[0029] The embodiment of the production process of the steel pipe fitting of the present invention will be further described below.
[0030] A production process for steel pipe fittings (applicable to pipe fittings of stainless steel, alloy steel and carbon steel elbows, tees, pipe caps, heads and flanges, etc., the diameter of the metric system is from DN15 to DN1200, and the inch system is from 1/2″ to 48″; wall thickness from 10S to 80S), including the following steps in sequence:
[0031] 1) Cutting and cutting corners and burrs: The operator takes the pipe and checks its material and surface quality, measures the inner and outer diameters of the pipe, the thickness of the pipe and the plate, and cuts the pipe on the sawing machine with a diameter of 8" (inclusive), 10" ( Including) The above use plasma cutting and cutting. When using plasma cutting, first mark the line according to the template and cut according to the line. When cutting the steel pipe, the pipe should be placed in the pipe or coated with anti-splash liquid to prevent the splash from sticking to the pipe and cutting the steel plate When the steel plate surface is coated with anti-spatter liquid; use a punch to cut the angle of the pipe diameter below 8" (inclusive), and use a grinder to grind the outer burr of the pipe, use an inner hole machine to grind the inner burr, and use a saw or plasma cutting for more than 8” (inclusive) Cut corners, inner burrs and outer burrs are all processed with angle grinders. When cutting the sawing machine, first adjust the saw blade, pay attention to the correct direction of the saw teeth, and then fix it. Loosen the clamp, place the work in the jaws and check whether the saw length meets the requirements. Note that the welding seam must be placed directly above or below the pipe bending saw material, and then clamp the work object and press the motor switch and make the saw blade slowly contact the workpiece. The rough edges must be fully ground (including the inner and outer surfaces and end surfaces). The ground pipe fittings must be blown clean with an air pump.
[0032] 2) Cold press forming: The purpose of cold press forming is to cold press the pipe fittings into the required shape with a cold press process, and to ensure that its size and quality meet the requirements. It mainly includes the processing steps and precautions of the following pipe fittings:
[0033] 2.1) Cold forming of elbow: The steps are 1. Confirm whether the content of the workpiece and the process card are consistent; 2. According to the process card, select the appropriate mold and core; 3. Load the mold into the equipment, and install the push head Put it on the ejector rod and adjust it to make the height of the pusher basically the same as the center height of the mold; 4. Install the mandrel on the equipment, and adjust the mandrel to make the gap with the mold even; 5. Adjust the stroke of the push rod, The push head can be pushed to the proper position to ensure that the molded pipe meets the process requirements; 6. Adjust the pressure of the clamping cylinder and the pushing cylinder; 7. After all adjustments are made, the mold and the equipment are connected firmly and reliably. And idling once; 8. Put the tube blank to be formed into the mold, and align the angle of the tube blank. Start forming; 9. Put the steel plate on the lower mold, adjust the position, and start press forming. Pay attention to during processing 1. Hydraulic oil should be added to the hydraulic system at any time; 2. The material must have a protective layer, and graphite lubricant can be applied to the difficult to form large-size pipe fittings; 3. Check items in advance: a full set of mold parts (upper and lower molds, Whether the pusher block, bolts, pressing plate, baffle, wedges, mandrel, etc.) are complete and easy to use; 4. The slide block of the machine should be kept lubricated and strictly follow the safety operation regulations; 5. The position of the weld bead should be in the bent part during forming 6. When the steel plate is formed, pay attention to its position must be adjusted properly and not be biased.
