SSAW Pipe

　　Stainless steel seamless pipe is a long strip of steel with a hollow section and no joints around it. 　　The characteristics of stainless steel seamless pipe: 　　First, the thicker the wall thickness of the product, the more economical and practical it is. The thinner the wall thickness, the higher the processing cost will be. Secondly, the process of the product determines its limited performance. The seamless steel tube has low precision: uneven wall thickness, low brightness inside and outside the tube, high fixed-length cost, and pitting and black spots on the inner and outer surfaces are not easy to remove; third, its detection and shaping must be processed offline. Therefore, it embodies its superiority in high-pressure, high-strength, mechanical structural materials. 　　The type of stainless steel pipe: 　　The rolling method is divided into hot rolling, hot extrusion and cold drawing (rolling) stainless steel tubes. According to the stainless steel metallographic structure...

　　Generally speaking, the welded steel pipes are divided into general welded pipe, galvanized welded pipe, oxygen welding tube, metric system welded tube, transformer tube, welding thin wall pipe and spiral welded pipe etc. 　　General welded pipe: General welded pipe adopts Q195A, Q215A and Q235A or mild steel as raw materials. It is used to transfer the low pressure fluid. In addition, the pipes need water pressure, bending and flattening test etc. Usually, it has some certain requirements on the surface quality. The length of delivery is often from 4 to 10mm. The specifications of welded pipe in nominal diameter are different from actual size. Depending on the wall thickness, welded pipe are also divided into common steel pipe and thicken steel pipe. 　　Galvanized welded pipe: In order to enhance the corrosion resistance, the general welded pipe is galvanized zinc as protective layer. Galvanized steel pipe has two types: hot dip galvanized pipe with thicken zinc layer and electric...

　　Large diameter LSAW steel pipe with its large wall thickness, good material, processing technology and stability, has become the first choice of steel large oil and gas transmission project at present at home and abroad. 　　Measures to control quality of LSAW steel pipe: 　　1. 1> before the welding quality control to quality first good raw materials, can be officially entered the construction site after passing inspection, and resolutely put an end to the use of substandard steel. 　　2> followed by the management of welding materials. Check whether the welding materials for qualified products, storage and baking system is executed, issued by the welding material surface is clean without rust, the electrode is intact, there is no mildew. 　　3> again is the welding area clean management. Check the welding area clean quality, no water, oil, rust and other dirt film, which plays an important role in avoiding weld external defects. 　　4> select the appropriate welding me...

　　1, In order to prevent corrosion of eye is generated due to a flange cover heating, welding current should keep shoulds not be too big, than carbon steel electrode less than 20%, arc shoulds not be too long, interlayer fast cooling, a narrow weld bead is appropriate. 　　2, The use of the electrode should be keep the drying, titanium calcium type should keep drying 150 DEG C for 1 hour and a low hydrogen type should be kept between 200 and 250 DEG C and dried for 1 hour, prevent electrode viscous oil and other dirt, so as not to cause the weld increase with carbon content, and the influence of welding quality. 　　3, Flat welding flange pipe welding by repeated heating and carbide precipitation and reduce the resistance and the mechanical properties of the corrosion properties of the product. 　　4, Chrome flange pipe after welding of flange American Standard hardening is large, easy to crack. If the same type of chromium stainless steel welding rod (G202, G207) welding, must be more...

　　SSAW pipeline is allowed to use in Italy. 　　In Canada, LSAW pipe and SSAW pipe is regarded as equally important, but in practice, SSAW pipe accounted for about 70% in the main line. 　　SSAW pipe was rarely used in the former United States, Japan and Germany. With the establishment of more and more oil and gas transport lines, seamless limitations and limits of the size of the welded tubes are slowly emerging. These countries are also increasingly using LSAW pipe and SSAW pipe. 　　Russia fully affirmed the advantages of SSAW pipe, so the main line is generally preferred SSAW pipe. 　　According to the forming process, the SSAW pipe has a lot of residual tensile stress (Maximum up to 200 ~ 300 Pa). While in the process of UOE forming process, there is an enlarged diameter. The surface of that compressive residual stress is - 200 ~- 300M Pa. 　　In the process of mechanical expansion, UOE tube has higher dimensional accuracy than SSAW pipe. 　　The weld length of SSAW pipe is long...

