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The pipe reducer is also one of the chemical pipe fittings used for the connection of two different pipe diameters. It is pided into concentric pipe reducer and eccentric pipe reducer. pipe reducer for diameter specification does not accord with the inner diameter of the process piping, should undertake the corresponding reducing or expanding process, if the shrink tube, pipe pressure loss caused by this should be considered whether will affect the process. In order to prevent the installation of pipe reducer influence the distribution of velocity field, pressure loss, and reduce the measurement accuracy of electromagnetic flowmeter, the requirements of the central Angle alpha is not more than 15 °, as small as possible. There are pided into two concentric and eccentric, concentric pipe reducer is generally used in vertical pipe; The eccentric pipe reducer is used for the horizontal pipe, and it should be noted that the top level or the bottom level. There are several main places: 1. When the flow of fluid in the pipe changes, such as increase or decrease, the flow rate of the flow will not change very much. 2. Pump inlet to prevent cavitation. 3. Contact with the instrument, such as flowmeter and regulating valve, in order to cooperate with the instrument’s joint, the pipe reducer should also be used Source: China pipe reducer Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The extension rate of 304 stainless steel pipe is low, the elastic modulus E is larger, the hardening exponent is higher, and the thickness is small (304 stainless steel pipe is 0.9 ~ 0.11, soft steel is 1.3 ~ 2.0). The 304 stainless steel pipe material is short in the plastic deformation stage, especially its plastic strain ratio. 304 stainless steel pipe sheet pull deep cracking sometimes occurs after pull deep deformation, and the gambling company sometimes occurs when the deep part is pulled out from the concave mold. Sometimes occurs when a deep deformation is subjected to impact or vibration; It can also occur after a period of storage or use after a deep deformation. This paper analyzes the causes of defects in 304 stainless steel pipe plate drawing, and puts forward some solutions. 1. Reasons for cracking formation Austenitic 304 stainless steel pipe has a high hardening index (304 stainless steel pipe is 0.34). The austenitic type 304 stainless steel pipe is a stable type, and the phase transition occurs when the deformation occurs, which induces the martensite phase. The martensite is brittle and therefore prone to cracking. In the case of plastic deformation, with the increase of deformation, the higher content of martensite, the greater the residual stress, and the more likely to crack in the process of processing. The reasons for the formation of surface scratches 304 stainless steel pipe the scratch on the surface of the deep drawing is mainly due to the workpiece and die surface relative motion, to a certain pressure, under the action of the local surface of billet and the mold friction directly, combined with the deformation of the billet hot billet and scrap metal deposition in the mold on the surface, the surface scratch scratch. Source: China Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Bellows compensator design fatigue calculation of the fatigue life of bellows compensator failure types and causes of analysis can be seen that the plane stability of bellows, circumferential stability and corrosion resistance are related to its displacement namely fatigue life. The fatigue life of low will be led to the decrease of the bellows stability and corrosion resistance. According to the test and use of the experience, the fatigue life of bellows used in heating engineering should not less than 1000 times. The bellows can not be loaded, should be hoisting separately; In addition to the predeformation of pretensioning or cold tightening, it is strictly forbidden to adjust the installation deviation of the pipe by means of the corrugated tube deformation. The installation process does not allow the welding slag to splash into the surface of the bellows and other mechanical damage; Bellows all active components shall not be jammed by external components or restricted to normal work. Most of the corrugated pipe failure was caused by external environment corrosion, so the structure design of the compensator, can consider to isolate external contact with corrugated pipe corrosion medium. As for the finale to type compensator in the outlet ring packing seal device with increased between the outlet pipe, its function is equivalent to the sleeve compensator, can resist the invasion of external corrosion medium, and added a safety barrier to bellows compensator, even if the corrugated pipe damage, compensator Can also be compensation effect and avoid corrugated pipe failure. Source: China Bellows Compensator Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Main technological process of steel pipe fittings: > shaping (welding) > heat treatment > surface treatment > cutting processing > non-destructive testing > surface protection > logo (1) blanking The material used for pipe fittings is mainly pipe, sheet and rod, and the method is selected according to the material characteristics and the shape of the blank of the product. The shape, size and other requirements of the blank are carried out according to the process