CN109772993B

CN109772993B - Ultrahigh-strength single-weld square and rectangular pipe forming process and forming die

Info

Publication number: CN109772993B
Application number: CN201811607643.7A
Authority: CN
Inventors: 陈红谓; 陈科润
Original assignee: Changzhou Kaneken Steel Section Co ltd
Current assignee: Changzhou Kaneken Steel Section Co ltd
Priority date: 2018-12-27
Filing date: 2018-12-27
Publication date: 2020-07-17
Anticipated expiration: 2038-12-27
Also published as: CN109772993A

Abstract

The invention belongs to the technical field of ultrahigh-strength single-weld steel pipe production, and particularly relates to a molding process and a molding die for an ultrahigh-strength single-weld square rectangular pipe, which comprises the following steps: step one, blanking: selecting an ultrahigh-strength steel plate, and blanking according to the size of the ultrahigh-strength single-weld square rectangular tube; step two, shaping: performing edge milling/groove preparation on two sides of the steel plate in the width direction, and eliminating side bending of the steel plate; step three, confirming the bending position: according to the size of the ultrahigh-strength single-weld-seam square rectangular tube, sequentially determining a first bending position, a second bending position, a third bending position and a fourth bending position of the steel plate on the surface of the steel plate; step four, bending and forming: firstly bending and forming a first bending part by using numerical control bending equipment; step five, closing and welding: and after the four steps of bending, closing up treatment is carried out, and then welding is carried out, so that the labor intensity of workers is reduced, the pipe fitting precision is high, the production efficiency is high, and demoulding is easy after bending is formed.

Description

Ultrahigh-strength single-weld square and rectangular pipe forming process and forming die

Technical Field

The invention belongs to the technical field of ultrahigh-strength single-weld steel pipe production, and particularly relates to a molding process and a molding die for an ultrahigh-strength single-weld square rectangular pipe.

Background

High-altitude operation platform and flexible arm-type fire engine etc. can often adopt high strength (or super high strength) square rectangular steel tube structure, and single welding seam square rectangular tube is more favored. The manufacturing of the single-welding-seam high-strength (or ultrahigh-strength) square rectangular steel tube usually comprises the steps of bending a knife to form reverse bending on the opposite side of the edge where the welding seam is located, then turning over to finish the other four bending steps, and finally flattening the previous reverse bending plane and drawing out the plane from the side edge of an upper die, so as to realize the single-welding-seam square rectangular tube which is not sealed, wherein the forming process is as shown in figure 1, and then welding and shaping are carried out to finally obtain the single-welding-seam square rectangular tube, and the method has the defects that: because of the needs reverse bending, the work piece needs turn-over and turn around, workman intensity of labour is big, the work piece location relies on the marking off, the precision is difficult to control, the plane that the turn-ups was flattened can not guarantee completely to press planar straightness, and is inefficient to the danger to operating personnel in the operation is big, in the last step of the shaping of bending, the board that the both sides upwarp can form the package to press from both sides and press from both sides the structure to last mould, can strike the mould, arouse easily that the mould damages, the clamp force of upwarp deformation is big, difficult drawing of patterns after bending, influence production efficiency.

Disclosure of Invention

The invention aims to solve the technical problems that the ultrahigh-strength single-welding-seam square rectangular tube forming process and the forming die are provided, the problems of high labor intensity of workers, difficulty in controlling precision and low efficiency caused by reverse bending in the bending process of the conventional ultrahigh-strength single-welding-seam square rectangular steel tube are solved, the die is easy to strip after the steel tube is bent, and the production is efficient.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the molding process of the ultrahigh-strength single-weld square rectangular pipe comprises the following steps of: step one, blanking: selecting an ultra-high-strength steel plate, blanking according to the size of the ultra-high-strength single-weld square rectangular tube to obtain the steel plate, and reserving edge milling/groove allowance in the width direction of the steel plate;

step two, shaping: performing edge milling/groove preparation on two sides of the steel plate in the width direction, correcting the plate body of the steel plate and eliminating side bending of the steel plate;