[0034] 2.2) Three-way cold forming: The steps are 1. Confirm whether the content of the workpiece and the process card are consistent; 2. According to the process card, select the appropriate mold, ejector pin and ejector rod; 3. Install the mold and ejector pin on the three When the machine is turned on, pay attention to the holed ejector pin into the oil-filled end of the belt, and adjust the position of the mold to make the ejector rod move normally in the cavity; 4. Connect the lower mold to the equipment firmly, and then adjust the upper mold to make it It is suitable for mold clamping with the lower mold, and the upper mold is firmly connected with the equipment; 5. Install the demolding rod, and debug it to run normally; 6. After all adjustments, check that all connections are firm and reliable, and run dry to ensure that it is normal Work; 7. Load the tube blank, first jog the shape, and then automatically shape; 8. The steel plate is pressed on a four-column press; 9. The steel plate is placed on the lower mold and the position is adjusted, and then the pressing is started. Pay attention to during processing 1. Check in advance whether the complete set of mold parts (upper and lower molds, ejector pins, stripping rods, bolts, pressing plates, etc.) are complete and easy to use, whether the mold is cleaned, whether the burrs on both ends of the workpiece are ground, and the workpiece is protected Whether the layer is suitable; 2. Note that the position of the weld bead should be directly above the cavity of the seamed pipe; 3. Note that the thickest part of the seamless pipe should be placed directly below the cavity; 4. When two people operate, one person must be used Responsible and command, consistent with each other; 5. Operators should submit the first piece for inspection, and random inspections should be carried out from time to time during forming; 6. Pay special attention to the inspection of the length of the tee main pipe, the wall thickness and height of the branch pipe; 7. Pipe fittings Handle with care and place neatly.
[0035] 2.3) Cold forming of small and small heads: the steps are 1. Confirm whether the content of the workpiece and the process card are consistent; 2. According to the process card, select the appropriate mold, inner core and stripping template; 3. Place the mold under the four-column hydraulic press, pay attention The minimum closing height of the machine tool, if necessary, add an auxiliary workbench; 4. The mold should be in the center of the upper workbench, and eccentric pressing is not allowed; 5. An auxiliary sling is installed on the upper workbench to facilitate the turning of the forming mold; Run the equipment once in a dry run to check whether the actions are suitable and make appropriate adjustments if necessary; 7. Load the tube blank with a protective layer for forming; 8. After the steel plate is cut, directly use the plate bending machine to roll the shape. Pay attention to during processing 1. Check in advance whether the full set of mold parts (forming mold, core mold, stripping template, bolts, pressing plate and other auxiliary tools, etc.) are complete and easy to use, whether the mold is cleaned, and whether the burrs on both ends of the workpiece are ground clean , Whether the protective layer of the workpiece is appropriate; 2. Pay attention to the position of the weld bead on the straight edge when the seam pipe is formed eccentrically; 3. Ensure that the equipment works within the maximum and minimum closed height range, and never allow over-limit work to prevent Equipment and personal accidents; 4. At work, be attentive, focused, and not allowed to be distracted or slipping away; 5. Operators should submit the first piece for inspection, and random inspections should be carried out from time to time during molding; 6. Two-person operation At the time, one person must be responsible and instructed to coordinate with each other; 7. The pipe fittings should be handled gently and placed neatly; 8. The steel plate rolling should be adjusted in time, especially the eccentric size head.
[0036] 2.4) Cold forming of the pipe cap: the steps are 1. Confirm whether the workpiece is consistent with the content of the process card; 2. According to the process card, select the appropriate mold; 3. Place the forming mold on the lower worktable of the four-column hydraulic press. The central part of the equipment; 4. Install the inner forming mold on the workbench of the equipment, and the connection is firm and reliable; adjust the appropriate gap with the lower mold, and tighten the connection between the lower mold and the equipment; 5. After all adjustments are made, check it again All connections are firm and reliable, and run once in an empty to ensure normal operation; 6. Install the circular plate and press it into shape. Pay attention to during processing 1. Check in advance whether the complete set of mold parts (forming mold, inner mold, fixing frame, bolts, pressure plate, etc.) are complete and easy to use, and whether the protective layer of the workpiece (coated with graphite lubricant) is suitable; 2. Small size pipe cap The blanking method is used for blanking, and plasma or waterjet cutting is used for large-scale cutting; 3. The burrs around the sheet must be cleaned; 4. The tolerance of the sheet must not exceed the positioning size; 5. The tightness of the pressing plate is appropriate. ; 6. The operator should submit the first piece for inspection, and random inspections should be carried out from time to time during forming; 7. Pay special attention to the inspection of the wall thickness and fine cracks around the cap.
