Forging and welding forming process of suspension bridge splay saddle

Abstract

The application relates to the application of forging and welding technology in the manufacturing and shaping of a cable saddle of a suspension bridge, and particularly discloses a forging and welding forming process of a cable saddle of a suspension bridge, which mainly comprises the following process flows: (1) adopting a forging process to form a bottom block and a bottom plate of a cable saddle groove, (2) plate material blanking, (3) welding the bottom plate and the side wall plate of the cable saddle groove to obtain the cable saddle groove, and (4) planning the welding sequence of the frame plate to obtain optimal welding space and welding quality. In the traditional process, the cable saddle groove is usually cast to form, so that the quality and strength are low, the bottom plate of the cable saddle groove is forged to form in the scheme, so that the light weight and the strength are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the application of forging and welding technology in the manufacturing of cable saddle of suspension bridge, in particular to a forging and welding forming process of cable saddle of suspension bridge. BACKGROUND

[0002] The design and construction capacity of bridge in China develops rapidly. In the world, China accounts for 8 out of the top 10 completed and under-construction suspension bridge projects in terms of main span. The cable saddle is an important load-bearing component of the suspension bridge. The larger the saddle span, the heavier the saddle body. There are generally 4 sets of main cable saddles and 4 sets of cable saddles in the whole bridge. In large-span suspension bridges, the traditional cast saddle is used, and the total weight of each set of cable saddle reaches 200 tons, and the maximum hoisting weight of a single piece reaches 150 tons, which is a great challenge to the transportation and installation of the cable saddle, especially in mountainous areas.

[0003] Due to the wide adaptability of castings, which is not limited by the size, thickness and complexity of the shape, and the flexible production mode, currently, the cable saddle mainly adopts a structure design of full casting or casting and welding combination. The casting process is used for the saddle head for limiting and directly bearing the main cable, and the welding process is used for the combination of the saddle head and the saddle body. However, the casting industry consumes a lot of energy and pollutes the environment. Therefore, in recent years, small-scale, backward, heavily polluting and poor working conditions of casting enterprises have been eliminated, resulting in a shortage of casting resources and a significant extension of the casting period of steel castings compared with the previous year. This further lengthens the manufacturing cycle of the cable saddle, increases the investment of funds, and increases the manufacturing cost of the cable saddle.

[0004] In addition, the cast steel has the characteristics of uneven organization, coarse internal grains and non-dense organization, which leads to low mechanical properties. With the increase of bridge span, oversized cable saddle structures are common, and the tensile strength grade of the main cable steel wire has increased from 1670MPa to more than 2000MPa. With the increase of the strength of the main cable, the pressure on the unit cross-section saddle groove increases, and the contact stress on the groove bottom increases. Through the sliding test of the cast steel cable saddle and the high-strength steel wire strand, it is found that there are very obvious dense main cable steel wire tensile and compressive marks on the saddle groove side wall and the strand groove bottom after the strand slips. The depth of the marks is between 0.5-1mm, and even the depth of the marks exceeds 1mm. Therefore, the forming quality and mechanical properties of the oversized cast saddle head are facing real challenges, and even the strength of the material does not match the high-strength main cable steel wire.

[0005] Affected by the casting conditions, quality and the demand of the saddle lightweight, the industry has proposed a new idea of using forging process instead of casting process. Since the material strength of the forging process is high, the mechanical properties are good, and the internal structure is compact, the use of forging process instead of casting process can reduce the material usage, and achieve the purpose of improving the quality and lightweight of the saddle. However, due to the limitation of the forging process, the whole saddle cannot be directly obtained by forging, so the structure of the saddle must be decomposed, and then welded as a whole by using welding process, that is, the structure of the saddle manufactured by forging process must be designed by combining forging and welding. Since the structure of the saddle combined with forging and welding is made of high-strength material, the requirement for welding strength is also very high; and the components of the saddle structure combined with forging and welding are too many, if the welding process and welding sequence are not planned, it will lead to narrow welding space, welding strength cannot meet the requirements, welding stress concentration leads to weld crack, etc., so that qualified products cannot be formed. SUMMARY

[0006] The purpose of the present application is to provide a forging and welding forming process for a suspension bridge spreader saddle, to improve the strength of the spreader saddle, realize the lightweight of the spreader saddle, and reduce the welding difficulty and ensure the product quality by reasonable planning of the welding process.

