Welding-free repair structure for cast iron cracks

Abstract

The utility model discloses a cast iron crack welding-free repairing structure which comprises a crack located on a casting, a plurality of dumbbell-shaped grooves with two large ends and a small middle are formed in the casting in the extending direction of the crack, and all the dumbbell-shaped grooves are distributed perpendicular to the extending direction of the crack. Dumbbell-shaped buckling keys matched with the dumbbell-shaped grooves in shape are embedded in the dumbbell-shaped grooves, each dumbbell-shaped buckling key comprises clamping parts located at the two ends and a connecting part connected between the two clamping parts, and the width of the clamping parts is larger than that of the connecting part; a plurality of rivets are arranged at the joint between the dumbbell-shaped groove and the dumbbell-shaped buckling key, and rivet groove holes connected with the rivets in an embedded mode are correspondingly formed in the inner side wall of the dumbbell-shaped groove and the outer side wall of the dumbbell-shaped buckling key. The structure that the dumbbell-shaped buckling key with the two ends large and the middle small is matched with the rivet is adopted for repairing, welding is not needed, the treatment time is short, the repairing and using cost is low, the repairing effect is good, and the device is particularly suitable for on-site repairing of cracks of large castings.

Description

Technical Field

[0001] The utility model relates to the technical field of cast iron crack repair, in particular to a welding-free repair structure for cast iron cracks. Background Art

[0002] At present, more and more building materials and chemical companies use vertical mills as grinding equipment to grind raw materials such as cement and mineral powder. The grinding disc is a large casting and a key core component inside the vertical mill. The grinding disc is usually made of ductile iron, but the welding performance of ductile iron is extremely poor. When the vertical mill is running, the temperature of the hot air entering the mill is 200-300℃. The material falls on the rotating grinding disc and bears the rolling pressure of the grinding roller when the material is rolled. If the moisture content of the material entering the mill is too high, and the temperature of the hot air entering the mill exceeds 500℃ for a long time, exceeding the annealing temperature of ductile iron, the strength, hardness and other properties of the grinding disc material will change, resulting in the grinding disc being prone to cracks under long-term heavy loads; in addition, if large pieces of iron are mixed into the material entering the mill, the grinding disc will be prone to cracks due to the load exceeding the design strength.

[0003] Since cast iron (such as ductile iron and grey cast iron) has poor welding performance and cracks are not easy to weld, they will crack again after a slight load after welding. This is more obvious for large, heavy-loaded or vibrating cast iron parts.

[0004] The existing metal fastening method for repairing cracks in parts directly inserts a steel brick-shaped reinforcement into the crack or fracture surface. This method is very easy to tear the parent material because of its rectangular shape and the stress-bearing part is in a straight line. The hot fastening method uses the principle of thermal expansion and contraction of metal to repair cracks in castings. After heating, a selected fastening key of a certain shape is placed in a groove that has been processed at the damaged part of the part and is the same as the insert. After cooling, the fastening part shrinks, thereby re-sealing the broken part. The process is relatively complicated, and in actual operation, due to the extremely high processing accuracy requirements for the groove, less than 0.05mm, the expansion of the fastening key is difficult to control, and if the reserved margin is too large, it cannot be installed, and if the margin is small, the ideal crack repair effect cannot be achieved, and the repair effect is not obvious, so it is not suitable for on-site processing and has great limitations. Utility Model Content

[0005] The purpose of the utility model is to provide a welding-free repair structure for cast iron cracks, which adopts a structure that cooperates with a dumbbell-shaped snap key and a rivet for repair, does not require welding, has good strength and repair effect, and the repaired casting is quite reliable in subsequent use. It is particularly suitable for on-site repair of cracks in large castings, and solves the problems mentioned in the above background technology that conventional welding methods cannot achieve good repair strength effects and that the existing metal snap method is difficult to construct and the repair effect is not obvious.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A welding-free repair structure for cast iron cracks, comprising a crack located on a casting, wherein the casting is provided with a plurality of dumbbell-shaped grooves with large ends and a small middle along the extension direction of the crack, each of the dumbbell-shaped grooves is vertically distributed to the extension direction of the crack, each of the dumbbell-shaped grooves is inlaid with a dumbbell-shaped snap-fit ​​key of a matching shape, the dumbbell-shaped snap-fit ​​key comprises a clamping portion located at both ends and a connecting portion connected between the two clamping portions, the width of the clamping portion is greater than the width of the connecting portion; a plurality of rivets are provided at the joint between the dumbbell-shaped groove and the dumbbell-shaped snap-fit ​​key, and the inner side wall of the dumbbell-shaped groove and the outer side wall of the dumbbell-shaped snap-fit ​​key are correspondingly provided with rivet slot holes inlaid and connected with the rivets.

