTM/ASME A/SA312.
http://www.xysteelpipe.com/info/Different-temperature-service-with-different-seamless-steel-pipe-1200-1.htm
Interpretation for JIS steel pipe
We’ve talked about details for DIN/EN steel pipe’s standard in recent essay. Today, we would continue this topic for another type of seamless steel pipe. It is JIS steel pipe. If you need this kind of standard, having a look for it.
We can figure out easily from the chart listed here. And thus we would know which kind of standard is our target. Of course, your requirement for dimension and steel grade is also clear here in the picture. What you need to do is negotiating for the price.
http://www.xysteelpipe.com/info/Interpretation-for-JIS-steel-pipe-1201-1.htm
We can figure out easily from the chart listed here. And thus we would know which kind of standard is our target. Of course, your requirement for dimension and steel grade is also clear here in the picture. What you need to do is negotiating for the price.
http://www.xysteelpipe.com/info/Interpretation-for-JIS-steel-pipe-1201-1.htm
The effect of cold expansion on LSAW steel pipe
The effect of cold expansion on LSAW steel pipe:
(1) Improve the geometrical dimensional accuracy of the pipe body and pipe end of the lsaw steel pipe, so that the diameter and roundness of the pipe body and the pipe end and the diameter difference between the two ends of the steel pipe meet the standard requirements, which is convenient for on-site welding construction.
(2) Conduct a comprehensive and effective inspection of the overall performance of the steel pipe.
(3) Reducing the uneven deformation of the forming and welding process of lsaw steel pipe, reducing the residual stress of the pipe body caused by molding and welding, improving the distribution and improving the overall mechanical properties of the steel pipe.
(4) The cold expansion diameter also has the effect of improving the straightness of lsaw steel pipe, especially the straightening effect on the smaller diameter straight seam submerged arc welded pipe.
After the cold expansion of the lsaw steel pipe, the diameter of the pipe body and the pipe end will increase by about one percent. The diameter, the roundness and the diameter difference between the two ends of the steel pipe are greatly improved, and the straightness of the steel pipe is also greatly improved. The length is reduced by about 0.5%, and the wall thickness is reduced by about 0.8%. In the development of the lsaw steel pipe process, these changes should be fully considered to determine the width, length and thickness of the pipe sheet and the outer diameter of the steel pipe before the diameter expansion, so as to avoid the geometrical dimension of the steel pipe after the expansion is not up to the final requirements.
http://www.xysteelpipe.com/info/The-effect-of-cold-expansion-on-LSAW-steel-pipe-1202-1.htm
(1) Improve the geometrical dimensional accuracy of the pipe body and pipe end of the lsaw steel pipe, so that the diameter and roundness of the pipe body and the pipe end and the diameter difference between the two ends of the steel pipe meet the standard requirements, which is convenient for on-site welding construction.
(2) Conduct a comprehensive and effective inspection of the overall performance of the steel pipe.
(3) Reducing the uneven deformation of the forming and welding process of lsaw steel pipe, reducing the residual stress of the pipe body caused by molding and welding, improving the distribution and improving the overall mechanical properties of the steel pipe.
(4) The cold expansion diameter also has the effect of improving the straightness of lsaw steel pipe, especially the straightening effect on the smaller diameter straight seam submerged arc welded pipe.
After the cold expansion of the lsaw steel pipe, the diameter of the pipe body and the pipe end will increase by about one percent. The diameter, the roundness and the diameter difference between the two ends of the steel pipe are greatly improved, and the straightness of the steel pipe is also greatly improved. The length is reduced by about 0.5%, and the wall thickness is reduced by about 0.8%. In the development of the lsaw steel pipe process, these changes should be fully considered to determine the width, length and thickness of the pipe sheet and the outer diameter of the steel pipe before the diameter expansion, so as to avoid the geometrical dimension of the steel pipe after the expansion is not up to the final requirements.
http://www.xysteelpipe.com/info/The-effect-of-cold-expansion-on-LSAW-steel-pipe-1202-1.htm
Korean cold rolled flat prices began to rise in July
In July, Korean cold-rolled flat product manufacturers began to increase prices. Among them, South Korea's Eastern Steel has identified new price tags, and other companies such as South Korea's Dongkuk Steel and South Korea's Shiya Group also participated in the price increase.
