A welding rod for repairing sintering trolley of nodular cast iron

Abstract

The present application relates to the technical field of surfacing material, and proposes a welding rod for repairing and surfacing of sintering trolley of nodular cast iron, which comprises a welding core and a coating arranged on the surface of the welding core, and the raw material of the coating comprises 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 comprises calcium carbide and calcium fluoride; and the welding core is an H08A welding core. Through the above technical solution, the problem of poor hardness of the surfacing layer after the welding rod is repaired in the related art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surfacing material, in particular, relates to a welding rod for repairing surfacing of spheroidal graphite cast iron sintering trolley. BACKGROUND

[0002] In the process of modernization of industry, metallurgy, chemical industry and other industries as the basic industries, its production efficiency and product quality is directly related to the stable development of the whole industrial system. In the sintering process of these industries, spheroidal graphite cast iron sintering trolley plays an important role.

[0003] Spheroidal graphite cast iron has become an ideal material for manufacturing sintering trolley due to its excellent comprehensive performance, such as high strength, good toughness and wear resistance. These trolleys are responsible for carrying materials and continuously running in high temperature environment, while bearing huge mechanical pressure and constant friction of materials. In the iron ore sintering process of metallurgical industry, the trolley needs to mix and sinter iron ore with various additives at a high temperature above 1000 DEG C to form sinter with specific performance. In the sintering process of some materials in the chemical industry, the trolley also faces the double test of high temperature and strong corrosive materials. The defects of sintering trolley are usually cracks in the beam and the body compartment, which are caused by the working characteristics of long-term high temperature and rapid cooling.

[0004] Long-term rapid cooling and heating change the original spheroidal graphite cast iron material to white mouth, which significantly changes its ductility and plasticity, and usually causes explosion cracking in the bearing seat part. This will cause the surface flatness of the trolley to decrease, the distribution of materials on the trolley to be uneven, and then affect the sintering quality; and the explosion cracking may cause the instability of the trolley structure, 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 sintering trolley damage can reach dozens of hours per year, and the direct economic loss is as high as several million yuan.

[0005] In order to solve the problem of sintering trolley damage, surfacing repair technology emerges as the times require. Surfacing is a process method of repairing worn surface and improving the performance of workpiece by depositing one or more layers of metal material on the surface of workpiece. Compared with replacing the whole sintering trolley, surfacing repair has the significant advantages of low cost and short cycle. However, the traditional surfacing welding rod has exposed many problems when applied to the repair of spheroidal graphite cast iron sintering trolley.

[0006] The most prominent problem is that the hardness of the surfacing layer is difficult to meet the actual demand. The sintering trolley has a poor working environment, and the hardness of the surfacing layer is extremely high. The surfacing layer with insufficient hardness will be abraded again in a short time, resulting in a short service life of the repaired trolley. When facing the special material of nodular cast iron, the welding core and the coating formula of the traditional electrode cannot effectively promote the formation of hard phases in the surfacing layer, and it is also difficult to inhibit the diffusion of harmful elements, thereby affecting the hardness and wear resistance of the surfacing layer. In addition, the traditional electrode is prone to defects such as pores and cracks during welding, further reducing the quality and reliability of the surfacing layer.

[0007] Therefore, it is of great importance to develop a nodular cast iron sintering trolley repair surfacing electrode with high hardness. SUMMARY

[0008] The application provides a nodular cast iron sintering trolley repair surfacing electrode, which solves the problem of poor hardness of the surfacing layer after repair of the electrode in the related art.

[0009] The technical scheme of the application is as follows:

[0010] The application provides a nodular cast iron sintering trolley repair surfacing electrode, which includes a welding core and a coating arranged on the surface of the welding core, and the raw material of the coating includes the following 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 molybdenum iron, 1-3 parts of high-carbon manganese iron, 1-3 parts of silicon iron, 4-7 parts of rare earth oxide and 5-10 parts of molybdenum boride.

[0011] The filler includes calcium carbide and calcium fluoride.

[0012] The welding core is an H08A welding core.

[0013] As a further technical scheme, the mass ratio of the welding core to the coating is 1:0.25-0.4.