[0008] Furthermore, the thickness of the dumbbell-shaped snap-fit ​​key is 0.3 to 0.9 times the maximum depth of the crack, and the length of the rivet is 1.0 to 1.3 times the thickness of the dumbbell-shaped snap-fit ​​key.

[0009] Furthermore, the width of the clamping portion is 1.3 to 1.5 times the width of the connecting portion.

[0010] Furthermore, the length of the dumbbell-shaped snap-fit ​​key is 280 to 320 mm, and the width of the connecting portion is 80 to 120 mm.

[0011] Furthermore, the distance between two adjacent dumbbell-shaped snap-fit ​​keys is 100 to 140 mm.

[0012] Furthermore, the dumbbell-shaped snap-fit ​​key is made of 18CrNiMo7-6 alloy material through quenching and tempering treatment.

[0013] Furthermore, the rivets are symmetrically distributed along both sides of the crack.

[0014] Furthermore, the number of the rivets and the rivet slots is 12 to 16.

[0015] Furthermore, the rivet is a cylindrical metal rod, and the diameter of the rivet is 10 to 14 mm.

[0016] Furthermore, the casting is a cast iron grinding disc with a wall thickness of more than 20 mm.

[0017] Compared with the prior art, the utility model provides a welding-free repair structure for cast iron cracks, which has the following beneficial effects:

[0018] The utility model adopts a structure in which a dumbbell-shaped snap-fit ​​key with large ends and a small middle is matched with a rivet for repair, without welding, and the clamping parts at both ends of the dumbbell-shaped snap-fit ​​key are used to clamp the dumbbell-shaped groove reliably, and the contact force is applied through the rivet. This repair structure enables multi-directional force to be applied between the casting base material at the crack and the dumbbell-shaped snap-fit ​​key, thereby providing a reliable tensioning effect, with good strength and repair effect, and the repaired casting is quite reliable in subsequent use, which is particularly suitable for on-site repair of cracks in large castings.

[0019] The utility model does not need to disassemble the casting parent material body or weld the cracks, has a short processing time, low repair cost and good repair effect, can reduce direct and indirect losses, and extend the service life of the grinding disc waiting for the casting to be repaired. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 It is a structural schematic diagram of the utility model;

[0022] Figure 2 It is a schematic diagram of the three-dimensional structure of a dumbbell-shaped snap-fit ​​key;

[0023] Figure 3 This is a schematic diagram of the distribution of cracks on the casting;

[0024] Figure 4 A schematic diagram of opening a dumbbell-shaped groove on a casting;

[0025] Figure 5 A schematic diagram of a dumbbell-shaped snap-fit ​​key being embedded in a dumbbell-shaped groove;

[0026] Figure 6 A schematic diagram of opening a rivet slot at the joint between the dumbbell-shaped groove and the dumbbell-shaped snap-fit ​​key.

[0027] Figure numerals: 1, casting; 11, crack; 12, dumbbell-shaped groove; 2, dumbbell-shaped snap-fit ​​key; 21, clamping part; 22, connecting part; 3, rivet; 4, rivet slot. DETAILED DESCRIPTION