According to industry sources, South Korea's Eastern Steel has issued a notice to increase the price of all cold-rolled flat products by 40,000 won/ton since July 16. South Korea's Dongkuk Steel and South Korea's Shiya Group announced that their cold-rolled flat products prices will increase by 50,000 won / ton.
South Korean manufacturers of cold-rolled flat products said that they will continue to bear the burden of increasing production costs in the middle of the year. Previously they had reduced losses by cutting production levels, and some producers had to overcome the current difficulties by raising prices. Related parties expect that although the shipment price of Korean cold-rolled flat products has been confirmed to increase in July, it is still difficult to make up for the losses of producers, so additional price increases may be difficult to avoid.
However, relevant sources believe that the continued weakening of steel demand in the Korean domestic market, coupled with consumer resistance to price increases, may hinder price increases. Therefore, Korean manufacturers of cold-rolled flat products have to increase processing fees or expand exports as an alternative to price increases.
http://www.xysteelpipe.com/info/Korean-cold-rolled-flat-prices-began-to-rise-in-July-1203-1.htm
According to industry sources, South Korea's Eastern Steel has issued a notice to increase the price of all cold-rolled flat products by 40,000 won/ton since July 16. South Korea's Dongkuk Steel and South Korea's Shiya Group announced that their cold-rolled flat products prices will increase by 50,000 won / ton.
South Korean manufacturers of cold-rolled flat products said that they will continue to bear the burden of increasing production costs in the middle of the year. Previously they had reduced losses by cutting production levels, and some producers had to overcome the current difficulties by raising prices. Related parties expect that although the shipment price of Korean cold-rolled flat products has been confirmed to increase in July, it is still difficult to make up for the losses of producers, so additional price increases may be difficult to avoid.
However, relevant sources believe that the continued weakening of steel demand in the Korean domestic market, coupled with consumer resistance to price increases, may hinder price increases. Therefore, Korean manufacturers of cold-rolled flat products have to increase processing fees or expand exports as an alternative to price increases.
http://www.xysteelpipe.com/info/Korean-cold-rolled-flat-prices-began-to-rise-in-July-1203-1.htm
The difference between socket welding and butt welding
SW joint is defined in ASME B16.11.Like the socket weld, the pipe is inserted into the indented portion of the fitting.Both the pipe and the fitting are square cut, with no need for beveled end or preparation other than cleaning the outside, which allows easy welding and installation. Butt weld (BW) fittings are defined in the ASME B16.9. They are welded at their ends to pipe end, with the same thickness as pipes. The end of butt weld fittings shall be beveled.
Application
Socket weld (the fillet weld) resists around 1/2 the strength of butt welding. So it is mainly used for small pipeline (Small Bore Piping) with diameters NPS 2 or smaller.
Butt weld keeps better strength, good for high pressure or high temperature pipelines. So it is used when a welded joint with strength not lower than that of the base metal itself is needed.
Feature
Socket weld is easy to install. But it requires approx. 1/16″ of gap at the bottom of the pipe to socket into, to allow thermal expansion. This gap can lead to over stress problem that cracks the fillet weld of the fitting. Socket weld is troublesome in corrosive fluid service due to crevice corrosion. And it is easy to corrode due to the discontinuity of the smooth pipe internals.
Butt weld is the “best” in terms of strength, fatigue, and corrosion resistance, and temperatures compliance. However, it is more difficult to fit-up and weld properly, needing skilled welder and much time.
Price
Normally, the price of socket weld fittings is higher than butt weld fittings in similar size. But the extra cost of butt weld is higher for installation, considering labor cost and skilled welder.
http://www.xysteelpipe.com/info/The-difference-between-socket-welding-and-butt-welding-1204-1.htm
Application
Socket weld (the fillet weld) resists around 1/2 the strength of butt welding. So it is mainly used for small pipeline (Small Bore Piping) with diameters NPS 2 or smaller.
Butt weld keeps better strength, good for high pressure or high temperature pipelines. So it is used when a welded joint with strength not lower than that of the base metal itself is needed.
Feature
Socket weld is easy to install. But it requires approx. 1/16″ of gap at the bottom of the pipe to socket into, to allow thermal expansion. This gap can lead to over stress problem that cracks the fillet weld of the fitting. Socket weld is troublesome in corrosive fluid service due to crevice corrosion. And it is easy to corrode due to the discontinuity of the smooth pipe internals.
