TW302309B - The manufacturing method for square and round steel pipe - Google Patents

Abstract

A manufacturing method for square steel pipe. Its features are: Select a round steel pipe with certain diameter, thickness and length that is suitable for final product. Heat this pipe inside heating furnace. Use round steel forming machine to proceed hot-forging forming process and produce refined steel pipe. Then use square steel pipe forming machine to proceed hot-forging forming process and produce square steel pipe. Finally, put square steel pipe on cooling bed to proceed cooling process.

Description

A7 A7 The Central Bureau of Economic Affairs of the Ministry of Economic Affairs Beigong Consumer Cooperation Du Printing _____ B7 V. Description of the invention (1) [Industry use field] 'The present invention is, for example, a cube shape used for manufacturing column materials for construction The manufacturing method of a large-diameter square steel pipe such as a rectangular shape or the like, and the manufacturing method similarly adopted for manufacturing a large-diameter round steel pipe. [Background of the Invention] Large-diameter square steel pipes that are generally used for building columns and the like are, for example, the manufacturing methods disclosed in Japanese Patent Publication No. 5 8-1 3 2 4 5. That is, this conventional method is to transfer a thick steel plate in the longitudinal direction to perform edge pre-processing, and then press it, and bend the four corners of the square steel tube to form an approximate The shape of the square steel pipe, and then the steel pipe that is similar to the square steel pipe is passed through the forming rollers of the subsequent plural sections to gradually form the square steel pipe, and the edge joint surface is sequentially welded in fixed points, and then the edge member is automatically welded. The inside and outside are welded together, and finally the correction work is carried out to make a large-diameter square steel pipe. For the large-diameter square steel pipe produced by the above cold forging and forming process, for example, it can be observed from the hardness distribution diagram on the inner surface side in FIG. 5 and the hardness distribution diagram on the outer surface side in FIG. The hardness of the seam welded part is much higher than the hardness of the flat part (base material). Therefore, the yield strength of the corner and seam welded parts is increased, which reduces the ductility, which may cause turtles during the second welding. The risk of cracking must be managed specially. In addition, residual stress is generated due to the non-uniformity of mechanical properties, which makes it difficult to carry out cutting and other processing. _ Tsukaru paper scale is applicable to the Chinese National Standard (CNS) A4 ^ (210X297 公 漦 _) 4 _ ~~ 一 J --------- "Installation-(Please read the precautions on the back before filling out this page)

J 30 ^ 309 A7 W1_ V. Description of the invention (2) In addition, for the conventional large-diameter square steel pipe, for example, it can be seen from the comparison diagram of the tensile stress-tensile curve of FIG. 7, corners, and seams The welded part and the flat part do not show the yield point, so for structures with uneven stress distribution in the local area, as long as the maximum reduction ratio exceeds 80%, then The local stretchability of the structure @ fear it will be reduced ... 〆 -------------------------- .. ... " ·· * > In addition, for the conventional large-diameter square steel pipes, tensile residual stress and compressive residual stress close to the yield point are generated particularly in the corners and seam welds. , Resulting in low buckling strength. Therefore, when welding construction, cutting processing, or melted lead plating are performed, cracking or unpredictable deformation will occur as residual stress occurs. Furthermore, for the conventional large-diameter square steel pipes, For example, as can be seen from the transition temperature curve in Figure 8, especially at the corners, because after bending, there is a large plastic strain remaining locally, __ ____________________ t-, *. · '≪! '··· < · * ·., · ..- .. 1] So in these places there will obviously be embrittlement of the present _ elephant _, and its transfer ... . When the temperature is far higher than normal temperature, it may cause brittle failure in the low temperature field. [Explanation of the invention] The main object of the present invention is to provide a steel pipe with full fracture ^ 1. .. * ._ Evenly soft surface, good elongation, almost no residual stress, and sufficient sturdiness The manufacturing method of square steel pipe and the manufacturing method of graphic steel pipe. In addition, another object of the present invention is to be able to provide a thermal paper standard applicable to the Chinese National Standard (CNS) A4 said grid (210 to 297 gong _) ,. n (j Binding ί, .Λ (please read first Note on the back and then fill out this page) Printed by the Ministry of Economic Affairs, Central Standards Bureau, Beigong Consumer Cooperatives Printed by the Ministry of Economic Affairs, Central Standards Bureau, Beigong Consumer Cooperatives A7 B7 V. Description of the invention (3) Forging forming method to reduce stamping Times, without the need for an edge ·-··-— — — — — — V... _ I _ Μ know .., bending machine, you can get a better yield, even easy to manufacture A method for manufacturing a square steel pipe with a certain radius of curvature of a corner. Furthermore, another object of the present invention is to provide a method of hot forging forming from the beginning of manufacturing a raw pipe, and to obtain a comparative The manufacturing method of square steel pipe with good yield rate. In order to achieve the above purpose, the manufacturing method of the square steel pipe of the present invention is characterized by using a certain caliber, plate thickness, and length suitable for the size of the final product Shape steel pipe, and put the steel pipe in a heating furnace to heat, and then use the round steel pipe forming and rolling machine to hot forge the processed steel pipe to produce refined steel pipe, and then use the square steel pipe forming and rolling machine This refined steel pipe is subjected to hot forging forming to form a square steel pipe, and finally the angular steel pipe is cooled on a cooling bed. 〃 For the above-mentioned configuration of the present invention, first, hot forging forming is performed on a round steel pipe forming mill. The refined original pipe is made to meet the size of the final square steel pipe, and then the refined original pipe is hot forged by a square steel pipe forming rolling mill to form a square steel pipe. After such hot forging forming , Can produce a kind; the steel pipe is uniform in all sections, good elongation, and there is almost no residual stress, at the same time, it can obtain high buckling strength, good secondary weldability, and a square steel pipe with sufficient sterility , Especially for the column material for construction, can provide an optimal square steel pipe. First, for the first In terms of the characteristics of the application form, the paper scale is applied to the Chinese national standard (匚 呢) 8 4 rules / grid (210 father 297 mm_) 6 _ J --------- ('installed- (Please read the precautions on the back before filling out this page)

J Ministry of Economic Affairs Central Bureau of Precision Industry®c, industrial and consumer cooperation to print this paper, using Chinese national standard (CNS) A4 specifications (210X297mm) A7 B7 V. Description of invention (4) Flat sheet material is formed by stamping and welding The formed polygonal hollow steel pipe is transported into a heating furnace for high temperature heating, and then a square steel pipe forming mill is used to perform hot forging forming to form a square steel pipe. According to the first embodiment, as long as the number of forming times required by the press forming machine (number of presses) can be reduced to the number of times the polygonal hollow steel pipe is made. In other words, the forming process can be completed quickly, and the cost can be reduced. In addition, it is also possible to omit the use of the edge bending machine, so that the equipment cost can be reduced, and at the same time, the process can be simplified and labor-saving. Second, for the second embodiment of the present invention, the polygonal hollow The width of the steel pipe is wider than the width of the final product, and the polygonal hollow steel pipe heated by the heating furnace at high temperature is subjected to hot forging forming process while being extruded by a square steel pipe forming rolling mill. With this second embodiment, a square steel pipe forming mill can be used to perform a hot forging process while extruding, and a square can be manufactured that satisfies the required size from the front end to the rear end. In this way, the operation of cutting off the front end and the rear end in the post process can be omitted, and the goal of accurate size and high yield is achieved. For the third embodiment of the present invention, the polygonal hollow steel pipe is formed to be larger than the width of the final product and the radius of curvature of the corners, and after high-temperature heating by a heating furnace, it is extruded by a square steel pipe forming mill While performing the hot forging process, the required width dimension and the radius of curvature of the corner are formed. If the third embodiment of the present invention is used, it is formed by stamping 7-(please read the note Ϋ on the back side and fill in this page). Pack. Order A7 _B7_ V. The curvature of the corner of the invention description (5) The radius will be larger than the radius of curvature of the corner of the final product, so for flat materials, it can be easily stamped and formed. Therefore, the multi-angle hollow of the original material (molecular arrangement) is restored by high-temperature heating Under the hot forging extrusion process, the steel pipe can promote the width and radius of curvature of the corners to be reduced, and the final product with a high cross-sectional coefficient of constant material can be obtained, that is, the desired corner can be easily obtained Square steel pipe with radius of curvature and width. For the feature of the fourth embodiment of the present invention, the original pipe in the shape of a figure is subjected to cold forging forming by a square steel pipe forming rolling mill to form a polygonal hollow steel pipe that is larger than the width of the final product, and After this polygonal hollow steel pipe is heated by a heating furnace, it is hot-forged and formed while being extruded by another square steel pipe forming rolling mill, and a square steel pipe is obtained. " (Read the precautions on the back before filling in this page.) With the fourth embodiment of the present invention, the original tube can be cold-forged by a square steel tube forming mill to form a wider width than the final product. Multi-angle hollow steel pipe, and after placing the multi-angle hollow steel pipe in a heating furnace to apply high temperature heating, then use another square steel pipe forming rolling mill to perform hot forging forming while extruding, so that a kind