[0014] As a further technical scheme, the mass ratio of the calcium carbide to the calcium fluoride is 2-3:7.

[0015] In the application, by adjusting the mass ratio of the calcium carbide to the calcium fluoride to 2-3:7, the hardness of the surfacing layer is further improved.

[0016] As a further technical scheme, the molybdenum boride is titanium-doped molybdenum boride.

[0017] As a further technical scheme, the raw material of the titanium-doped molybdenum boride includes molybdenum boride and titanium powder.

[0018] In the application, titanium is doped in the molybdenum boride, which can cause large lattice distortion, so that plastic deformation is more difficult to occur under stress, thereby improving the wear resistance of the surfacing layer.

[0019] As a further technical solution, the preparation method of the titanium-doped molybdenum boride comprises the following steps:

[0020] The molybdenum boride and titanium powder are uniformly mixed and ball milled to obtain the titanium-doped molybdenum boride.

[0021] 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 h.

[0022] As a further technical solution, the mass ratio of the molybdenum boride and titanium powder is 12-18:5.

[0023] In the present application, by adjusting the mass ratio of the molybdenum boride and titanium powder to 12-18:5, the wear resistance of the surfacing layer is further improved.

[0024] As a further technical solution, the rare earth oxide comprises one or more of yttrium oxide, lanthanum oxide, and cerium oxide.

[0025] The present application also proposes a preparation method of the welding rod for repairing and surfacing of a spheroidal graphite cast iron sintering trolley, comprising the following steps:

[0026] The components of the coating are uniformly mixed, the coating agent is applied to the surface of the welding core, and drying is performed to obtain the welding rod for repairing and surfacing of the spheroidal graphite cast iron sintering trolley.

[0027] As a further technical solution, the mass ratio of the coating to the coating agent is 1:0.2-0.3.

[0028] As a further technical solution, the coating agent comprises water glass.

[0029] As a further technical solution, the modulus of the water glass is 2.7-3.0, and the Baume degree is 48-50.

[0030] The working principle and beneficial effects of the present application are as follows:

[0031] In the present application, calcium carbide and calcium fluoride are used as fillers, which helps to improve the forming quality of the weld during the welding process, adjust the basicity, create good metallurgical conditions for the melting of alloying elements and the formation of weld structure, and thus improve the hardness of the weld. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only a 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 are within the scope of protection of the present application.

[0033] In the following examples and comparative examples, the marble particle size is 300 mesh, the kaolin particle size is 300 mesh, the molybdenum content in molybdenum iron 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.

[0034] Example 1

[0035] A welding rod for repairing and surfacing of nodular cast iron sintering trolley, comprising a H08A welding core and a coating arranged on the surface of the welding core, the raw materials of the coating comprise the following components by weight: marble 50 parts, kaolin 6 parts, filler 30 parts, molybdenum iron 5 parts, high-carbon ferromanganese 3 parts, ferrosilicon 3 parts, yttrium oxide 7 parts, and molybdenum boride 10 parts.

[0036] The mass ratio of the welding core and the coating is 1:0.4;

[0037] The filler comprises calcium carbide and calcium fluoride in a mass ratio of 5:7;

[0038] A preparation method of the welding rod for repairing and surfacing of nodular cast iron sintering trolley, comprising the following steps:

[0039] Mixing the components of the coating uniformly, applying the adhesive on the surface of the welding core, drying, and obtaining the welding rod for repairing and surfacing of nodular cast iron sintering trolley;

[0040] The mass ratio of the coating and the adhesive is 1:0.3;

[0041] The adhesive is water glass with a modulus of 2.7-3.0 and a Baume degree of 48-50.

[0042] Example 2

[0043] A welding rod for repairing and surfacing of nodular cast iron sintering trolley, comprising a H08A welding core and a coating arranged on the surface of the welding core, the raw materials of the coating comprise the following components by weight: marble 35 parts, kaolin 3 parts, filler 20 parts, molybdenum iron 2 parts, high-carbon ferromanganese 1 part, ferrosilicon 1 part, lanthanum oxide 4 parts, and molybdenum boride 5 parts.

