A multi-angle special-shaped steel pipe processing process

Abstract

The application provides a multi-angle special-shaped steel pipe processing technology and relates to the technical field of steel pipe processing.A multi-angle special-shaped steel pipe processing technology comprises the following processing steps:S1, steelmaking;S2, component injection molding processing;S3, blank reprocessing;S4, blank assembly;S5, special-shaped pipe blank forming;S6, special-shaped pipe blank heat treatment;S7, cutting, polishing and corrosion prevention treatment.By sleeving a secondary lining pipe on the inside of a primary lining pipe, inserting a clamping plate and a V-shaped plate into the primary lining pipe, pouring molten steel into the gap until the gap is filled with the molten steel, and solidifying the molten steel in the gap after natural cooling, compared with the traditional special-shaped steel pipe processing which needs to customize more stamping dies and forming processing equipment and has high processing investment cost, the dies used in the processing technology can mostly be the dies for conventional circular steel pipes, the processing cost is lower, and the multi-angle special-shaped steel pipe has higher strength and better bending resistance than the hollow special-shaped steel pipe.

Description

Technical Field

[0001] This invention relates to the field of steel pipe processing technology, specifically to a processing technology for multi-angle irregular steel pipes. Background Technology

[0002] Special-shaped seamless steel pipes are a general term for seamless steel pipes with cross-sectional shapes other than round pipes. According to the different cross-sectional shapes and sizes of steel pipes, they can be divided into special-shaped seamless steel pipes with equal wall thickness, special-shaped seamless steel pipes with unequal wall thickness, and special-shaped seamless steel pipes with variable diameter.

[0003] Currently, the processing of multi-angle special-shaped steel pipes requires customized stamping die sets. When processing multi-angle special-shaped steel pipes of different sizes, more die sets of various specifications are required, which makes the processing cost of multi-angle special-shaped steel pipes very high. Furthermore, the strength of multi-angle special-shaped steel pipes that are directly stamped and welded is lower than that of cylindrical pipes of the same specifications, and they are more prone to bending. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a processing technology for multi-angle shaped steel pipes, which solves the problems of high processing costs, low strength, and easy bending of existing multi-angle shaped steel pipes.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a processing method for multi-angle irregular steel pipes, comprising the following processing steps:

[0008] S1. Steelmaking

[0009] First, pig iron is added to the converter, and the converter temperature is controlled at 1550℃~1600℃ to smelt the pig iron. Then, air is blown into the molten pig iron to oxidize impurities such as silicon and manganese. A certain amount of quicklime is added, and then air is blown in and the converter is rotated to make it upright. At this time, the surface of the liquid pig iron reacts violently, causing iron, silicon, and manganese to oxidize and form slag. Utilizing the convection of molten steel and slag, the reaction is spread throughout the entire furnace. After 5 to 10 minutes, when only a small amount of silicon and manganese remain in the molten steel, carbon begins to oxidize, generating carbon monoxide, which causes the molten steel to boil violently. A huge flame appears at the furnace mouth due to the combustion of overflowing carbon monoxide. Finally, phosphorus is also oxidized and further generates ferrous phosphate. Ferrous phosphate then reacts with quicklime to generate stable calcium phosphate and calcium sulfide, which together become slag. When phosphorus and sulfur gradually decrease, the flame recedes, and brown steam of iron(III) oxide appears at the furnace mouth, it indicates that the steel has been smelted. At this time, the blowing is stopped immediately, and the converter is rotated to a horizontal position to add deoxidizer to obtain molten steel.

[0010] S2. Component Injection Molding

[0011] First, preheat the component mold of the multi-angle special-shaped steel pipe, then pour the molten steel obtained in step S1 into the mold and obtain the main liner, secondary liner and steel plate after cooling and demolding. Then cut the steel plate to obtain the clamping plate, and then heat the steel plate to 1000℃~1250℃ and put it into the mold for stamping to obtain V-shaped plate.