[0007] The spreader saddle is composed of a bottom block, a saddle groove and a frame welded from high-strength steel plates. The saddle groove is composed of a bottom plate and side wall plates cut from high-strength steel plates. The forging and welding forming process for the suspension bridge spreader saddle comprises the following steps:

[0008] Step 1: forming the bottom block and the bottom plate of the saddle groove by using the forging process;

[0009] Step 2: cutting each component of the frame and the side wall plates of the saddle groove;

[0010] Step 3: welding the bottom plate and the side wall plates of the saddle groove to obtain the saddle groove;

[0011] Step 4: positioning two transverse rib plates, two longitudinal rib plates and a small rib plate in the same plane as the transverse rib plate on the bottom block by spot welding, the two longitudinal rib plates are arranged in parallel, the transverse rib plates are distributed on both sides of the longitudinal rib plates along the length direction of the bottom block to form a longitudinal and transverse interlaced structure, and the butt welding of the bottom block and the frame main body is completed;

[0012] Step 5: positioning the saddle groove on the frame main body, completing the combined welding of the saddle groove and the frame main body, and welding the small rib plate connecting the longitudinal rib plate and the bottom plate of the saddle groove on both sides and between the longitudinal rib plates;

[0013] Step 6: positioning the side plate perpendicular to the transverse rib plate on the side edge of the transverse rib plate, and welding the butt joint of the side plate, the transverse rib plate, the bottom block and the bottom plate of the saddle groove; welding several transverse rib plates connecting the side plate, the bottom plate of the saddle groove and the side wall plate of the saddle groove on both sides of the saddle groove;

[0014] Step 7: The frame side corresponding to the two ends of the saddle groove is respectively welded and closed with three end plates.

[0015] The beneficial effects of the present scheme are:

[0016] (1) The saddle groove of the loose saddle directly contacts with the cable, and the bottom plate of the saddle groove directly bears the pressure transmitted by the cable, so the strength and toughness of the saddle groove bottom plate are the highest; the traditional saddle groove is generally processed by casting, in order to enable the saddle groove to bear the pressure transmitted by the cable, the material usage of the saddle groove is usually increased to ensure the reliability of the strength. In the present scheme, the saddle groove bottom plate is processed by forging, which can ensure the reliability of the strength while reducing the material usage; the side wall plate of the saddle groove is not the main force bearing part, and it also uses high-strength steel plate with the frame structure, which fully embodies the design principle of "good steel used at the cutting edge"; the frame and the side wall plate of the saddle groove are made of high-strength steel plate, which can simplify the process and reduce the processing cost.

[0017] (2) In the traditional loose saddle structure, the structure is usually divided into two parts, namely the saddle head and the saddle seat, that is, in the traditional cast-welded loose saddle structure, the saddle head is integrally formed by casting, and the saddle seat is welded by steel plate, after the saddle head and the saddle seat are processed, the saddle head and the saddle seat are connected into one by welding or bolt connection, which is conducive to improving the processing efficiency; when the saddle head and the saddle seat are connected by welding, the side partition plate connecting the saddle head and the saddle seat usually plays the role of force transmission. In the present scheme, the longitudinal rib plate, the horizontal rib plate and the small rib plate play the role of force transmission from the saddle groove to the frame; if the traditional idea of first forming the saddle head and the saddle seat and then combining and welding the saddle head and the saddle seat is adopted, the saddle groove bottom plate and the longitudinal rib plate, the horizontal rib plate and the small rib plate cannot be double-sided welded, which will result in insufficient welding strength.

[0018] (3) In the present scheme, the horizontal rib plate and the longitudinal rib plate are longitudinally and horizontally positioned and welded on the bottom block, and a small rib plate is welded at the same time, which is more conducive to forming a stable structure of the horizontal rib plate and the longitudinal rib plate; then the saddle groove is welded on the longitudinal rib plate, which can reserve the welding space of the horizontal rib plate and the small rib plate, and facilitate to ensure the connection strength of the frame and the saddle groove; finally, the side plate, the end plate and other surrounding structures of the frame are welded to strengthen the stability of the frame.

[0019] Preferred scheme one: as a further optimization of the basic scheme, the longitudinal rib plate is formed by welding the large plate welded with the saddle groove bottom plate and the small plate welded with the bottom block; in step 4, the large plate and the small plate are butt-welded to form the longitudinal rib plate, and the two horizontal rib plates and the small rib plate are connected in the same plane through the auxiliary beam, and then the horizontal rib plate and the longitudinal rib plate are positioned and welded to the bottom block.

[0020] The longitudinal rib plate is formed by welding large plates and small plates, which can make full use of the plates, and the welds between the transverse rib plate and the longitudinal rib plate are long and in a single direction, and the welds between the transverse rib plate and the longitudinal rib plate and the welds between the large plates and the small plates are cross-shaped, so that stress concentration can be avoided.

[0021] The two transverse rib plates and the small rib plate are spliced in the same plane by the auxiliary beam, and then are staggered with the longitudinal rib plate, so that positioning is facilitated. Gaps should be formed between the transverse rib plate and the small rib plate to allow the upper end of the longitudinal rib plate to be inserted, so that a stable structure can be formed between the transverse rib plate and the longitudinal rib plate by welding. The auxiliary beam can be cut after the positioning and welding of the transverse rib plate, the small rib plate and the longitudinal rib plate are completed.

[0022] In the preferred solution two, as a further optimization of the preferred solution one, when welding, after the positioning welding of the components is completed, the welding bevel and the surrounding area are preheated by natural gas flame, the preheating temperature of the high-strength steel plate butt joint should be controlled at 100-150℃, and the preheating temperature of the forge piece is controlled at 250-300℃.

