Welding rod for repairing surfacing welding of nodular cast iron sintering pallet

Abstract

The invention relates to the technical field of surfacing materials, and provides a surfacing welding rod for repairing a nodular cast iron sintering pallet, the surfacing welding rod comprises a core wire and a coating arranged on the surface of the core wire, the coating comprises the following raw material components in parts by weight: 35-50 parts of marble, 3-6 parts of white clay, 20-30 parts of a filler, 2-5 parts of ferromolybdenum, 1-3 parts of high-carbon ferromanganese, 1-3 parts of ferrosilicon, 4-7 parts of rare earth oxide and 5-10 parts of molybdenum boride; the filling agent comprises calcium carbide and calcium fluoride; and the core wire is an H08A core wire. Through the technical scheme, the problem of poor hardness of the surfacing layer after the welding rod is repaired in the related technology is solved.

Description

Technical Field

[0001] The invention relates to the technical field of surfacing materials, and in particular to a welding rod for repairing surfacing of a ductile iron sintering trolley. Background Art

[0002] In the process of modernization, metallurgy, chemical industry and other industries are the basic industries, and their production efficiency and product quality are directly related to the stable development of the entire industrial system. In the sintering process of these industries, ductile iron sintering trolleys play a pivotal role.

[0003] Ductile iron is an ideal material for manufacturing sintering trolleys due to its excellent comprehensive properties, such as high strength, good toughness and wear resistance. These trolleys are responsible for carrying materials and running continuously in high temperature environments, while bearing huge mechanical pressure and constant friction of materials. In the iron ore sintering process of the metallurgical industry, the trolley needs to sinter the iron ore with various additives at a high temperature of more than 1000℃ into a sintered ore with specific properties. In the sintering process of certain materials in the chemical industry, the trolley also faces the dual test of high temperature and highly corrosive materials. The defects of sintering trolleys are usually cracks in the beams and car bodies, which are caused by the working characteristics of long-term high temperature and rapid cooling.

[0004] Long-term rapid changes in temperature make the original ductile iron material white, resulting in significant changes in its ductility and plasticity, usually resulting in cracks in the bearing seat. This will cause the surface flatness of the trolley to decrease, and the material to be unevenly distributed on the trolley, which will in turn affect the sintering quality; and the cracks may cause the trolley structure to be unstable, and even cause the trolley to be scrapped in extreme cases. According to incomplete statistics, in some large metallurgical enterprises, the production line downtime caused by damage to the sintering trolley can reach dozens of hours per year, causing direct economic losses of up to millions of yuan.

[0005] In order to solve the damage problem of sintering trolleys, cladding repair technology came into being. Cladding is a process method that repairs the worn surface and improves the performance of the workpiece by depositing one or more layers of metal materials on the surface of the workpiece. Compared with replacing the entire sintering trolley, cladding repair has the significant advantages of low cost and short cycle. However, traditional cladding electrodes have exposed many problems when used in the repair of ductile iron sintering trolleys.

[0006] The most prominent problem is that the hardness of the cladding layer is difficult to meet the actual needs. Due to the harsh working environment of the sintering trolley, the hardness of the cladding layer is required to be extremely high. The cladding layer with insufficient hardness will wear out again in a short time, resulting in a short service life of the repaired trolley. When facing the special material of ductile iron, the core and coating formula of the traditional welding rod cannot effectively promote the formation of hard phases in the cladding layer, and it is difficult to inhibit the diffusion of harmful elements, thus affecting the hardness and wear resistance of the cladding layer. In addition, traditional welding rods are prone to defects such as pores and cracks during the welding process, which further reduces the quality and reliability of the cladding layer.

[0007] Therefore, it is of vital importance to develop a welding rod with high hardness for repairing and surfacing welding of ductile iron sintering trolley. Summary of the invention

[0008] The invention provides a welding rod for repairing and surfacing welding of a ductile iron sintering trolley, which solves the problem of poor hardness of the surfacing layer after the welding rod is repaired in the related art.

[0009] The technical solution of the present invention is as follows: The invention provides a welding rod for repairing and surfacing welding of a ductile iron sintering trolley, comprising a welding core and a coating arranged on the surface of the welding core, wherein the raw materials of the coating comprise the following components in parts by weight: 35-50 parts of marble, 3-6 parts of white clay, 20-30 parts of filler, 2-5 parts of ferromolybdenum, 1-3 parts of high-carbon ferromanganese, 1-3 parts of ferrosilicon, 4-7 parts of rare earth oxide, and 5-10 parts of molybdenum boride; The filler includes calcium carbide and calcium fluoride; The welding core is H08A welding core.