[0012] S3. Reprocessing of blanks

[0013] First, make several M-shaped grooves vertically and equidistantly around the outer perimeter of the main liner tube obtained in step S2, and make several insertion holes vertically and equidistantly between each pair of adjacent M-shaped grooves. Then, cut slots on the card plate according to the distance between the upper and lower ends of the adjacent insertion holes to form insertion blocks between the slots. Finally, make through holes in the middle of each insertion block, and cut beveled surfaces on both sides of the end of the card plate away from the insertion block according to the inner angle of the V-shaped plate.

[0014] S4. Blank Assembly

[0015] First, seal the bottom of the main liner tube with high-temperature resistant material. Then, fit the secondary liner tube inside the main liner tube, creating a gap between the outer wall of the secondary liner tube and the inner wall of the main liner tube. Next, insert the insert of the clamping plate into the insertion hole of the main liner tube. Then, insert both ends of the V-shaped plate into the M-shaped grooves on both sides of the corresponding insertion hole, allowing the side with the beveled edge to be inserted into the inner angle of the V-shaped plate. At this point, fix the clamping plate in the inner angle of the V-shaped plate by spot welding the two ends of the clamping plate. Then, pull the clamping plate out of the insertion hole and weld the two sides of the connection between the clamping plate and the inner angle of the V-shaped plate. Complete the assembly of all clamping plates and V-shaped plates in this way. Then, insert all the clamping plates into the insertion hole of the main liner tube, while inserting both ends of the V-shaped plate into the corresponding M-shaped grooves. Then, weld the gap connecting the two ends of the V-shaped plate. Finally, tie the V-shaped plate around the main liner tube with steel wire.

[0016] S5. Forming of irregularly shaped tube blanks

[0017] First, place the assembled blank obtained in step S4 vertically, then pour the molten steel obtained in step S1 into the gap until the gap is filled. After natural cooling, the molten steel in the gap solidifies and forms a shape. Then remove the steel wire tied to the V-shaped plate. At this time, the multi-angle irregular tube blank is formed.

[0018] S6. Heat treatment of irregularly shaped tube blanks

[0019] Normalizing: The shaped tube blank obtained in step S5 is placed in the furnace and heated to Ac3 or Acm. After holding at the temperature for a period of time, the shaped tube is taken out of the furnace and cooled by spraying water or blowing air in the air to refine the grains and uniformly distribute the carbides, remove the internal stress of the material, stabilize the size of the workpiece, and prevent deformation and cracking.

[0020] Tempering: After the normalized and cooled shaped tube is placed back into the furnace for heating, and then kept at that temperature for a period of time. After that, the shaped tube is taken out of the furnace and cooled by spraying water or blowing air in the air to eliminate the internal stress of the shaped tube blank after normalizing and improve the mechanical properties of the shaped tube.

[0021] S7. Cutting, polishing, and anti-corrosion treatment

[0022] Cut off both ends of the shaped tube obtained in step S6, then polish the surface of the shaped tube, and finally perform anti-corrosion and anti-oxidation treatment on the surface of the shaped tube to obtain the finished multi-angle shaped steel pipe.

[0023] Preferably, in step S2, the preheating temperature of the multi-angle irregular steel pipe component mold is 850-900℃, and the mold is kept at a constant temperature after preheating.

[0024] Preferably, in step S3, the width of the insertion hole is slightly greater than the thickness of the card plate, and the height of the insertion block is slightly lower than the height of the insertion hole.

[0025] Preferably, the high-temperature resistant material in step S4 is silicon dioxide, and the length of the insert block extends through the insertion hole and contacts the outer wall of the sub-liner.

[0026] Preferably, in step S6, the normalizing temperature to Ac3 is 727℃~912℃, the heating temperature to Acm is 750℃~960℃, the tempering temperature in step S6 is 500~650℃, and the holding time in step S6 is 40~60min.