of front end can be manufactured It can form a square steel pipe of a certain size from the bottom to the back section. Therefore, in the latter stage of the manufacturing process, those who do not need to cut off the front end and the rear end can obtain accurate size and high yield. For the fifth embodiment of the present invention, the polygonal hollow steel pipe system has a large width and a radius of curvature at the corners, and the high temperature of the paper after the heating furnace is applicable to the A4 standard (21S) Χ 腾 着 _) _ Printed 302309 A7 B7 by the Ministry of Economic Affairs, Central Bureau of Economic Cooperation and Consumer Cooperative V. Description of the invention (6) After heating, hot forging forming is carried out while extruding by another square steel tube forming rolling mill, To form the required width, scale and corner radius of curvature. With the fifth embodiment of the present invention, the radius of curvature of the formed corner will be larger than the curvature of the corner of the final product, so cold forging from the original pipe to the hollow hollow steel pipe can be easily performed The forming process, therefore, the high-temperature heating of the polygonal hollow steel pipe that restores the original material (molecular arrangement) can be reduced by the hot forging extrusion process to promote the width and the radius of curvature of the corner to obtain the material The final product with a high constant cross-section coefficient, that is, a square steel pipe with a desired radius of curvature and width at the corner can be easily obtained. For the feature of the sixth embodiment of the present invention, a round tube with a certain diameter, plate thickness, and length suitable for the size of the final product is used, and this tube is placed in a heating furnace for heating, Secondly, the heated original tube is hot-forged by a patterned steel tube forming and rolling machine to produce a U-shaped steel tube, and then the round steel tube is cooled on a cooling bed, and the end is cut off with a cutting device The bad part of the part. According to the sixth embodiment of the present invention, by performing hot forging forming on a round steel pipe forming mill, a steel pipe conforming to the predetermined size of the round steel pipe can be manufactured. After such hot forging forming, Can produce a kind; the steel pipe is evenly soft throughout the entire section, has good elongation, and there is almost no residual stress, at the same time it can obtain high buckling strength, good secondary weldability, and square steel pipe with sufficient ties. It is the most suitable square steel pipe for the column material used in construction. _ This paper is based on the Chinese National Standard (匸 呢> Bao 4 said (2 丨 0; < 297 public _) 9 _ (please read the precautions on the back and then fill out this page) Γ 装

J Printed by the Consumer Cooperative of the Central Department of Economics of the Ministry of Economic Affairs «. A7 B7 V. Invention description. ) [Embodiments] The embodiments described below are mainly for the manufacture of large-diameter square steel pipes or round steel pipes, but the same can also be produced for medium-diameter or small-diameter square steel pipes and Round steel tube. Hereinafter, a first embodiment of the present invention will be described based on FIGS. 1 to 8. As shown in Figure 1, the round steel pipe (original pipe 1, namely the mother pipe) with a certain diameter, plate thickness, and length that is suitable for this square steel pipe is selected when manufacturing a large-diameter square steel pipe. Prepare to move into bed 10. Here, the original pipe 1 is welded by high frequency welding or arc welding, etc. __m I — to form a steel pipe with a seam welded part 2, but a seamless original pipe 1 can also be used »In addition, the transfer bed 1 0 It is tied to a form of conveyance, which supports multiple original tubes 1 in parallel, and carries out the conveying operation in a transverse manner perpendicular to the longitudinal direction. The original pipe 1 transported to the end of the bed 10 is placed on the conveyor 11 in the heating section in the form of a roller conveyor, and then travels in the longitudinal direction. After that, the original tube .1 is transferred to the heating furnace 1 2, and the original tube 1 being transported in the heating furnace 12 is heated at high temperature (7 2 3. (: ~ 9 5 0 ° C, that is, A 3 above the metamorphosis point). When the original tube 1 is transported to the heating furnace __ · ................ The heating furnace 1 2 is sequentially transported into the heating furnace 1 2 at a certain interval L, Therefore, it is possible to prevent the collision between the end faces of the original tubes caused by the extension of the original tube during heating and the difference in conveying speed. However, if the interval L is too long, it will cause inefficiency, so In, 5-0- -CX m. Hk ψ ^ ^ This paper scale is applicable to the Chinese national standard (CNS> Α4 specification (210Χ297 mm) 1Λ -1U-(please read the precautions on the back before filling this page) · Printed and printed A7 Β7 by Beigong Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention (8) In addition, the original tube 1 that has been heated at a certain temperature is transferred out of the heating furnace 12 before being transported to welding Seam position adjusting device 15 5. This ^ -------------- Seam position adjusting device 15 is the support roller 16 and the pressing roller. ______________ " · ........-~ '* UL .. etc .. With these rollers 16, 17, the original tube 1 is rolled --- V7, and the position of the seam welded part 2 Adjust to a certain direction. For this certain direction, it means that when the final square steel pipe is made, the seam welded part 2 is kept at a position near the center of the flat part. In addition, if seamless V.- -If the original tube 1 is used, skip the adjustment of the seam position during the manufacturing process and set the pen 1 5... One ----- one--.................... ...............................-one ... ~-part, or delete this welding seam Part of position adjustment device 15 ............................... -----------. ·-· ----------------------------------- ---------------------------------------------- · --- ------- --------- " **-* —— · \ The original tube 1 of the welding seam position adjusting device 15 was moved into the round steel tube forming rolling mill 20. Here, the original tube 1 is subjected to non-forging forming processing in the extruded state by a plurality of forming rollers 2 1-etc., and can be added ...--------... . ..1 ......... "" The final size of the final square steel pipe (final product) is the goal, and the original tube 1 is refined to a certain size. In this case, the round steel tube forming rolling mill 20 is configured as two front and rear #, but it can also be configured as one or more stages. Necessary places around the i-shaped steel tube forming rolling mill 20 (moved into-*…-.. 1-before and after the round steel tube forming rolling mill 20, or only the front section, or only the rear section, or between the stands, etc.) Equipped with the required amount of residual scale device 23. The descaling device 23 is sprayed with pressurized water to the refined original pipe 1 Α, so the sprayed water can be used to remove the milk steel scale (mill scale one ... one ... ------- ------------), and get a good surface. In this way, the refined raw tube 1 A produced by the group 20 of round steel tube forming rolling mills is formed into a Huan shape lanthanum tube. Here, because the Chinese National Standard (CNS) A4 specification (210X297 mm) is applied through this paper standard, Λ — -11-j — HI ^ I II — order — ^-Λ (Please read the notes on the back first (Fill in this page) A7 B7_ Printed A7 B7_ by the Consumer Cooperation Department of the Central Bureau of Economic Affairs of the Ministry of Economic Affairs 5. Description of the invention (9) A plurality of thin waist rollers 2 6 etc. to perform the final hot forging process (forming temperature A 3 Above the abnormal point), so the square steel pipe 3 immediately after hot forging is processed as shown in FIG. 4, and each flat portion 3 a will form an arc surface along the outside of the narrow waist surface. In addition, the complex m into 2 5 series is configured as the front and back hidden sections, but it can also be configured as one or two sections with one one. One — ... »— ~ · 〆.,. * ^^ L.- 一 " one One _ τ „_.- +. + ~. ·....-&Quot; · u. The square steel pipe 3 after such hot forging forming is placed on the heating section conveyor 1 1 On the cooling bed 28. The cooling bed 28 is in the form of a conveyor belt, so that a plurality of square steel pipes 3 are parallel to each other and are transported in a horizontal direction. The square steel pipes 3 in the transport of this cooling bed 28 are air-cooled Come to cool slowly. That is to say, the square steel pipe 3 is chilled in the same temperature environment, so the occurrence of bending during cooling will be reduced. According to the flat plates of the square steel pipe 3 after chilling 3 a will shrink ------ V, as shown in Fig. 4B, and the arc surface will form a vertical surface, and the corner 3Bb will also form a sharp edge, g will increase the section coefficient. The transportation of the group of square steel pipes 3 on the cooling bed 28 is carried out by separating the adjacent square steel pipes 3 or by clamping both sides in contact But the most important thing is to enable the square steel pipe 3 to be cooled in the same temperature environment, so as to reduce the deformation caused by cooling. The square steel pipe 3 that reaches the cooling bed 2 8 terminal is placed on the roller On the first conveying conveyor 2 9 in the form of conveyance, the conveying operation is carried out in the longitudinal direction. After that, the square steel pipe 3 is carried into the correction cold place 30 as shown in FIG. 2, where the length generated during cooling is corrected The bending in the axis direction, that is, the bending above the reference value is corrected. And, if the bending degree is at the standard paper size, the Chinese National Standard (CNS) A4 specification (210X297 mm) 1-10-1--"Binding ^ (please (Read the precautions on the back before filling in this page) A7 ____B7 5. If the value of the invention (10) is below the value, the correction device 30 can also be skipped in the manufacture of the square steel tube 3, or all corrections can be made by the correction device Operation. (Please read the precautions on the back before filling in this page) The square steel pipe 3 through the straightening device 30 is moved to the roller bed-type secondary bed 3 2 through the first conveying conveyor 2 9 and then Fang ~ ............. - · <-* — * One ^ way to be transported. After that, the square steel pipe 3 that reached the end of this relay bed 3 2 was placed on the second conveying conveyor in the form of roller conveyance — 3... 