[0023] The welding of thick plates and super-thick plates has problems such as large welding residual stress, large post-welding deformation, easy generation of hot cracks and cold cracks, etc. The purpose of preheating is to slow down the temperature gradient and the cooling speed when the welding joint is heated, to reduce or avoid the generation of hardened structure, to reduce the welding stress and deformation, to be beneficial to the escape of hydrogen, and to prevent the generation of cracks.

[0024] In the preferred solution three, as a further optimization of the preferred solution two, after the welding of the welds on the saddle groove bottom plate and the bottom block is completed, the welds and their two sides are heated to about 350℃, and then are naturally cooled after being kept warm for 2-3h; so as to prevent hydrogen-induced cracks.

[0025] In the preferred solution four, as a further optimization of the preferred solution one, the welding of each plate adopts a multi-layer and multi-pass welding process; so as to preheat the previous pass by the subsequent pass, and to post-heat treat the previous pass by the subsequent pass, so as to achieve the purpose of improving the welding quality.

[0026] In the preferred solution five, as a further optimization of the preferred solution two, the bottom block is made of Q345R forged and shaped, the saddle groove bottom plate is made of 30CrMo forged and shaped, and the high-strength steel plate is selected from Q420qE steel plates.

[0027] In terms of material selection, in the cast-welded cable saddle structure, in order to ensure good weldability with the saddle body steel plate, the cast saddle head generally selects weldable cast steel; and the highest material strength grade of the weldable cast steel is ZG340-550H, and the yield strength is not less than 340 MPa. There is a serious mismatch between the main cable saddle at this strength and the high-strength cast steel wire. And the only four cast materials that meet the requirements of the cable saddle and meet the standard are ZG230-450H, ZG270-480H, ZG300-500H and ZG340-550H. After using the forging process, there are as many as 75 kinds of materials that meet the requirements, of which there are 15 kinds of carbon steel forgings and 60 kinds of alloy steel forgings. This provides more possibilities for designing and manufacturing high-strength and high-performance cable saddles.

[0028] Based on the matching requirement of the tensile strength of the main cable steel wire increasing to 2000 MPa at present, based on the accumulation of engineers' experience and the comparison of related experimental structure analysis, the bottom forged steel piece is preferred to be 30CrMo forged steel; based on the weldability of the steel plate and the forged steel piece, the steel plate of Q420qE grade is selected.

[0029] Preferred scheme six: as a further optimization of preferred scheme five, the cable saddle groove bottom plate forming process is as follows:

[0030] Step A: the cable saddle groove bottom plate adopts a two-section or three-section segmented forging process, and the segmented forging obtains each section of the cable saddle groove bottom plate blank and performs heat treatment;

[0031] Step B: mechanically rough machining each section of the cable saddle groove bottom plate blank to obtain a rough machining piece;

[0032] Step C: welding each section of the rough machining piece to obtain a cable saddle groove bottom plate;

[0033] After completing the step 6, the cable saddle groove bottom plate is mechanically finished.

[0034] The cable saddle groove bottom plate plays a major role in bearing the steel cable pressure and dispersing force. Based on the force requirement, the cable saddle groove bottom plate is designed as an arc structure; therefore, if the cable saddle groove is directly forged into an arc structure, a forging die must be used. However, the structure size of the cable saddle is usually designed according to the structure, span and other factors of the bridge, and generally only 4 sets of cable saddles are produced under the same structure size, that is, the manufacturing of the cable saddle does not meet the conditions of batch production, and the forging die is usually batch-produced to improve efficiency, but the cost of the forging die is relatively high, especially the cost of large forging dies.

[0035] For cost considerations, this solution employs a dieless forging method, directly using a press to forge the raw material into a rectangular billet similar in shape to the cable saddle groove bottom plate, followed by machining for shaping. However, due to the curved structure of the cable saddle groove bottom plate, forging it as a single piece and then machining it requires a large amount of cutting from the rectangular billet, leading to significant material waste. Therefore, this solution uses segmented forging for the cable saddle groove bottom plate, where the segments are roughly machined and then welded together to form a complete plate. Reducing the curvature of each segment decreases the amount of material cutting, thus reducing material waste. Furthermore, the cable saddle structure is large, and forging the cable saddle groove bottom plate as a single piece requires forging from a single block of forged steel, increasing the procurement and acquisition costs of forged steel.

[0036] The bottom plate of the cable saddle groove is composed of multiple welded sections. During the welding process, errors are inevitable. The steps formed at the joints of the sections will create concentrated compressive stress on the steel cable, thus having an adverse effect on the steel cable. Therefore, this solution involves reassembling the cable saddle groove bottom plate and then performing precision machining.

[0037] Preferred Option Seven: As a further optimization of Preferred Option Six, step A includes the following steps:

[0038] Step a1: Place the steel ingot on a 3500-ton press, control the initial forging temperature at 1220℃ and the final forging temperature at 850℃, and then return it to the heating furnace for further heating after chamfering and removing risers.

[0039] Step a2: Place the billet on a 3500-ton press, control the initial forging temperature at 1220℃ and the final forging temperature at 850℃, and return the billet to the heating furnace for further heating after upsetting and drawing.

[0040] Step a3: Place the billet on a 3500-ton press, control the initial forging temperature at 1220℃ and the final forging temperature at 850℃, and return the billet to the heating furnace for further heating after a second upsetting and drawing process.