requirements of different products. For the pipe, the commonly used feeding method has a sawing machine, cutting, gas cutting, and plasma cutting. For plank, the commonly used method is gas cutting, plasma cutting, punching and cutting. For rod, the commonly used method is to cut with sawing machine or bow sawing machine. Forming (welding) Forming is an indispensable process for the manufacturing process of all pipes. Due to different forming process of different products, the length of the required length will be described in section 15.2.4. Here, a brief introduction to the heating and welding of some of the forming processes. A.. heating In order to meet the requirement of deformation of material in forming process, heating of billet is needed to meet the requirement of forming process. The heating temperature is usually determined by the material and process. The method of using medium or high frequency induction heating is usually adopted when the hot bending or hot bending pipe is formed, and the method of flame heating is also adopted. This heating method is continuous heating with the bend or pipe forming process. The tube billet is heated in the movement and completed the forming process. The method of heating of the reverberatory furnace, the method of flame heating, the method of induction heating, or the method of heating of the furnace are usually used when the hot-pressing bend, the hot pressing tee or forging is formed. This heating is the first to heat the tube to the desired temperature, then put it into the mould to press or forge. B. the welding Weld pipe fittings including two cases, one is made of welded pipe fitting, for pipe fittings manufacturer, using the forming process of welded pipe forming process of using seamless tube of basic same, pipe forming process does not include the welding process; Another is done by fitting factory the welded pipe forming need process, such as single chip to suppress again after assembling welding elbow, use steel drum welding into the pipe and then to suppress the tee, etc. The welding methods of pipe fittings are used in manual arc welding, gas shielded welding and automatic welding. Manufacturer shall prepare the welding procedure specification to guide the welding work, and should be in accordance with codes for the corresponding welding procedure qualification, to verify the correctness of the welding procedure specification and assess of welding the weld ability. Welders engaged in pipe welding operations shall be determined by the quality and technical supervision departments of examination and obtain a corresponding qualification certificate shall not engage in relevant steel welding work (according to the regulation of some industries, used for welding pipe fittings to get industry rules in some sectors of welder and welding procedure qualification examination, such as Marine welding pipe fittings to obtain corresponding class welder test and welding procedure qualification). (3) heat treatment Heat treatment process is an important part of pipe fitting. By heating, heat preservation and cooling of the heat treatment step, eliminate the forming process of work hardening, residual stress, the metal deformation defects, etc., make the pipe after forming metal organization, performance, change, return to the front of the deformation processing of status, or make it improved and improve performance. The commonly used heat treatment equipment is the reverberatory furnace, electric furnace and so on; The usual control mode is for the thermocouple in the furnace to connect to the temperature – time recorder control device through the sensor. There are different rules for heat treatment of different pipe fittings. Not all through the deformation of the pipe fittings are to be heat treatment, usually, for low carbon steel material pipe fitting its final forming temperature is not lower than 723 ℃(recrystallization temperature), can be heat treatment, not because of the temperature under the condition of its ultimate state of organizations is basically normalizing state, or lower than the temperature higher than 980 ℃ heat treatment should be; The pipe fittings of alloy steel or stainless steel shall be heat treated regardless of cold forming or hot forming. The general test of heat treatment is usually accomplished by hardness test. Surface treatment Pipe surface treatment usually adopt sand blasting, shot blasting, polishing, pickling, such as method, to remove rust on the surface of the product, such as scratches, make products to achieve smooth surface, to meet the requirements of the subsequent processing and inspection. The surface hardness of the surface treated with shot blasting is increased slightly. Top cutting Cutting machining is the process of finishing the welding end, structure dimension and shape tolerances of pipe fittings. The machining of some pipe pieces is also included in the process of internal and external diameter. The cutting process is mainly done by special machine tool or universal machine tool. When the existing machine tool capacity cannot meet the processing requirements, the processing can be completed in other ways. For example, the method of the burnishing of the large diameter elbow is used. The appearance and dimension of pipe fittings are usually carried out after machining. Nondestructive testing Nondestructive testing is an important process for inspection of defects