Butt weld is the “best” in terms of strength, fatigue, and corrosion resistance, and temperatures compliance. However, it is more difficult to fit-up and weld properly, needing skilled welder and much time.
Price
Normally, the price of socket weld fittings is higher than butt weld fittings in similar size. But the extra cost of butt weld is higher for installation, considering labor cost and skilled welder.
http://www.xysteelpipe.com/info/The-difference-between-socket-welding-and-butt-welding-1204-1.htm
2018年7月3日星期二
Pile-driving pipe production process
Spiral Pipe is a strip coil as raw material, often warm extrusion molding, automatic double wire-sided submerged arc welding process welded spiral seam steel pipe.
(1) raw materials that strip, wire, flux. We must go through rigorous physical and chemical testing before it is put.
(2) strip head and tail docking, single or double wire submerged arc welding, in rolled steel by automatic submerged arc welding.
(3) before forming the strip after flattening, cutting, trimming, planing, surface cleaning conveyor and I crimping process. (4) the use of electric contact pressure gauge to control both sides of the conveyor pressure cylinder pressure to ensure the smooth delivery of the strip.
(5) the use of internal or external control roll forming.
(6) adopted the weld gap control device to ensure the weld gap to meet the welding requirements, diameter, the wrong side and the weld gap have been strictly controlled.
(7) within the welding and soldering are used outside the United States Lincoln welding machine for single or double wire submerged arc welding, thereby obtaining a stable welding specifications.
(8) finished welding the weld line continuous ultrasonic injury checks to ensure 100% coverage of non-destructive testing of spiral weld. If defective, automatic alarm and spraying tags, production workers so adjusting the process parameters, and remove defects.
(9) by air plasma cutting machine will cut a single tube.
(10) cut into a single steel pipe, each consisting of three steel head to conduct strict inspection system, the mechanical properties of the weld inspection, chemical composition, fusion status, steel pipe surface quality and after NDT inspection to ensure that the process pipe after passing to formally put into production.
(11) with a continuous sonic flaw marks the site of the weld, manual ultrasonic and X-ray review, if there are defects after repair again after destructive testing, until the confirmation defect has been eliminated.
(12) strip butt weld and intersect with spiral weld small joint where the pipe all through the X-ray television or film examination.
(13) of each pipe after hydrostatic test pressure radial seal. Test pressure and time by the steel pipe pressure microcomputer detection device strictly controlled. Test parameters are automatically printed record.
(14) pipe end machining, so that the end vertical, bevel and blunt edge be accurately controlled.
(1) raw materials that strip, wire, flux. We must go through rigorous physical and chemical testing before it is put.
(2) strip head and tail docking, single or double wire submerged arc welding, in rolled steel by automatic submerged arc welding.
(3) before forming the strip after flattening, cutting, trimming, planing, surface cleaning conveyor and I crimping process. (4) the use of electric contact pressure gauge to control both sides of the conveyor pressure cylinder pressure to ensure the smooth delivery of the strip.
(5) the use of internal or external control roll forming.
(6) adopted the weld gap control device to ensure the weld gap to meet the welding requirements, diameter, the wrong side and the weld gap have been strictly controlled.
(7) within the welding and soldering are used outside the United States Lincoln welding machine for single or double wire submerged arc welding, thereby obtaining a stable welding specifications.
(8) finished welding the weld line continuous ultrasonic injury checks to ensure 100% coverage of non-destructive testing of spiral weld. If defective, automatic alarm and spraying tags, production workers so adjusting the process parameters, and remove defects.
(9) by air plasma cutting machine will cut a single tube.
(10) cut into a single steel pipe, each consisting of three steel head to conduct strict inspection system, the mechanical properties of the weld inspection, chemical composition, fusion status, steel pipe surface quality and after NDT inspection to ensure that the process pipe after passing to formally put into production.
(11) with a continuous sonic flaw marks the site of the weld, manual ultrasonic and X-ray review, if there are defects after repair again after destructive testing, until the confirmation defect has been eliminated.
(12) strip butt weld and intersect with spiral weld small joint where the pipe all through the X-ray television or film examination.
(13) of each pipe after hydrostatic test pressure radial seal. Test pressure and time by the steel pipe pressure microcomputer detection device strictly controlled. Test parameters are automatically printed record.