[0041] Step a4: Place the material on a 3500-ton press, then stretch and trim it into shape before placing it in an annealing furnace to keep it warm and await further processing.

[0042] Step a5: Once the planned quantity of products to be loaded into the annealing furnace is completed, the normalizing + tempering heat treatment process will begin. The normalizing temperature will be controlled at 880±15℃, and the tempering temperature will be controlled at 650±10℃.

[0043] In the existing forging process of 30CrMo forged steel, the forging temperature is generally selected between 1100℃-850℃ in the normalizing or tempering state. However, the base material of the cable saddle groove bottom plate has large size and heavy weight, and it is difficult to transfer between the heating furnace and the press, and it is more difficult to transfer repeatedly. Therefore, increasing the interval value of the initial forging temperature and the terminal temperature can reduce the transfer frequency of the blank during forging. Secondly, the weight and thickness of the blank are high, which also leads to slow internal temperature rise of the material. Therefore, appropriately increasing the heating temperature is beneficial to improve the heating rate. Secondly, the temperature gradient inside and outside the blank increases the surface temperature of the blank. The main influence on the material is the reduction of the performance of the surface material. On the one hand, the surface material will be mechanically cut, and on the other hand, the cable saddle groove directly contacts the steel cable, and the surface strength requirement is less than the steel cable, which is beneficial to the steel cable. The cable saddle groove formed by the temperature forging is matched with the steel cable in the indentation experiment, and the cable saddle groove has good matching performance with the steel cable.

[0044] Preferred solution eight: as a further optimization of preferred solution seven, the ingot or blank is heated in the heating furnace, the heating furnace includes a first heating furnace and a second heating furnace, and the 3500-ton press is arranged between the first heating furnace and the second heating furnace. A chain plate conveyor belt is arranged between the furnace opening of the first heating furnace, the forging table of the 3500-ton press and the furnace opening of the second heating furnace to transport the ingot or blank, and the forging table of the 3500-ton press can be lifted. After the ingot or blank is heated in the first heating furnace, the forging table of the 3500-ton press is lowered below the chain plate conveyor belt, the ingot or blank is transported to the forging table of the 3500-ton press through the chain plate conveyor belt, and after the temperature of the ingot or blank is reduced to the final forging temperature, the forging table of the 3500-ton press is lifted to the height of the chain plate conveyor belt. The blank is sent to the second heating furnace for heating again through the chain plate conveyor belt.

[0045] In the process of transporting the ingot or blank from the heating furnace to the forging table of the 3500-ton press by the chain plate conveyor belt, when the ingot or blank reaches the intersection of the chain plate conveyor belt and the forging table, if the chain plate conveyor belt and the forging table are in the same level, as the contact area between the ingot or blank and the chain plate conveyor belt becomes smaller and smaller, the chain plate conveyor belt cannot completely send the ingot or blank into the forging table. By lowering the height of the forging table, the chain plate conveyor belt can throw the ingot or blank to the forging table, so that the ingot or blank can directly enter the forging table. When the ingot or blank needs to be returned to the heating furnace, due to the large weight of the ingot, the ingot falling onto the chain plate conveyor belt can easily damage the chain plate conveyor belt. Therefore, when the ingot or blank needs to be returned to the heating furnace, the forging table is lifted to the height of the chain plate conveyor belt, and the ingot or blank is manually pushed into the chain plate conveyor belt. By using the chain plate conveyor belt to cooperate with the lifting of the forging table to transfer the ingot or blank, the transfer difficulty of the ingot or blank can be effectively reduced, and the transfer efficiency can be improved.

[0046] Furthermore, the forging process of steel ingots involves operations such as position adjustment and flipping. While clamps are typically used to hold the ingots for these operations, making positional movement relatively easy, flipping often requires multiple people and is time-consuming. In this proposed solution, the steel ingots are moved onto a chain conveyor belt, and the forging platform is lowered to create a height difference between the conveyor belt and the platform. The conveyor belt then reverses the flow, returning the ingots to the platform. This height difference, combined with clamps, allows for control of the ingots, reducing the difficulty of flipping. Secondly, in bridge construction, four sets each of main cable saddles and auxiliary cable saddles are required. Additionally, the bottom plate of the cable saddle grooves is designed in sections. Therefore, the same batch of forged steel ingots may involve more than ten or even twenty pieces, and each ingot may undergo multiple forging processes. Using two heating furnaces in conjunction with the forging press facilitates batch management of the steel ingots. Attached Figure Description

[0047] Figure 1 This is a structural diagram of the cable saddle in this invention;

[0048] Figure 2 This is a flowchart of the welding and forming process of the cable saddle of the present invention;

[0049] Figure 3 Finite element extrusion analysis diagram of ZG270-480H casting material;

[0050] Figure 4 Finite element extrusion analysis diagram of ZG300-500H casting material;

[0051] Figure 5 The figure shows the finite element extrusion analysis of 30CrMo forged steel.