in the machining process of materials and fittings. The requirements for nondestructive testing are stipulated in most pipe product standards, but the requirements are not consistent. In addition to meet the requirements of product standards and order for nondestructive testing, some of the more stringent quality control of the factory is according to the material, processing technology and quality of internal control regulation on nondestructive testing requirements, in order to guarantee the quality of products. In the actual work, the determination of the non-destructive testing of the pipe piece shall be specified in accordance with the requirements or criteria of the order. For fitting surface basically is the original state of pipe, plate, or forging, the surface quality of pipe nondestructive testing (MT, PT), if there is no clear requirement according to Ⅱ level grade, but no matter how qualified level regulation, for sandwich and this is not easy to determine the depth of crack defect shall be considered not qualified. Internal quality of pipe nondestructive testing (RT, UT,), radiographic testing if there is no clear grading standards should pressⅡ level (such as weld testing), ultrasonic testing should press Ⅰ level. In order to prevent the possible defects of the product during heat treatment, the final nondestructive testing of the pipe shall be carried out after heat treatment. The JB/T 4730 specification is usually used for nondestructive testing of pipe parts in China. Personnel engaged in nondestructive testing shall be entitled to the relevant provisions. Surface protection On the surface of carbon steel, alloy steel pipe protection usually adopt the method of painting, after the adoption stainless steel pickling passivation methods (for all surface machining of stainless steel pipe fittings, can need not passivation treatment). The main purpose of surface protection of pipe fittings is anticorrosion, as well as the effect of cosmetic appearance. Normally, the ordering party makes specific requirements on the surface protection, and the manufacturer shall complete the protection of the surface of the fittings according to the requirements of the ordering party. Today marks The hallmark is an integral part of the product, which is the basis for achieving traceability requirements. In general, product standards define the content and method of the logo. The contents of a pipe will generally include the manufacturer’s trademark or name, material grade, specification and other contents of the order. The method of marking includes permanent mark, such as steel seal, engraving, etching, etc. Non-permanent marker, such as print, label, etc. In addition to the above normal manufacturing processes, the manufacturer shall complete the inspection of raw materials and ensure the correct materials used in order to control the quality of raw materials. In order to meet the special requirements of orders or materials, it should also carry out inspection and testing such as metallographic structure, intercrystalline corrosion, ferrite, etc., to ensure that the supplied products meet the requirements of customers. Source: China Pipe Fittings Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

One, corrosion of stainless steel pipes Corrosion occurs at the entire interface between the stainless steel pipe and the dielectric environment and is characterized by uniform thinning along the section, which occurs mostly in the acid and hot alkaline medium. Corrosion resistance of stainless steel pipes is often evaluated by corrosion rate (mm/a). Two, stainless steel pipe corrosion reasons Can not form a passivation film or passivation film instability and passivation membrane damage and can not timely repair; in the actual engineering application, the electrolyte in many corrosive environment, even if the stainless steel pipe is in a passive state, often at different speeds (sometimes very slowly) were dissolved; finally, the control equipment, components, stainless steel vessel thickness (or section) gradually thinning and failure. Three, prevent stainless steel pipe corrosion measures Choose the grade of corrosion resistance according to the kind, concentration, temperature and specific requirements of the corrosive medium. Then choose the appropriate stainless steel grade according to the corrosion resistance grade requirements. Stainless steel pipe corrosion resistance when there are ten levels of standards. Choose which level to meet the requirements of anti-corrosion equipment, components, in addition to the length of life, the characteristics of equipment and components (thick, thin, big or small) and the product quality (color purity, impurities, etc.) are considered in the. For example, the use of the process, equipment, use components required to maintain smooth mirror or precise size and impurities, the purity of the product, the color has special requirements, generally 1 ~ 3 level standard; while the demand is not high, the maintenance is convenient or life is not very long, the equipment components, can use 4 ~ 6 grade standard. However, in normal circumstances, the standard greater than 6 is not selected. The corrosion resistance of stainless steel pipes is actually evaluated by their corrosion rate in the medium. In this medium, the corrosion rate of the stainless steel pipe is corrosion resistant within the allowable range, but this is not corrosion