step three, confirming the bending position: determining a first bending position, a second bending position, a third bending position and a fourth bending position of the steel plate on the surface of the steel plate in sequence according to the size of the ultrahigh-strength single-weld-seam square rectangular tube along the width direction of the steel plate by taking one end port of the steel plate processed in the step two in the width direction as a reference, wherein the distances from the first bending position, the second bending position, the third bending position and the fourth bending position to the reference port are increased in sequence in the width direction of the steel plate;

step four, bending and forming: placing a steel plate on a bending die of numerical control bending equipment, bending to form a first bending part, bending to form a second bending part, bending to form a fourth bending part, and finally forming a third bending part, wherein the bending angles of the first bending part, the second bending part and the fourth bending part are all 90 degrees, the bending angle of the third bending part is less than 90 degrees, in the bending of the third bending part, the third bending part is subjected to asymmetric free bending through a special asymmetric bending lower die, and the third bending part is moved out from the numerical control bending equipment after bending forming to obtain an ultrahigh-strength single-weld-seam square rectangular blank tube with an opening;

step five, closing and welding: performing closing and shaping treatment on the ultrahigh-strength single-weld-seam square rectangular blank tube obtained in the step four, closing the opening of the ultrahigh-strength single-weld-seam square rectangular blank tube, welding the ultrahigh-strength single-weld-seam square rectangular blank tube after closing the opening of the ultrahigh-strength single-weld-seam square rectangular blank tube, and performing shaping treatment again after welding to obtain an ultrahigh-strength single-weld-seam square rectangular finished product;

the bending die of the numerical control bending device comprises an upper die part arranged on a gooseneck die shank of the numerical control bending machine and a lower die part arranged on the bottom side of the upper die part, wherein the lower die part comprises a lower die seat, a limiting block, a left panel and a right panel, the lower die seat is provided with a forming groove, the left panel and the right panel are respectively arranged at two opposite side walls in the forming groove, the left panel and the right panel are detachably connected with the side walls of the forming groove, an adjusting mechanism capable of adjusting the position distance from the left panel and the right panel to the center of the upper die is respectively arranged between the left panel and the right panel, two side surfaces of the limiting block are respectively contacted with the corresponding surfaces of the left panel and the right panel, the bottom surface of the forming groove is provided with a spring for supporting the limiting block to move up and down, the limiting block is provided with a limiting structure for avoiding the sliding of a workpiece, the limiting structure is a limiting groove arranged in the middle of the upper surface of the limiting block, the left panel before terminal surface, the right panel that are close to the shaping groove center before terminal surface form second grade die orifice contact surface near the shaping groove center, right panel is greater than left panel to last mould central distance, adjustment mechanism be a plurality of backing plates, left panel, right panel pass through the screw and are connected with the shaping groove lateral wall, correspond the through-hole that the department was equipped with the cooperation screw on the backing plate, the spring pass through the step screw fixation at the shaping inslot.

The invention has the beneficial effects that: by adopting the scheme, the invention fully utilizes the elastic characteristics of the high-strength and ultrahigh-strength steel plate, applies a unique asymmetric free bending method, adopts the specially-made upper and lower dies to bend the steel plate successively and continuously, greatly reduces the degree of clamping the upper die by the steel plate, and after the steel plate is bent, through elastic recovery original state, reach the closure of part open-ended, once only accomplish the bending of single welding seam square rectangle steel pipe part, need not carry out turn-over, the turn-around operation to the steel sheet, bend in succession, only rearrange through the order of fifty percent discount elbow, bend in succession and take shape, alleviateed workman's intensity of labour on the one hand, keep the shape rule of pipe fitting, the uniformity is good, need not turn-over, turn-around, reduced the danger of production, on the other hand is efficient, 5 ~ 10 times of current method, can satisfy the demand of mass production, the forming method is practical.

Drawings

The foregoing and other objects, features, and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.

Fig. 1 is a flow chart of a conventional square rectangular steel pipe bending process.

FIG. 2 is a flow chart of the bending process of the present invention.

Fig. 3 is a schematic structural diagram of a bending mold according to an embodiment of the invention.

Fig. 4 is a schematic view of a working state of a bending die according to an embodiment of the present invention.