[0027] (III) Beneficial Effects

[0028] This invention provides a processing technology for multi-angle irregular-shaped steel pipes. It has the following beneficial effects:

[0029] 1. This invention obtains a main liner tube, a secondary liner tube, and a steel plate through steel injection molding. Then, plates and clamping plates are cut from the steel plate according to the required specifications. Finally, V-shaped plates are obtained by heating and stamping the plates. Insertion holes and M-shaped grooves are made on the main liner tube. Insert blocks and beveled surfaces are cut on the clamping plates, and through holes are made on the insert blocks. The bottom end of the main liner tube is then sealed with a high-temperature resistant material. The secondary liner tube is then fitted inside the main liner tube. The clamping plates and V-shaped plates are then combined and inserted into the main liner tube. Molten steel is then injected into the gap until it fills the gap. After natural cooling, the molten steel in the gap solidifies and forms a shape. Normalizing and tempering heat treatments are then performed to increase the mechanical properties of the shaped tube. Finally, after cutting, polishing, and anti-corrosion treatment, a multi-angle shaped steel pipe is obtained. Compared to traditional shaped steel pipe processing, which requires many customized stamping dies and forming equipment, resulting in high processing costs, the dies used in this invention can mostly be the same as those for conventional round steel pipes, and there is no need for specialized equipment for forming shaped tubes, thus reducing processing costs.

[0030] 2. The present invention uses the main liner, the secondary liner, the clamping plate, and the molten steel poured into the gap to solidify, which play a supporting and reinforcing role in the multi-angle special-shaped steel pipe composed of V-shaped plates. This makes the formed multi-angle special-shaped steel pipe stronger and better resistant to bending than the hollow special-shaped steel pipe. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall splicing structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the disassembled structure of the present invention;

[0033] Figure 3 This is a schematic diagram of the disassembled structure of the V-shaped plate and the card plate of the present invention;

[0034] Figure 4 This is a schematic diagram of the main liner and inner liner of the present invention.

[0035] Among them, 1. main liner tube; 2. secondary liner tube; 3. V-shaped plate; 4. clamping plate; 5. M-shaped groove; 6. insertion hole; 7. beveled surface; 8. clamping edge; 9. clamping groove; 10. insertion block; 11. through hole; 12. gap. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1:

[0038] like Figure 1-4 As shown in the figure, an embodiment of the present invention provides a processing technology for multi-angle special-shaped steel pipes, including the following processing steps:

[0039] S1. Steelmaking

[0040] First, pig iron is added to the converter, and the converter temperature is controlled at 1550℃ to melt the pig iron. Then, air is blown into the molten pig iron to oxidize impurities such as silicon and manganese. This oxidation process releases a large amount of heat, allowing the furnace to reach a sufficiently high temperature. Therefore, converter steelmaking does not require additional fuel. Converter steelmaking takes place inside a pear-shaped furnace with refractory bricks on the inner wall and many small tuyeres on the sides. Compressed air is blown into the furnace through these tuyeres, hence the name "side-blown converter." A certain amount of quicklime is added, and then air continues to be blown in while the converter is rotated to make it upright. At this point, a violent reaction occurs on the surface of the molten pig iron, causing iron, silicon, and manganese to oxidize and form slag. The convection between the molten steel and the slag further facilitates the reaction... Throughout the entire furnace, after 5 minutes, when only a small amount of silicon and manganese remain in the molten steel, carbon begins to oxidize, generating carbon monoxide, which causes the molten steel to boil violently. A huge flame appears at the furnace mouth due to the combustion of the overflowing carbon monoxide. Finally, phosphorus also oxidizes and further generates ferrous phosphate. Ferrous phosphate then reacts with quicklime to generate stable calcium phosphate and calcium sulfide, which together become slag. When phosphorus and sulfur gradually decrease, the flame recedes, and brown ferric oxide vapor appears at the furnace mouth, it indicates that the steel has been refined. At this point, the blasting is immediately stopped, and the converter is rotated to a horizontal position to add deoxidizer for deoxidation to obtain molten steel. Using an oxygen top-blown converter, which blows in high-pressure industrial pure oxygen, the reaction is more vigorous, which can further improve production efficiency and steel quality.

