A surface hardening and surfacing device for a mill eccentric shaft and a repairing process

Abstract

The application discloses a rolling mill eccentric core shaft surface strengthening surfacing device and a repairing process, the surfacing device comprises a structural part fixing tool, an upper semicircular movable clamping plate and a heating tool; the structural part fixing tool comprises a bottom plate, a fixed circular table is arranged at the center of the upper surface of the bottom plate, four supports are fixedly arranged on the upper surface of the bottom plate and inclined to the inside and upwards, the top of two supports on each side is fixedly provided with a connecting frame, an upper semicircular fixed supporting frame is fixedly arranged between one side of the two connecting frames, and an upper semicircular movable clamping plate is detachably arranged between the other side, a semicircular groove is formed in the inner side of the upper semicircular fixed supporting frame and the upper semicircular movable clamping plate in correspondence, and a lower semicircular fixed supporting frame is arranged between the middle portions of the two supports on one side, and a semicircular groove is formed in the inner side of the lower semicircular fixed supporting frame. The application has the advantages of low investment cost, convenient on-site operation and maintenance, short repairing time, and the eccentric core shaft can effectively meet the rolling operation after the surfacing repairing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of machinery, and relates to a surface strengthening and overlay welding device for a rolling mill eccentric shaft and a repairing process. BACKGROUND

[0002] At present, the production process of various specifications of ring pieces in steel enterprises is as follows: the raw material ingot that passes the inspection is cut into the required length by a machine tool, the cut ingot is heated to the process temperature by a heating ring furnace, and then is clamped by a movable manipulator to a water pressure machine for roughing and piercing, and then the pierced ingot is clamped by a fixed manipulator and sent to a ring rolling mill for rolling forming. The ring rolling mill mainly comprises a vertical rotating eccentric shaft, horizontally movable upper and lower inclined roller shafts and a pinch roll, etc. The vertical rotating eccentric shaft and the pinch roll mainly control the wall thickness and diameter of the ring piece, and the horizontally movable upper and lower inclined roller shafts control the axial height of the ring piece. The vertical rotating eccentric shaft is irregular (such as the eccentric shaft 2 in FIG. 1), and a vertical lifting slot 22 is arranged at the top, and the rest is an irregular shaft body. The shaft body mainly comprises a body, a transition layer outside the body, and a wear-resistant alloy surface layer outside the transition layer. Since the vertical rotating eccentric shaft is matched with a die for rolling the ring piece, the die is subjected to stress generated by alternating cold and hot for a long time, and the vertical rotating eccentric shaft is subjected to extrusion, so that the surface of the vertical rotating eccentric shaft is worn and partially falls off, forming a worn or fallen surface 21. With the continuous rolling operation of the production process, the wear and fall-off defects are continuously deepened, reducing the effective cross-sectional area of the eccentric shaft, which cannot meet the installation process of the rolling die, and thus cannot meet the performance requirements of the original rolling mill for rolling products, and the quality of the rolled products cannot be controlled. For the worn eccentric shaft, if new spare parts are continuously replaced, a large amount of procurement cost is required, and if the worn eccentric shaft is repaired off-line, the repair cycle is long, which affects the orderly production, and cannot meet the rolling work requirements of heavy production task, tight time and continuous development of new products of the ring production line. If the worn eccentric shaft is repaired by welding, the following difficulties mainly exist: 1. The shape of the rolling mill eccentric shaft is irregular, and it is impossible to place or rotate the overlay welding by normal tooling; 2. How to strictly control the key process parameters such as welding line energy, fusion ratio, preheating, postheating, interlayer temperature, and metallurgical bonding of the base material, transition layer and adjacent base layer of the hard alloy, and filling thickness in the welding process to solve the welding defects such as surface wear and fall-off of the eccentric shaft of the ring rolling mill. In addition, the surface of the repaired eccentric shaft of the ring rolling mill also needs to meet the following requirements: 1. Local manual grinding and overall machining are required, and the running size is inspected by a conforming sample; 2. The welded layer of the metallurgical bonding meets the periodic use; 3. The repaired eccentric shaft can ensure the rolling quality. Figure 2 SUMMARY

[0003] ​In view of the problems in the background art, the present application provides a rolling mill eccentric shaft surface strengthening surfacing device and a repairing process, which not only has low investment cost, is convenient for on-site operation and maintenance, and has short repairing time, but also can effectively meet the rolling operation after surfacing repair.

