SSAW Pipe

　　 1. Definition of lsaw steel pipe pressure pipeline 　　 LSAW steel pipe pressure piping should include all straight seam steel pipe pipes that use pressure to deliver gas or liquid. From the point of view of safety production, it is the name of the straight seam steel pipe pressure vessel. Therefore, it is not a pressure pipe in a simple sense. The possibility of accidents and the hazard of the accident define the scope of the straight seam steel pipe pressure pipe. The pressure line uses a certain pressure, a tubular device for conveying gas or liquid, a liquid medium having a temperature higher than or equal to the standard boiling point, and a pipe having a nominal diameter of more than 25 mm. Straight seam steel pipe pressure equipment, in addition to its own blasting, will also cause explosions and fires due to leakage of the medium. 　　 2. Application of lsaw steel pipe pressure pipeline 　　LSAW steel pipe pressure piping is an important part of the production process, main...

　　Fracture of lsaw steel pipe , mechanical properties of hydraulic (pneumatic) parts used in design, brittle fracture is also related to the use temperature of the component. 　　It has been found through research that when the temperature is lower than a certain temperature value, it is found that the data will be transformed into a brittle state, and the impact absorption work is obviously reduced. This phenomenon is called cold brittleness, and low stress brittle fracture occurs in high-strength metal materials. In the process, the data organization is far from uniform and isotropic, there will be cracks, and there will be defects such as inclusions and pores. These defects can be regarded as microcracks in the material. Therefore, the design should also select the data with the appropriate cold-brittle transition temperature according to the working temperature of the component. 　　In general, it is assumed that the data is uniform and continuous isotropic. According to this metho...

　　Metal and atmospheric oxygen of 321 stainless steel seamless pipe in response to the appearance will constitute an oxide film. However, in the general carbon steel pipe on the composition of the continuous oxidation of iron oxide, so that corrosion continues to expand, resulting in holes. So that good stainless steel seamless pipe is damaged, we can use paint or oxidation of metal such as zinc, nickel and chromium plating to cover the appearance of carbon steel, but, as we expected, this maintenance only is a layer of maintenance film, assuming that the maintenance layer is damaged, steel will start to be corroded. The corrosion resistance of stainless steel depends on the chromium, chromium is a part of the composition of steel, chromium on the steel treatment, the appearance of the oxide type will be changed to similar to pure chromium metal on the surface oxide. This tightly adhered chromium-rich oxide maintains the appearance and avoids further oxidation. 　　The heat treatment ...

　　In order to improve the performance effect of square tube , we can hot-dip galvanized square tube, hot-dip galvanizing is a heat treatment process effect, in the process of galvanized square tube, in order to meet the demand effect, we need to constantly testing, if not measured for the square tube quality has a lot of impact. 　　First, It need to be from the ability to carry out the test, in fact, galvanized thickness of the hot galvanized square tube. Because the galvanized square galvanized layer determines whether it can meet the requirements of corrosion protection, in the testing process can be used to detect the use of professional measurement tools, in the detection process of hot galvanized square tube galvanized layer thickness is a certain requirement, in use is the need to be based on these provisions to identify. Followed by homogeneity to be detected, in fact, the thickness of the surface of the galvanized layer. In the detection process to improve the quality of the u...

　　 Galvanized square tube welding method and the general low-carbon steel is the same: welding the first layer of welding in the weld, try to make the zinc layer and vaporization, evaporation and escape the weld, can greatly reduce the liquid zinc Stay in the weld. In the welding of the weld, the same layer in the first layer as much as possible so that the zinc layer melting and vaporization, evaporation and escape the weld, the method is the first part of the electrode forward out about 5 ~ 7mm or so, when the zinc layer melt and then return to the original position to continue to apply welding. And then welding and vertical welding, such as the use of short slag electrode such as J427, undercut tendency will be very small; if the use of front and rear transport technology, but also can be defect-free welding quality. 　　Welding process control of the pipe before the preparation of welding with the general low-carbon steel is the same, need to pay attention to is to carefully handl...

　　The pickling process acid pickling solution is generally a mixture of various acids, mainly sulfuric acid, nitric acid and hydrofluoric acid, etc. These mixed acids are highly corrosive and have a strong oxidizing property and a high temperature of corrosive medium. This puts high demands on the corrosion resistance of anticorrosive materials. Stainless steel seamless steel pipe pickling production line process from production to waste gas recovery system, there is a strong corrosion state in all aspects, so the choice of anti-corrosion materials is directly related to the environmental recovery system of equipment, workshop floor, trench, waste water and waste gas Normal use of etc. 　　 Seamless steel pipe pickling process 　　The pickling of seamless steel tubes uses solvents and emulsions to clean the surface of welded steel pipes for low-pressure fluid transport to remove oil, grease, dust, lubricants and similar organic matter, but it does not remove rust, scale, etc. from the ...