[0010] As a further technical solution, the mass ratio of the welding core to the coating is 1:0.25~0.4.

[0011] As a further technical solution, the mass ratio of calcium carbide to calcium fluoride is 2~3:7.

[0012] In the present invention, the hardness of the cladding layer is further improved by adjusting the mass ratio of calcium carbide to calcium fluoride to 2-3:7.

[0013] As a further technical solution, the molybdenum boride is titanium-doped molybdenum boride.

[0014] As a further technical solution, the raw material of the titanium-doped molybdenum boride includes molybdenum boride and titanium powder.

[0015] In the present invention, titanium is doped into molybdenum boride, which can cause greater lattice distortion, making it more difficult to cause plastic deformation when subjected to force, thereby improving the wear resistance of the cladding layer.

[0016] As a further technical solution, the preparation method of titanium-doped molybdenum boride comprises the following steps: The molybdenum boride and titanium powder are mixed evenly and ball-milled to obtain titanium-doped molybdenum boride; During the ball milling, the ball-to-material ratio is 5-6:1, the rotation speed is 300-500 rpm, and the time is 17-20 hours.

[0017] As a further technical solution, the mass ratio of the molybdenum boride to the titanium powder is 12-18:5.

[0018] In the present invention, the wear resistance of the cladding layer is further improved by adjusting the mass ratio of molybdenum boride to titanium powder to 12-18:5.

[0019] As a further technical solution, the rare earth oxide includes one or more of yttrium oxide, lanthanum oxide, and cerium oxide.

[0020] The present invention also proposes a method for preparing a welding rod for repairing and surfacing welding of a ductile iron sintering trolley, comprising the following steps: The components of the coating are mixed evenly, coated on the surface of the welding core with a binder, and dried to obtain the welding rod for repairing and surfacing welding of the ductile iron sintering trolley.

[0021] As a further technical solution, the mass ratio of the coating to the binder is 1:0.2-0.3; As a further technical solution, the binder includes water glass.

[0022] As a further technical solution, the modulus of the water glass is 2.7-3.0 and the Baume degree is 48-50.

[0023] The working principle and beneficial effects of the present invention are: In the present invention, calcium carbide and calcium fluoride are used as fillers, which are helpful to improve the forming quality of the weld during welding, adjust the basicity, create good metallurgical conditions for the melting of alloy elements and the formation of weld structure, and thus improve the hardness of the weld. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the following embodiments and comparative examples, the marble particle size is 300 mesh, the clay particle size is 300 mesh, the molybdenum content in ferromolybdenum is 60wt%, the carbon content in high carbon ferromanganese is 7wt%, the manganese content is 78wt%, the silicon content in ferrosilicon is 75wt%, the D90 particle size of titanium powder is 100nn, and the D90 particle size of molybdenum boride is 45μm.

[0026] Example 1 A welding rod for repairing and surfacing welding of a ductile iron sintering trolley comprises an H08A welding core and a coating arranged on the surface of the welding core, wherein the raw materials of the coating comprise the following components in parts by weight: 50 parts of marble, 6 parts of white clay, 30 parts of filler, 5 parts of ferromolybdenum, 3 parts of high-carbon ferromanganese, 3 parts of ferrosilicon, 7 parts of yttrium oxide, and 10 parts of molybdenum boride.

[0027] The mass ratio of welding core and coating is 1:0.4; The filler includes calcium carbide and calcium fluoride in a mass ratio of 5:7; A method for preparing a welding rod for repairing and surfacing welding of a ductile iron sintering trolley comprises the following steps: The components of the coating are mixed evenly, coated on the surface of the welding core with a binder, and dried to obtain a welding rod for repairing and surfacing welding of a ductile iron sintering trolley; The mass ratio of the coating to the binder is 1:0.3; The binder is water glass with a modulus of 2.7~3.0 and a Baume degree of 48~50.