[0052] The reference numerals in the accompanying drawings include: base plate 01, side wall plate 02, cable saddle groove 10, frame structure 03, transverse stiffener 111, transverse stiffener 31, small stiffener 32, longitudinal stiffener 33, side plate 34, end plate 35, and bottom block 04. Detailed Implementation

[0053] The following detailed description illustrates the specific implementation method:

[0054] Example 1:

[0055] The design of the cable saddle structure for the forged and welded suspension bridge is attached. Figure 1 and attached Figure 2 As shown, the cable saddle consists of a base block 04, a cable saddle groove 10, and a supporting frame structure 03. The base block 04, the cable saddle groove 10, and the frame structure 03 are connected by welding. To enhance the connection strength between the cable saddle groove 10 and the frame structure 03, a horizontal stiffening plate 111 is used to weld the sides of the cable saddle groove 10 and the frame structure 03.

[0056] The cable saddle groove 10 is composed of a cable saddle groove 10 bottom plate 01 and a side wall plate 02 welded into a groove type structure, the cable saddle groove 10 bottom plate 01 is forged into three sections and then spliced into a whole. The frame structure 03 is welded from a steel plate, which takes the longitudinal and transverse intersecting transverse rib plates 31 and longitudinal rib plates 33 as the frame main body, small rib plates 32 are arranged in the frame for reinforcement, end plates 35 and side walls are arranged around for reinforcement and sealing.

[0057] Since the components constituting the above-mentioned cable saddle are more, and in order to realize lightweight, the structure design of forging and welding combination is adopted, in order to realize the matching with the tensile strength of 2000MPa level main cable wire, based on material selection, welding performance and welding planning, reasonable design is needed, therefore, the following forging and welding forming process of the cable saddle of the suspension bridge is formed through comprehensive analysis.

[0058] Step 1: forging

[0059] 1.1, the cable saddle groove 10 bottom plate 01 is forged into shape.

[0060] Material selection: the cable saddle groove 10 bottom plate 01 adopts 30CrMo brand forged steel ingot as raw material, the ingot requires electric arc furnace smelting (EAF) + ladle refining (LF) + vacuum degassing (VD) + argon gas protection casting; the cable saddle groove 10 bottom plate 01 is forged into three sections, so as to select the ingot and reduce the processing difficulty.

[0061] Ingot loading: special ingot is loaded into the furnace in batches with the same furnace number, and heated to the initial forging temperature.

[0062] Forging blank: the blank forging adopts dieless forging, which forms a rectangular block corresponding to the cable saddle groove 10 bottom plate 01 by plastic processing, and the specific forging steps are as follows:

[0063] (1) the ingot is discharged from the furnace, and is put into the 3500 ton press, and after light chamfering, pressing the pincer handle and removing the riser, it is returned to the heating furnace for continuous heating, the initial forging temperature is 1220℃, and the final forging temperature is 850℃;

[0064] (2) the blank is discharged from the furnace, and is put into the 3500 ton press, and is subjected to upsetting and elongation, after the elongation and blanking, it is returned to the heating furnace for continuous heating, the initial forging temperature is 1220℃, and the final forging temperature is 850℃;

[0065] (3) the blank is discharged from the furnace, and is put into the 3500 ton press, and is subjected to the second upsetting and elongation, after the elongation and blanking, it is returned to the heating furnace for continuous heating, the initial forging temperature is 1220℃, and the final forging temperature is 850℃;

[0066] (4) the blank is discharged from the furnace, and is put into the 3500 ton press, and is elongated and trimmed into shape, and then is put into the annealing furnace for heat preservation;

[0067] (5) The product quantity of the annealing furnace is completed, and the first heat treatment process (normalizing 880±15℃ + tempering 650±10℃) is started.

[0068] Mechanical roughing: the mechanical roughing is performed on the forged blank, so that the roughing forging pieces can form the preliminary shape of the saddle groove 10 bottom plate 01 after splicing.

[0069] 1.2, bottom block 04 forging: the bottom block 04 is forged by using Q345R grade steel ingot, since the bottom block 04 is a trapezoidal block composed of straight planes, a simple mold can be manufactured for direct forging.

[0070] Step 2: Steel plate material selection and blanking: based on the strength and weldability between different materials, the side wall plate 02 of the saddle groove 10 and each steel plate component of the frame structure 03 are selected from Q420qE grade steel plate.

[0071] Step 3: welding: since the components of the spreader saddle are more, after combination, the space between each component is narrow, which leads to difficulty in welding, and canceling part of the welding or reducing the welding strength due to space limitation needs to be considered comprehensively from the overall structure of the spreader saddle, therefore, it is important to determine the main weld and plan the welding sequence, the welding sequence is shown in the attached Figure 2 .

[0072] 3.1, preheating before welding: after completing the positioning welding of the components to be welded, before starting the welding of the weld, the natural gas flame is used to preheat the weld bevel and the surrounding area, the butt joint preheating temperature of Q420qE steel plate should be controlled at 100-150℃, the preheating temperature of 30CrMo forged piece and Q345R forged piece is controlled at 250-300℃; the preheating range is generally more than 75mm on each side of the weld, and the temperature is measured within 30-50mm range from the weld.