3, and then in the length direction Be transported. The square steel tube 3 being transported is first cut and removed by the front-end cutting device 3 5 to form the defective part formed at the front end (one end). Second, then The rear-end cutting-breaking device 36 is used to cut and remove the defective part of the rear end (the other end) formed during forming, so as to obtain a square tube (final product) 3 of a predetermined size with good accuracy. The square steel pipe 3 formed in this way is moved from the second conveying conveyor 3 3 to the washing bed 3 8 as shown in FIG. 3, and then in the lateral direction —.____ _ · ... . '· -..... Printed by the Consumer Cooperative of the Ministry of Economic Affairs of the Central Bureau of Accreditation. The square steel pipe 3 in this transportation is the washing water sprayed by the outer cleaning nozzle 4 1 and the inner surface #clean nozzle 4 2 of the cleaning device 40, which will be used in various processes (heating, forming, cooling, Correction, cutting, etc.) The rust, dirt, cuttings, etc. attached to the inside and outside of the steel pipe are washed and removed. Next, the square steel pipe 3 is moved from the washing bed 38 to the third conveying conveyor 44 in the form of roller conveyance, and is conveyed in the longitudinal direction. The square steel pipe 3 being transported is passed through an anti-rust device 4 5 to perform anti-rust treatment. After that, the square steel pipe 3 is sent from the third conveying conveyor 4 to the roll-out bed 4 of the roll-out bed 4 6 'and is laterally transported for intensive storage during the exhibition. _ I paper scale is applicable to China National Standard Falcon (CNS > A4 specification (21〇Χ297 male rabbit) 13 _ A7 B7 V. Description of invention (11) From round tube to square tube manufactured by hot forging The large-diameter square steel pipe 3, that is, the hot-forged square steel pipe, can be seen from, for example, the inner surface hardness distribution diagram of FIG. 5 and the outer surface hardness distribution diagram of FIG. 6, the flat plate portion 3 a, and The mechanical properties of the full section such as the corner 3 b and the seam welded part 2 are almost homogeneous. Therefore, the yield strength of the corner 3 b and the seam welded part 2 is reduced, which promotes the increase in ductility, and because of the construction in _____ For secondary welding, etc., no special management is required to obtain uniform mechanical properties, so it is easy to perform operations such as cutting. In addition, for hot-forged square steel pipes, the tensile stress is from FIG. 7 It can be seen from a drawing of the tensile curve comparison that the flat points 3 a, corners 3 b, and seam welded parts 2 can all show the yield point, and the yield ratio is also far, which is more than 80% lower than the specification value. Halo is in a stable state, and has a full _ stretch Therefore, it can reduce the risk of brittle failure when using localized concentrated stress such as building pillars, especially when it is used as a building pillar with good vegetable resistance. Central Ministry of Economic Affairs Printed by Cooperative of Consumers of the Ministry of Industry and Commerce (please read the precautions on the back before filling in this page) In addition, for the square steel pipe formed by hot forging, its flat part 3 a, corner part 3 b, and seam The welded part 2 and the like have almost no tensile residual stress and compressive residual stress, so high buckling strength can be obtained. Therefore, when performing welding operations, cutting processes, or melting of sub-lead plating treatment V, etc. , It will not cause cracking and uncontrollable deformation. Furthermore, for the square steel pipe formed by hot forging, it can be seen from the temperature transfer curve of Qi 8 that the flat part 3 a and the corner 3 b, The 2nd seam welded part shows the same transition temperature as the original plate, and it can have sufficient sturdiness even in the low temperature area. — ^ ,, 丨 * ·· »^, ... This paper wave scale is suitable for Chinese countries Standard (CNS) A4 Grid (210X297mm), j -14 A7 B7 Printed by the Ministry of Economic Affairs Central Bureau of Precision Industry Beigong Consumer Cooperative V. Description of the invention (12 1 9 The figure shows the structure of the second embodiment which is different from the first embodiment. 1 〇 就是 是> The difference from the first embodiment »is to use round Λκη steel pipe into I-shaped rolling mill 2 0 after the hot forging forming of the refined raw pipe> as a finished product (1 please 1 I (Finished product of round steel pipe) 5 Transferred into the cooling bed 2 8 0 and then I read the cold first 1 1 read 1 but the bed 2 8 After performing the cold operation y, then Cto the same as the first embodiment 1 through 1 Over-correcting device 3 0 y Relay bed 3 2 9 Cutting device 3 5 > 3 6 »Wash i 1 I clean bed 3 8 > Washing device 4 0 and anti-rust device 4 5» Finally stored in item ψ 1 Move out of bed 4 6 A hundred Pack I The large-diameter round steel pipe that has been hot-forged and shaped in this way (finally manufactured H′w- 1 1 I product) 5 The above-mentioned square λρβ steel pipe 3 has the same mechanical properties 1 1 1 〇1 The third embodiment will be described based on FIGS. 1 0 and 1 2 and 1 9 is the same as the first embodiment. The same reference numbers are the same-the structure is omitted here. 1 1 Detailed description 0 1 1 For example, in the manufacture of large diameter The square steel pipe will be suitable for this side first. A certain plate thickness length & width of the octagonal steel pipe & flat width plain plate 9 that is steel 1 I plate 5 1 are stored in a state where most of the pieces overlap. Then store these Overlapping 1 I of Aim steel plates 5 1 in the group »The top of-the steel plate 5 1 is lifted by, for example, a magnet 1 attached to the stone crane * and then transported to the conveyor 6 0 after Ο > I ΛΙΓΗ steel plate 5 1 is conveyed to the edge pre-processing machine 6 1 1 1 by the conveyor 6 0 »and the edge part is formed for one of the desired seam welding to form the edge of the welding 1 1 m 5 2 〇1 1 In addition I After making the welding edge 5 2 in advance * It is also possible to store these steel plates 5 1 in an overlapping manner 1 or use a coiled wire 1 The paper size is applicable to the Chinese National Standard (CNS) A4 specification (2丨 0 侂 297 公 *) 15 The A7 printed by Beigong Consumer Cooperative of the Central Bureau of Economic Affairs of the Ministry of Economic Affairs ____B7_ V. Description of the invention (13) The coiled steel plate 51, and then the coiled steel plate 51 is spread out on one side It is also feasible to perform the cutting operation at the same time. The steel marks 5 1 after forming the edge pre-processing for welding are carried into the press forming machine 6 by the conveyor 6 _ • The steel plate 5 1 of the press forming machine 6 2 is formed into a polygonal t hollow steel pipe 5 3 · That is, _ 〆 -------------- ~~ · D.-&Quot; η · --- For example, 7 places are stamped and formed, and a pair of welding An opening is left between the used edges 52 to form a polygonal hollow steel pipe 5 3 punched into an octagonal shape. At this time, the polygonal hollow steel pipe 53 is used to keep the seam welded portion near the center of the flat plate portion when the square steel pipe of Qin Zhong was obtained. The polygonal hollow steel pipe 53 is carried into the temporary positioning welding machine 63 by the conveyor 60, and then the welding edges 53 are brought into contact with each other by external force, and then the welding work is carried out . Then, the polygonal hollow steel pipe 53 is carried into the inside welding machine 6 4 by the conveyor 60, and the inside welding 55 is performed. Secondly, the polygonal hollow steel, '—. _ — —-— ~ Tube 5 3 was carried into the outer welding machine 6 5 to perform the outer welding 5 6 operation, and finally made into an octagon with a seam welding part 5 7 There are many shapes ... I. _. &Quot; 5 8. In addition, each reciprocating welding operation is performed by high frequency welding or arc welding. The polygonal hollow steel pipe 58 produced in this way is transferred from the conveyor 60 to the bed 66. The polygonal hollow steel pipe 58 that is transported to the terminal portion of the transport bed 6 6 is transported to the heating furnace 12 again, and the heating temperature of the heating furnace 1 2 is carried out to perform the high temperature heating above the A 3 metamorphic point. _ ··. After heating at a certain temperature, the polygonal hollow steel pipe 58 is removed from the heating furnace 12 and then transferred into the square steel pipe forming mill 25. This paper scale is applicable to China National Standard (CNS) Α4 Talk (210X297 public) 16 _ (please read the precautions on the back and then fill out this page). . A7 __B7______ V. Description of Invention (Η) This square steel tube forming rolling mill 2 5 is formed by a number of thin waist rollers 2 6 into the final hot forging forming process, when the corners of the polygonal hollow steel tube 5 8 While being formed into a flat surface, the corners are re-formed on the flat plate part, that is, hot forging is processed into a square steel pipe with a large diameter and a square shape .. „—Γ. 5 9 At this moment, the square steel pipe that has just been hot forged 5 9, each flat portion 5 9 a forms a circular arc surface toward the outer side of the narrow waist surface, but then, each flat portion 5 9 a of the square steel pipe 5 9 shrinks to make the curved surface of the curved surface straight Shape, and the corner R forms a sharp edge state, the section coefficient increases accordingly. In addition, because the polygonal hollow steel tube 58 has a positive octagonal shape, one of the flat parts can often be used when conveyed by a conveyor Keep a certain direction Promotes that the position of the seam welded part 5 7 can be kept in a certain direction at all times when the square steel tube forming rolling mill 25 performs hot forging forming, that is, the position of the seam welded part 5 7 can always be kept at the flat plate part 5 9 a Near the center. In addition, the square steel pipe 5 9 of the cooling bed 28 is air-cooled to dissipate the heat I, that is, the cooling operation is performed by the cold cooling method. Next, the description will be made based on FIGS. 13 and 14 The fourth embodiment differs from the configuration of the third embodiment. That is, the difference is that when the press forming machine 6 2 is used to press-shape the polygonal hollow steel pipe 5 3, the position of the seam welded portion 5 7 is It is located at one corner of the polygonal hollow steel pipe 53, and the press forming process is performed. Therefore, when the final square steel pipe 5 9 is obtained, the position of the seam welded portion 5 7 is kept near the center of the flat plate portion 5 9 a. The standard of this paper is applicable to the Chinese National Standard (CNS) A4 (210X297mm " — -17 — 1 -------- (installation-(please read the precautions on the back before filling this page) Order B7 V. Description of invention (15) In this form The polygonal hollow steel pipe 58 before being transferred into the square steel pipe forming mill 25 is adjusted and positioned by means of a welding seam position adjustment device (not shown), etc. Figure 15 shows that it is different from the first The configuration of the third embodiment is the fifth embodiment. That is, after the polygonal hollow steel pipe 5 8 having a regular octagonal shape with a seam welded portion 5 7 is formed, the