[0028] Example 2 A welding rod for repairing and surfacing welding of a ductile iron sintering trolley, comprising an H08A welding core and a coating arranged on the surface of the welding core, wherein the raw materials of the coating comprise the following components in parts by weight: 35 parts of marble, 3 parts of white clay, 20 parts of filler, 2 parts of ferromolybdenum, 1 part of high carbon ferromanganese, 1 part of ferrosilicon, 4 parts of lanthanum oxide, and 5 parts of molybdenum boride; The mass ratio of welding core and coating is 1:0.25; The filler includes calcium carbide and calcium fluoride in a mass ratio of 1:9; A method for preparing a welding rod for repairing and surfacing welding of a ductile iron sintering trolley comprises the following steps: The components of the coating are mixed evenly, coated on the surface of the welding core with a binder, and dried to obtain a welding rod for repairing and surfacing welding of a ductile iron sintering trolley; The mass ratio of the coating to the binder is 1:0.2; The binder is water glass with a modulus of 2.7~3.0 and a Baume degree of 48~50.

[0029] Example 3 A welding rod for repairing and surfacing welding of a ductile iron sintering trolley, comprising an H08A welding core and a coating arranged on the surface of the welding core, wherein the raw materials of the coating comprise the following components in parts by weight: 40 parts of marble, 4 parts of white clay, 25 parts of filler, 3 parts of ferromolybdenum, 2 parts of high carbon ferromanganese, 2 parts of ferrosilicon, 5 parts of cerium oxide, and 8 parts of molybdenum boride; The mass ratio of welding core and coating is 1:0.3; The filler includes calcium carbide and calcium fluoride in a mass ratio of 1:7; A method for preparing a welding rod for repairing and surfacing welding of a ductile iron sintering trolley comprises the following steps: The components of the coating are mixed evenly, coated on the surface of the welding core with a binder, and dried to obtain a welding rod for repairing and surfacing welding of a ductile iron sintering trolley; The mass ratio of the coating to the binder is 1:0.25; The binder is water glass with a modulus of 2.7~3.0 and a Baume degree of 48~50.

[0030] Example 4 The only difference between this embodiment and embodiment 3 is that the mass ratio of calcium carbide to calcium fluoride in this embodiment is 4:7.

[0031] Example 5 The only difference between this embodiment and embodiment 3 is that the mass ratio of calcium carbide to calcium fluoride in this embodiment is 2:7.

[0032] Example 6 The only difference between this embodiment and embodiment 3 is that the mass ratio of calcium carbide to calcium fluoride in this embodiment is 3:7.

[0033] Example 7 The only difference between this embodiment and embodiment 3 is that the molybdenum boride in this embodiment is replaced by an equal weight of titanium-doped molybdenum boride; The raw materials of titanium-doped molybdenum boride material include molybdenum boride and titanium powder in a mass ratio of 19:5; The preparation method of titanium-doped molybdenum boride comprises the following steps: The molybdenum boride and titanium powder are mixed evenly and ball-milled to obtain titanium-doped molybdenum boride; During ball milling, the ball-to-material ratio was 5:1, the rotation speed was 300 rpm, and the time was 20 h.

[0034] Example 8 The only difference between this embodiment and Embodiment 7 is that the raw material of titanium-doped molybdenum boride in this embodiment includes molybdenum boride and titanium in a mass ratio of 11:5.

[0035] Example 9 The only difference between this embodiment and Embodiment 7 is that the raw material of titanium-doped molybdenum boride in this embodiment includes molybdenum boride and titanium in a mass ratio of 12:5.

[0036] Example 10 The only difference between this embodiment and Embodiment 7 is that the raw material of titanium-doped molybdenum boride in this embodiment includes molybdenum boride and titanium in a mass ratio of 18:5.

[0037] Embodiment 11 The only difference between this embodiment and embodiment 3 is that the molybdenum boride in this embodiment is replaced by an equal weight of titanium-doped molybdenum boride; The raw material of titanium-doped molybdenum boride includes molybdenum boride and titanium powder in a mass ratio of 15:5; The preparation method of titanium-doped molybdenum boride comprises the following steps: The molybdenum boride and titanium powder are mixed evenly and ball-milled to obtain titanium-doped molybdenum boride; During ball milling, the ball-to-material ratio was 6:1, the rotation speed was 500 rpm, and the time was 17 h.

[0038] Comparative Example 1 The only difference between this comparative example and Example 2 is that the filler in this comparative example is calcium carbide.

[0039] Comparative Example 2 The only difference between this comparative example and Example 2 is that the filler in this comparative example is calcium fluoride.

[0040] Comparative Example 3 The only difference between this comparative example and Example 2 is that this comparative example does not contain a filler.