[0037] 2.5) Flanging cold forming: The steps are 1. Confirm whether the content of the workpiece and the process card are consistent; 2. According to the process card, select the appropriate mold; 3. Place the forming mold on the lower worktable of the four-column hydraulic press. The central part of the equipment; 4. Install an auxiliary sling on the upper workbench to facilitate the turning of the forming mold; 5. Small-size flanging is formed by non-welding pressing; 6. After all adjustments, check all the appliances and run it once , To ensure its normal operation; 7. Load the tube blank and press it into shape; 8. The flanging of the pipe diameter of 24" and above is welded by steel plate: the straight pipe part is cut into a straight pipe, and the large plate part is cut into a ring. The car is equipped with inner holes, paired, and then welded to form. Pay attention to during processing 1. Check in advance whether the complete set of mold parts (forming mold, press mold, inner mold, fixing frame, bolts, pressure plate, etc.) are complete, easy to use, and protect the workpiece Whether the layer (coated with graphite lubricant) is appropriate; 2. The burrs at both ends of the pipe material must be removed cleanly; 3. The material flow control should be paid attention to when the small size flanging is pressed; 4. The blanking size is guaranteed to be within the tolerance range; 5. The hydraulic press cannot be eccentrically pressed 6. The operator should submit the first piece for inspection, and random inspections should be carried out from time to time during forming; 7. Pay special attention to the wall thickness and outer diameter and height of the flanged pan to meet the finishing requirements; 8. Steel plate welded flanged straight pipe The steel plate of different thickness is used for the plate and the plate. After the plate is rolled, it should be leveled.
[0038] 3) Semi-inverted operation: The semi-inverted operation is to remove the excess part of the cold-pressed stainless steel, alloy steel and carbon steel pipe ends by mechanical processing or cutting, leaving a machining allowance for the finished chamfer . Half-reversed pipe fittings use welding tools or quick-change blades, made of YG6. Before processing, use a brush or air pump to remove dust, iron filings and other debris on the pipes and fixtures. Turn on the power and start the chamfering machine. If the speed needs to be changed, stop and open the wheel box and replace the wheel. Install and adjust the fixture, and press firmly. Adjust the appropriate range and amount of feed. Put the semi-finished pipe fittings into the mold, and adjust the positions of both ends appropriately. Start the equipment, start jog cutting, and automatically cut after normal. Pipe diameters below 8" (including) are half-turned on the chamfering machine, 10"~24" half-turned on the beveling machine, and the half-turning of the plate pipe fittings above 26" is carried out by scribing and plasma cutting. The acceptance standard is based on the inspection that its geometric size is 3~5mm larger than the requirements of the relevant technical specifications, and the machining allowance of the finished product under 8" (including) is 3mm, and the remaining half of the finished product is 5mm. Only those who meet the requirements Judged as qualified.
[0039] 4) Heat treatment: heat treatment is for the solid solution, annealing and normalizing treatment of stainless steel, alloy steel and carbon steel pipe fittings after cold pressing to eliminate stress and meet the quality requirements of pipe fittings. Put the semi-finished products that need heat treatment in the basket, and the 1/2”, 3/4”, 1” pipe fittings shall not exceed 1/3 of the volume of the heat treatment basket. 1 1/4”, 1 1/2”, 2”, 2 The 1/2" pipe fittings shall not exceed 2/3 of the volume of the heat treatment basket. Pipe fittings of different materials cannot be mixed into the same furnace for processing. For stainless steel, the first furnace should be empty and heated to 1000 ℃ ± 25 ℃, and the heat preservation is 0.5 Hours, the temperature should not be lower than 800℃ when each furnace is put into the furnace. For alloy steel and carbon steel, the heating temperature is set in the range of 890℃~940℃, and the temperature is kept for 20 minutes. Use a forklift to move the basket fork with stainless steel pipe fittings Put it into the furnace, heat up to 1070 ℃ ± 20 ℃, keep the temperature for 20 minutes. Once the constant temperature time is up, quickly take out the stainless steel basket, put it into the cooling water, and swing in the water for 2 minutes, let the pipes completely cool down and take them out. Alloy steel and The carbon steel basket is taken out, placed in a dry place, and air-cooled. The operator must inspect each furnace tube and use a magnetic pen to check the stainless steel tube. It must not have residual magnetism, and the alloy steel and carbon steel tube should have no cold forming stress. One piece of each furnace shall be taken for hardness inspection, and the average value shall be measured at 5 points and recorded in the heat treatment inspection record table. The hardness of stainless steel shall be lower than HRB90 or HB≤187. Alloy steel and carbon steel HB≤180. Visual inspection Method, observe whether the surface color is consistent, and mottling is not allowed. The hardness test is carried out in accordance with GB230-85. The magnetic test stainless steel uses a φ10×4 mm magnet to test the pipe fittings after solution treatment. If there is between the magnet and the workpiece Obvious suction power is judged as unqualified.