　　As with other materials exposed to the atmosphere, seamless stainless steel pipe is also dirty. Future lectures will analyze the design factors that affect maintenance and cleanup costs. However, there is a relationship between rain erosion, manual flushing and dirty surfaces. 　　The effect of rainwater scuffing was determined by placing the same slats in the atmosphere directly and on the shelter. The effect of manual flushing is determined by manually scrubbing the right side of each slab every six months with a sponge stained with soapy water. It was found that dust and siltation on the surface by rainwater scrubbing and manual scrubbing had a good effect on the surface condition compared to the slats placed in the shed and not washed. But also found that the surface processing of the situation also has an impact on the surface of the slab than the surface of the rough effect is better. 　　So the interval between the scrubbing by a variety of factors, the main factor is the req...

　　Stainless seamless steel pipe surface treatment is mainly in the following ways: 　　Chemical cleaning: Chemical cleaning pipe refers to the temporary conversion of the use of chemical chemicals pipeline, the use of temporary pipes and circulating pump from the pipeline at both ends of the use of chemical ring cleaning. The technology has the features such as flexibility, speed, thorough cleaning, and the shape of the pipe is not required, such as chemical cleaning is completed, but the residue to be cleaned. Otherwise, will be running in the future effect. 　　PIG operation: Pig industry technology to rely on the pump to drive the fluid to promote PIG in the tube to promote the power, in the pipeline discharge dust, so as to achieve the purpose of cleaning. The technology is widely used to clean pipes of various processes, oil and oil pipelines , especially for long-distance transmission of fluid piping cleaning, with the advantage that other technologies can not be replaced. 　　Hi...

　 　1, Grade and chemical composition 　　The grades and chemical compositions of hot-dip galvanized steel strip shall comply with the grades and chemical composition of the black tube for GB 3092. 　　 2, Manufacturing methods 　　The manufacturing method of the black tube (furnace welding or welding) is selected by the manufacturer. Galvanized by hot dip galvanizing method. 　　 3, Thread and pipe joints 　　1) With the delivery of galvanized steel pipe, the thread should be in the galvanized car system. The thread should be in accordance with YB 822. 　　2) Steel pipe fittings shall comply with YB 238; malleable cast iron fittings shall comply with the requirements of YB 230. 　 　4, Mechanical properties 　　Steel pipe galvanized before the mechanical properties should be consistent with the provisions of GB 3092. 　　5, Galvanized layer uniformity galvanized steel pipe should be galvanized layer uniformity test. Steel samples in the copper sulfate solution for 5 times can not be re...

　　First, sample 　　The performance test of hot-dip galvanized strip is an important production link to improve the product quality and reduce the production cost. 　　In order to improve the performance test, the first sampling should be reasonable. That is, the number of samples to be less, the sampling position to be representative. The hot-dip galvanized steel strip, which is rolled by continuous casting slab, is not limited in its sampling position and one is a cold rolled coil as a test unit. The hot-dip galvanized steel strip rolled by the initial billet shall be used as a test unit for each ingot to be sampled at the head, center or tail according to the special requirements of the steel and inspection, The According to experience, the sampling position of the sedated steel is specified in the middle of the ingot, ie 50% from the head of the strip, while the boiled steel is sampled at the most segregated part, 25% from the head of the ingot. 　　And, galvanized defects are not ...

　　Galvanized steel strip, with its excellent strength, corrosion resistance, excellent formability, smooth, and many other outstanding features, in the construction industry, industry, transportation, pipe is widely used in industries, as the products are growing, production scale expands unceasingly, some unscrupulous traders take flood the market.Some consumers have found that the products are not as good as the merchants introduced, and have lost faith in products such as galvanized steel strip and hot galvanized steel strip.Not all products are so, and the reason for this delusion is that consumers lack a choice.So how do we identify the quality of the product? 　　First of all, the key to the corrosion and durability of the product is the hot galvanizing technology and the thickness and uniformity of the coating.Secondly, if the quality of raw materials is determined and the heat treatment process is in place, if the process is not good, the hardness will be too high and the subse...