[0028] The technical solution of the utility model will be clearly and completely described below through detailed embodiments and in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] Please refer to Figure 1 to Figure 6 The present embodiment provides a welding-free repair structure for cast iron cracks, including a crack 11 located on a casting 1, wherein the casting 1 is provided with a plurality of dumbbell-shaped grooves 12 with large ends and a small middle along the extension direction of the crack 11, each of the dumbbell-shaped grooves 12 is vertically distributed to the extension direction of the crack 11, and each of the dumbbell-shaped grooves 12 is inlaid with a dumbbell-shaped snap-fit ​​key 2 of a matching shape, wherein the dumbbell-shaped snap-fit ​​key 2 includes a clamping portion 21 located at both ends and a connecting portion 22 connected between the two clamping portions 21, wherein the width of the clamping portion 21 is greater than the width of the connecting portion 22, and the dumbbell-shaped snap-fit ​​key 2 is generally in the shape of a horizontal "I" character; a plurality of rivets 3 are provided at the joint between the dumbbell-shaped groove 12 and the dumbbell-shaped snap-fit ​​key 2, and the inner side wall of the dumbbell-shaped groove 12 and the outer side wall of the dumbbell-shaped snap-fit ​​key 2 are correspondingly provided with a rivet slot 4 inlaid and connected with the rivet 3. The repair is performed by using a dumbbell-shaped snap-on key with a large end and a small middle and a rivet structure, without welding. The clamping parts at both ends of the dumbbell-shaped snap-on key and the dumbbell-shaped groove are used for reliable clamping, and the contact force is applied through the rivet. This repair structure allows the casting parent material at the crack and the dumbbell-shaped snap-on key to have multi-dimensional force, thereby providing a reliable tensioning effect, with good strength and repair effect. The repaired casting is quite reliable in subsequent use, and is particularly suitable for on-site repair of cracks in large castings. In addition, since the treatment of the crack does not require disassembly of the casting parent material body and does not require welding, the treatment time is short, the repair cost is low, and the repair effect is good, which can reduce direct and indirect losses and extend the service life of the grinding wheel waiting for repair castings.

[0030] In some specific embodiments, the thickness of the dumbbell-shaped snap-fit ​​key 2 is 0.3 to 0.9 times the maximum depth of the crack 11, and the length of the rivet 3 is 1.0 to 1.3 times the thickness of the dumbbell-shaped snap-fit ​​key 2. As an example, the thickness of the dumbbell-shaped snap-fit ​​key can be set to 0.3 times, 0.32 times, 0.5 times, 0.75 times, 0.83 times, 0.9 times, etc., of the maximum depth of the crack; the length of the rivet can be set to 1 times, 1.1 times, 1.2 times, 1.3 times, etc., of the thickness of the dumbbell-shaped snap-fit ​​key.

[0031] In some specific embodiments, the width of the clamping portion 21 is 1.3 to 1.5 times the width of the connecting portion 22. As an example, the width of the clamping portion may be 1.3, 1.33, 1.4, 1.5, etc., of the width of the connecting portion.

[0032] In some specific embodiments, the dumbbell-shaped snap-fit ​​key 2 has a length of 280 to 320 mm, and the width of the connecting portion 22 has a width of 80 to 120 mm. As an example, the dumbbell-shaped snap-fit ​​key can be set to a length of 280 mm, 300 mm, 320 mm, etc. The width of the connecting portion can be set to 80 mm, 100 mm, 120 mm, etc. The width of the clamping portion can be set to 120 mm, 140 mm, 160 mm, etc.

[0033] In some specific implementations, the distance between two adjacent dumbbell-shaped snap-fit ​​keys 2 is 100-140 mm. As an example, the distance between two adjacent dumbbell-shaped snap-fit ​​keys can be set to 100 mm, 120 mm, 130 mm, 140 mm, etc.

[0034] In some specific implementations, the dumbbell-shaped snap-fit ​​key 2 can be made of 18CrNiMo7-6 alloy material through quenching and tempering treatment.

[0035] In some specific implementations, the rivets 3 are symmetrically distributed along both sides of the crack 11 .

[0036] In some specific embodiments, the number of the rivets 3 and the rivet slots 4 is set to 12 to 16. As an example, the number of the rivets and the rivet slots 4 can be set to 12, 16, etc.

[0037] In some specific embodiments, the rivet 3 is a cylindrical metal rod made of steel, and the diameter of the rivet 3 is 10-14 mm. As an example, the diameter of the rivet can be set to 10 mm, 12 mm, 14 mm, etc.

[0038] In some specific embodiments, the casting 1 is a cast iron grinding disc with a wall thickness of more than 20 mm. As an example, the casting is a ball mill cast iron vertical mill grinding disc.