free. There are a lot of stainless steel pipe corrosion Handbook for reference, and the test data of stainless steel in a large number of practical medium for use, and there are a lot of practical engineering experience using stainless steel pipe, as long as we have the correct selection and reasonable use of stainless steel, stainless steel corrosion accident can be prevented. Generally speaking, in the practical application, the corrosion resistance of the stainless steel pipe to advance in the medium, the corrosion rate of stainless steel pipe, master the equipment under the reasonable use of the service life. Source: China Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel pipe and carbon steel pipe can not be stacked together, because the carbon steel pipe and stainless steel pipe material is not the same, in a humid environment, if the carbon steel pipe and stainless steel pipe together is very simple attack chemical reaction, and then Damage the protective layer of stainless steel pipe, resulting in rusty stainless steel pipe. Different pieces of steel together with the touch of the words will be the potential difference, and then lead to electrochemical corrosion, especially in the case of water when the stainless steel pipe and carbon steel pipe between the electrochemical corrosion rate will be accelerated. Like the principle of the same battery, chemical energy in the chemical cell can be directly converted into electrical energy due to the internal combustion of the battery recovery response. Source: China Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The surface of the stainless steel pipe (especially after electrolytic polishing and mechanical polishing) has a good passivation layer and has a strong corrosion resistance. The inner and outer surface of the surface is clean and high, and the adhesion of the medium is rarely conducive to corrosion resistance. The less the surface finish, the less the liquid medium, which is good for washing, especially in the pharmaceutical industry. 1. Internal surface electrolytic polishing (electrochemical polishing) : electrolytic polishing liquid is phosphoric acid, sulphuric acid, chromium anhydride, gelatin, potassium dichromate, etc. The surface of the stainless steel pipe is on the anode and the polishing solution is electropolishing with low voltage and high current. At the same time, there are two contradictory processes on the surface of the pipe, namely the formation and dissolution of the passivation layer of the metal surface (including the thick mucosa). Because the surface microcosmic bulge and the concave part of the film enter passivation condition is different, and because of the anode dissolving. Because of the part surface micro convex and concave part into the membrane into the passivation condition is different, and because of the anodic dissolution, anode area metal salt concentration increasing, the surface to form a high resistance of thick mucous membrane. Different thickness of the membrane in the concave and convex leads to the surface of the anode current density is big, point discharge dissolving speed, in a short time, achieve the goal of made outstanding micro parts, can achieve very high roughness Ra 0.2 to 0.4 microns or less. Under this action, the inner table increases the chromium content and increases the corrosion resistance of the metal surface passivation layer. How to master the quality of polishing is related to electrolyte formula, concentration, temperature, current density, electrode condition and surface treatment. Technical mastery is bad it will destroy the pipe surface finish, electrolytic degree will have more greater concave and convex surface, even pipe scrap, really make good quality needs certain technology, cost is higher. 2. Internal surface mechanical polishing: rotation and linear polishing. For example, the mechanical polishing equipment is relatively simple, the power and the polishing disc, the advanced polishing equipment is relatively simple, the power and the polishing disc, advanced polishing wax. The cloth disk and cloth plate made of fine sand are used for polishing and polishing on the surface of the inner surface of the pipe for many times, and the smoothness can reach the Ra less than 0.2-0.4 mu m. Mechanical polishing and electrolytic polishing are relatively simple and easy to master, with low cost and low cost. Therefore, it is widely used. However, it is much better to electropolish the surface printing layer to resist corrosion. Source: China Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Duplex stainless steel is generally pided into four types: Cr18, Cr21, Cr25 and super duplex stainless steel with 25% to 26%. UNS S31803 is a standard duplex stainless steel, Cr21 type, accounting for more than 80% of the total duplex stainless steel. In the production of UNS S31803 is widely used, especially in the application of many operation medium acid, nitrogen, acetophenone equipment, the medium is highly toxic and explosive, temperature is generally high and equipment, close to 200 degrees, so the weld requirement is very high. Based on the wide application of UNS S31803 in production and the poor use of media in contact, it is of great practical significance to choose UNS S31803 as the welding base material to study its weldability. The composition characteristics of UNS S31803: the mass fraction of C in 0.02% ~ 0.03%, which