　　The heat-expanded seamless steel pipe is a heat expansion pipe that we often say, and the steel pipe with a relatively low density but a strong shrinkage can be simply referred to as a heat expansion pipe. A roughing finishing process for expanding the diameter of a pipe by a cross-rolling method or a drawing method. In a relatively short period of time, the outer diameter of the steel pipe is increased, and a non-standard, special type of seamless pipe can be produced, and the cost is low, and the production efficiency is high, which is a development trend in the international rolling pipe field. 　　The raw material for rolling the seamless pipe is a round tube blank, and the round tube blank is cut into a blank having a length of about 1 m by a cutting machine, and sent to a furnace for heating via a conveyor belt. The billet is fed into a furnace and heated to a temperature of approximately 1200 degrees Celsius. The fuel is hydrogen or acetylene. Furnace temperature control is a...

　　If stainless steel welded pipe in a specific working environment, the need for welding repair, the welding preparation should be carefully checked before, in order to ensure complete removal of defects. Welding of stainless steel tubes shall be carried out in accordance with the welding procedure as assessed in ASME Code Section IX. Welding operators or welding equipment operators performing welding shall comply with the qualification requirements of Volume IX. In addition to A1 or A2 component of the weld metal can be used for P1 material, the weld metal should be equivalent to plate P-No A-No component requirements. When the purchaser agrees, other weld metal that matches the material matrix of the material to be welded may also be used. The weld metal must be evaluated in accordance with ASME Code, Volume IX. 　　If a stainless steel pipe material is required to be subjected to a Charpy impact test, the weld qualification test shall also include welds, heat affected zones and Cha...

　　The straightening method of DSAW tube: 　　One, the DSAW tube is bent in the same direction 　　Reason: Welding normalization is insufficient, the pipe has thermal stress on the welding side, and bent in one direction after cooling. 　　Solutions: 1, adjust the middle roller, properly increase the deflection curve; 2, two straightening; 3, the whole tempering pipe can not be straightened directly. 　　Two. The DSAW tube is unrule bending 　　Reasons: 1. the pressure between the three rollers is not consistent; 2. the straightening roller wears a lot. 　　Solution: check whether the adjustment of the straightening roller is loose, and use the sample rod to straighten the contact line length between the three. 　　Third, the length of the DSAW tube is short 　　The reason is that the angle of the three roller straightening roller is different, and the straightening pressure is larger. 　　Solution: adjust the rolling angle as much as possible and adjust the straightening pressure prope...

　　 Advantages of LSAW pipes 　　It can destroy the casting structure of steel ingots, refine the grain of steel, eliminate the defects of structure, make the steel structure compact and improve the mechanical properties. This improvement is mainly reflected in the rolling direction, so that the steel pipe is no longer isotropic to some extent; the dumping bubble, the crack and the loose stratum can also be welded at high temperature and high pressure. 　　 LSAW pipeline 　　Sawing defect 　　1, the residual stress caused by unequal cooling. The residual stress is the internal self balancing stress in the absence of external force. All cross-sections of hot rolled steel have such residual stresses. The greater the size of the general section, the greater the residual stress. Although the residual stress is self balanced, the steel structure may have adverse effects on the external force, such as deformation, stability, fatigue and so on. 　　2, after welding, the non-metallic inclusions...

　　In order to maintain a stable heat treatment product during the induction heat rapid heat treatment process, the following measures should be taken on the production line: 　　(1) The casing plant adopts the technology of continuous heating of steel bridges and uses bridging technology to improve the phenomenon of low steel temperature and increase steel production. A computer is used to control the head and tail of the steel; dual-frequency power is used to control the temperature at the end of the steel pipe ; rotary joints are used to achieve great progress, etc. to increase the longitudinal temperature uniformity of the steel. 　　(2) Advanced steel conveyors are used to ensure uniform steel speeds. Steel tubes and large bars should rotate at a constant speed. The transmission mechanism should use variable frequency drive to improve the stability and reliability of the mechanism. This is one of the important conditions for ensuring that the longitudinal temperature of the phase m...

　　Internationally, the requirements for casing threads between one pair of inner and outer cones meet the requirement of end face allowance only, and the axial displacement can be used to complete the interference of the connection surface. And it can be used to improve the processing quality of the connection area, increase the axial force to increase the pressure of touch area and touch area, and then get a more compact ring pressure touch area. The larger the touch area, the less likely the leakage path is, and the more reliable the sealing function is. Casing thread is a special conical seal with thread grooves and taper pipe threads. 　　When the conical tube thread meets, only the surface allowance is satisfied, and the preload in the seal surface can be easily obtained by tightening the thread and causing the axial displacement. After reviewing the conical sealing method, when the inner and outer cone threads match each other, a continuous and discontinuous ring pressure contact...