[0039] In this embodiment, the specific operation process of repairing the crack is as follows:

[0040] like Figure 3 and Figure 4 As shown, according to the size of the casting 1, the length and depth of the crack, a number of dumbbell-shaped grooves 12 with large ends and small middle are processed along the extension direction of the crack 11, and each dumbbell-shaped groove 12 is perpendicular to the extension direction of the crack 11; Figure 2As shown, a dumbbell-shaped snap-fit ​​key 2 made of a high-strength alloy material is manufactured by mechanical processing; then, as shown in FIG. Figure 5 As shown, the dumbbell-shaped snap-fit ​​key 2 is sequentially embedded into the dumbbell-shaped groove 12; then a corresponding number of rivets 3 are set according to the size of the dumbbell-shaped snap-fit ​​key 2, specifically, as Figure 6 As shown, holes are drilled at the joint between the dumbbell-shaped snap-fit ​​key 2 and the dumbbell-shaped groove 12 to form a corresponding number of rivet slots 4, and then the rivets 3 are heated red and hammered into the rivet slots 4 with force. After the repair is completed, it is shown as shown in 1.

[0041] Some specific repair application scenarios are provided below.

[0042] Repair Example 1

[0043] The grinding disc of the No. 1 vertical mill was cracked to form a crack with a length of 1.8 meters. The welding-free repair structure of the utility model was used for repair without welding. The schematic diagram is shown in FIG. Figure 1 It has been used since the repair and has been inspected 11 times. No crack extension has been found and the vehicle is in good condition.

[0044] Some process parameter settings during specific repair are as follows:

[0045] (1) The thickness of the vertical mill grinding disc base material is 250 mm, and the material is ductile iron. The cracks formed are not through-breaks, and the crack depth is 40 to 80 mm.

[0046] (2) The dumbbell-shaped snap-fit ​​key is made of 18CrNiMo7-6 alloy material after quenching and tempering, and its thickness is 60 mm, which is 0.75 times the maximum depth of the crack (or 0.24 times the thickness of the vertical mill grinding disc base material); the width of the connecting part is set to 100 mm, and the width of the clamping part is set to 140 mm (corresponding to 1.4 times the width of the connecting part); the total length of the dumbbell-shaped snap-fit ​​key is 320 mm, and the distance between two adjacent dumbbell-shaped snap-fit ​​keys is set to 130 mm.

[0047] (3) The rivet is a cylindrical steel rod with a diameter of 10 mm. The length of the rivet is set to 72 mm (corresponding to 1.2 times the thickness of the dumbbell-shaped snap-fit ​​key). The rivets are symmetrically distributed along both sides of the crack. The number of rivets and rivet slots is set to 12 each, and 6 rivets are set on each side of the crack.

[0048] Repair Example 2

[0049] The grinding disc of the No. 2 vertical mill was cracked to form two cracks, one of which was 0.8 meters long and the other was 0.6 meters long. The welding-free repair structure of the utility model was used for repair without welding. The schematic diagram is shown in FIG. Figure 1 It has been used since the repair and has been inspected 6 times. No crack extension has been found and the vehicle is in good condition.

[0050] Some process parameter settings during specific repair are as follows:

[0051] (1) The thickness of the vertical mill grinding disc base material is 250 mm, and the material is ductile iron. The two cracks formed are not through-breaks, and the crack depths are 30 to 60 mm.

[0052] (2) The dumbbell-shaped snap-fit ​​key is made of 18CrNiMo7-6 alloy material after quenching and tempering treatment, and its thickness is 50 mm, which is 0.83 times the maximum depth of the crack (or 0.2 times the thickness of the corresponding vertical mill grinding disc base material); the width of the connecting part is set to 80 mm, and the width of the clamping part is set to 120 mm (corresponding to 1.5 times the width of the connecting part); the total length of the dumbbell-shaped snap-fit ​​key is 280 mm, and the distance between two adjacent dumbbell-shaped snap-fit ​​keys is set to 140 mm.

[0053] (3) The rivet is a cylindrical steel rod with a diameter of 10 mm. The length of the rivet is set to 60 mm (corresponding to 1.2 times the thickness of the dumbbell-shaped snap-fit ​​key). The rivets are symmetrically distributed along both sides of the crack. The number of rivets and rivet slots is set to 12 each, and 6 rivets are set on each side of the crack.