[0041] Experimental Example 1 The welding rods for repairing and surfacing welding of ductile iron sintering trolleys prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were used to repair the cracks of the sintering trolleys of Shougang Mining Pellet Plant. Before welding, the welding rods were dried at 250°C for 1 hour, and a DC welding machine was used for reverse connection, with a welding current of 200A. The welding rods did not need to be preheated before welding, and did not need heat treatment after welding. The Vickers hardness of the samples was tested according to the single-point determination test method specified in GB / T 2654-2008 "Test Method for Hardness of Welded Joints". The test results are shown in Table 1.

[0042] Table 1 Hardness test results

[0043] Comparing Example 2 with Comparative Examples 1 to 3, the hardness of Example 2 is improved, which indicates that the calcium carbide and calcium fluoride in the present invention work synergistically to improve the hardness of the cladding layer.

[0044] Comparing Examples 5-6 with Examples 3-4, Examples 5-6 have higher hardness, indicating that when the mass ratio of calcium carbide to calcium fluoride is 2-3:7, the hardness of the cladding layer is further improved.

[0045] Experimental Example 2 The welding rods for repairing and surfacing welding of ductile iron sintering trolleys prepared in Examples 3, 7 to 11 were used to repair the cracks of the sintering trolleys of Shougang Mining Pellet Plant. Before welding, the welding rods were dried at 250°C for 1 hour, and a DC welding machine was used for reverse connection, with a welding current of 200A. The welding rods did not need to be preheated before welding, and did not need heat treatment after welding. The surfacing layers were made into φ32×10mm cylinders, and the test was carried out on an MMW-1A vertical universal friction and wear testing machine. The wear time was 10min, and the wear weight loss was measured by the mass difference before and after wear. The test results are shown in Table 2.

[0046] Table 2 Wear weight loss test results

[0047] Compared with Example 3, Examples 7 to 11 have less weight loss due to wear, indicating that the wear resistance of the surfacing layer is improved by doping titanium in molybdenum boride in the present invention. Compared with Examples 7 to 8, Examples 9 to 10 have less weight loss due to wear, indicating that when the mass ratio of molybdenum boride to titanium powder is 5:12 to 18, the wear resistance of the surfacing layer is further improved.

[0048] The above are only preferred embodiments of the present invention and are 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.

Claims

1. A welding rod for repairing and surfacing welding of a ductile iron sintering trolley, characterized in that: It comprises a welding core and a coating arranged on the surface of the welding core, wherein the raw materials of the coating include the following components in parts by weight: 35-50 parts of marble, 3-6 parts of white clay, 20-30 parts of filler, 2-5 parts of ferromolybdenum, 1-3 parts of high carbon ferromanganese, 1-3 parts of ferrosilicon, 4-7 parts of rare earth oxide, and 5-10 parts of molybdenum boride; The filler includes calcium carbide and calcium fluoride; The welding core is H08A welding core.

2. The welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to claim 1, characterized in that: The mass ratio of calcium carbide to calcium fluoride is 2-3:

7.

3. The welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to claim 1, characterized in that: The molybdenum boride is titanium-doped molybdenum boride.

4. The welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to claim 3, characterized in that: The raw materials of titanium-doped molybdenum boride include molybdenum boride and titanium powder.

5. The welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to claim 4, characterized in that: The preparation method of titanium-doped molybdenum boride comprises the following steps: The molybdenum boride and titanium powder are mixed evenly and ball-milled to obtain the titanium-doped molybdenum boride; During the ball milling, the ball-to-material ratio is 5-6:1, the rotation speed is 300-500 rpm, and the time is 17-20 hours.

6. The welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to claim 4, characterized in that: The mass ratio of the molybdenum boride to the titanium powder is 12-18:

5.

7. The welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to claim 1, characterized in that: The rare earth oxide includes one or more of yttrium oxide, lanthanum oxide and cerium oxide.

8. The method for preparing a welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to any one of claims 1 to 7, characterized in that: The following steps are involved: The components of the coating are mixed evenly, coated on the surface of the welding core with a binder, and dried to obtain the welding rod for repairing and surfacing welding of the ductile iron sintering trolley.

9. The method for preparing a welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to claim 8, characterized in that: The binder includes water glass.

10. The method for preparing a welding rod for repairing and surfacing welding of a ductile iron sintering trolley according to claim 9, characterized in that: The modulus of the water glass is 2.7-3.0, and the Baume degree is 48-50.

Images