[0044] The mass ratio of the welding core and the coating is 1:0.25;

[0045] The filler comprises calcium carbide and calcium fluoride in a mass ratio of 1:9;

[0046] A preparation method of the welding rod for repairing and surfacing of nodular cast iron sintering trolley, comprising the following steps:

[0047] Mixing the components of the coating uniformly, applying the adhesive on the surface of the welding core, drying, and obtaining the welding rod for repairing and surfacing of nodular cast iron sintering trolley;

[0048] The mass ratio of the coating to the binder is 1:0.2;

[0049] The binder is water glass with a modulus of 2.7-3.0 and a Baume degree of 48-50.

[0050] Example 3

[0051] The welding rod for repairing and surfacing of spheroidal graphite cast iron sintering trolley comprises a H08A welding core and a coating arranged on the surface of the welding core, and 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.

[0052] The mass ratio of the welding core to the coating is 1:0.3.

[0053] The filler comprises calcium carbide and calcium fluoride in a mass ratio of 1:7.

[0054] The preparation method of the welding rod for repairing and surfacing of spheroidal graphite cast iron sintering trolley comprises the following steps:

[0055] The components of the coating are uniformly mixed, the binder is coated on the surface of the welding core, and then drying is performed to obtain the welding rod for repairing and surfacing of spheroidal graphite cast iron sintering trolley.

[0056] The mass ratio of the coating to the binder is 1:0.25.

[0057] The binder is water glass with a modulus of 2.7-3.0 and a Baume degree of 48-50.

[0058] Example 4

[0059] The difference between the present example and example 3 is that the mass ratio of calcium carbide to calcium fluoride in the present example is 4:7.

[0060] Example 5

[0061] The difference between the present example and example 3 is that the mass ratio of calcium carbide to calcium fluoride in the present example is 2:7.

[0062] Example 6

[0063] The difference between the present example and example 3 is that the mass ratio of calcium carbide to calcium fluoride in the present example is 3:7.

[0064] Example 7

[0065] The difference between the present example and example 3 is that molybdenum boride in the present example is replaced by titanium-doped molybdenum boride with the same weight.

[0066] The raw materials of the titanium-doped molybdenum boride material comprise molybdenum boride and titanium powder in a mass ratio of 19:5.

[0067] The preparation method of the titanium-doped molybdenum boride comprises the following steps:

[0068] The molybdenum boride and the titanium powder are uniformly mixed and ball milled to obtain the titanium-doped molybdenum boride.

[0069] During the ball milling, the ball-to-material ratio is 5:1, the rotating speed is 300 rpm, and the time is 20 h.

[0070] Example 8

[0071] The difference between this example and Example 7 is that the raw material of the titanium-doped molybdenum boride in this example comprises molybdenum boride and titanium with a mass ratio of 11:5.

[0072] Example 9

[0073] The difference between this example and Example 7 is that the raw material of the titanium-doped molybdenum boride in this example comprises molybdenum boride and titanium with a mass ratio of 12:5.

[0074] Example 10

[0075] The difference between this example and Example 7 is that the raw material of the titanium-doped molybdenum boride in this example comprises molybdenum boride and titanium with a mass ratio of 18:5.

[0076] Example 11

[0077] The difference between this example and Example 3 is that the molybdenum boride in this example is replaced by titanium-doped molybdenum boride with the same weight;

[0078] The raw material of the titanium-doped molybdenum boride comprises molybdenum boride and titanium powder with a mass ratio of 15:5.

[0079] The preparation method of the titanium-doped molybdenum boride comprises the following steps:

[0080] The molybdenum boride and the titanium powder are uniformly mixed and ball milled to obtain the titanium-doped molybdenum boride.

[0081] During the ball milling, the ball-to-material ratio is 6:1, the rotating speed is 500 rpm, and the time is 17 h.

[0082] Comparative Example 1

[0083] The difference between this comparative example and Example 2 is that the filler in this comparative example is calcium carbide.

[0084] Comparative Example 2

[0085] The difference between this comparative example and Example 2 is that the filler in this comparative example is calcium fluoride.