[0041] S2. Component Injection Molding

[0042] First, preheat the component mold of the multi-angle special-shaped steel pipe, then inject the molten steel obtained in step S1 into the mold, and after cooling and demolding, obtain the main liner 1, the secondary liner 2 and the steel plate. Then cut the steel plate to obtain the clamping plate 4, and then heat the steel plate to 1000℃ and put it into the mold for stamping to obtain the V-shaped plate 3.

[0043] S3. Reprocessing of blanks

[0044] First, several M-shaped grooves 5 are vertically and equidistantly opened around the outer perimeter of the main liner tube 1 obtained in step S2, and several insertion holes 6 are vertically and equidistantly opened between each two adjacent M-shaped grooves 5. Then, according to the distance between the upper and lower ends of the adjacent insertion holes 6, a slot 9 is cut on the card plate 4 to form an insertion block 10 between the slots 9. Finally, a through hole 11 is opened in the middle of each insertion block 10, and according to the inner angle of the V-shaped plate 3, oblique cut surfaces 7 are cut on both sides of the end of the card plate 4 away from the insertion block 10.

[0045] S4. Blank Assembly

[0046] First, seal the bottom end of the main liner tube 1 with a high-temperature resistant material. Then, fit the secondary liner tube 2 inside the main liner tube 1, forming a gap 12 between the outer wall of the secondary liner tube 2 and the inner wall of the main liner tube 1. Next, insert the insert block 10 of the clamping plate 4 into the insertion hole 6 of the main liner tube 1. Then, insert both ends of the V-shaped plate 3 into the M-shaped grooves 5 on both sides of the corresponding insertion hole 6, so that the side with the beveled surface 7 is inserted into the inner angle of the V-shaped plate 3. At this time, fix the clamping plate 4 by spot welding the two ends of the clamping plate 4. Fix it in the inner angle of the V-shaped plate 3, then pull out the card plate 4 from the insertion hole 6, and then weld the two sides of the connection between the card plate 4 and the inner angle of the V-shaped plate 3. Complete the assembly of all card plates 4 and V-shaped plates 3 in this way. Then insert all card plates 4 into the insertion hole 6 of the main liner tube 1. At the same time, the two ends of the V-shaped plate 3 are inserted into the corresponding M-shaped groove 5. Then weld the gap connecting the two ends of the V-shaped plate 3. Finally, tie the V-shaped plate 3 around the main liner tube 1 with steel wire.

[0047] S5. Forming of irregularly shaped tube blanks

[0048] First, place the assembled blank obtained in step S4 vertically, then pour the molten steel obtained in step S1 into the gap 12 until the molten steel fills the gap 12. After natural cooling, the molten steel in the gap 12 solidifies and forms a shape. Then remove the steel wire tied to the V-shaped plate 3. At this time, the multi-angle irregular tube blank is formed.

[0049] S6. Heat treatment of irregularly shaped tube blanks

[0050] Normalizing: The shaped tube blank obtained in step S5 is placed in the furnace and heated to Ac3. Ac3 refers to the final temperature at which all free ferrite is transformed into austenite during heating, or Acm. Acm is 40 to 50 degrees above the critical temperature line for complete austenitization of hypereutectoid steel in actual heating. After holding at this temperature for a period of time, the shaped tube is taken out of the furnace and cooled by spraying water or blowing air in the air to refine the grains and homogenize the distribution of carbides, remove the internal stress of the material, stabilize the size of the workpiece, and prevent deformation and cracking.