[0040] 5) Shaping: Shaping is to make the shape and size of the stainless steel pipe fittings after solid solution, through this process to meet the standard quality requirements of the production of pipe fittings. First install the mold and adjust each stroke position to the correct position, being careful not to bias. If necessary, apply a protective layer to the semi-finished product to prevent plastic strain. The elbow is first flared, then flattened, and then molded; the tee is first flattened and then molded; the others are directly shaped with a forming mold and a suitable inner mold to ensure that the geometric size and shape tolerance meet the requirements of the standard.
[0041] 6) Polishing: The polishing operation is to make the pipe fittings that have been reshaped, the shape and size have fully met the requirements of the specified manufacturing standards, and the inner and outer surfaces of the pipe fittings are polished to cause the inner and outer surfaces of the pipe fittings to be strained by the previous process Defects such as unevenness and unevenness are removed to make the surface bright and smooth. During internal polishing, the workpiece should be clamped in a bench vise, and both hands should be held firmly by the electric grinder or air grinder, and the work should be concentrated and concentrated, and the machine should be stopped when changing the workpiece. Polishing of large pipes uses vibrating rods for internal and external polishing of pipes. The operator should make visual inspection of each piece after polishing. The quality inspector conducts random inspections and, if found to be unqualified, he shall notify the operator to perform his own inspection and rework until the appearance is qualified.
[0042] 7) Shot blasting and sand blasting: The shot blasting or sand blasting operation is to perform surface shot blasting of the polished pipe fittings in a crawler or hook type shot blasting machine. The large pipe fittings use a compressor and a sand blasting mechanism to blast the inside and outside of the pipe fittings. Perform surface treatment. The shot blasting machine required for the shot blasting operation should be qualified. The pipe fittings below 6" (including) are shot in the crawler shot blasting machine, and the pipe fittings above 8" (including) are shot blasted in the hook type shot blasting machine. The shot uses 0.5mm alloy steel shot. Sandblasting is a surface treatment method used for large pipe fittings above 24". The sand is made of sand. The operator checks the "Product Process Card" to check whether the specifications, quantity, and identification of the semi-finished products are correct. Open the shot blasting machine door to 6" or less ( Included) pipe fittings are placed on the drum liner, and the quantity shall not exceed 2/5 of the capacity of the shot blasting machine; hang the 8" or more (inclusive) pipe fittings on the hook to ensure their balance and free access and rotation. Shot blasting machine door, and check whether the fixed pin is properly buckled to prevent loosening. Shot blasting time control: about 25 minutes below 4″; about 30 minutes above 4″. When the shot blasting time is up, turn off the stop switch and wait for all to stop After it is stable, the machine door can be opened, the pipe fittings can be taken out, and they should be placed neatly in the designated place. The operator should perform visual inspection on each piece after polishing. Finally, the operator should check whether there are deposits or surface defects in the pipe fittings after shot blasting. Whether the outer color of the pipe fittings is uniform.