polygonal hollow steel pipe 58 is passed through a round forming rolling mill (Figure (Not shown) to perform cold forging forming to form a round tube 6 8. Then, the round tube 6 8 is carried into the heating furnace 12 to apply high temperature heating H, and finally into a square steel tube forming rolling mill 25 to form a square steel tube 5 9 〇 For this fifth embodiment, it is easy to perform cold forging from polygonal hollow steel tube 58 to round tube 6 8 and even hot forging from round tube 6 8 to square tube 5 9 Very easy to implement * with good accuracy. Alternatively, the polygonal hollow steel pipe 58 may be carried into the heating furnace 12 and subjected to high-temperature heating H, and then hot-forged by a drawing forming machine to form a round pipe 68. Printed by the Beigong Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page) For the above 3rd to 5th embodiments, although all are square square steel pipes 5 9 that are made of regular squares, but Similarly, rectangular square steel pipes 59 can also be manufactured. Even if the arrangement of the rollers of the square steel tube forming rolling mill 25 is changed, hot forging forming of polygonal steel tubes 59 such as pentagonal steel tubes or hexagonal steel tubes can be performed. In the third to fifth embodiments of the above-mentioned embodiments, although all 7 places are selected to be stamped to form an octagonal polygonal hollow steel pipe 5 3, but only the paper standard uses the Chinese National Standard (CNS) Α4 specification (2丨 0 '/ 297mm) 1-10-10- Printed by the Ministry of Economic Affairs Central Bureau of Industry and Commerce Beigong Consumer Cooperative A7 ΒΊ__ V. Description of invention (l6) To change the number of stamping places, the same can also be formed arbitrarily Hexagonal shape, or ten-corner shape and other multi-angle hollow steel pipes 5 8. In addition, the more stamping parts, the easier it is to form an acute angle with the bending angle of the multi-angle hollow steel ~ ----........................ tube 5 3, and promote the multi-angle hollow cup Solution 5 The tube shape of 3 3 is close to a circle, and it is more suitable for the shape of square steel tube 5 9 _ —-一 1 — * · —..— shape. However, at this moment, even if the stamping process is added, it is far less than the number of stamping times of ordinary round tube forming. In the above-described third to fifth embodiments, the polygonal hollow steel pipe 53 having an octagonal shape with one opening is welded, and the polygonal hollow steel pipe 58 is formed. However, it is also possible to combine a pair of segment-shaped C-shaped members (plural divided forming members) and form two (plural) places-~ ..................... ..... 一一 '—.................. Welding operation is performed on the seam welding part 5 7 to form a polygonal hollow steel pipe 5 8 〇 Secondly, according to FIG. 16 The seventh embodiment will be described with reference to Fig. 17. The ones with the same drawing number as the first embodiment or the second embodiment are the same structure, and their detailed description will be omitted here. When manufacturing a large-diameter square steel pipe, you must first select the square steel pipe suitable for this ( The final product) a certain plate thickness, length, and flat material that is wider than the width of the unfolded square steel tube, and then these steel plates 51 are stored in an overlapping manner. In addition, the steel plate 5 1 that forms the welding edge 5 2 by the edge pre-machining machine 6 1 is formed by pressing the four parts in sequence by the press forming machine 6 2, and then the pair is opened. The welding edge 52 is stamped and formed, so that the four-corner shape of the multi-corner medium-sized paper is applicable to the Chinese National Standard (CNS) A4 specification (2 丨 Ο X 297 公 |) 丨 9 _ 'I ---- ---- ^ _ _ I --- 丁 _______ Λ ^ 0¾. I ^-· (please read the precautions on the back before filling this page) A7 ______B7__ printed by the employee consumer cooperative of the Central Bureau of Standards of the Ministry of Economy V. Inventions Description (Π) Hollow steel pipe 5 3A · At this moment, from the polygonal hollow steel pipe 53A to the final square steel pipe, the position of the seam welded portion is kept near the center of the flat plate portion, and the press forming is performed. machining. For this multi-angle hollow steel pipe, first, a temporary fixed welding machine 5 3 is used to temporarily fix the two welding edges 5 2, and then, the inner surface welding is performed on the steel pipe by the inner surface welding machine 6 4 5 5 Furthermore, the outside welding 56 is applied to the steel pipe by the outside welding machine 65, and finally a polygonal hollow steel pipe 5 8 A having a regular square shape with a seam welded portion 5 7 is produced. The polygonal hollow steel tube 5 8 A produced in this way is made of steel plate 51 wider than the width of the unfolded steel tube as described above, so the width Wi of each flat plate portion 5 8 A is lower than the final product ( As described later), the width of the flat plate portion is wide. The polygonal hollow steel tube 5 8 A produced as described above is transported from the conveyor 60 to the carrying-in bed 6 6, and then transported from the terminal to the heating furnace 12, and then heated at high temperature in the heating furnace Η. In addition, the polygonal hollow steel pipe 58A heated to a certain temperature is removed from the heating furnace 12 and then transferred to the former square steel pipe forming rolling mill 70. For the former square steel tube forming rolling mill 70, after performing hot forging through a plurality of thin waist rollers 7 1 (forming temperature, Α3 metamorphic point or more), then for the polygonal hollow steel tube 5 8 Α Extrusion of the front section. After that, the polygonal hollow steel pipe 5 8 A is transported to the rear square steel pipe forming rolling mill 72. For the subsequent square steel tube forming rolling mill 7 2, hot forging is carried out through a plurality of thin 1 shaped rollers 7 3 and the paper size is adopted. The Chinese National Standard (CNS) A4 specification (210X 297 mm)- ώϋ-^ 1. ^^^ 1 ^^^^ 1 ί In Λ nm ^^^ 1 — ^ ϋ ml ^^ 4 (Please read the precautions on the back before filling this page) Employee consumption of the Central Bureau of Economic Development of the Ministry of Economic Affairs Cooperative cooperative printing A7 £ 7_ V. Description of the invention (l8) After the construction (forming temperature, above A 3 metamorphic point), the polygonal hollow steel pipe 5 8 A is extruded and formed. Finally, the hot forging forming process of the square steel pipe 59 is completed with a certain size. This square steel pipe 5 9 is the final product, and the width W of the flat plate portion 5 9 a is the width of the flat plate portion 5 8 a of the above-mentioned polygonal hollow steel pipe 5 8A by two-stage (plural) extrusion processing Wi is larger than the width boundary of the flat part 5 9 3 (boundary < World 1). Then, the hot-forging extrusion is used to complete the forming of the front end to the rear end of the square steel pipe 59. Therefore, it is not necessary to cut the front end or the rear end during the replication process. In addition, it is produced in a short distance, so the yield is naturally improved. In addition, the square steel pipe 5 9 immediately after hot forging is formed in which each flat portion 5 9 a is a straight surface, and the corner R forms a sharp edge, which increases the cross-sectional coefficient. Second, after hot forging The square steel pipe 59 is used for heat dissipation I in the form of air cooling during the transportation on the cooling bed 28, that is, to perform cold cooling. For the sixth embodiment described above, the front square steel pipe forming rolling mill 70 and the rear square steel pipe forming rolling mill 72 are used to perform hot forging forming while extruding in the front and back two stages, but it is also possible to use only one side, or Processing is performed in a majority of two or more stages. Next, the seventh embodiment, which is different from the sixth embodiment, will be described based on FIG. 18. The thick steel plate 5 1 is punched into a polygonal hollow steel pipe 5 3 A by a press forming machine 6 2, and for this polygonal hollow steel pipe, the welding edge 5 is first temporarily welded by a temporary fixing welding machine 5 3 2 Temporary paper size is applicable to China National Standards (CNS) 8 4 specifications (210X297 g) 21 _ ^^^ 1 ^ i · — an— ^^^ 1 ^^^ 1 In tn J 1 ^ 1 In ^ ^ 1 «In -0¾ " · (Please read the precautions on the back before filling in this page) A7 B7 printed by the Employee Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. The invention description (l9) is temporarily difficult, second, borrow The inner surface welding machine 6 4 applies the inner surface welding to the steel pipe 5 5 'Furthermore', the outer surface welding machine 6 5 applies the outer surface welding 5 6 to the steel pipe, and finally a polygon with a square shape with a seam weld 5 5 Hollow steel pipe 5 8A. The polygonal hollow steel tube 5 8A produced in this way is made of a steel plate (flat material) 51 that is wider than the width of the unfolded square steel tube (final product) during stamping, so each flat portion 5 8 The width Wi of A is wider than the width of the flat plate portion of the final product (described later), and the radius of curvature Ri of the corner portion 5 8 b is larger than the radius of curvature of the corner portion of the final product. The polygonal hollow steel pipe 5 8 A produced as described above is transported from the conveyor 60 to the carrying bed 6 6, and then transported from the terminal portion to the heating furnace 12, and then heated at high temperature in the heating furnace Η. In addition, the polygonal hollow steel pipe 5 8 A heated to a certain temperature is removed from the heating furnace 12 and then transferred to the former square steel pipe forming rolling mill 70. For the former square steel tube forming rolling mill 70, it is hot-forged through a plurality of thin waist rollers 7 1 (forming temperature, A 3 metamorphic point or higher), and then for the polygonal hollow steel tube 5 8 A Extruding the front section. After that, the polygonal hollow steel pipe 5 8 A is transported to the rear square steel pipe forming rolling mill 72. For the subsequent square steel tube forming rolling mill 7 2, after the hot forging process is performed through a plurality of thin waist rollers 7 3 (forming temperature, A 3 metamorphic point or higher), then for the polygonal hollow steel tube 5 8 A Extruding the front section. For such a polygonal hollow steel tube 5 8 A, the Chinese national standard (CNS) A4 specification (210X 297 pens) is applicable to the front-end square paper size _ 22 (please read the precautions on the back and fill in this page) -4 Printed by Beigong Consumer Cooperative of Central Bureau of Standards, Ministry of Economic Affairs «. A7 _____B7_ V. Description of invention (2〇) Extrusion processing of plural sections of shaped steel tube forming rolling mill 70 and back section square steel tube forming rolling mill 72 (or Singular section extrusion), and then made into the final product square. At this moment, the width W of the flat plate portion 5 9 a of