[0051] Tempering: After the normalized and cooled shaped tube is placed back into the furnace for heating, and then kept at that temperature for a period of time. After that, the shaped tube is taken out of the furnace and cooled by spraying water or blowing air in the air to eliminate the internal stress of the shaped tube blank after normalizing and improve the mechanical properties of the shaped tube.

[0052] S7. Cutting, polishing, and anti-corrosion treatment

[0053] The two ends of the shaped tube obtained in step S6 are cut off, and then the surface of the shaped tube is polished. Finally, the surface of the shaped tube is treated with anti-corrosion and anti-oxidation to obtain a multi-angle shaped steel tube finished product. Compared with the traditional shaped steel tube processing, which requires more customized stamping dies and forming equipment, resulting in high processing costs, the dies used in the processing process of this invention can mostly be the same as those for conventional round steel tubes, and there is no need to specially process shaped tube forming equipment, which makes the processing cost lower.

[0054] In step S2, the preheating temperature of the multi-angle irregular steel pipe component mold is 850℃, and the mold is kept at a constant temperature after preheating.

[0055] In step S3, the width of the insertion hole 6 is slightly larger than the thickness of the card plate 4, and the height of the insertion block 10 is slightly lower than the height of the insertion hole 6. This allows the insertion block 10 to be inserted into the insertion hole 6 while also providing a certain degree of sealing to prevent a large amount of molten steel from flowing out of the gap. A small amount of molten steel overflowing will flow down the outer wall of the vertical main liner tube 1, which can also play a certain role in reinforcement.

[0056] The high-temperature resistant material in step S4 is silicon dioxide, and the length of the insert 10 extends through the insertion hole 6 and contacts the outer wall of the auxiliary liner tube 2.

[0057] In step S6, the normalizing temperature is 727℃ to Ac3 and the temperature is 750℃ to Acm. In step S6, the tempering temperature is 500℃ and the holding time is 40min.

[0058] Example 2:

[0059] like Figure 1-4 As shown in the figure, an embodiment of the present invention provides a processing technology for multi-angle special-shaped steel pipes, including the following processing steps:

[0060] S1. Steelmaking

[0061] First, pig iron is added to the converter, and the converter temperature is controlled at 1600℃ to melt the pig iron. Then, air is blown into the molten pig iron to oxidize impurities such as silicon and manganese. This oxidation process releases a large amount of heat, allowing the furnace to reach a sufficiently high temperature. Therefore, converter steelmaking does not require additional fuel. Converter steelmaking takes place inside a converter shaped like a pear, with refractory bricks lining the inner wall and numerous small tuyeres on the sides. Compressed air is blown into the furnace through these tuyeres, hence the name "side-blown converter." A certain amount of quicklime is added, and then air continues to be blown in while the converter is rotated to make it upright. At this point, a violent reaction occurs on the surface of the molten pig iron, causing iron, silicon, and manganese to oxidize and form slag. The convection between the molten steel and the slag further facilitates the reaction... Throughout the entire furnace, after 10 minutes, when only a small amount of silicon and manganese remain in the molten steel, carbon begins to oxidize, generating carbon monoxide, which causes the molten steel to boil violently. A huge flame appears at the furnace mouth due to the combustion of the overflowing carbon monoxide. Finally, phosphorus also oxidizes and further generates ferrous phosphate. Ferrous phosphate then reacts with quicklime to generate stable calcium phosphate and calcium sulfide, which together become slag. When phosphorus and sulfur gradually decrease, the flame recedes, and brown ferric oxide vapor appears at the furnace mouth, it indicates that the steel has been refined. At this point, the blasting is immediately stopped, and the converter is rotated to a horizontal position to add deoxidizer for deoxidation to obtain molten steel. The converter is top-blown with oxygen. This type of converter blows high-pressure industrial pure oxygen, which makes the reaction more intense and can further improve production efficiency and steel quality.