[0043] 8) Finished product chamfering: The finished product chamfering operation is to make the length, elevation and welding groove angle of pipe fittings meet the standard. Quick-change alloy blades are used for chamfering of pipe fittings, made of YG8. First turn on the power and start the chamfering machine. If the speed needs to be changed, stop and open the wheel box and replace the wheel. Install and adjust the fixture, and press firmly. Adjust the appropriate range and amount of feed. Adjust the cutting surface of the tool, and the position and angle of the three tools at each end are appropriate. Adjust the jig and the feed to make the workpiece's elevation cutting surface correct. Put the semi-finished pipe fittings into the mold, and adjust the positions of both ends appropriately. Manual single-head trial feed cutting and adjustment at any time to ensure the best position. Double-head jog cutting the first piece, after qualified, fix all adjustments. Switch to the automatic program to start work. For pipes larger than 10", use beveling machine chamfering.
[0044] 9) Surface treatment: The surface treatment operations are divided into pickling passivation and painting operations. The pickling passivation operation is to remove impurities on the surface of stainless steel pipe fittings and form a passivation film to make the surface color of the pipe fittings uniform and meet the surface quality requirements of the pipe fittings. . Painting operation is to paint the surface of finished alloy steel and carbon steel pipe fittings to protect the surface from corrosion. During pickling passivation, the size of the pickling tank should be sufficient to accommodate the pipe fittings that need to be pickled, and there are sufficient quantities of 55% hydrofluoric acid and 98% nitric acid. During the operation, first blow the inner and outer surfaces of the stainless steel pipe fittings to be pickled with an air pump, and put them neatly into the pickling passivation basket. After that, soak the pickling basket with pipe fittings in the acid solution (hydrofluoric acid: nitric acid: water=1:1:10) with a crane for 10-20 minutes. The acid concentration should not be too high, otherwise water will leak out of the pipe surface. Traces or a layer of colored film; pipe fittings should not be soaked in acid for too long, otherwise there will be a white mist on the chamfered surface. Lift the pickling passivation basket with a crane, wash the pipe fittings with water, and use a high-pressure water gun to rinse the residual acid on the surface and the cavity. If necessary, wash the inner and outer surfaces of the pipe fittings with detergent solution. Arrange the pipe fittings neatly on the stainless steel wire mesh and do not overlap to facilitate the flow of water, and place them in a ventilated environment to air dry, or put them in a drying box to dry quickly to avoid water marks on the surface. After each batch of pipe fittings are pickled and passivated, the operator observes that the color of the pipe fittings should be uniform and free of dirt. If there is uneven color or dirt, they should be pickled again. The inner and outer surfaces of alloy steel and carbon steel pipe fittings are sprayed with a spray gun to control the uniform paint surface.
[0045] 10) Inspection: In addition to inspecting the appearance quality and geometric dimensions, non-destructive inspection is also performed according to customer requirements or relevant standards. According to the following standards: State Council Order No. 373 (March 11, 2009)-Special Equipment Safety Supervision Regulations; Ministry of Labor issued (1996) No. 140-Pressure Pipeline Safety Management and Supervision Regulations; issued by the Bureau of Quality and Technology Supervision (2000) ] No. 07-Safety Registration and Management Measures for Pressure Piping Components Manufacturing Units; GB12459-2005-Steel Butt Welding Seamless Pipe Fittings; GB/T13401-2005-Steel Plate Butt Welding Pipe Fittings; H3408-96-Steel Pairing Welded seamless pipe fittings; SH3409-96-steel plate butt welding pipe fittings; SME/ANSI B16.9-2007-factory-manufactured forged steel butt welding pipe fittings; DIN2605-92-German standard pipe fittings; GB/T10752-2005— —Marine pipe fittings, etc. Including X-ray inspection, ultrasonic inspection, magnetic particle inspection and penetrant inspection, etc.
[0046] 11) Finished product identification: in order to identify product specifications and materials and trace product quality issues to ensure product traceability. The steps are carried out according to customer requirements or company internal regulations, and final material confirmation of product materials is carried out before marking.
[0047] 12), packaging and storage, according to customer requirements, to prevent moisture, rust, collision and deformation.
[0048] The above embodiments only describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications made by ordinary engineers in the art to the technical solutions of the present invention All improvements and improvements should fall within the scope of protection determined by the claims of the present invention.
