Welding electrode and preparation method thereof

Abstract

The invention relates to an electric welding rod. A core wire comprises the following chemical components in percentage by weight: less than or equal to 0.07% of C; mn < = 0.65%; less than or equal to 0.03% of Si; less than or equal to 0.015% of S; less than or equal to 0.020% of P; the powder components in the coating comprise the following components in percentage by weight: 3-15% of rutile; 40-55% of reduced ilmenite; 3-9% of wood flour; 2-9% of marble; 8-15% of mica; 12 to 18% of feldspar; 4-9% of medium carbon ferromanganese; and 4-13% of attapulgite. The invention also provides a preparation method of the welding electrode, which comprises the following steps: selecting a core wire rod according to the chemical components of the core wire and the weight percentage of the core wire, and drawing the core wire rod into the core wire with the required production specification; and then the prepared coating powder is pressed and coated on the surface of the core wire, then baking forming is conducted, and the electric welding rod is obtained. By adjusting the chemical components of the welding core of the welding electrode and the formula of the coating powder, the welding performance and the welding quality of the welding electrode are improved, and the welding cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of welding materials, in particular to an electric welding rod and a preparation method thereof. Background Art

[0002] Electric welding rods have played an extremely critical role in the process of industrial development. The earliest metal welding was completed entirely by electric welding rods. Although now, due to the emergence of new welding materials such as gas shielded solid welding wire, submerged arc welding wire, and flux-cored welding wire, electric welding rods account for only about 40% of welding materials, but electric welding rods are still an excellent welding material that cannot be ignored in the field of welding because of their advantages such as easy operation, beautiful shape, less spatter, and convenient transition of alloy elements. They are widely used in the welding of products in industries such as shipbuilding, steel structures, locomotives and vehicles, marine engineering, construction, and oil pipelines.

[0003] Among the welding rod product categories, the national standard model J421 welding rod is a widely used rutile welding rod, which is equivalent to the American AWS standard E6013 welding rod. This welding rod belongs to the titanium calcium type coating low carbon structural steel, acid welding rod, AC and DC dual-purpose. It is suitable for all-position welding, good operating performance, easy to re-strike, especially suitable for intermittent welding of thin plates and small pieces and short welding and cover welding requiring smooth surface.

[0004] Ordinary J421 welding rods have been produced in China for decades. The arc stabilizing and slag-forming agents in the J421 formulas of various welding material companies are all rutile. Since rutile is basically not produced in China, the main sources of rutile are in Australia, Africa and other places, and procurement needs to be imported. Procurement is not only very inconvenient, but also the price of rutile fluctuates greatly, causing large fluctuations in the production costs of enterprises, affecting the competitiveness of enterprises. In addition, the large amount of natural rutile used in the formula has an adverse impact on resources and the environment. In addition, due to the uneven quality of materials used by various companies, especially the quality of welding cores cannot be guaranteed, the welding rods need to use a relatively large current to ensure welding performance during the welding process. These problems are a waste of resources and energy, and will also affect the welding quality. To this end, we hope to develop a welding rod product with low production cost, better welding performance and low welding cost. Summary of the invention

[0005] The purpose of the present invention is to provide a welding rod and a preparation method thereof, which improves the welding performance and welding quality of the welding rod and reduces the welding cost.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The first aspect of the present invention provides an electric welding rod, comprising a welding core and a coating wrapped on the surface of the welding core, wherein the chemical composition of the welding core is as follows by weight percentage: C≤0.07%; Mn≤0.65%; Si≤0.03%; S≤0.015%; P≤0.020%; the remainder is Te element; The powder components in the medicine coating are calculated by weight percentage: Rutile 3~15%; reduced ilmenite 40~55%; wood powder 3~9%; marble 2~9%; mica 8~15%; feldspar 12~18%; medium carbon ferromanganese 4~9%; attapulgite 4~13%.

[0007] Furthermore, the rutile content is 87%.