[0062] S2. Component Injection Molding

[0063] First, preheat the component mold of the multi-angle special-shaped steel pipe, then inject the molten steel obtained in step S1 into the mold, and after cooling and demolding, obtain the main liner 1, the secondary liner 2 and the steel plate. Then cut the steel plate to obtain the clamping plate 4, and then heat the steel plate to 1250°C and put it into the mold for stamping to obtain the V-shaped plate 3.

[0064] S3. Reprocessing of blanks

[0065] First, several M-shaped grooves 5 are vertically and equidistantly opened around the outer perimeter of the main liner tube 1 obtained in step S2, and several insertion holes 6 are vertically and equidistantly opened between each pair of adjacent M-shaped grooves 5. Then, according to the distance between the upper and lower ends of the adjacent insertion holes 6, slots 9 are cut on the card plate 4 to form insertion blocks 10 between the slots 9. Finally, through holes 11 are opened in the middle of each insertion block 10. According to the inner angle of the V-shaped plate 3, beveled surfaces 7 are cut on both sides of the end of the card plate 4 away from the insertion block 10. The beveled surfaces 7 can increase the contact surface with the inner angle of the V-shaped plate 3, making the welding more stable.

[0066] S4. Blank Assembly

[0067] First, seal the bottom end of the main liner tube 1 with a high-temperature resistant material. Then, fit the secondary liner tube 2 inside the main liner tube 1, forming a gap 12 between the outer wall of the secondary liner tube 2 and the inner wall of the main liner tube 1. Next, insert the insert block 10 of the clamping plate 4 into the insertion hole 6 of the main liner tube 1. Then, insert both ends of the V-shaped plate 3 into the M-shaped grooves 5 on both sides of the corresponding insertion hole 6, so that the side with the beveled surface 7 is inserted into the inner angle of the V-shaped plate 3. At this time, fix the clamping plate 4 by spot welding the two ends of the clamping plate 4. Fix it in the inner angle of the V-shaped plate 3, then pull out the card plate 4 from the insertion hole 6, and then weld the two sides of the connection between the card plate 4 and the inner angle of the V-shaped plate 3. Complete the assembly of all card plates 4 and V-shaped plates 3 in this way. Then insert all card plates 4 into the insertion hole 6 of the main liner tube 1. At the same time, the two ends of the V-shaped plate 3 are inserted into the corresponding M-shaped groove 5. Then weld the gap connecting the two ends of the V-shaped plate 3. Finally, tie the V-shaped plate 3 around the main liner tube 1 with steel wire.

[0068] S5. Forming of irregularly shaped tube blanks

[0069] First, place the assembled blank obtained in step S4 vertically, then pour the molten steel obtained in step S1 into the gap 12 until the molten steel fills the gap 12. After natural cooling, the molten steel in the gap 12 solidifies and forms a shape. Then remove the steel wire tied to the V-shaped plate 3. At this time, the multi-angle irregular tube blank is formed.

[0070] S6. Heat treatment of irregularly shaped tube blanks

[0071] Normalizing: The shaped tube blank obtained in step S5 is placed in the furnace and heated to Ac3. Ac3 refers to the final temperature at which all free ferrite is transformed into austenite during heating, or Acm. Acm is 40 to 50 degrees above the critical temperature line for complete austenitization of hypereutectoid steel in actual heating. After holding at this temperature for a period of time, the shaped tube is taken out of the furnace and cooled by spraying water or blowing air in the air to refine the grains and homogenize the distribution of carbides, remove the internal stress of the material, stabilize the size of the workpiece, and prevent deformation and cracking.

[0072] Tempering: After the normalized and cooled shaped tube is placed back into the furnace for heating, and then kept at that temperature for a period of time. After that, the shaped tube is taken out of the furnace and cooled by spraying water or blowing air in the air to eliminate the internal stress of the shaped tube blank after normalizing and improve the mechanical properties of the shaped tube.