[0004] The technical solutions of the present application for solving the technical problems are as follows:

[0005] The present application is a rolling mill eccentric shaft surface strengthening surfacing device, which comprises a structural part fixing tool, an upper half circle movable clamping plate and a heating tool.

[0006] Further, the same side end of the two connecting frames is fixedly provided with a ladder outside the bottom plate.

[0007] Further, the outside of the ladder is provided with a handrail.

[0008] Further, the bottom of the lower half circle fixed support and the upper surface of the bottom plate are provided with a support plate.

[0009] Further, one of the connecting frames connected with the upper half circle movable clamping plate is provided with a rotating shaft, and the other connecting frame is provided with a fixed hole.

[0010] Further, the heating tool comprises a plurality of annular branch pipes which are uniformly spaced and connected by a plurality of communication pipes, one of the annular branch pipes is connected with a gas inlet pipe, and a plurality of burners are uniformly installed on the inner side of each annular branch pipe.

[0011] The application discloses a repairing process of the surface strengthening and surfacing device of the mill eccentric shaft, the top of the eccentric shaft is provided with a vertical hoisting groove, the upper part is a worn or fallen surface, first, the overall frame of the structural part fixing tool is processed and manufactured according to the specification of the eccentric shaft, then, the lower semicircular fixed support is welded and fixed through the position of the fixed circular table and the position of the vertically placed eccentric shaft, the upper semicircular fixed support, the rotating shaft and the fixed hole are welded and installed on the two connecting frames according to the position of the vertically placed eccentric shaft, the upper semicircular movable clamping plate is installed outside the rotating shaft, then, the ladder and the handrail are welded and installed, finally, the steel wire rope is used to hoist the eccentric shaft with the worn or fallen surface into the structural part fixing tool through the vertical hoisting groove of the eccentric shaft, the lower end of the eccentric shaft is inserted into the fixed circular table, the middle position is fixed through the lower semicircular fixed support, the upper part is close to the semicircular groove of the upper semicircular fixed support, the upper semicircular movable clamping plate is rotated to clamp the upper part of the eccentric shaft and is locked with the connecting frame through the movable pin 4, finally, the heating tool is installed on the worn or fallen surface of the eccentric shaft, then, the heating and welding repairing can be carried out, and the specific process is as follows:

[0012] S1, preparation before welding:

[0013] 1.1), welding equipment: digital control inverter type manual welding arc welding and argon arc welding combined with direct current welding machine; the D256 electrode is used for welding the wear-resistant alloy surface layer; the HS1Cr18Ni9Ti welding wire is used for welding the transition layer, and the argon purity is greater than or equal to 99.999%;

[0014] 1.2), heating device: heating tool;

[0015] 1.3), auxiliary facilities: angle grinder, file, hammer, flat shovel, mask, sample plate, temperature measuring instrument, magnifying glass, heat preservation cotton;

[0016] 1.4), welding material: the body is 40CrNiMoA, the transition layer is stainless steel HS1Cr18Ni9Ti, and the outer layer is a wear-resistant alloy surface layer;

[0017] 1.5), requirements before welding: various defects on the surface of the eccentric shaft to be surfacing are removed through mechanical processing, and the cracks are confirmed to be completely removed through color inspection;

[0018] 1.6), welding position: vertical surfacing;

[0019] 1.7), welding requirements: all welding layers must be free of any welding defects and be fused to the base material;

[0020] 1.8), welding process parameters: the welding parameters are determined according to the welding equipment, the welding material, the welding material quality and the welding requirements;

[0021] S2, welding implementation:

[0022] 2.1), by heating tooling using coal gas heating method to wear or shed surface from the outside to the inside of the uniform preheating to the set temperature, and then in turn the transition layer and the surface of the surfacing layer welding;

[0023] 2.2), normal welding, whether the transition layer or the surface of the surfacing layer needs to strictly control the interlayer temperature of the weld is not less than the preheating temperature; the transition layer is divided into several symmetrical welding areas along the circumference, and each symmetrical welding area is synchronously vertically welded; the surface of the surfacing layer is welded by circle from bottom to top;

[0024] 2.3), after the whole surface of the eccentric shaft is worn or shed, the welding area is heated by the heating tooling from the outside to the inside, and the heat treatment of 400-550℃×6h is carried out to eliminate the welding stress, and then the slow cooling to 250℃ is carried out, and the whole is covered with insulation cotton, and then cooled to room temperature;

[0025] 2.4), the eccentric shaft is lifted away from the structure fixing tooling, and the welding seam of the eccentric shaft wear surface is detected by the detection flaw, and the sample is compared, and the tolerance size is restored.