the square steel pipe 5 9 after the above extrusion forming process is narrower than the width Wi of the polygonal hollow steel pipe 5 8 A, that is, w < Wi. Moreover, the curvature radius R of the corner portion 5 9 is smaller than the curvature radius R 1 of the corner portion 5 8 b of the polygonal hollow steel pipe 5 8 A, that is, R < R 1. As described above, the radius of curvature Ri of the corner portion 5 8 b formed by stamping will be larger than the radius of curvature R of the corner portion 5 9 b of the square steel pipe 5 9 (final product), so it can be easily stamped and formed Processing, and by returning the original material (molecular arrangement) of the polygonal hollow steel pipe 5 8 A by high-temperature heating Η, under hot forging extrusion processing, the width W and the radius of curvature of the corner 5 9 b can be promoted R is reduced, and the final product with a constant cross-sectional coefficient of the same material is obtained, that is, the square steel pipe 5 of the desired radius of curvature and width of the corner can be easily obtained. For the above-mentioned sixth and seventh embodiments, first, the polygonal hollow steel pipe 5 3 A is temporarily fixed and welded 5 4, then the inner surface is welded 5 5, and then the outer surface is welded 5 6 to make a polygonal hollow Steel pipe 58A, but it is also possible to perform outer welding 56 first, then inner welding 55, or inner and outer welding 55, 56 at the same time, and the step of temporarily fixing welding 5 4 can also be omitted. Next, the eighth embodiment will be described based on FIGS. 19 and 20. For example, when manufacturing a large-diameter square steel pipe, you must first prepare a plate thickness and length suitable for the square steel pipe (final product). The paper size is not in accordance with the Chinese National Standard (CNS) A4 specification (210X297 g *) '^' n · n —Bm · — In mn. ^ 1 ^^ 1 ^^ 1 ^^ 1 (please read the precautions on the back before filling in this page) 〇023dd A7 ____B7_ V. Material of the invention description (21) , That is, rolled steel plate 81. The steel plate 8 1 is unwound by a rewinding device 90 formed by a reel, etc., and then the bridge is flattened by the road roller 9 1 "Finally, the flat shape is cut by the cutting device 9 2 The front end portion of the steel plate 81. The flat steel plate 8 1 which has been moved successively is cut off by the trimming device 9 3 at both end portions, and its width is wider than the width of the square steel pipe (final product). Next, the steel plate 81 is gradually formed into an R shape by a preforming device 94, and then is gradually formed into a U shape by a separating device 95. The U-shaped steel plate 8 1 is bent inward by a pair of vertical plate portions of the upper part by a cluster rolling mill 96, and then is slowly formed into a circular tubular shape by using a fin rolling device 9 7 To promote the formation of a circular hollow steel pipe 82 by pressing the pair of right and left side edges against each other by press forming. The round hollow steel pipe 8 2 is then sent to a high-frequency resistance welding machine 98 to perform heating-melting welding, and then the cutting device 9 9 is used to remove the joint traces of the ball formed on the surface after welding, and the A hollow steel pipe (original pipe) 84 having a circular shape with a seam welded portion 8 3 is formed. The Ministry of Economic Affairs, Central Bureau of Standards, Male Workers ’Consumer Cooperative printed a crack (please read the precautions on the back before filling out this page). The hollow steel tube 8 4 was produced in this way, and it was transported into plural (two) forming devices 1 0 0 , Through a plurality of thin waist rollers 10} to form (correct) an approximately true circle shape. Next, the hollow steel pipe 84 is moved into the square steel pipe forming rolling mill 102. The square steel tube forming and rolling mill 102 is a plurality of (five) units, which are slowly cold-forged and formed through a plurality of thin waist rollers 103, respectively, to form a polygonal hollow steel tube with a rectangular shape. 8 5 · This paper scale is applicable to China National Standard (CNS) A4 specifications (2 丨 0 X 297 mm). '~ -24-A7 _ B7 printed by Beigong Consumer Cooperative of the Central Bureau of Economic Affairs of the Ministry of Economy V. Description of invention (22 ) At this moment, when obtaining the final square steel pipe, the polygonal hollow steel pipe 85 is always cold-forged by holding the seam welded portion 8 3 straight in the vicinity of the center of the flat plate portion. Then, the polygonal hollow steel pipe 85 formed by cold forging is formed by using a steel plate 8 1 wider than the width of the unfolded square steel pipe as described above, so the width Wi of each flat plate portion 8 5 a is larger than that of the final product ( It will be described later) The width of the flat plate part should be wider. In addition, the polygonal hollow steel tube 85 is subjected to the bending correction by the bending bridge device 104, and then is cut to a certain length by the mobile cutting device 105. The polygonal hollow steel pipe 85 produced in this way is transported directly or from a place stored in another place to the transport bed 106. Next, the polygonal hollow steel pipe 85 transported to the terminal portion of the carrying bed 106 is fed into the furnace 107 in the longitudinal direction, and high-temperature heating Η above the A 3 transformation point is performed. After completion of heating at a certain temperature, the polygonal hollow steel pipe 8 5 was moved out of the heating furnace 107 and then moved into the former square steel pipe forming rolling mill 108. For the former square steel tube forming rolling mill 108, hot forging is performed through a plurality of thin waist rollers 109 (forming temperature, 3 or more abnormal points), and then the polygonal hollow steel tube 85 is subjected to the front stage Extrusion processing. Next, the polygonal hollow steel pipe 85 is sent to the rear square steel pipe forming mill 1 1 0. For this second-stage square steel tube forming rolling mill 1 1 0, hot forging is performed through a plurality of flat-shaped rollers 11 1 (forming temperature, A 3 or more abnormal point), and then the polygonal hollow steel tube 85 is entered into the second stage ( The final stage) is extruded and processed to complete the paper size with a certain caliber. Using Chinese National Standard Rate (CNS) A4 (210X297 male turtle) 25 _ '^^ 1 · HH i ^ i —Bn In ^ ^^ 1 4. J m —B ^ i In nn J 0¾ j (please read the precautions on the back before filling in this page) A7 _B7____ printed by the Employee Consumer Cooperative of the Central Escalation Bureau of the Ministry of Economic Affairs V. Description of invention (23) Hot forging and forming to form square steel pipes 86. This square steel pipe 85 is the final product, and the width W of the flat plate portion 8 6 a is made by the extrusion processing of two stages (plural stages) to make the flat plate portion 5 8 a of the above-mentioned polygonal hollow steel pipe 5 8 A The width of Wi is larger than the width boundary of the flat plate portion 5 9 3 (that is, the boundary < World 1). Then, the hot-forging extrusion is used to complete the forming of the front end to the rear end of the square steel pipe 59. Therefore, it is not necessary to cut the front end or the rear end in the post-production process. In addition, the production is carried out at a moment distance, so the yield is naturally improved. In addition, the square steel pipe 86 immediately after the hot forging process has its flat plate portions 8 6 a forming straight surfaces, and its corner portions R are sharp-edged, and the breaking factor is also improved. In addition, a descaling device 1 1 2 is provided around the front and rear square steel tube forming rolling mills 108, 120, and the descaling device 1 12 sprays pressurized water on the square steel tube 86 Remove the rolled steel scales on the surface of the steel pipe to improve its surface. The square steel tube 86 formed by hot forging is connected to the cooling bed 113 into the air-cooling form of heat dissipation I, that is, the cold cooling is performed under the same temperature environment, so that the bending deformation during cooling is reduced. For the eighth embodiment described above, although the cold forging forming process from the hollow steel tube 84 to the polygonal hollow steel tube 85 is performed by a one-section square steel tube forming rolling mill 102, a plurality of sections of square steel tubes may also be used The forming mill 102 is used. In addition, hot forging forming is carried out by extruding at the front and rear two stages with the former square steel tube forming rolling mill 108 and the rear forming rolling mill 1 10 '. In addition, it may be carried out in one stage or two or more stages. __ This paper scale adopts China National Standard (CNS) A4 specification (21〇 > < 297 public *) 26 _ (please read the precautions on the back before filling in this page). Binding · Order Λ A7 __B7 5. Description of the invention (24) For the 8th embodiment mentioned above, although it is a circle The hollow steel pipe 8 2 is welded at one opening to form the hollow steel pipe 84. However, a pair of semicircular cross-section members (plural divided arc-shaped members) may be combined and welded to form There is a hollow steel pipe 4 with a seam welded portion 83. Next, a ninth embodiment with a configuration different from that of the eighth embodiment will be described based on FIG. 21. The approximately circular hollow steel tube 8 (formed) formed (corrected) by the narrow-roller roller 1 〇1 in the forming apparatus 100 is transferred into the square steel tube forming rolling mill 1 0 2 and uses a plurality of thin-roller rollers 1 〇3 to slowly perform cold forging forming to form a rectangular polygonal hollow steel pipe 85. At this moment, the polygonal hollow steel tube 85 is cut off by the trimming device 93 to remove the bad edges on both sides, and the width of the trimmed steel plate 81 is wider than the width of the unfolded square steel tube, so its flat plates The width Wi of the portion 85 is formed to be wider than the width of the flat plate portion of the final product, and the radius of curvature R \ of the corner portion 85 b is much larger than the radius of curvature of the corner portion of the final product. Printed by the Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs (please read the precautions on the back before filling in this page). The polygonal hollow steel tubes 8 5 that are generally made in this way are transported into the heating furnace 1 0 7 in the longitudinal direction. Heat Η at high temperature. Then, the polygonal hollow steel pipe 85 is conveyed into the square steel pipe forming rolling mill 1 02 of the front stage, and hot forging is performed through a plurality of thin waist rollers 109 (forming temperature, A3 or more abnormal point), that is, After the extruding process in the front stage, the descaling device 1 1 2 is used to spray the pressurized water on the surface of the steel pipe to remove the steel scales, and then sent to the rear square steel pipe forming mill. The paper size is applicable to the Chinese National Standard (CNS) Α4 specification 1 210X297 mm) '-Z