Wherein: 1 is last mould portion, 2 is the die holder, 3 is the restriction piece, and 31 is the spacing groove, and 4 is left panel, and 5 is right panel, and 6 is the backing plate, and 7 is the spring, and I is first bend, and II is the second bend, and III is the third bend, and IV is the fourth bend.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

The process example comprises the following steps: referring to fig. 2, the forming process of the ultrahigh-strength single-weld square rectangular pipe comprises the following steps:

step one, blanking: selecting a high-strength and ultrahigh-strength steel plate with yield strength sigmas ≧ 700MPa, wherein the plate has better elastic property, calculating the expansion size of a pipe fitting according to the forming size of the ultrahigh-strength single-weld square rectangular pipe, cutting and blanking the plate according to the calculated expansion size to obtain a steel plate, and reserving edge milling/groove allowance in the width direction of the steel plate;

step two, shaping: the two ends of the steel plate in the width direction obtained in the step one are milled by using an edge milling machine, the shape of the steel plate is trimmed, the precision of the steel plate is improved, welding grooves are machined at the two ends of the steel plate in the width direction by using groove machining equipment, the subsequent welding is facilitated, the plate body of the steel plate is corrected by using correction equipment, the sidewise bending of the steel plate is eliminated, and the steel plate is ensured to be flat and have high dimensional precision;

step three, confirming the bending position: calculating the width of each surface by taking one end port in the width direction of the steel plate processed in the step two as a reference according to the size of the formed and unfolded ultrahigh-strength single-weld-seam square rectangular tube, obtaining position parameters of a position where the steel plate needs to be bent, sequentially determining a first bent part I, a second bent part II, a third bent part III and a fourth bent part IV of the steel plate on the surface of the steel plate along the width direction of the steel plate according to the calculated position parameters, sequentially increasing the distance from the first bent part, the second bent part, the third bent part and the fourth bent part to the reference port in the width direction of the steel plate, controlling the position of a single weld seam of the ultrahigh-strength single-weld-seam square rectangular tube to be in the middle of one surface of the square rectangular tube, controlling the square rectangular tube to be bilaterally symmetrical about the weld seam, and symmetrical about the weld seam, so as to balance stress distribution after welding forming of the square tube, and improve the structural strength of the tube, in addition, the steel pipe is convenient to bend and form, and the production efficiency is improved;

step four, bending and forming: the steel plate is placed on a numerical control bending device, the steel plate is positioned between an upper die and a lower die of a bending die, the steel plate is stopped and positioned by using a numerical control bending machine, a first bending part of the steel plate is vertically aligned with a forming part of the upper die and the lower die of the bending die, the bending machine is started to bend the first bending part, the bending angle of the first bending part is 90 degrees, then a second bending part and a fourth bending part are sequentially bent and formed, the bending angle is 90 degrees, a third bending part is finally bent and formed, the bending angle of the third bending part is less than 90 degrees, the bending forming of the first three parts does not generate an upper die interference phenomenon, namely, a tilted plate body does not collide with an upper die in the bending forming of the first bending part, the second bending part and the fourth bending part, and the tilting range of the bending forming plate body of the third bending part is large because the first bending part and the third bending part are formed in the bending forming of a pipe fitting, in the third bending part, the formed first bending part and the second bending part will always tilt and impact the upper die, interference phenomenon is generated, even if the gooseneck-shaped upper die is adopted, the tilted plate still collides, the tilted plate can block the gooseneck-shaped upper die, separation is difficult, and the elastic bending magnitude of the plate is large, the process adopted by the invention comprises the steps of forming the first bending part and the second bending part, and forming the fourth bending part, wherein the process aims at that two sides of the third bending part are provided with longer large bending spaces, a larger span is formed between the second bending part and the fourth bending part to provide a space for bending and forming the third bending part, so that the steel plate body corresponding to the formed first bending part and the second bending part is far away from the gooseneck die handle, the bending angle in the third bending part is less than 90 degrees, and the two ends of the tilted plate body after forming are controlled to be about to contact with the upper die, because the plate bodies on the two sides of the position are all formed, the formed plate bodies have different volumes, the bending forming of the position is an asymmetric structure, the third bending position is asymmetrically freely bent through a special asymmetric bending lower die, the bending forming is an asymmetric free bending method, the two ends are asymmetric, the upturned degrees are different, the upturned amounts are different, the degree of clamping the upper die on the two sides of the steel plate is equivalent, the magnitude value of elastic bending required for the steel plate is reduced, namely the clamping force is reduced, the pipe can be directly separated after the bending forming, the pipe can be separated from the upper die more easily, finally, the third bending position is bent, the interference phenomenon is avoided, the ultrahigh-strength single-welding-seam square blank pipe with an opening is obtained after the bending forming, the ultrahigh-strength single-welding-seam square blank pipe with the opening is of a welding seam after the separation,