[0073] S7. Cutting, polishing, and anti-corrosion treatment

[0074] The two ends of the shaped tube obtained in step S6 are cut off, and then the surface of the shaped tube is polished. Finally, the surface of the shaped tube is treated with anti-corrosion and anti-oxidation to obtain a multi-angle shaped steel tube finished product. Compared with the traditional shaped steel tube processing, which requires more customized stamping dies and forming equipment, resulting in high processing costs, the dies used in the processing process of this invention can mostly be the same as those for conventional round steel tubes, and there is no need to specially process shaped tube forming equipment, which makes the processing cost lower.

[0075] In step S2, the preheating temperature of the multi-angle irregular steel pipe component mold is 900℃, and the mold is kept at a constant temperature after preheating.

[0076] In step S3, the width of the insertion hole 6 is slightly larger than the thickness of the card plate 4, and the height of the insertion block 10 is slightly lower than the height of the insertion hole 6. This allows the insertion block 10 to be inserted into the insertion hole 6 while also providing a certain degree of sealing to prevent a large amount of molten steel from flowing out of the gap. A small amount of molten steel overflowing will flow down the outer wall of the vertical main liner tube 1, which can also play a certain role in reinforcement.

[0077] The high-temperature resistant material in step S4 is silicon dioxide, and the length of the insert 10 extends through the insertion hole 6 and contacts the outer wall of the auxiliary liner tube 2.

[0078] In step S6, the normalizing temperature to Ac3 is 912℃, the heating temperature to Acm is 960℃, the tempering temperature in step S6 is 650℃, and the holding time in step S6 is 60min.