[0026] Further, the digital control inverter type manual welding rod arc welding and argon arc welding combined with DC welding machine is HT400D or HT500D digital control inverter type manual welding rod arc welding and argon arc welding combined with DC welding machine.

[0027] Further, the set temperature of preheating before welding is 200-350℃, and the whole is uniformly raised at 50℃ / h.

[0028] Further, during the welding of the transition layer, the welding wire with a diameter of 2.5mm is used, the welding current is 100-120A, the arc voltage is 23±1V, and the welding speed is 7±1cm / min; during the welding of the surface of the surfacing layer, the welding rod with a diameter of 3.2mm is used, the welding current is 90-130A, the arc voltage is 22±1V, and the welding speed is 15±1cm / min.

[0029] Compared with the prior art, the rolling mill eccentric shaft surface strengthening surfacing device has the advantages that the structure is simple and reasonable, the manufacturing is convenient, the investment cost is low, and the welding defects such as micro-cracks in the base material caused by uneven high-temperature heating of the welding seam of the transition layer, the surface surfacing layer and the base material fusion can be effectively reduced by the device in combination with the repair process, the local temperature difference stress can be effectively reduced by the whole uniform preheating before welding, the internal organization can be improved, and the hardened organization can be prevented from being generated or reduced; the transition layer is welded in a segmented and symmetrical vertical direction, the surface surfacing layer is circularly surfaced from the bottom to the top, the stress and deformation during the whole surfacing can be effectively reduced, the welding wire is linearly transported, the electrode is obliquely circularly transported, the upper part of the surface surfacing layer is higher than the body, and the sufficient allowance processing is more favorable; the welding stress can be effectively eliminated by the post-welding heat treatment. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structural schematic view of the rolling mill eccentric shaft surface strengthening surfacing device of the present application.

[0031] Figure 2 It is an exploded structural schematic view of the rolling mill eccentric shaft surface strengthening surfacing device of the present application.

[0032] Figure 3 It is a schematic view of the heating tool in the present application.

[0033] Figure 4 It is a welding schematic view (elevation) of the eccentric shaft in the present application.

[0034] Figure 5 It is a welding schematic view (plan) of the eccentric shaft in the present application.

[0035] Figures 1-3 In the figure: 1, structural part fixing tool; 11, bottom plate; 12, support; 13, fixed circular table; 14, lower half circular fixed support; 15, ladder; 16, handrail; 17, connecting frame; 18, upper half circular fixed support; 19, rotating shaft; 110, fixing hole; 2, eccentric shaft; 21, worn or fallen surface; 22, vertical hoisting notch; 3, upper half circular movable clamping plate; 4, movable pin; 5, heating device; 51, gas inlet pipe; 52, annular branch pipe; 53, communication pipe; 54, burner. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0037] Unless otherwise defined, the technical or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present disclosure belongs. The terms "upper", "lower", "left", "right", "front", "back", "inside", "outside", "horizontal", "vertical", etc. used in the present patent application specification and claims are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship also changes accordingly. Similar terms such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Anything not described in detail in the present invention is a common knowledge to those skilled in the art.