step five, closing and welding: and C, performing closing and shaping treatment on the ultrahigh-strength single-weld-seam square and rectangular blank pipe obtained in the step four, closing the opening of the ultrahigh-strength single-weld-seam square and rectangular blank pipe, welding the ultrahigh-strength single-weld-seam square and rectangular blank pipe after the opening of the ultrahigh-strength single-weld-seam square and rectangular blank pipe is closed, and performing shaping treatment again after welding to obtain an ultrahigh-strength single-weld-seam square and rectangular finished product.

In the process of producing the ultrahigh-strength single-weld square rectangular tube, the steel plate is not required to be turned over and turned around, the steel plate is continuously bent, and the steel plate is rearranged only through the sequence of the turning over and the turning around, so that the continuous bending and forming are realized, on one hand, the labor intensity of workers is reduced, the shape rule and the consistency of the tube are kept good, the turning over and the turning around are not required, the production danger is reduced, on the other hand, the efficiency is high, which is 5-10 times of that of the existing method, the requirement of mass production can be met, and the forming method is practical.

The structure embodiment is as follows: referring to fig. 3 and 4, the ultra-high strength single-weld square rectangular pipe forming die comprises an upper die part 1 of a gooseneck shape and a lower die part at the bottom side of the upper die part 1, wherein the lower die part comprises a lower die holder 2, a limiting block 3, a left panel 4 and a right panel 5, the lower die holder 2 is provided with a forming groove arranged along the front-rear direction of the die, the left panel 4 and the right panel 5 are oppositely arranged at the left side wall and the right side wall in the forming groove, the left panel 4 and the right panel 5 are respectively detachably connected with the side walls at the left side and the right side of the forming groove through transversely arranged screws, a plurality of base plates 6 capable of adjusting the distance from the left panel 4 and the right panel 5 to the center of the upper die part are respectively arranged between the left panel 4 and the right panel 5 and the side walls of the forming groove, the number of the base plates 6 is multiple, the thickness of the base plates 6 is different, through holes for the screws to pass through are arranged on the base plates 6, the distance between the right inserts 5 controls the left inserts 4 and the right inserts 5 to respectively reach the center of the upper die part, the front end of the left insert 4 close to the center of the forming groove is of a 90-degree right-angle structure to form a left second-stage die orifice contact surface with a supporting point for a steel plate, the front end of the right insert 5 close to the center of the forming groove is of an inward 90-degree concave right-angle structure, the inward concave right-angle structure forms a right second-stage die orifice contact surface, the right second-stage die orifice contact surface is provided with two supporting points for supporting the steel plate, the left second-stage die orifice contact surface and the right second-stage die orifice contact surface form a second-stage die orifice contact surface of the lower die part, the limiting block 3 is arranged between the left insert 4 and the right insert 5, two side surfaces of the limiting block 3 are respectively contacted and abutted against the inner end surfaces of the left insert 4 and the right insert 5, the groove bottom surface of the forming groove is provided with a spring 7 for supporting the limiting block 3 to, the upper surface of the limiting block 3 is provided with a limiting groove 31, the limiting groove 31 is opposite to the bottom end of the upper die part up and down, the position is a steel plate bending deformation position, the bottom end of the position is positioned in the limiting groove, a limiting groove 31 is arranged corresponding to the center of the upper die part 1, the limiting groove 31 is used for contacting with the bottom end surface of the steel plate bending position to limit the steel plate bending position, so as to avoid the left and right displacement of the steel plate bending position, a spring 7 is fixed in a forming groove through a step screw, the left and right positions of the limiting block 3 are limited by a left panel and a right panel, the left panel, the right panel and a cushion plate are connected with the side wall of the forming groove of the lower die base through screws, the spring is connected with the bottom surface of the lower die base through the step screw, the spring carries out floating support on the limiting block, the upper and lower movement of the limiting block is kept, the lower die is integrated, the forming groove opening, after the steel plate is placed and positioned, the upper die part 1 is pressed downwards, the bottom end of the upper die part presses and covers the steel plate on the limiting block 3, the