[0054] Repair Example 3

[0055] The grinding disc of the No. 3 vertical mill was cracked to form two cracks, one of which was 3.2 meters long and the other was 1.1 meters long. The welding-free repair structure of the utility model was used for repair without welding. The schematic diagram is shown in FIG. Figure 1 It has been used since the repair and has been inspected twice. No extension of the crack was found and the product is in good condition.

[0056] Some process parameter settings during specific repair are as follows:

[0057] (1) The thickness of the vertical mill grinding disc base material is 220 mm, and the material is ductile iron. The two cracks formed have penetrated the base material (i.e., the depth of the cracks is 220 mm).

[0058] (2) Keying is performed on both sides of the vertical mill grinding disc. The dumbbell-shaped snap-fit ​​key is made of 18CrNiMo7-6 alloy material after quenching and tempering. Its thickness is 70 mm, which is 0.32 times the crack depth (or 0.32 times the thickness of the vertical mill grinding disc base material). The width of the connecting part is set to 120 mm, and the width of the clamping part is set to 160 mm (corresponding to 1.33 times the width of the connecting part). The total length of the dumbbell-shaped snap-fit ​​key is 320 mm, and the distance between two adjacent dumbbell-shaped snap-fit ​​keys is set to 130 mm.

[0059] (3) The rivet is a cylindrical steel rod with a diameter of 12 mm. The length of the rivet is set to 84 mm (corresponding to 1.2 times the thickness of the dumbbell-shaped snap-fit ​​key). The rivets are symmetrically distributed along both sides of the crack. The number of rivets and rivet slots is set to 12 each, and 6 rivets are set on each side of the crack.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0061] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A welding-free repair structure for cast iron cracks, comprising a crack located on a casting, characterized in that: The casting is provided with a plurality of dumbbell-shaped grooves with large ends and small middle along the extension direction of the crack, each of the dumbbell-shaped grooves is distributed perpendicularly to the extension direction of the crack, each of the dumbbell-shaped grooves is inlaid with a dumbbell-shaped snap-fitting key of a matching shape, the dumbbell-shaped snap-fitting key comprises a clamping part located at both ends and a connecting part connected between the two clamping parts, the width of the clamping part is greater than the width of the connecting part; a plurality of rivets are provided at the joint between the dumbbell-shaped groove and the dumbbell-shaped snap-fitting key, and the inner side wall of the dumbbell-shaped groove and the outer side wall of the dumbbell-shaped snap-fitting key are correspondingly provided with rivet slot holes inlaid and connected with the rivets.

2. The welding-free repair structure for cast iron cracks according to claim 1, characterized in that: The thickness of the dumbbell-shaped snap-fit ​​key is 0.3 to 0.9 times the maximum depth of the crack, and the length of the rivet is 1.0 to 1.3 times the thickness of the dumbbell-shaped snap-fit ​​key.

3. The welding-free repair structure for cast iron cracks according to claim 1, characterized in that: The width of the clamping portion is 1.3 to 1.5 times the width of the connecting portion.

4. The welding-free repair structure for cast iron cracks according to claim 3 is characterized in that: The dumbbell-shaped buckle key has a length of 280 to 320 mm, and the connecting portion has a width of 80 to 120 mm.

5. The welding-free repair structure for cast iron cracks according to claim 1, characterized in that: The distance between two adjacent dumbbell-shaped snap-fit ​​keys is 100 to 140 mm.

6. The welding-free repair structure for cast iron cracks according to claim 1, characterized in that: The dumbbell-shaped snap-fit ​​key is made of 18CrNiMo7-6 alloy material after being quenched and tempered.

7. The welding-free repair structure for cast iron cracks according to claim 1, characterized in that: The rivets are symmetrically distributed along both sides of the crack.

8. The welding-free repair structure for cast iron cracks according to claim 7, characterized in that: The number of the rivets and the rivet slots is set to 12 to 16.

9. The welding-free repair structure for cast iron cracks according to claim 1, characterized in that: The rivet is a cylindrical metal rod, and the diameter of the rivet is 10-14 mm.

10. The welding-free repair structure for cast iron cracks according to any one of claims 1 to 9, characterized in that: The casting is a cast iron grinding disc with a wall thickness of more than 20 mm.

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