[0038] Example 1:

[0039] like Figures 1-3 As shown, the present invention is a surface strengthening surfacing device for the eccentric shaft of a rolling mill, which includes a structural member fixing fixture 1, an upper semicircular movable clamping plate 3 and a heating fixture 5; the structural member fixing fixture 1 is a frame structure for placing the eccentric shaft 2 of the rolling mill, and is manufactured according to the size specifications of the eccentric shaft of the rolling mill to be placed, and includes a bottom plate 11, a fixed circular platform 13 is provided at the center of the upper surface of the bottom plate 11, and a fixing hole is opened at the center of the fixed circular platform 13 to adapt to the bottom end of the eccentric shaft 2 and to fix the bottom end of the eccentric shaft 2. Four brackets 12 are fixedly arranged obliquely on the inner and upper sides around, and a connecting frame 17 is fixed between the tops of the two brackets 12 on the front and rear sides respectively. An upper semicircular fixed support frame 18 is fixed between the same side of the two connecting frames 17, and an upper semicircular movable splint 3 is detachably arranged between the other sides of the two. Semicircular grooves are provided on the inner sides of the upper semicircular fixed support frame 18 and the upper semicircular movable splint 3 respectively. A lower semicircular fixed support frame 14 is provided between the middle parts of the two brackets 12 on one side, and a semicircular groove is provided on the inner side of the lower semicircular fixed support frame 14. In this embodiment, the semicircular grooves corresponding to the inner sides of the upper semicircular fixed bracket 18 and the upper semicircular movable splint 3, as well as the semicircular grooves on the inner side of the lower semicircular fixed bracket 14, are respectively adapted to the outer circumferences of the corresponding parts of the eccentric shaft 2. When the eccentric shaft 2 is lifted to the inner side of the structural member fixing tool 1 through the vertical lifting slot 22, its bottom end is inserted into the fixed circular table 13, the lower part is close to the semicircular groove of the lower semicircular fixed bracket 14, and the upper part is arranged in the semicircular grooves corresponding to the inner sides of the upper semicircular fixed bracket 18 and the upper semicircular movable splint 3 for fixation, and the worn or detached surface 21 on the upper part of the eccentric shaft 2 is heated, welded, heat-treated, etc. by the heating tool 5.

[0040] In the embodiment, the heating tool 5 comprises a plurality of annular branch pipes 52 which are uniformly spaced and communicated by a plurality of communicating pipes 53, one of the annular branch pipes 52 is connected with a gas inlet pipe 51, and a plurality of burners 54 are uniformly installed on the inner side circumference of each annular branch pipe 52. The heating tool 5 is made according to the outer diameter size of the worn or shed surface 21 of the eccentric shaft 2, and when the worn or shed surface 21 of the eccentric shaft 2 is preheated before welding and heat treated after welding by the heating tool 5, the heating tool 5 can be sleeved on the worn or shed surface 21, then the gas is turned on and ignited at the burners, and the heating can be performed.

[0041] In the embodiment, a ladder 15 is fixedly arranged between the same side end of the two connecting frames 17 and the bottom plate 11, so as to facilitate the workers to go up and down; in addition, a handrail 16 can be arranged outside the ladder 15, so as to ensure the safety of the workers.

[0042] In the embodiment, a support plate 111 can be further arranged between the bottom of the lower semicircular fixed backrest 14 and the upper surface of the bottom plate 11, so as to improve the stability of the whole device.

[0043] In the embodiment, in order to facilitate the fixing of the upper part of the eccentric shaft 2 through the semicircular groove of the upper semicircular movable clamping plate 3 corresponding to the upper semicircular fixed backrest 18, a rotating shaft 19 is arranged on one of the connecting frames 17 connected with the upper semicircular movable clamping plate 3, a fixing hole 110 is formed on the other connecting frame 17, and a through hole which is adapted to the rotating shaft 19 and the fixing hole 110 is formed on the upper semicircular movable clamping plate 3 at the corresponding positions, one end of the through hole is sleeved on the rotating shaft 19 and can rotate with the rotating shaft 19 as the center, and the other side is connected and fixed by passing through the through hole and the fixing hole 110 through the movable pin 4.

[0044] In the embodiment, the structural part fixing tool 1 can be machined and welded from 80mm steel plate and 50mm square steel, the fixed circular table 13 is made of φ400mm round steel ingot and welded on the structural part fixing tool 1, each backrest is machined from 40mm steel plate, the ladder is cut and welded from 40mm square tube, the upper semicircular movable clamping plate is machined from 30mm steel plate, and the heating tool 5 is made of φ20mm round tube. The materials used in the whole device are common materials, which are easy to obtain, convenient to manufacture and low in investment cost.