(14) pipe end machining, so that the end vertical, bevel and blunt edge be accurately controlled.
Diffrence between HDG and GI
HDG: Also called hot dip galvanized and hot-dip galvanized: is an effective way of metal corrosion, mainly for various sectors of the metal structure facilities. Is immersed steel rust after about 500 ℃ melted liquid zinc, steel member attached to the surface layer of zinc, which serve the purpose of preservation.
Cold galvanized: is galvanized, zinc less, only 10-50g / m2, so is the use of electrolysis or other parts of the metal surface of the material attached to a metal film craft. The formation of uniform, dense, good adhesion of the metal layer process can serve to prevent corrosion, improve the wear resistance, electrical conductivity, reflectivity and enhance the aesthetics and so on.
HDG and GI diffrence:
1, Different corrosion resistance, hot-dip galvanizing cold galvanizing several times.
2, On the way different jobs: HDG is 450-480 degrees in the molten liquid zinc plated zinc plating is cold at room temperature by plating zinc plating or other methods.
3, Zinc coating thickness, is far greater than the thickness of the hot-dip galvanizing cold galvanizing.
4, The surface smoothness is different than the hot-dip galvanizing cold galvanizing look nice and smooth.
5, Different prices, the price is higher than the hot-dip galvanized cold galvanizing.
6, Cold galvanizing can only plated one side, the whole quest galvanized plating.
7, Different adhesion, cold galvanizing adhesion better than galvanized.
8, Different charges, according to the thickness of the hot-dip galvanized material charges, according to the majority of cold-plated square meter charges.
Check www.tjxysteel.com for more info
Cold galvanized: is galvanized, zinc less, only 10-50g / m2, so is the use of electrolysis or other parts of the metal surface of the material attached to a metal film craft. The formation of uniform, dense, good adhesion of the metal layer process can serve to prevent corrosion, improve the wear resistance, electrical conductivity, reflectivity and enhance the aesthetics and so on.
HDG and GI diffrence:
1, Different corrosion resistance, hot-dip galvanizing cold galvanizing several times.
2, On the way different jobs: HDG is 450-480 degrees in the molten liquid zinc plated zinc plating is cold at room temperature by plating zinc plating or other methods.
3, Zinc coating thickness, is far greater than the thickness of the hot-dip galvanizing cold galvanizing.
4, The surface smoothness is different than the hot-dip galvanizing cold galvanizing look nice and smooth.
5, Different prices, the price is higher than the hot-dip galvanized cold galvanizing.
6, Cold galvanizing can only plated one side, the whole quest galvanized plating.
7, Different adhesion, cold galvanizing adhesion better than galvanized.
8, Different charges, according to the thickness of the hot-dip galvanized material charges, according to the majority of cold-plated square meter charges.
Check www.tjxysteel.com for more info
The characteristics of precision seamless tube and use
Precision seamless steel tube is roughly divided into five categories, respectively: precision hydraulic seamless steel tube, cold drawn precision seamless steel tube, cold rolled precision seamless steel tube, high precision seamless steel tube, precision seamless steel tube.
The characteristics of precision seamless tube and use
Feature: steel pipe inside and outside wall without oxidation layer, under high pressure, no leakage, high precision, high finish, cold bending deformation, flaring, flattening without cracks, surface rust proofing.
USES: it is widely used in the hydraulic system in steel tube, injection molding machine in steel tube, hydraulic press in steel, shipbuilding, steel tube, EVA foam hydraulic machinery, precision hydraulic steel pipe cutting machine, shoe-making machinery, hydraulic equipment, high pressure tubing, hydraulic tubing, card sets of joints, pipe joints, rubber machinery, forging machinery, casting machinery, engineering machinery, automotive high pressure steel pipe concrete pump, sanitation vehicle, automobile industry, shipbuilding industry, metal processing, military industry, diesel engine, the internal combustion engine, air compressor, construction machinery, forestry machinery, etc., can completely replace the imports of seamless steel tube with standard.
The characteristics of precision seamless tube and use
Feature: steel pipe inside and outside wall without oxidation layer, under high pressure, no leakage, high precision, high finish, cold bending deformation, flaring, flattening without cracks, surface rust proofing.