belongs to the ultra low carbon; the mass fraction of Cr in 23% ~ 26%, belongs to the high concentration of Cr; its organizational features: two phase (austenite and ferrite) each accounted for about 50%; performance characteristics: because both ultra low carbon and iron at room temperature the ferrite and austenite, high Cr content and add features of Mo, N and other elements, so it has a higher resistance to stress corrosion, crevice corrosion resistance, Cl- corrosion, intergranular corrosion resistance, high temperature resistance and sediment erosion ability, has good mechanical properties and low thermal expansion properties, good solderability and low cost etc.. In the process of welding, the microstructure of the heat affected zone of the welded metal box has undergone a series of changes under the action of thermal cycling. The microstructure of duplex stainless steel is composed of ferrite at high temperature, while austenite is precipitated during cooling. UNS S31803 welding process should pay attention to the following three aspects: (1) welding crack. The Creq/Nieq of UNS S31803 is higher, the content of Cr is 23%, and the content of Ni is 6.5%, that is duplex stainless steel UNS S31803 Creq/Nieq=3.54. Therefore, the weld of UNS S31803 belongs to the ferrite solidification zone, and has certain sensitivity to solidification cracks. Therefore, in the welding process, it is necessary to use appropriate welding materials, welding methods and control welding process parameters, so that the welding seam has a good ability to resist solidification cracks. Cold crack is related to the delayed crack susceptibility of hydrogen, but the cold crack can be avoided if the welding material is used correctly. (2) embrittlement of heat affected zone. In the welding process, the weld heat affected zone is in a fast cooling non-equilibrium state, and more ferrite is retained after cooling so as to increase the corrosion tendency and the susceptibility to hydrogen induced cracking. Therefore, the main problem of UNS S31803 welding is the heat affected zone. The main problem of heat affected zone is the loss of corrosion resistance, toughness loss and post weld crack. In order to avoid these problems, the welding process should consider reducing the material at a temperature range of hot time. (3) stomatal sensitivity. The formation of pores depends on the welding parameters and alloy composition. In order to prevent porosity and reduce porosity sensitivity, the nitrogen content in the weld should be controlled during the welding process, so as to strengthen the protection of the welding seam and improve the permeability of the slag. Source: China Duplex Stainless Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The stainless steel pipes of different sizes, in accordance with the stainless steel pipe welding unique place, as far as possible to reduce the amount of heat input, so the use of manual electric arc welding and argon arc welding of two methods, d> with the diameter of 159 mm using the argon arc welding, manual arc cap. The TIG D is less than or equal to 159 mm. Stainless steel pipe welding technical requirements are as follows: In manual arc welding, the welding machine adopts DC reverse welding, and the DC welding is adopted in the argon arc welding; The welding should be welding wire for stainless steel wire brush off the surface oxide, and washing with acetone; electrode should be at 200-250 deg.c drying 1H, the; Before welding, clean the oil in the range of 25 mm within the groove of the workpiece, and clean the 25 mm area on both sides of the groove with acetone; When argon arc welding, the nozzle diameter is 2 mm, and the tungsten is a bowl of tungsten tungsten. The specification is 2.5 mm; When argon arc welding of stainless steel, the back must be filled with argon to protect the back. Using the method of partial argon filling in the pipeline, the flow rate is 5-14L/min, and the positive argon flow rate is 12 13L/min. When the weld backing welding thickness should be as thin as possible, and root fusion to become outstanding, the arc slope, such as arc shrinkage, application of grinding out. The arc extinguishing shall be carried out in the groove, and when the arc is extinguished, the arc pit shall be filled to prevent the crack in the arc pit. Because the stainless steel pipe fittings for austenitic stainless steel pipe, to prevent the precipitation of carbide sensitization and intergranular corrosion, should strictly control the layer temperature and cooling rate after welding, welding interlayer temperature controlled at 60 DEG C, cooling after welding must immediately, at the same time by welding. This symmetrical and dispersed welding sequence can increase the cooling rate of the joint and reduce the welding stress. Source: China Steel Pipes Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