[0073] 3.2, welding of the saddle groove 10: first, the three roughing forged pieces of the saddle groove 10 bottom plate 01 are spliced and welded to form a whole, and then the side wall plate 02 is welded on both sides of the saddle groove 10 bottom plate 01.

[0074] 3.3, frame body welding:

[0075] (1) The two transverse rib plates 31 and a small rib plate 32 are spliced in the same plane by positioning welding through the auxiliary beam, and a gap is reserved between the two transverse rib plates 31 and the small rib plate 32 for embedding the longitudinal rib plate 33, so as to position the transverse rib plate 31 and the longitudinal rib plate 33; the auxiliary beam is arranged on the arc-shaped side of the upper side of the transverse rib plate 31 and the small rib plate 32, and spot welding reinforcing ribs can be performed on the side of the transverse rib plate 31, the small rib plate 32 and the auxiliary beam in order to enhance the stability.

[0076] (2) The longitudinal rib plate 33 is spliced by upper large plates and lower small plates, and the large plates and the small plates are spliced and welded to form the longitudinal rib plate 33;

[0077] (3) The transverse rib plate 31 is positioned and welded on the bottom block 04 along the length direction of the bottom block 04, and then the longitudinal rib plate 33 is inserted into the gap between the transverse rib plate 31 and the small rib plate 32 from one side to form a longitudinal and transverse interlaced structure, and the positioning is completed after adjustment, and welding is performed on each weld to obtain the frame body;

[0078] (4) The auxiliary beam and the reinforcing rib are removed.

[0079] Since the bottom block 04 is a regular block structure, the frame body is positioned on the bottom block 04 to meet the stability requirement during positioning; and the transverse rib plate 31 is welded on the bottom block 04 first, and the side edge of the transverse rib plate 31 and the gap between the transverse rib plate 31 and the small rib plate 32 facilitate the positioning of the longitudinal rib plate 33.

[0080] 3.4, the cable saddle groove 10 is welded with the frame body:

[0081] (1) The cable saddle groove 10 is placed on the frame body and is positioned by spot welding;

[0082] (2) The frame body is inverted, the cable saddle groove 10 faces downward, and the welds between the longitudinal rib plate 33, the transverse rib plate 31 and the bottom plate 01 of the cable saddle groove 10 are welded; the weld between the longitudinal rib plate 33 and the bottom plate 01 of the cable saddle groove 10 is the most important weld for connecting the frame mechanism and the cable saddle groove 10, and this welding sequence makes the weld have sufficient welding space, which is beneficial to ensure the welding quality;

[0083] (3) The small rib plate 32 is welded between the longitudinal rib plates 33 and on both sides, and the small rib plate 32 is gradually welded to both ends of the cable saddle groove 10 with the transverse rib plate 31 as the center, so as to facilitate the formation of a good welding space; the small rib plate 32 is used to strengthen the transverse weld between the frame and the cable saddle groove 10.

[0084] 3.5, the side plate 34 and the transverse rib plate 111 are welded:

[0085] (1) The side plate 34 is welded on both sides of the cable saddle groove 10, and the side plate 34 is welded with the transverse rib plate 31, the bottom block 04 and the cable saddle groove 10 respectively; the side plate 34 has the effect of stabilizing the transverse rib plate 31 and the cable saddle groove 10, and this welding step is beneficial to welding each weld on the transverse rib plate 31;

[0086] (2) The transverse rib plate 31 is welded to strengthen the effect of the side plate 34, the bottom plate 01 of the cable saddle groove 10 and the side wall plate 02 of the cable saddle groove 10.

[0087] 3.6. Welding of end plates 35: The two sides of the frame body corresponding to both ends of the saddle groove 10 are welded and sealed with three end plates 35 respectively.

[0088] 3.7. Welding requirements for welds: Each weld adopts the multi-layer and multi-pass welding process, that is, a weld is completed through multiple passes of welding. The subsequent weld covers the previous weld to gradually process the weld. The previous weld "preheats" the subsequent weld, and the subsequent weld "post-heat treats" the previous weld to improve the welding quality.

[0089] 3.7. Post-weld heat treatment: After the key welds (mainly including the welds of ultra-thick plates) are welded, the welds and the surrounding areas on both sides are heated to about 350 °C, held for 2 - 3 h, and then cooled naturally to prevent hydrogen-induced cracks.

[0090] Step 4: Machining finish: After completing the above steps, the bottom plate 01 of the saddle groove 10 is machined.

[0091] In terms of material selection, especially the material selection of the bottom plate 01 of the saddle groove 10 that directly bears the pressure of the steel cable is crucial. In the material selection experiment, to match the steel cable wire of 2000 MPa grade, the yield strength of the forged steel material should reach the target of not less than 390 MPa. Based on past work experience, the engineer carried out a comparative study on the strength indexes of the forged steel materials required for the forged-welded combined saddle for three materials, namely 30CrMo, 20CrMnMo, and 20CrNiMo. The research results show that while the strength index of the forged steel 30CrMo material meets the requirements, the slope is gentler, and the material has relatively consistent mechanical properties from the core to the surface, and can be used as the preferred forged steel material for the saddle. At the same time, the impact resistance performance of the 30CrMo material under different low-temperature conditions was further studied, and this material has relatively excellent low-temperature toughness. The test results of the forged steel 30CrMo + Q420qE welded test plate show that the MT test of the welding evaluation test plate meets the requirements of Grade 1 in GB / T 26952 - 2011, and the UT test meets the requirements of Grade I in NB / T47013.3 - 2015. The performance of the structural welds all meets the requirements of the high-performance forged-welded combined saddle, forming good quality and efficiency.