USES: it is widely used in the hydraulic system in steel tube, injection molding machine in steel tube, hydraulic press in steel, shipbuilding, steel tube, EVA foam hydraulic machinery, precision hydraulic steel pipe cutting machine, shoe-making machinery, hydraulic equipment, high pressure tubing, hydraulic tubing, card sets of joints, pipe joints, rubber machinery, forging machinery, casting machinery, engineering machinery, automotive high pressure steel pipe concrete pump, sanitation vehicle, automobile industry, shipbuilding industry, metal processing, military industry, diesel engine, the internal combustion engine, air compressor, construction machinery, forestry machinery, etc., can completely replace the imports of seamless steel tube with standard.
How to prevent decarbonization of steel surface
In the steel products market, buyers at sellers the service life of steel products is a very important factor. So what the service life of steel products and related, for instance, wire rope its service life of the rope depends mainly on its fatigue strength and wear resistance, if excessive decarburization on the surface of wire rope, will reduce as reinforcement and wear-resistant phase carbide in the surface layer, thus will directly affect the two performance. , such as tool steel, bearing steel, the surface of the decarburization layer if not clean, to make the tool steel, bearing steel surface hardness and wear resistance is reduced, and the quenching, due to the outer volume change in the different and the workpiece surface cracks. Can look for the degree of surface decarburization steel products will greatly influence the service life of it. So how to prevent the surface of the steel decarburization is should pay attention to the problems in the production process.
It is understood that foreign imports of the decarburization layer of the wire rod is 0.02 ~ 0.04 mm, of kobe wire rod surface can be done without decarburization, decarburization layer and the domestic like product average depth of more than 0.05 mm. So how to take measures to solve this problem?
Solve the problem of surface decarburization, key on the heat treatment process. Because the decarbonization and the oxidation of steel wire was conducted at the same time, therefore, as long as make less steel wire in the process of heat treatment is exposed to air can reach the purpose of improving the decarburization.
Check www.tjxysteel.com for more info
It is understood that foreign imports of the decarburization layer of the wire rod is 0.02 ~ 0.04 mm, of kobe wire rod surface can be done without decarburization, decarburization layer and the domestic like product average depth of more than 0.05 mm. So how to take measures to solve this problem?
Solve the problem of surface decarburization, key on the heat treatment process. Because the decarbonization and the oxidation of steel wire was conducted at the same time, therefore, as long as make less steel wire in the process of heat treatment is exposed to air can reach the purpose of improving the decarburization.
Check www.tjxysteel.com for more info
Medium and High Pressure Boiler Pipe
Most common boiler steel pipe can be devided into two kinds, one is midium pressure boiler pipe, the other is high pressure boiler pipe. Please kindly note that most of high pressure boiler pipe are made from seamless steel pipe.
Boiler pipe has been widely used at heat exchanger pipe and tubing services, high pressure boiler, petrochemical industry pipes, tube exchanger bundle, economizer, super heater, etc.
Based on different working temperature, the medium or high pressure boiler pipe shall be used. Normally classified as below cases:
The operation temperature of general boiler pipe is lower than 450℃. The medium pressure boiler pipe mainly adopts hot rolling process or cold drawing process.
High pressure boiler pipe are often used in high temperature and high pressure working conditions. Under the action of high temperature flue gas and steam, the pipe will occur oxidation and corrosion. It is required high pressure boiler pipe that has high endurable strength, high oxidation corrosion resistance and good tissue stability.
http://www.xysteelpipe.com/info/Medium-and-High-Pressure-Boiler-Pipe-1174-1.htm
Boiler pipe has been widely used at heat exchanger pipe and tubing services, high pressure boiler, petrochemical industry pipes, tube exchanger bundle, economizer, super heater, etc.
Based on different working temperature, the medium or high pressure boiler pipe shall be used. Normally classified as below cases:
The operation temperature of general boiler pipe is lower than 450℃. The medium pressure boiler pipe mainly adopts hot rolling process or cold drawing process.
High pressure boiler pipe are often used in high temperature and high pressure working conditions. Under the action of high temperature flue gas and steam, the pipe will occur oxidation and corrosion. It is required high pressure boiler pipe that has high endurable strength, high oxidation corrosion resistance and good tissue stability.
http://www.xysteelpipe.com/info/Medium-and-High-Pressure-Boiler-Pipe-1174-1.htm
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