How to keep and transport stainless steel pipe fittings? Many people have doubts on this issue, fear of stainless steel pipe fittings will be contaminated and damaged, wilsonpipeline Pipe Industry Co., Limited according to their own experience, to give you the best answer. Here’s our experience: 1. Stainless steel pipe fittings should be sealed at both ends of the pipe to avoid dust and other sources of pollution into the pipe to prevent the deformation of the tube during transport; 2. Stainless steel pipe fittings should be outside the protective material to prevent the custody and transportation of water, dust, to prevent the appearance of the pipe was scratched; 3. Stainless steel pipe fittings in the transport process should be lightly moved, can not be squeezed by heavy objects to prevent the physical impact of pipe deformation; 4. Stainless steel pipe fittings should be packaged bags to prevent contamination of pipe fittings. 5. Stainless steel pipe fittings are packed with waterproof cardboard boxes, or wooden boxes. In the custody or transport works to do so to maximize the guarantee of stainless steel pipes and stainless steel pipe fittings are not contaminated and damaged. wilsonpipeline Pipe Industry Co., Limited to follow the “no 1% of the negligence, resulting in 100% inconvenience to customers,” the service concept, and carefully build first-class service level, first-class product quality. Source: China Pipe Fittings Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Different pipe elbows have different materials. The main difference between the stainless steel elbow and the carbon steel elbow is that the chemical composition of the stainless steel elbow will keep the elbow surface from rusting for a long time and will not corrode easily. Stainless steel elbow material is to maintain elbow, will not produce quality problems, ensure the service life of elbow, guarantee elbow can play an important role in use. Stainless steel has different types, and different types of stainless steel contain different components, and their properties are different. Stainless steel Steel with stainless steel, corrosion resistance, chromium content of at least 10.5%, and carbon content of no more than 1.2%. austenitic stainless steel The matrix is mainly the austenite structure (gamma phase) of the face centered cubic structure, without magnetism, which is mainly strengthened by cold working (and may lead to a certain magnetic) stainless steel. AUSTENITIC FERRITIC (duplex) stainless steel The matrix of both austenite and ferrite two-phase structure (including content is less than 15% of the general), magnetic, can through the cold strengthens the stainless steel. Ferritic stainless steel The matrix is based on ferrite structure (alpha phase) in the body centered cubic crystal structure, and has magnetic properties which are generally not hardened by heat treatment but can be slightly hardened by cold working. Martensitic stainless steel The matrix is a martensitic structure with magnetic properties, and the mechanical properties of the stainless steel can be adjusted by heat treatment. Precipitation hardened stainless steel The matrix is made of austenite or martensite and can be treated by precipitation hardening (also known as age hardening) to make it hard (strong) stainless steel. The above is about the different properties and different matrix of stainless steel, stainless steel with different properties and uses and value in use, in use and making elbow to choose different material of stainless steel production and production, to ensure the production of stainless steel elbow with good product performance and use. Source: China Pipe Elbows Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Sulfuric acid is an important fundamental chemical raw material, its output value is often a symbol of a country’s industrial development level. For the production of acid equipment and acid-filled tanks, containers and other general selection of acid-resistant stainless steel pipe. Although sulfuric acid is an oxygenic acid, dilute sulfuric acid and medium concentration of sulfuric acid oxidation is weak, so they are attributed to the reductive acid. And concentrated sulfuric acid, especially hot concentrated sulfuric acid is a strong oxidizing, and thus attributed to oxidizing acid. Because of this characteristics of sulfuric acid, in the selection of sulfuric acid resistant stainless steel pipe, with the sulfuric acid concentration, the temperature is not the same, the selected grades are not the same. Dilute sulfuric acid, medium concentration of sulfuric acid is reduced, can be selected 316 stainless steel pipe, 316L stainless steel pipe, 316Ti stainless steel pipe containing molybdenum in 2% to 3% of the stainless steel pipe. Molybdenum-free stainless steel pipe 18-8 Cr-N austenitic stainless steel, because it is not resistant to dilute sulfuric acid, medium concentration of sulfuric acid corrosion, it can not be used for sulfuric acid corrosion situation. When the high molybdenum content (Mo ≥ 4%), the corrosion resistance of the stainless steel pipe will be further improved. Steel containing molybdenum, copper, silicon (3% to 4%) of chromium-nickel austenitic stainless steel and duplex stainless steel pipe resistance to sulfuric acid better. In the concentration of 90% to 98% of the high temperature concentrated sulfuric acid, according to the use of temperature and concentration, the choice of silicon about 6% of stainless steel can get a satisfactory effect, such as 022Cr17Ni17Si6,022Cr18Ni20Si6MoCu. In the production of pickling, synthetic rubber, rayon dipping tank and sulfuric acid touch equipment, optional 06Cr18Ni18Mo2Cu2Ti stainless steel pipe. In the production of sulfuric acid corrosion resistant pipes, pumps, valves, towers and containers and other equipment and components, can choose 06Cr12Ni25Mo3Cu3Si2N stainless steel pipe. Source: China Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)