ί-A7 __ B7_ 5. Description of the invention (25) (Please read the precautions on the back before filling in this page) 1 1 0' Proceed through a plurality of flat rollers 1 1 1 Hot forging forming (forming temperature, A3 abnormal point or higher), that is, extrusion forming in the rear stage (final stage). For such a polygonal hollow steel tube 85, after the extrusion processing (or singular extrusion) of the plural sections of the former square steel tube forming rolling mill 108 and the rear square steel tube forming rolling mill 110, And the square steel tube made into the final product 8 6. At this moment, the width W of the flat plate portion 8 6 a of the square steel pipe 8 6 after the above-mentioned extrusion forming process is narrower than the width Wi of the polygonal hollow steel pipe 8 6 a, that is, WSWi. Moreover, the radius of curvature R of the corner portion 8 6 is smaller than the radius of curvature Ri of the corner portion 8 5 of the polygonal hollow steel pipe 8 5, that is, R < Ri. The corner section 8 5 b formed by the square steel pipe rolling mill 1 〇2 as described above is printed by the Central Ministry of Economic Affairs of the Ministry of Economic Affairs. The radius of curvature R of 6 b should be large, because for hollow steel tube 8 4 to polygonal hollow steel tube 8 5, cold forging can be easily performed, and then the original material can be restored by heating Η (Molecular arrangement) of the multi-angle hollow steel. Tube 8 5, under hot forging extrusion process, to reduce the width W and the curvature radius R of the corner 8 6 b, and to obtain a high cross-sectional coefficient of the same material The final product, that is, a square steel tube that can easily obtain the radius of curvature and width of the desired corners 86. For each of the above-mentioned embodiments, the original tube 1 is heated while being transported in the longitudinal direction in the heating furnace 12, but it can also be as shown in the 10th embodiment shown in FIGS. 2 2 to 28 ， Use the form perpendicular to the length direction of the original tube 1 to carry out the transportation and heating operation》 This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X 297 public) 28 _ A7 __B7____ V. Description of invention ( 26) In addition, the figures having the same figure numbers as those in the first or third embodiment are all the same structure, and their detailed descriptions are omitted here. As shown in FIG. 22, for example, when manufacturing a large-diameter square-shaped steel pipe 3, first, an original pipe 1 having a rectangular shape is prepared on the carrying-in bed 120. The carry-in bed 1 20 is a conveyor belt type provided on the floor 1 2 1, supports a plurality of original tubes 1 in parallel, and carries out the conveying work in a horizontal direction B perpendicular to the longitudinal direction A. Then, the original tube 1 at the end of the carrying bed 1 20 is sent to the heating furnace 1 30, where the steel tube is transported in the transverse direction B perpendicular to the longitudinal direction A while High temperature heating H is applied to the steel pipe at a temperature higher than the A 3 metamorphosis or higher. The above-mentioned heating furnace 1 30 is shown in FIGS. 2 3 to 25, and is composed of: a bottom furnace wall 1 3 1 with a support surface 1 3 1 a formed on the upper portion; The side furnace wall 1 3 2 in the state; and the front furnace wall 1 3 3 established from the front end of the bottom furnace wall 131; and printed by the Central Sample Bureau of the Ministry of Economic Affairs. (Notes to fill out this page) From the rear end of the bottom furnace wall 1 3 1 above, the rear furnace wall 1 3 4 is established; and the side furnace wall 1 3 2 and the front furnace wall 1 3 3 and the rear furnace The top furnace wall 1 3 5 and the like between the upper ends of the walls 1 3 4 form a box-shaped heating furnace. The heating furnace 1 3 0 is supported on the floor 1 2 1 by a support frame 1 2 2 and the like. In addition, the paper scales are set on the front furnace wall 1 3 3 and the rear furnace wall 1 3 4 respectively. The Chinese National Standard (CNS) A4 specification (210X297 pen) is applied. A7 B7 V. Description of the invention (27) The import entrance 1 36 and the export exit 1 37 are installed, and the opening and closing doors 138, 139 are installed on the import entrance 1 36 and the export exit 137 respectively. Here, the import entrance 136 and the export exit are installed 137 is formed by the smallest size and shape that can pass the original tube 1 of the largest diameter and length to be heated in the form of a vertical direction A and a transverse direction B. In addition, a certain number of heating burners 1 4 0 are provided at predetermined positions of each furnace wall 1 3 2 to 1 3 5 and so on. In addition, a smoke exhaust port 1 4 1 in the vertical direction is provided in a portion adjacent to the outlet 1 3 5 of the top furnace wall 1 3 5 »In addition, a lift operation is provided on the bottom furnace wall 1 3 1 And the movable furnace body that moves back and forth. That is, in the left and right directions of the bottom furnace wall 1 3 1 at a plurality of places (the embodiment of this case is 4 places), slits 1 4 3 almost the same length as the bottom furnace wall are provided, and the movable furnace body 1 4 2 series Lifting and back-and-forth movement are freely fitted into these slits 1 4 3. Further, on the upper surface of the movable furnace body 1 4 2, a concave arc-shaped lifting surface 1 4 2 a is provided at a position corresponding to a certain pitch described later. Furthermore, one or more of the supporting surfaces 1 3 1 a of the bottom furnace wall 1 3 1 are provided with turning protrusions 1 4 4. The turning protrusion 1 4 4 is in contact with the original pipe 1 which is lowered before the supporting surface 1 3 1 a. In order to rotate the original pipe 1, the front end of the heating furnace 1 3 0 is taken as the upper position , The rear end side is down to form an inclined surface. The heating furnace 1 3 0 is constituted by the above-mentioned figures No. 1 3 1 to 1 44 and the like. The carrying-in means 1 4 5 is arranged outside the carrying-in port 1 3 6 and the carrying-out means 1 4 6 »is arranged outside the carrying-out port 1 3 7» such carrying-in means 1 4 5 and carrying-out means 1 4 6, It is in the form of clamping and raising and lowering the size of the paper, using the Chinese National Standard (CNS) A4 specification (210X297 public exemption) 3 (please read the precautions on the back and then fill out this page) binding 30S309 A7 _____B7_ (28) The components are used in the form, and the conveying force of the carrying bed 120 can also be omitted. In addition, the original tube 1 that is carried into the heating furnace 1 30 is intermittently sequentially conveyed by the movable furnace body 1 4 2 to move up and down and back and forth, and the vertical direction is perpendicular to the longitudinal direction A In the B method, the original pipe is transported to the rear end, and high-temperature heating is performed while being transported. In addition, a recess 123 on the side of the floor 121 is formed below the bottom furnace wall 1 31, and a base 15 1 is arranged in the recess 123. From this base, a plurality of support rods 1 5 2 are erected on the base 15 1, and the bottom side of the bottom furnace wall 1 3 1 is supported by the upper ends of these support rods 1 5 2. The movable body 1 5 3 which can be moved up and down and back and forth is configured to avoid the above-mentioned support rods 1 5 2 group. The movable body 1 5 3 is composed of: a lower frame 1 5 4; and the Ministry of Economic Affairs Central Standards The bureau of the Bureau of Social Security and Economic Cooperation (please read the precautions on the back before filling in this page). In this lower frame, there are several places in the left and right directions of 1 5 4 (the embodiment of the present invention is four places). The support rod 155; and the support plate 15 6 provided between the upper ends of the support rods 1 5 5 at the front and rear of each place. In addition, the movable furnace body 1 4 2 is fixed to the upper surface of these support plates 1 5 6. In addition, the raising and lowering actuating device 1 5 7 for raising and lowering the movable body 1 5 3 is composed of: The base 151 located in a plurality of places in the front-rear direction is applicable to the Chinese National Standards (CNS) Α4 by horizontal paper standard Specifications (210 X 297 public |) A7 _B7_ V. Description of the invention (29) Pin 1 5 8 to set a plurality of horizontal bars 1 5 9 that can be shaken in the front and back directions; and (please read the precautions on the back first (Fill in this page again) The push-pull rod 1 60 that is connected to the lower end of these cross-bars 1 5 9 acting in the front-rear direction; and the cylinder 1 6 1 that is connected to the end of the push-pull rod 1 6 0 for lifting operation ; And rollers 1 6 2 etc. which are pivoted to the upper end of each cross bar 1 5 9 and are abutted to the lower frame hip 1 5 4 of the movable body 1 5 3》 In addition, the lifting actuator 1 5 7 series is configured as a pair of left and right. Also, the two cylinders 161 for actuating movements operate simultaneously. The front-rear actuating cylinder 163 is placed between the wrist body 164 connected to the lower frame 154 and the base 1 151 to move the movable body 153 forward and backward. The front-rear actuating cylinder 163 and the above-mentioned lifting cylinder 161 are connected to the connecting member so as to oscillate relatively freely. The intermittent sequential conveying device 1 5 0 is constituted by the drawing number 1 5 1 ~ 1 6 4 printed on the Male Workers' Consumer Cooperative of the Central Ministry of Economic Affairs of the Ministry of Economic Affairs. In addition, due to the action of the movable furnace body 142, the gap gradually formed at the part of the slit 143 can be properly closed by a sealing device (not shown). As mentioned above, the original pipe 1 that was transported to the terminal of the loading bed 1 20 was opened by opening and closing the door 1 3 8, and moved by the loading means 1 4 5 to the transverse direction B perpendicular to the longitudinal direction A The original pipe 1 is transported into the heating furnace 1 30 through the loading port 1 36. At this moment, the movable furnace body 1 42 is lowered and moves forward toward the loading port 1 3 6 side. Therefore, the original tube 1 that was moved into the heating furnace, as shown in circle 25, is supported on the bottom of the furnace. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 public soap) 32 _ A7 B7 Central Ministry of Economy Printed by the quasi-bureau employee consumer cooperative V. Description of the invention (30 1 1 Wall 1 3 1 Support surface 1 3 1 a on 9 Then and after moving into the original tube 1 1 1 Close the opening and closing door 1 3 8 0 1 I in this state Next, by the contraction of the cylinder 1 6 1 for lifting and lowering, please 1 first 1 rock the cross bar 1 5 9 group> and move the reading 1 1 movable body 1 5 3 by the roller 1 6 2 group moving upward Then, through this movable body 1 5 3, move the back of the movable furnace body 1 1 Note I 1 4 2 The group moves up within the slot 1 4 3 D »Therefore > As shown in Figure 2 6 intention 1 ♦ By supporting Face 1 3 1 a The original tube supported by 1 1 * It is lifted by the lifting item and then 4 1 Face 1 4 2 a is lifted 0 Next by Cylinder 1 6 3 for front and back operation The movement of the extension 1 installed on this page makes the movable body supported by the roller 1 6 2 group'—✓ 1 I 1 5 3 back and move the furnace body through this movable body 1 5 3 1 4 2 The group 1 1 performs the retreating action within the slit 1 4 3 E. As shown in Figure 2 7 I 1 Order the original tube 1 to be lifted by the lifting surface 1 4 2 a at a fixed distance of _. Move 1 I to the rear end side 〇1 1 In addition, the stretching action of the lifting cylinder 1 6 1 makes the crossbar 1 1 1 5 9 group shake j and then move through the roller 1 6 2 group that can be shaken downward. '' The body 1 5 3 is lowered * and the movable furnace body 1 4 2 1 is made through this movable body 1 5 3 | The group performs the lowering operation F 9 in the slit 1 4 3 and therefore, as shown in Figure 2 8 Figure 1 I shows 9 by lifting Raised surface 1 4 2 a The original tube that was lifted 1 After the delivery can be delivered to the support 1 1 After the braced surface 13 1 a 〇 • Use W- back gas The shrinkage of the cylinder 1 6 3 1 »The movable body 1 5 3->-八 刖 进> 1 supported by the roller 1 6 2 group and the movable furnace body 1 4 through this movable body 1 5 3 The 2 groups move forward within the slot 1 4 3 1 1 G »Therefore 1 As shown in Figure 2 5 t lift the empty 1 1 side 1 4 2 a back to the front end by a fixed distance 〇1 I In this way, the original tube 1 can be moved into the original tube 1 through a short period of time. This paper standard is applicable to the Chinese national standard (CNS> A4 specification (210X29 * 7 mm)) 33 302309 A7 _B7 5. Description of the invention (31) 1 3 6 came into the heating furnace 1 30. Then, the original tube 1 located in the heating furnace 1 3 0 will pass through the movable furnace body that is hardly affected by heat (please read the precautions on the back before filling this page) 1 4 2 and use the intermittent sequential conveying device 1 5 0 Acting, the original pipe 1 is sequentially conveyed from the end side to the rear end side at a constant pitch in a forward direction in the lateral direction B perpendicular to the longitudinal direction A. Thereafter, the original tube 1 being transported in the heating furnace 1 30 is heated at a high temperature above the A3 transformation point by the heating burner 140. In addition, in the heating furnace 130, a plurality of original tubes 1 can be simultaneously transported. In addition, when carrying out the sequential conveying operation, the original pipe 1 is basically carried out in a stationary state, so that the original pipe

Under the condition of heating and transporting. In addition, in the original pipe 1 that performs the lowering operation F, it first comes into contact with the inclined surface of the rotating protrusion 144, and secondly, the original pipe 1 itself rotates by the rotation of the inclined surface, and finally stops at the support Face 1 3 1 a. In this way, the original tube 1 can be rotated in a single or multiple times during heating to change its supported surface, so that the heating can be homogenized. After being heated in this way, it was transported to the original exit of the Ministry of Economic Affairs, Central Bureau of Economic Affairs, Beigong Consumer Cooperative Printed 1 near the transport outlet 1 3 7, which was opened in a short time under the time difference of the coordinated decline action F as described above. Outlet 1 3 7 and then using the action of the carrying out means 1 4 6 to take the original pipe 1 out of the heating furnace 1 3 0 and place it on the conveyor 1 6 5 by the conveying method perpendicular to the longitudinal direction B , Open and close the door 1 9 3 after the original pipe 1 is carried out. In addition, the original tube 1 that was moved out of the heating furnace 1 30 after being heated at a certain temperature in the heating furnace 1 30, as shown in FIG. 22, was transported to the size of the welding paper. The Chinese National Falcon (CNS ) A4 specification (210 X297 male turtle) 34 _ Printed A7 _____B7_______ by the Beigong Consumer Cooperative of the Central Bureau of Economic Affairs of the Ministry of Economic Affairs 5. Description of the invention (32) Seam position adjusting device 15 to the seam welding part of the original pipe 1 Adjust the position of 2 to a certain direction. After that, the original pipe 1 is carried into the round steel pipe forming rolling mill 20, and hot forging forming is performed through a plurality of forming rollers 21, to produce a refined original pipe 1A. Next, the refined raw pipe 1A is transferred to a square steel pipe forming and rolling mill 25, and hot-forged by thin waist rollers to form a large-diameter square-shaped square steel pipe 3 of the final product with a certain size. Next, the 11th embodiment which is different from the 10th embodiment will be described based on Fig. 29. That is, when manufacturing a large-diameter square steel pipe 3 * first prepare a square steel pipe (or rectangular steel pipe) 1 B of a certain diameter, plate thickness, and length suitable for this square steel pipe 3 as the original pipe Place it on the carrying bed 1 2 0. Then, the square steel pipe 1 B at the end of the carrying bed 1 20 is carried into the heating furnace 1 30, and is generally transported in the heating furnace 1 30 in the transverse direction B perpendicular to the longitudinal direction A A 3 High temperature heating above the abnormal point. At this moment, the upper surface of the movable furnace body 1 4 2 is formed with a flat raised surface 1 4 2 b. In addition, the square steel pipe 1 B carried out from the heating furnace 1 30 is not subjected to the circular steel pipe forming rolling mill 20, but is subjected to hot forging forming through the square steel pipe forming rolling mill 25 through the conveyor 1 65. In the above-mentioned 10th embodiment and 11th embodiment, when the original pipes 1, 1B are carried into the front end of the heating furnace 130 and out from the rear end, the opening of the inlet 1 3 6 and outlet 1 3 7 can be shortened Time, and this paper scale is applicable to China National Standards (CNS > A4 specification (210X297 male rabbit) 35 ^ (please read the notes on the back ^ before filling out this page) Printed by the cooperative A7 B7 5. Description of the invention (33) Reduce the flow of flame from the heater 1 4 0 to the inlet 1 3 6 and the outlet 1 3 7 to further improve the thermal efficiency. In addition, by intermittent sequential conveyor 1 50 to move the movable furnace body 1 4 2 up and down and back and forth, so that the original tubes 1 and 1B in the heating furnace 130 can pass through the movable furnace body 1 4 2 that is not affected by heat from the front end side to the rear end side. Intermittent at certain pitch positions Sequential transportation. The sequential transportation and transportation at this moment, basically, the original pipes 1, 1B themselves are at a standstill, which facilitates the transportation work without damaging the steel pipe. • Even the heavy-weight and large-diameter original pipes 1, 1B, there will be no damage to the intermittent sequential conveying device 1 5 0, and the operation of conveying can be always maintained in a stable state. [Simple description of the drawings] FIG. 1 is a diagram showing the use of the square of the first embodiment of the present invention Engineering perspective view of the hot forging forming method of the steel pipe manufacturing method. Figure 2 is an engineering perspective view of the post-processing part of the above-mentioned square steel pipe manufacturing method. Figure 3 is a washing part of the same square steel pipe manufacturing method Engineering perspective view. Figure 4 shows the square steel pipe manufactured by the same method as the above square steel pipe, A is the steel pipe just formed, B is the front view after cooling. Figure 5 is the comparison with the conventional products The hardness distribution on the inner side ® 〇 The paper wave scale is suitable for the Chinese National Standard (〇 奶) 84 specifications (210 father 297 male rabbits) 36_ (please read the notes on the back first Please fill out this page again.) Pack. Order A7 B7 Printed and printed by the Employee Consumer Cooperative of the Central Bureau of Economic Development of the Ministry of Economic Affairs. 5. Description of the invention (34 1 1 6th. The figure shows the hardness distribution on the outer side after comparison with the conventional product. 1 1st 7 The graph shows the tensile akg stress-tensile curve ratio after comparison with conventional products. S 1 1 1 first 1 compares the graph. It 1 • η back 1 The 8th graph shows the transfer curve after comparison with conventional products. 0 1 Note 9 is a drawing showing the intention of manufacturing a round steel pipe according to the second embodiment of the present invention. 1 method of the hot forging process of the three-dimensional engineering, 0 items, and 1 is filled in. The first 10 is a square showing the third embodiment of the present invention. Production of steel pipes. This page is installed. 1 Engineering perspective view of the manufacturing method. 0 1 | Page 1 1 The chart is the same as the manufacturing method of the above square steel pipe. Description of the process 1 I Figure 〇1 1 Order 1 2 ren The drawing is the same as the above description of the manufacturing method of the square steel pipe 1 Figure 0 1 1 The first 1 3 tat circle shows the manufacturing of the square steel pipe according to the fourth embodiment of the present invention 1 1 Engineering description of the manufacturing method Fig. 0 J Λ No. 1 4 The figure shows the welding theory same as the above-mentioned square steel pipe manufacturing method 1 I Detailed drawing 〇1 1 1 The first 1 5 Figure shows the square of the fifth embodiment of the present invention Steel pipe manufacturing 1 I Engineering description diagram of the manufacturing method 〇1 Figure 16 is a perspective view showing the process of manufacturing a square steel pipe according to the sixth embodiment of the present invention 〇1 1 17th figure is the same as the above square steel pipe The engineering method of the manufacturing method 1 | Bright picture 〇1 I Figure 1 8 shows the present invention 7 The production of square Λκη steel pipes according to the examples 1 1 The paper size is applicable to the Chinese National Standard (CNS) Μ specifications (2 丨 OX297 male rabbit) 3 Printed by the Ministry of Economic Affairs, Central Bureau of Economic and Social Affairs Employee Consumer Cooperative A7 _____B7_ V. Description (35) The engineering description drawing of the manufacturing method. Fig. 19 is an engineering perspective view showing a method of manufacturing a square steel pipe according to an eighth embodiment of the present invention. Figure 20 is an explanatory drawing showing the process of manufacturing the same square steel pipe as described above. Fig. 21 is an engineering perspective view showing a method for manufacturing a square steel pipe according to a ninth embodiment of the present invention. Fig. 22 is an engineering perspective view showing a method for manufacturing a square steel pipe according to the tenth embodiment of the present invention. Fig. 23 is a longitudinal side view showing a portion of the heating furnace in the same method as the above-mentioned method for manufacturing square steel pipes. Fig. 24 is a longitudinal sectional front view of the heating furnace portion of the method for manufacturing the square steel pipe described above. Fig. 25 is a longitudinal side view showing the inlet portion of the heating furnace in the same manner as the above-mentioned method for manufacturing square steel pipes. Fig. 26 is an explanatory diagram showing the upward movement of the same method of manufacturing the square steel pipe. Figure 2 7 shows the explanatory diagram of the same method of manufacturing the square steel pipe after the retreat * Figure 2 8 shows the explanatory diagram of the same as the manufacturing method of the above square steel pipe when the descent action · Figure 2 9 shows the book Longitudinal side view of the entrance of the heating furnace of the manufacturing method of the square steel pipe according to the first embodiment of the invention β This paper scale is applicable to the Chinese national rate (CNS > A4 specifications (210X297 male rabbit > 38-J --------- 1 outfit-(Please read the precautions on the back before filling out this page)