[0079] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for machining a multi-angle shaped steel pipe, characterized by: The processing steps include the following: S1. Steelmaking First, pig iron is added to the converter, and the converter temperature is controlled at 1550℃~1600℃ to smelt the pig iron. Then, air is blown into the molten pig iron to oxidize impurities such as silicon and manganese. A certain amount of quicklime is added, and air is continued to be blown in while the converter is rotated to make it upright. At this time, the surface of the liquid pig iron reacts violently, causing iron, silicon, and manganese to oxidize and form slag. Utilizing the convection of molten steel and slag, the reaction is spread throughout the entire furnace. After 5 to 10 minutes, when only a small amount of silicon and manganese remain in the molten steel, carbon begins to oxidize, generating carbon monoxide, which causes the molten steel to boil violently. A huge flame appears at the furnace mouth due to the combustion of overflowing carbon monoxide. Finally, phosphorus also oxidizes and further generates ferrous phosphate. Ferrous phosphate then reacts with quicklime to generate stable calcium phosphate and calcium sulfide, which together become slag. When phosphorus and sulfur gradually decrease, the flame recedes, and brown steam of iron(III) oxide appears at the furnace mouth, it indicates that the steel has been smelted. At this time, the blowing is immediately stopped, and the converter is rotated to a horizontal position to add deoxidizer to obtain molten steel. S2. Component Injection Molding First, preheat the component mold of the multi-angle special-shaped steel pipe, then inject the molten steel obtained in step S1 into the mold and obtain the main liner (1), the secondary liner (2) and the steel plate after cooling and demolding. Then cut the steel plate to obtain the clamping plate (4), and then heat the steel plate to 1000℃~1250℃ and put it into the mold for stamping to obtain the V-shaped plate (3). S3. Reprocessing of blanks First, several M-shaped grooves (5) are vertically and equidistantly opened around the outer perimeter of the main liner tube (1) obtained in step S2, and several insertion holes (6) are vertically and equidistantly opened between each two adjacent M-shaped grooves (5). Then, according to the distance between the upper and lower ends of the adjacent insertion holes (6), a slot (9) is cut on the card plate (4) to form an insertion block (10) between the slots (9). Finally, a through hole (11) is opened in the middle of each insertion block (10), and a beveled surface (7) is cut on both sides of the end of the card plate (4) away from the insertion block (10) according to the inner angle of the V-shaped plate (3). S4. Blank Assembly First, seal the bottom of the main liner tube (1) with high-temperature resistant material, then put the secondary liner tube (2) inside the main liner tube (1). At this time, a gap (12) is formed between the outer wall of the secondary liner tube (2) and the inner wall of the main liner tube (1). Then insert the insert block (10) of the clamping plate (4) into the insertion hole (6) of the main liner tube (1). Then, insert the two ends of the V-shaped plate (3) into the M-shaped groove (5) on both sides of the corresponding insertion hole (6), so that the side with the beveled surface (7) is inserted into the inner angle of the V-shaped plate (3). At this time, the clamping plate (4) is secured by spot welding the two ends of the clamping plate (4). ) is fixed in the inner angle of the V-shaped plate (3), and then the card plate (4) is pulled out from the insertion hole (6). Then the two sides of the connection between the card plate (4) and the inner angle of the V-shaped plate (3) are welded. This process is repeated to complete the assembly of all card plates (4) and V-shaped plates (3). Then all card plates (4) are inserted into the insertion hole (6) of the main liner tube (1). At the same time, the two ends of the V-shaped plate (3) are inserted into the corresponding M-shaped groove (5). Then the gaps connecting the two ends of the V-shaped plate (3) are welded. Finally, the V-shaped plate (3) is tied around the main liner tube (1) with steel wire. S5. Forming of irregularly shaped tube blanks First, place the assembled blank obtained in step S4 vertically, then inject the molten steel obtained in step S1 into the gap (12) until the molten steel fills the gap (12), and after natural cooling, the molten steel in the gap (12) solidifies and forms a shape. Then remove the steel wire tied to the V-shaped plate (3). At this time, the multi-angle irregular tube blank is formed. S6. Heat treatment of irregularly shaped tube blanks Normalizing: The shaped tube blank obtained in step S5 is placed in the furnace and heated to Ac3 or Acm. After holding at the temperature for a period of time, the shaped tube is taken out of the furnace and cooled by spraying water or blowing air in the air to refine the grains and uniformly distribute the carbides, remove the internal stress of the material, stabilize the size of the workpiece, and prevent deformation and cracking. Tempering: After the normalized and cooled shaped tube is placed back into the furnace for heating, and then kept at that temperature for a period of time. After that, the shaped tube is taken out of the furnace and cooled by spraying water or blowing air in the air to eliminate the internal stress of the shaped tube blank after normalizing and improve the mechanical properties of the shaped tube. S7. Cutting, polishing, and anti-corrosion treatment Cut off both ends of the shaped tube obtained in step S6, then polish the surface of the shaped tube, and finally perform anti-corrosion and anti-oxidation treatment on the surface of the shaped tube to obtain the finished multi-angle shaped steel pipe.

2. The process for processing a multi-angle special-shaped steel pipe according to claim 1, characterized in that: In step S2, the preheating temperature of the multi-angle irregular steel pipe component mold is 850-900℃, and the mold is kept at a constant temperature after preheating.

3. The process for processing a multi-angle special-shaped steel pipe according to claim 1, characterized in that: In step S3, the width of the socket (6) is slightly greater than the thickness of the card plate (4), and the height of the plug (10) is slightly lower than the height of the socket (6).

4. The process for processing a multi-angle special-shaped steel pipe according to claim 1, characterized in that: The high-temperature resistant material in step S4 is silicon dioxide, and the length of the insert (10) extends through the insertion hole (6) and contacts the outer wall of the sub-liner (2).

5. The process for processing a multi-angle special-shaped steel pipe according to claim 1, characterized in that: In step S6, the normalizing temperature to Ac3 is 727℃~912℃, the heating temperature to Acm is 750℃~960℃, the tempering temperature in step S6 is 500~650℃, and the holding time in step S6 is 40~60min.

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