[0045] Embodiment 2:

[0046] As Figures 1 to 5As shown, the repair process of the rolling mill eccentric shaft surface hardening and surfacing device according to the application is as follows: the top of the eccentric shaft 2 is provided with a vertical lifting slot 22, and the upper part is a worn or fallen surface 21. First, the overall frame of the structural part fixing tool 1 is processed and manufactured according to the specifications of the eccentric shaft 2, then the fixed circular table 13 is welded on the bottom plate 11, the lower semicircular fixed support 14 is welded and fixed through the position of the fixed circular table 13 and the position of the vertically placed eccentric shaft 2, then the upper semicircular fixed support 18, the rotating shaft 19 and the fixed hole 110 are welded and installed on the two connecting frames 17 according to the position of the vertically placed eccentric shaft 2, the upper semicircular movable clamping plate 3 is installed outside the rotating shaft 19, then the ladder 15 and the handrail 16 are welded and installed, finally, the steel wire is used to lift the eccentric shaft 2 with the cleaned worn or fallen surface 21 to the inside of the structural part fixing tool 1 through the vertical lifting slot 22 of the eccentric shaft 2, the lower end of the eccentric shaft 2 is inserted into the fixed circular table 13, the middle position is fixed through the lower semicircular fixed support 14, the upper part is tightly clamped in the semicircular groove of the upper semicircular fixed support 18, then the upper semicircular movable clamping plate 3 is rotated to clamp the upper part of the eccentric shaft 2 and lock it with the connecting frame 17 through the movable pin 4, finally, the heating tool 5 is installed on the position of the worn or fallen surface 21 on the surface of the eccentric shaft 2, then the heating and welding repair can be carried out, and the specific process is as follows:

[0047] S1, preparation before welding:

[0048] 1.1), welding equipment: HT400D or HT500D digital control inverter type manual welding and argon arc welding combined direct current welding machine; D256-4 welding rod is used for welding the wear-resistant alloy surface layer; HS1Cr18Ni9Ti welding wire is used for welding the transition layer, and the purity of argon is greater than or equal to 99.999%;

[0049] 1.2), heating device: heating tool 5;

[0050] 1.3), auxiliary facilities: angle grinder, file, hammer, flat shovel, mask, sample plate, temperature measuring instrument, magnifying glass, heat preservation cotton;

[0051] 1.4), welding material: the body is 40CrNiMoA, the transition layer is stainless steel HS1Cr18Ni9Ti, and the outer layer is a wear-resistant alloy surface layer;

[0052] 1.5), requirements for surfacing before welding: various defects on the eccentric shaft to be surfacing are removed by mechanical processing, and the cracks are confirmed to be completely removed by dye penetrant testing;

[0053] 1.6), welding position: vertical surfacing;

[0054] 1.7), welding requirements: all welding layers must be free of any welding defects and be fused to the base material;

[0055] 1.8) Welding process parameters: Welding parameters are determined based on welding equipment, welding materials, weldment materials and welding requirements;

[0056] Welding process parameters

[0057]

[0058] S2. Welding implementation:

[0059] Welding process route: Machining and cleaning the worn or detached surface of the eccentric shaft 2 - Installing the structural fixture 1 and placing the fixed eccentric shaft 2 - Using gas to preheat the worn or detached surface 21 from the outside to the inside through the heating fixture 5 - Welding the transition layer in sections and symmetrically - Confirming weld defects - Surface cladding - cladding from bottom to top - Confirming weld defects - cladding acceptance - Post-weld heat treatment - Covering with insulation cotton for slow cooling - Machining - Inspection and acceptance - Delivery for use. Specifically:

[0060] 2.1) The worn or peeled surface 21 is uniformly preheated from the outside to the inside to a set temperature of 200-350°C by using a gas heating method through the heating tool 5. The temperature of the heating position is detected by a thermometer, and the temperature is uniformly preheated at 50°C / h. The preheating is for the entire surface to be fully covered. This can reduce local temperature stress, improve the internal structure, prevent or reduce the generation of hardened structure, and avoid uneven high-temperature heating of the weld seam of the transition layer, surface cladding layer and base material, which may cause microcracks and other welding defects inside the base material. After reaching the preheating temperature, the transition layer and surface cladding layer are welded in sequence;