　　Choosing a suitable warehouse is very important for company especially for steel pipe suppliers. Now we introduce some basic knowledge of steel pipe storage for you. 　　1. Steel pipe is not suitable pile up directly on the floor. First, the first layer of steel pipes must keep a distance from the ground floor (not less than 0.2 mtr). 　　2. Pipe ends must be packed with paper or plastic caps to avoid dust entering and other pollution. 　　3. Arrange the steel pipes by furnance number, specifications, materials. 　　4. For cold drawn steel pipes, cold rolled steel pipes and bright annealed steel pipe, it is not allowed outdoor storage generally. If outdoor storage is the case, appropriate precautions to avoid rain, snow, fog, and other pullution is necessary. 　　5. Steel pipes must be placed at appropriate intervals in the same horizontal level, and the pipe ends are alignment. 　　6. Annealed brass hose, or aluminum hose should be placed between the layers of isolation sleepers. ...

　　In the long-distance pipeline construction, with steel lines account for a large proportion, under normal circumstances, 35% to 40% of line pipe investments accounted for total project investment. How to choose a reasonable price, excellent performance of the pipe is particularly important, a reasonable choice to save the pipe construction investment, to facilitate the construction and safe operation of the pipeline system has a very important impact. LSAW steel pipe advantage make it can be widely used for its unique long-distance oil and gas pipelines. 　　Advantages of LSAW steel pipe are: 　　(1) without the unwind process, the base material indentation, scratch less. 　　(2) the wrong side, slotted, and other easy-to-diameter perimeter control, excellent welding quality. 　　(3) the elimination of flaring basically does not exist residual stress after stress. 　　(4) because it is a straight line weld, the weld is short, little risk of defects. 　　(5) after expanding, pipe geo...

　　The surface heat treatment technology of the 45th thick-walled seamless steel pipe is constantly being innovated, and the current technology has been developed more and more sophisticated. Let's take a look at several methods of 45-thick thick-walled seamless pipe processing. 　 　1. Surface hardening: 　　Rapid heating of No. 45 thick-walled seamless pipe by different heat sources, when the surface temperature of the part reaches above the critical point (when the temperature of the 45# seamless pipe core is below the critical point), it is quickly cooled, so that 45# seamless The surface of the tube is hardened and the heart remains in its original tissue. The most widely used in the industry is induction heating and flame heating surface quenching. 　　 2. Chemical heat treatment: 　　The 45# seamless tube is placed in a medium containing active elements to heat and keep warm, so that the active atoms in the medium penetrate into the surface layer of the 45-thick thick-walled ...

　　The main differences between SSAW and LSAW steel pipes are in their length and pattern of welding seam. SSAW pipes have longer welding seams than LSAW pipes and so have a higher risk of seam defects. Meanwhile, for SSAW steel pipes, the welding seam is at a certain angle with the orientation of the priciple stress. This shortens the faulty welding joints of an SSAW steel pipe when compared with an LSAW steel pipe of an equivalent length. (This reduces the danger of a single defect). The disadvantage and advantage mentioned above cancel out each other. The difference between the orientation of the welded seam and the special directivity often major raw material of a SSAW steel pipe enhance its resistance against fracture. 　　In 1998, the Tubular Goods Research Center of CNPC, together with China Petroleum Planning and Engineering Institute conducted a comparative experiment systemically on domestically produced SSAW steel pipes and imported LSAW (UOE) steel pipes. 　　The following ...

　　Welding preheating is the process before high frequency welding or submerged-arc welding process for producing welded steel pipes . When the environment temperature is too low, welding preheating process is quite necessary. Besides, this process is widely applied for the weldments has large thickness, high strength level, hardening tendency, and good thermal conductivity. 　　In general, the welding preheating is applicapable in the welded seam areas or the whole steel pipes. For example, during the ERW Steel Pipes manufacturing process, the welding preheating process will be only applied in the welded seam areas. 　　The purpose of the welding preheating process is to reduce the cooling speed of the welded joints and preheating temperature. Welding preheating can reduce the cooling speed, but it will not influence the high temperature maintaining time. Therefore, in order to decreases the hardening tendency, applying welding preheating process to reduce the cooling rate is significa...