[0092] Through finite element analysis and the extrusion test of the cable strands and the saddle groove using steel components cast from different types of raw materials and 30CrMo forged steel, as shown in the appendix Figures 3-5 as follows, the following conclusions are obtained:

[0093] (1) The order of the indentation depth is: 30CrMo < ZG300 - 500H < ZG270 - 480H. The finite element analysis results of the indentation depth of the forging 30CrMo are relatively more uniform.

[0094] (2) The order of entering the plastic deformation unit is 30CrMo < ZG300-500H < ZG270-480H.

[0095] (3) Among the three research materials, the forged steel 30CrMo has better extrusion deformation resistance, higher surface hardness, and lower cost, and can be used as the forged steel material of the saddle groove bottom pressure component of the forged and welded combined cable saddle.

[0096] Combined with finite element analysis and extrusion test, the reasonable form and performance analysis of the forged and welded combined cable saddle structure, the forged and welded combined lightweight cable saddle uses high-strength forged steel (30CrMo) + Q420qE to replace the cast and welded cable saddle (ZG270-480H + Q345R), the overall strength of the structure is improved by 44%, and at the same time the weight of the main cable saddle is reduced by 26%, which achieves the purpose of high strength and lightweight of the cable saddle structure, and the use of Q420qE grade forged steel has higher strength, can effectively prevent the erosion and pressure deformation of the main cable to the cable saddle, and the quality is greatly improved.

[0097] In terms of welding performance, the MT test of the welding evaluation test plate meets the requirements of GB / T 26952-2011 level 1, and the UT test meets the requirements of NB / T47013.3-2015 level I. The performance of the welded joint meets the requirements of high-performance forged and welded combined cable saddle, and good quality and efficiency are formed.

[0098] Example two:

[0099] The difference between example two and example one is that the forging and pressing equipment related to the cable saddle groove bottom plate 01 is integrated in example two. Specifically, the heating furnace for heating the ingot and the blank includes a first heating furnace and a second heating furnace, and the 3500-ton press is arranged between the first heating furnace and the second heating furnace. A chain conveyor belt is arranged between the furnace opening of the first heating furnace, the forging and pressing table of the 3500-ton press and the furnace opening of the second heating furnace to transport the ingot or blank, and the running direction of the chain conveyor belt can be changed, so that the conversion of discharging and feeding can be realized.

[0100] The forging and pressing table of the 3500-ton press is liftable, and the lifting of the forging and pressing table is driven by a hydraulic cylinder. A bearing platform is arranged below the forging and pressing table. When the forging and pressing table is lowered to the lowest position, the forging and pressing table falls on the bearing platform and is supported by the bearing platform. During the forging and pressing process of the ingot or blank, the forging and pressing table is supported by the bearing platform.

[0101] After the steel ingot or billet is heated in the first heating furnace, the forging platform of the 3500-ton press is lowered below the chain conveying belt, the steel ingot or billet is conveyed to the forging platform of the 3500-ton press through the chain conveying belt, and after the temperature of the steel ingot or billet is reduced to the final forging temperature, the forging platform of the 3500-ton press is lifted to the height level with the chain conveying belt, and the billet is conveyed to the second heating furnace through the chain conveying belt to be heated again. In the process of turning over the steel ingot or billet, the steel ingot is moved to the chain conveying belt, then the forging platform is lowered to form a gap between the chain conveying belt and the forging platform, and the chain conveying belt is used to send the steel ingot back to the forging platform in the opposite direction, so that the difficulty of turning over operation is reduced by using the gap and cooperating with the clamp to control the steel ingot.

[0102] The above is only an embodiment of the present application, and the specific structure and characteristics of the scheme and other common knowledge are not described in detail. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, and these will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode and other records in the specification can be used to explain the content of the claims.