bottom end of the bending position of the steel plate is positioned in the limiting groove, the bending deformation point is a bending deformation point, the limiting block supports the bottom of the steel plate, the position of the bending deformation point is limited by the limiting groove, the phenomenon that the plate body moves transversely due to the stress of the steel plate when the steel plate is pressed downwards in the upper die part is avoided, the damage of a die is avoided, the damage of the die is avoided, the two ends of the steel plate gradually upwarp, the initial deformation of the steel plate is avoided, the plate bodies on the two sides of the bending deformation point are supported by a first-stage die orifice contact surface or directly supported by a second-stage die orifice contact surface, the steel plate continuously deforms, when the deformation angle of the steel plate is 110 degrees, the bottom end of the left plate body of the bending deformation point is in contact with the support point of the left second-stage, because the distance between the contact surface of the second-stage die orifice on the left side and the bending center is less than the distance between the contact surface of the second-stage die orifice on the right side and the center of the upper die, the bottom end of the plate body on the right side of the bending deformation point is contacted with the first supporting point of the contact surface of the second-stage die orifice on the side, the first supporting point is closer to the center of the forming groove than the second supporting point, the second supporting point is higher than the first supporting point, along with the continuous bending, the variation of the included angle between the steel plate body on the left side of the bending deformation point and the bending center is larger than that between the steel plate body on the right side of the bending deformation point and the bending center, so that the steel plate integrally rotates rightwards around the center of the die point fillet of the upper die part by an angle, the gooseneck depth of the upper die can be reduced, the thickness of the upper die is further reduced, finally, bending the steel plate into a pipe fitting with an opening, after forming, reducing the elastic deformation amount required by the steel plate, thereby reducing the clamping degree of the two sides of the steel plate body to an upper die, reducing the clamping force, further facilitating the demoulding of the pipe fitting, wherein the forming die is an asymmetric bending die and is used for processing asymmetric bending forming steel plates, during the bending processing using the die, the steel plate is still freely bent in a symmetric manner at the initial stage of the bending processing (the bending angle is 110 degrees), along with the continuous bending, when the bending angle is less than or equal to 110 degrees, the left plate body of the steel plate is contacted with a second-stage die orifice of a left panel, the distance from the die orifice to the bending center is less than that from the second-stage die orifice of a right panel to the center of the upper die, along with the continuous bending, the included angle between the left plate body of the steel plate and the bending center is more than the right side, namely, the part rotates an, the rotating angle can reduce the gooseneck depth of the upper die, further reduce the thickness of the upper die, finally reduce the elastic deformation required by the steel plate, reduce the clamping degree of the steel plate to the upper die, further make the part demoulding easier, the limit groove of the limit block can limit the deviation of the upper die during asymmetric bending, the workpiece rotates a certain angle during bending by controlling the distance from the left panel and the right panel to the center of the upper die, the two sides are asymmetrically bent and deformed, the elastic deformation of the plate is reduced, the clamping force to the upper die is reduced, the demoulding is convenient, meanwhile, the interference between the upper die and the plate is avoided, the die is prevented from being damaged, the bending production efficiency is improved, the workpiece is limited by the limit block, the asymmetric bending is effectively ensured, the die has simple structure, low cost and high universality, various large-size bending pieces are processed, the asymmetric upper edge of the plate body is impacted on the upper die, the upper die is effectively protected, damage is avoided, and the service life of the die is prolonged.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiment according to the present invention are within the scope of the present invention.

Claims

1. The molding process of the ultrahigh-strength single-weld square rectangular pipe is characterized by comprising the following steps of:

step one, blanking: selecting an ultra-high-strength steel plate, blanking according to the size of the ultra-high-strength single-weld square rectangular tube to obtain the steel plate, and reserving edge milling/groove allowance in the width direction of the steel plate;