[0061] 2.2) During normal welding, the interlayer temperature of the weld must be strictly controlled to be no lower than the preheating temperature, regardless of the transition layer or the surface cladding layer; welding methods such as Figure 4 and Figure 5 As shown, the shaft body at the welding repair position is A, the transition cladding layer is B, and the surface cladding layer is C. The transition layer is welded in sections and symmetrically, and the transition layer is divided into several symmetrical areas to be welded along the circumference, such as Figure 5 As shown, the symmetrical data indicates: 1-2, 3-4, 5-6, 7-8, each symmetrical area to be welded is welded vertically and synchronously first. Figure 5 1-2, then 3-4, 5-6 and 7-8 are welded synchronously in sequence; the surface surfacing layer adopts circle surfacing from bottom to top (such as Figure 5 This reduces stress and deformation during overall cladding. The welding wire adopts a straight line method, and the welding rod adopts an oblique circle method. In addition, the upper part of the surface cladding layer is higher than the main body, which is conducive to sufficient margin processing.

[0062] 2.3) After the whole surface of the eccentric shaft 2 and the whole surface of the wear or shedding surface 21 are completed, the welding area is heated by the heating tool 5 from the outside to the inside at 400-550℃ for 6 hours to eliminate the welding stress, and then slowly cooled to 250℃, covered with heat preservation cotton, and then cooled to room temperature;

[0063] 2.4) The eccentric shaft 2 is lifted away from the structural part fixing tool 1, and after the detection and flaw detection confirm that there is no defect, the welding seam of the eccentric shaft wear surface is machined, and the previously prepared sample is used for comparison to restore the tolerance size.

Claims

1. A device for surface hardening of a misaligned shaft of a rolling mill, characterized in that: It include structure fixed tooling (1), upper semicircle movable clamping plate (3) and heating tooling (5), structure fixed tooling (1) include bottom plate (11), bottom plate (11) upper surface center is provided with fixed circular table (13), its upper surface four around is fixedly arranged with four supports (12) to inside top, every side two supports (12) top is fixedly arranged with connecting frame (17), two connecting frames (17) one side is fixedly arranged with upper semicircle fixed leaning frame (18), the other side is detachably provided with upper semicircle movable clamping plate (3), upper semicircle fixed leaning frame (18) and upper semicircle movable clamping plate (3) inside corresponding half circle groove is set up, one side two supports (12) middle part is provided with lower semicircle fixed leaning frame (14), and lower semicircle fixed leaning frame (14) inside half circle groove is set up; One connecting frame (17) is provided with pivot (19) and is connected with the upper semicircle movable clamping plate (3), and the other connecting frame (17) is provided with fixed hole (110), the upper semicircle movable clamping plate (3) is respectively provided with the through hole that is adapted with pivot (19) and fixed hole (110) corresponding position, and one end through hole is set on pivot (19) and can pivot (19) as the center of rotation, and the other side is connected through movable pin (4) and passes through the side through hole and fixed hole (110) and is fixed; The heating tooling (5) includes a plurality of annular branch pipes (52) that are uniformly spaced and connected by a plurality of communication pipes (53), one of the annular branch pipes (52) is connected with a gas inlet pipe (51), and a plurality of burners (54) are installed on the inner circumferences of the annular branch pipes (52).

2. A device for surface hardening of the eccentric shaft of a rolling mill according to claim 1, characterized in that: Two connecting frames (17) same side end and bottom plate (11) between fixed setting have ladder (15).

3. A device for surface hardening of the eccentric shaft of a rolling mill according to claim 2, characterized in that: The outside of the ladder (15) is provided with a handrail (16).

4. The surface hardening and build-up welding device for the eccentric shaft of a rolling mill according to claim 1, characterized in that: The bottom of the lower semicircle fixed leaning frame (14) and the upper surface of the bottom plate (11) are provided with a support plate (111). The outside of the ladder (15) is provided with a handrail (16).