Claims

1. The forging and welding forming process of the cable saddle of a suspension bridge, characterized in that: The cable saddle consists of a base block, a saddle groove, and a frame welded from high-strength steel plates. The saddle groove consists of a base plate and side wall plates made of high-strength steel plates. The forging and welding process of the cable saddle includes the following steps: Step 1: The bottom block and the bottom plate of the cable saddle groove are formed by forging. The bottom block is forged from Q345R, and the cable saddle groove bottom plate is forged from 30CrMo. The forming process of the cable saddle groove bottom plate is as follows: Step A: The bottom plate of the cable saddle groove is forged in two or three sections using a segmented forging process. Each section of the cable saddle groove bottom plate blank is obtained by segmented forging and then heat-treated. Step A includes the following steps: Step a1: Place the steel ingot on a 3500-ton press, control the initial forging temperature at 1220℃ and the final forging temperature at 850℃, and then return it to the heating furnace for further heating after chamfering and removing risers. Step a2: Place the billet on a 3500-ton press, control the initial forging temperature at 1220℃ and the final forging temperature at 850℃, and return the billet to the heating furnace for further heating after upsetting and drawing. Step a3: Place the billet on a 3500-ton press, control the initial forging temperature at 1220℃ and the final forging temperature at 850℃, and return the billet to the heating furnace for further heating after a second upsetting and drawing process. Step a4: Place the material on a 3500-ton press, then stretch and trim it into shape before placing it in an annealing furnace to keep it warm and await further processing. Step a5: Once the planned quantity of products to be loaded into the annealing furnace is completed, the normalizing + tempering heat treatment process will begin. The normalizing temperature will be controlled at 880±15℃, and the tempering temperature will be controlled at 650±10℃. Step B: Perform rough machining on the bottom plate blanks of each section of the cable saddle groove to obtain the rough-machined parts; Step C: Weld the rough-machined parts together to obtain the bottom plate of the cable saddle groove; Step 2: Cut out the components of the frame and the side wall panels of the cable saddle groove; Step 3: Weld the bottom plate and side wall plate of the cable saddle groove to obtain the cable saddle groove; Step 4: Connect two transverse stiffening plates and one small stiffening plate to the same plane using tack welding via an auxiliary beam, leaving a gap between the two transverse stiffening plates and the small stiffening plate for the longitudinal stiffening plate to be inserted. The auxiliary beam is set on the arc-shaped edge above the transverse stiffening plates and the small stiffening plate. Weld the transverse stiffening plates to the bottom block along the length of the bottom block, and then insert the longitudinal stiffening plates into the gap between the transverse stiffening plates and the small stiffening plate from one side to form a crisscross structure. After adjustment, the positioning is completed. Weld each weld to obtain the main frame and remove the auxiliary beam. Step 5: Position the cable saddle groove onto the main frame body, complete the combined welding of the cable saddle groove and the main frame body, and weld the small stiffening plates connecting the longitudinal stiffening plates and the bottom plate of the cable saddle groove to both sides and between the longitudinal stiffening plates; Step 6: Position a side plate perpendicular to the transverse stiffener on the side of the transverse stiffener, and weld the side plate to the joint of the transverse stiffener, the bottom block, and the bottom plate of the cable saddle groove; weld several transverse stiffeners connecting the side plate, the bottom plate of the cable saddle groove, and the side wall plate of the cable saddle groove on both sides; then perform precision machining on the bottom plate of the cable saddle groove. Step 7: The frame sides corresponding to both ends of the cable saddle groove are welded and sealed with three end plates respectively.

2. The forging and welding forming process of the suspension bridge cable saddle according to claim 1, characterized in that: The longitudinal stiffener is formed by welding a large plate to the bottom plate of the cable saddle groove and a small plate to the bottom block. In step 4, the large plate and the small plate are first welded together to form a longitudinal stiffener. After the two transverse stiffeners and one small stiffener are spliced ​​on the same plane by an auxiliary beam, the transverse stiffeners and the longitudinal stiffeners are then positioned and welded to the bottom block.

3. The forging and welding forming process of the suspension bridge cable saddle according to claim 2, characterized in that: During welding, after the components are tack welded, the weld bevel and surrounding area are preheated with a natural gas flame. The preheating temperature for butt welding of high-strength steel plates should be controlled at 100-150℃, and the preheating temperature for forgings should be controlled at 250-300℃.

4. The forging and welding forming process of the suspension bridge cable saddle according to claim 3, characterized in that: After the welds on the bottom plate and bottom block of the cable saddle groove are completed, the welds and their surrounding areas on both sides are heated to about 350℃, kept at that temperature for 2-3 hours, and then allowed to cool naturally.

5. The forging and welding forming process of the suspension bridge cable saddle according to claim 4, characterized in that: The welding of each plate adopts a multi-layer, multi-pass welding process.

6. The forging and welding forming process of the suspension bridge cable saddle according to claim 5, characterized in that: The high-strength steel plate is made of Q420qE grade steel plate.

7. The forging and welding forming process for the suspension bridge cable saddle according to claim 6, characterized in that: Steel ingots or billets are heated in a heating furnace, which includes a first heating furnace and a second heating furnace. A 3500-ton press is positioned between the first and second heating furnaces. A chain conveyor belt is installed between the furnace opening of the first heating furnace, the forging platform of the 3500-ton press, and the furnace opening of the second heating furnace to transport steel ingots or billets. The forging platform of the 3500-ton press is adjustable. After the steel ingots or billets have been heated in the first heating furnace, the forging platform of the 3500-ton press is lowered below the chain conveyor belt. The steel ingots or billets are then transported to the forging platform of the 3500-ton press via the chain conveyor belt. After the temperature of the steel ingots or billets drops to the final forging temperature, the forging platform of the 3500-ton press is raised to the same height as the chain conveyor belt. The billets are then sent to the second heating furnace for reheating via the chain conveyor belt.

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