J Printed by the Ministry of Economic Affairs, Central Bureau of Industry and Fisheries Co., Ltd. A7 _B7 V. Description of invention (36) [Explanation of drawing number] 1: Original tube (round steel tube) 1 A: Refined round tube 2: Seam welding part 3: Square steel pipe (final product) 3 a: Flat part 3 b: Corner part 5: Round steel pipe (final product) 1 0: Carry-in bed 1 1: Heating part conveyor 1 2: Heating furnace 1 5: Welding seam position adjusting device 1 6: Support roller 1 7: Press roller 20: Round steel tube forming rolling mill 2 1: Side roller 2 3: Descaling device 2 5: Square steel tube forming rolling mill 2 6: Slim waist roller 2 8: Cooling bed 29: 1st conveying conveyor 3 0: rectifying device 3 2: Relay bed 3 3: 2nd conveying conveyor _ This paper size is applicable to China National Standard (CNS) A4 specification (21〇297 297) 39 1 * ·: ·.---^^^ 1 · -I country i I--I-(1 ^^ (please read the precautions on the back before filling out this page)

J Printed by Beigong Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs ^ 02309 A7 _______B7 V. Description of the invention (37) 35: front-end cutting device 3 6: rear-end cutting device 4 0: washing device 4 1: outside washing Nozzle 4 2: Inner surface cleaning nozzle 43: Third conveying conveyor 4 5: Anti-rust device 4 6. Carry out bed 5 1: Steel plate (flat material) 5 2: Edge 5 3: Polygonal hollow steel pipe 5 3A: Polygonal Hollow steel pipe 5 4: locating point welding 5 5: inside welding 5 6: outside welding 5 7: seam welded part 5 8: polygonal hollow steel pipe 5 8A: polygonal hollow steel pipe 5 8 a: flat plate part 5 8 b: corner part 5 9: square steel pipe (final product) 5 9 a: flat plate part 5 9 b; corner part 6 0: conveyor _ This paper size is applicable to China National Standard (CNS) A4 specification (210X297 public examination) 4〇i --- ----- [installed-- (please read the precautions on the back before filling in this page)

J Printed and printed A7 ___B7 by the Ministry of Economic Affairs, Central Bureau of Preservation and Consumer Cooperative V. Description of the invention (38) 6 1: Edge pre-processing 6 2: Press forming machine 63: Positioning point welding machine 6 4: Inner surface welding machine 6 5: Outside welding machine 6 6: Carry-in bed 6 8: Round tube 7 0: Front square steel pipe forming rolling mill 7 1: Slim waist roller 7 2: Rear square steel pipe forming rolling mill 7 3: Flat roller 8 1: Steel plate (material) 8 2: Round hollow steel pipe 8 3: Seam welded part 84: Hollow steel pipe (original pipe) 85: Polygonal hollow steel pipe 8 5 a: Flat part 8 5 b: Corner part 8 6: Square steel pipe (final product) 8 6 a: Flat part 8 6 b: Corner part 9 0: Rewinding device 9 1: Leveling machine 9 2: Cutting device _ This paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 public pen) 4 j (Please read the precautions on the back before filling out this page). Packing. Order A7 B7. The Central Standard Falcon Bureau of the Ministry of Economic Affairs, Beigong Consumer Co., Ltd. Du Printed Fifth. Description of the invention (39 1 1 9 3 Trimming device 1 1 9 4; pre Forming device i I 9 5 Separation device please} first 1 9 6 cluster mill reading 1 Back 1 9 7 • 1 d of the fin roll device | 9 8 • High frequency resistance welding machine 1 1 9 9 Cutting device re 1 0 0; Forming device write this page 1 1 0 1; Slim waist roller * — ^ 1 I 1 0 2: Square steel tube forming and rolling mill 1 I 1 0 3 Slim waist roller 1 1 Set 1 0 4 Bend correction device 1 1 1 0 5: Mobile cutting device 1 1 1 0 6; Move into bed 1 1 1 0 7 Heating furnace Λ 1 0 8 Sectional square steel tube forming rolling mill 1 1 1 0 9 Slim waist roller 1 I 1 1 0 Rear section square steel tube forming rolling mill 1 1 1 1 1 Flat shape roller 1 1 1 1 2 Descaling device 1 1 1 3 Cooling device 1 1 1 A Square steel tube (original tube) 1 1 1 2 0 Carry-in bed 1 I 1 2 1 Floor 1 This paper size is applicable to China National Standard (CNS) A4 specification (21〇X297 Pen) 42 V. Description of invention (4〇) A7 B7 Printed by the Beigong Consumer Cooperative of the Central Bureau of Economic Affairs of the Ministry of Economic Affairs 1 2 2: Support frame 1 2 3: Recess 1 3 0: Heating furnace 1 3 1: Bottom furnace wall 1 3 1 a · Support surface 1 3 2: Side furnace wall 1 3 3: Front furnace wall 1 3 4 : Rear furnace wall 1 3 5: Top furnace wall 1 3 6: Moving in □ 1 3 7: Moving out □ 1 3 8: Opening and closing door 1 3 9: Opening and closing door 1 4 0: Heating burner 1 4 1: Smoke exhaust □ 1 1 4 2: Movable furnace body 1 4 2 a Concave arc-shaped lifting surface 1 4 2 b: Flat-shaped lifting surface 1 4 3: Slotting 1 4 4: Rotating protrusion 1 4 5: Loading Means 1 4 6: Unloading means 1 5 0: Intermittent sequential conveying device 1 5 1: Base frame (please read the precautions on the back before filling in this page) Pack. Order Λ This paper size applies to China National Standard (CNS) A4 Specifications (210 > < 297 pens) "A7 B7 V. Description of Invention Ul) 1 5 2: Support bar 1 5 3: Support bar 1 5 4: Lower frame 1 5 5 •• Support bar 1 5 6 •• Support plate 1 5 7: lifting Actuator 1 5 8 * 4 ^; • Cross pin 1 5 9. Anger rod 1 6 0: Push rod 1 6 1: Lifting cylinder 1 6 2: Roller 1 6 3: Front and rear actuating cylinder 1 6 4: Wrist Body 1 6 5: Conveyor (please read the precautions on the back before filling in this page) Binding-Order Printed by the Ministry of Economic Affairs Central Bureau of Customs and Excise Consumer Cooperatives A: Length direction B: Horizontal direction D: Upward movement E: Backward Action F: Falling action G: Forward action L: Interval H: High-temperature heating I: Heat dissipation W: Width of the flat part 59a (86a) of the square steel tube (86) The paper size is in accordance with Chinese National Standard (CNS) M specifications (210X297 Shame_) 44 23d9 A7 B7 5. Description of the invention (42) Size Wi: width of the flat part 58a (85a) of the polygonal hollow steel pipe 58A (85) R dimension: corner part 59b (86b) of the square steel pipe 59 (86) Radius of curvature Ri: The radius of curvature of the corner 58b (85b) of the multi-angle hollow steel tube 58A (85) (please read the notes on the back before filling this page). The paper is printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economy. Standard (CNS) A4 specification (210X297 public free) & _

Claims (1)

A8 Β8 C8 D8 々 printed by Beigong Consumer Cooperative of the Central Ministry of Economic Affairs of the Ministry of Economic Affairs, the scope of patent application 3 1-a method of manufacturing square steel pipes, characterized by the use of a certain caliber, plate suitable for the size of the final product Thick, round steel tubes of length and length, and put this tube in a heating furnace to heat, then this heated steel tube is hot forged by a round steel tube forming mill to produce refined steel tubes, and then The refined steel pipe is subjected to hot forging forming using a square steel pipe forming and rolling machine to form a square steel pipe, and finally the angular steel pipe is cooled on a cooling bed. Two kinds of manufacturing methods for square steel pipes, which are characterized by: flat sheet material is stamped and then seam welded to form a polygonal hollow steel pipe and placed in a heating furnace for heating, and then hot square forging processing is performed by a square steel pipe forming mill Square steel pipe. 3. The manufacturing method of the square steel pipe as claimed in item 2 of the patent scope, wherein the width dimension of the polygonal hollow steel pipe is larger than the size of the final product, and then the polygonal hollow steel pipe after the heating furnace is heated by the square Steel pipe forming rolling mill, hot forging forming while extruding "4 · For example, the method of manufacturing square steel pipe in patent application No. 2, wherein the width of the polygonal hollow steel pipe is larger than the final product, And increase the radius of curvature of the corners, and then through the steel tube forming rolling mill, the polygonal hollow steel pipe heated by the heating furnace is subjected to hot forging while squeezing the width and the radius of curvature of the corners. 5. A method for manufacturing square steel pipes, characterized by: cold forging forming of round steel pipes by a square steel pipe forming rolling mill to form a polygonal hollow steel pipe that is larger than the width of the final product, and then the polygonal steel pipe The hollow steel tube is placed in a heating furnace for heating, and then the Chinese paper is used from the original paper (C Gang M secret (2 丨 0X bumps! 46 (Please read the precautions on the back before filling this page) Γ Ministry of Economic Affairs Printed A8 B8 C8 D8々 by Beigong Consumer Cooperative of the Central Bureau of Customs, and applied for a patent Fan 4 using another square steel tube forming rolling mill * to perform hot forging forming while extruding, to make square steel tubes. Patent Fan No. 5 of the manufacturing method of square steel pipes * Among them, the multi-angle hollow hollow pipe system increases its width and increases the radius of curvature of its corners, and then the multi-angle hollow steel pipe heated by the heating furnace is passed through another Square steel tube forming rolling mill, while shrinking the width and the radius of curvature of the corners, while performing hot forging forming process. 7.-The manufacturing method of the seed-shaped steel tube, which is characterized by: A round pipe with a certain diameter, plate thickness, and length suitable for the size of the final product, and this pipe is placed in a heating furnace and then heated. The heated steel pipe is hot forged by a round steel pipe forming rolling mill After forming, a round steel pipe is produced, and then the round steel pipe is cooled in a cooling bed *, and then a cutting device is used to cut off the badly formed part of the end. --------- Guangyu ------ Order (please read the precautions on the back and then fill out this page) This paper uses the Chinese National Standard (CNS & A4 specifications (210X297mm2