5. A repair process based on the hardfacing device for the eccentric shaft surface of a rolling mill according to any one of claims 1-4, wherein the eccentric shaft (2) is provided with a vertical lifting slot (22) at the top, and the upper part is a worn or fallen surface (21), characterized in that: First, according to the specification of the eccentric shaft (2) to process the overall frame of the structure of the fixed tooling (1), then welded to the fixed circular table (13) on the bottom plate (11), through the fixed circular table (13) position and the position of the eccentric shaft (2) when placed vertically welded to the lower half of the fixed bracket (14), then according to the position of the eccentric shaft (2) when placed vertically in two connecting frame (17) welded to the upper half of the fixed bracket (18), shaft (19) and open fixed hole (110), and in the outside of the shaft (19) installation of the upper half of the movable clamping plate (3), then welded to the ladder (15) and handrail (16), finally using steel wire through the vertical hoisting slot (22) of the eccentric shaft (2) to the inside of the structure of the fixed tooling (1) has been cleaned over the wear or fall surface (21) of the eccentric shaft (2) hoisting, the lower end of the eccentric shaft (2) is inserted into the fixed circular table (13), the middle position is fixed by the lower half of the fixed bracket (14), the upper part is close to the upper half of the fixed bracket (18) semicircular groove, then rotate the upper half of the movable clamping plate (3) to clamp the upper part of the eccentric shaft (2) and lock it with the connecting frame (17) through the movable pin 4, finally the heating tooling (5) is installed on the wear or fall surface (21) of the eccentric shaft (2), then the heating welding repair can be carried out, the specific process is as follows: S1, preparation before welding: 1.1), welding equipment: digital control inverter type manual welding and argon arc welding combined with direct current welding machine; wear-resistant alloy surface layer welding uses D256 electrode; transition layer welding uses HS1Cr18Ni9Ti welding wire, argon purity ≥ 99.999%; 1.2), heating device: heating tooling (5); 1.3), auxiliary facilities: angle grinder, file, hammer, flat shovel, mask, template, temperature meter, magnifying glass, heat preservation cotton; 1.4), welding material: body 40CrNiMoA, transition layer stainless steel HS1Cr18Ni9Ti, outer layer wear-resistant alloy surface layer; 1.5), requirements before welding: remove various defects on the eccentric shaft to be welded by mechanical processing, and confirm that the cracks have been completely removed by dye penetrant testing; 1.6), welding position: vertical welding; 1.7), welding requirements: all welding layers must be free of any welding defects and be fused to the base metal; 1.8), welding process parameters: develop welding parameters according to welding equipment, welding material, welding piece quality and welding requirements; S2, welding implementation: 2.1), use heating tooling (5) to uniformly preheat the wear or fall surface (21) to the set temperature from the outside to the inside by gas heating, and then sequentially weld the transition layer and the surface build-up layer; 2.2), when welding normally, the interlayer temperature of the weld seam must be strictly controlled not lower than the preheating temperature whether it is the transition layer or the surface build-up layer; the transition layer is welded by sectional symmetric welding, which divides the transition layer along the circumference into several symmetric welding areas, and each symmetric welding area is synchronously vertically welded; the surface build-up layer is welded by circular build-up from the bottom to the top. 2.3) After the whole surface of the eccentric shaft (2) is entirely built up, the welded area is heated by a heating tool (5) from outside to inside at 400-550 DEG C x 6h to eliminate welding stress, and then slowly cooled to 250 DEG C, covered by heat preservation cotton, and cooled to room temperature; 2.4) The eccentric shaft (2) is lifted away from the structural part fixing tool (1), and then detected for no defects, and the welded seams of the built up surface of the eccentric shaft are machined, and compared with the previously prepared sample to restore the tolerance size.

6. The repair process of claim 5, wherein: The digital control inverter type manual electrode arc welding and argon arc welding combined DC welding machine is HT400D or HT500D digital control inverter type manual electrode arc welding and argon arc welding combined DC welding machine.

7. The repair process of claim 5, wherein: The setting temperature of preheating before welding is 200-350 DEG C, and the whole is uniformly raised at 50 DEG C / h.

8. The repair process of claim 5, wherein: During the welding of the transition layer, the welding wire is HSi8Ni9Ti with a diameter of 2.5 mm, the welding current is 100-120 A, the arc voltage is 23+ / -1 V, and the welding speed is 7+ / -1 cm / min; during the welding of the surface built up layer, the electrode is D256 with a diameter of 3.2 mm, the welding current is 90-130 A, the arc voltage is 22+ / -1 V, and the welding speed is 15+ / -1 cm / min.

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