[0086] Comparative Example 3

[0087] The difference between this comparative example and Example 2 is that this comparative example has no filler.

[0088] Experimental Example 1

[0089] The spheroidal graphite cast iron sintering trolley repair surfacing welding rods prepared from Examples 1-6 and Comparative Examples 1-3 were used to repair the sintering trolley of Shougang Mining Pellet Plant which was cracked and repaired by welding. The rods were dried at 250℃ for 1h before welding, and a direct current welding machine was used for reverse connection with a welding current of 200A. The rods were not preheated before welding and were not heat treated after welding. The Vickers hardness of the samples was tested according to the single-point testing method specified in GB / T 2654-2008 "Hardness Test Method for Welded Joints".

[0090] Table 1 Hardness test results

[0091]

[0092] Compared with Comparative Examples 1-3, the hardness of Example 2 is improved, indicating that the synergistic effect of calcium carbide and calcium fluoride improves the hardness of the surfacing layer.

[0093] Compared with Examples 3-4, the hardness of Examples 5-6 is higher, indicating that when the mass ratio of calcium carbide to calcium fluoride is 2-3:7, the hardness of the surfacing layer is further improved.

[0094] Experimental Example 2

[0095] The spheroidal graphite cast iron sintering trolley repair surfacing welding rods prepared from Examples 3, 7-11 were used to repair the sintering trolley of Shougang Mining Pellet Plant which was cracked and repaired by welding. The rods were dried at 250℃ for 1h before welding, and a direct current welding machine was used for reverse connection with a welding current of 200A. The rods were not preheated before welding and were not heat treated after welding. The surfacing layer was made into a cylinder with a diameter of 32mm and a thickness of 10mm, and tested on a MMW-1A vertical universal friction and wear testing machine. The wear time was 10min, and the weight loss was measured by the difference in mass before and after wear. The test results are shown in Table 2.

[0096] Table 2 Wear loss test results

[0097]

[0098] Compared with Example 3, Examples 7-11 have less wear loss, indicating that the addition of titanium to the molybdenum boride improves the wear resistance of the surfacing layer. Compared with Examples 7-8, Examples 9-10 have less wear loss, indicating that when the mass ratio of molybdenum boride to titanium powder is 5:12-18, the wear resistance of the surfacing layer is further improved.

[0099] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A welding rod for repairing sintered dolly of ductile cast iron, characterized by, The welding core and the coating arranged on the surface of the welding core, the raw material of the coating comprises the following components 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, 5-10 parts of titanium-doped molybdenum boride; The filler comprises calcium carbide and calcium fluoride; The mass ratio of the calcium carbide to the calcium fluoride is (2-3):7; The welding core is H08A welding core; The raw material of the titanium-doped molybdenum boride comprises molybdenum boride and titanium powder; The mass ratio of the molybdenum boride to the titanium powder is (12-18):

5.

2. The welding rod for repairing sintered jigger according to claim 1, wherein The preparation method of the titanium-doped molybdenum boride comprises the following steps: Mixing the molybdenum boride and the titanium powder uniformly, ball milling to obtain the titanium-doped molybdenum boride; When the ball milling is performed, the ball-to-material ratio is (5-6):1, the rotating speed is 300-500 rpm, and the time is 17-20 h.

3. The welding rod for repairing sintered jigger according to claim 1, wherein The rare earth oxide comprises one or more of yttrium oxide, lanthanum oxide and cerium oxide.

4. The method for preparing the welding rod for repairing and surfacing of spherulitic cast iron sintering trolley according to any one of claims 1-3, characterized in that, The method comprises the following steps: Mixing the components of the coating uniformly, coating the adhesive on the surface of the welding core, drying to obtain the welding rod for repairing and surfacing of nodular cast iron sintering trolley.

5. The method of producing an electrode for repairing a sinter pallet of nodular cast iron according to claim 4, characterized in that, The adhesive comprises water glass.

6. A method of manufacturing an electrode for repairing a sinter pallet of nodular cast iron according to claim 5, characterized in that, The modulus of the water glass is 2.7-3.0, and the Baume degree is 48-50.

Images