[0008] A second aspect of the present invention provides a method for preparing a welding rod, comprising the following steps: S1: Select the welding core wire rod according to the chemical composition and weight percentage of the welding core, compress and draw the welding core wire rod into the required specifications by using a roller die and a coating die, and then cut the welding core wire rod into welding cores of required length by a high-speed wire cutter, preheat the cut welding core for 1 to 1.5 hours, and slowly cool it to below 30°C before taking it out; S2: selecting various raw materials according to the powder components of the coating and their weight percentages, crushing and screening them, and mixing them evenly to obtain a coating mixed powder; S3: adding 8% to 10% of the total weight of water glass to the mixed powder of the coating in step S2, stirring evenly for 50 to 60 minutes to form a mass, and placing the mass in a press coater and the welding core which has been slowly cooled to below 30° C. in step S1 to form a mass; S4: After the welding rod is formed, it is baked to obtain the welding rod.

[0009] Furthermore, the water glass is sodium water glass, potassium water glass or potassium-sodium water glass.

[0010] Furthermore, the Baume concentrations of the sodium water glass, the potassium water glass and the potassium-sodium water glass are 39-42˚Bé.

[0011] Furthermore, in step S4, the baking time is 35 minutes.

[0012] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: (1) The present invention adjusts the chemical composition of the welding core of the welding rod to reduce the content of harmful substances such as S and P in the welding core, improve the fluidity of the molten iron in the molten pool, and reduce welding spatter; (2) By adjusting the formula of the coating powder, the amount of reduced ilmenite in the welding rod formula was increased, the amount of rutile was reduced, and the dependence on imported natural rutile was reduced, which significantly reduced the production cost of the welding rod. At the same time, the amount of natural rutile used was saved, and the degree of dependence on it and the damage to the environment were reduced; (3) By adjusting the coating powder formula and welding core, the welding rod can also strike an arc well under lower current and voltage conditions. DETAILED DESCRIPTION

[0013] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0014] The present invention provides an electric welding rod and a preparation method thereof. Specifically, the electric welding rod comprises a welding core and a coating covering the surface of the welding core.

[0015] The chemical composition of the above welding core is as follows by weight percentage: C≤0.07%; Mn≤0.65%; Si≤0.03%; S≤0.015%; P≤0.020%; the balance is Te element; and the powder components in the coating are as follows by weight percentage: rutile 3~15%; reduced ilmenite 40~55%; wood powder 3~9%; marble 2~9%; mica 8~15%; feldspar 12~18%; medium carbon ferromanganese 4~9%; attapulgite 4~13%.

[0016] In the embodiment of the present invention, the content of rutile used is 87%, which replaces the 92% rutile used in the prior art, and the amount of rutile used is reduced from 40-50% in the prior art to 3-15%, and the reduced rutile is replaced by reduced ilmenite, which significantly reduces the production cost of the welding rod.

[0017] In the embodiment of the present invention, the chemical composition of the welding core is adjusted simultaneously, and harmful elements such as S and P are clearly defined, so that the quality of the welding core of the welding rod is significantly improved.

[0018] The preparation method of the welding electrode specifically comprises the following steps: (1) Select the welding core wire rod according to the chemical composition and weight percentage of the welding core, compress and draw the welding core wire rod into the required specifications by using a roller die and a coating die, and then cut the welding core wire rod into welding cores of the required length by a high-speed wire cutter, preheat the cut welding core for 1 to 1.5 hours, and slowly cool it to below 30°C before taking it out; (2) The required powder is selected according to the powder components and weight percentages of the coating, and the raw materials are crushed and sieved. Then, the powder is prepared using an automatic powder mixing line, and the prepared powder is sent to a powder mixer for mixing. Then, 8% to 10% of the total weight of the mixed powder of the coating is added with water glass, and the mixing is continued for 50 to 60 minutes; (3) feeding the stirred powder into a coating machine and coating the weld core which has been slowly cooled to below 30°C in step S1; (4) The coated welding rod is sent to the baking oven through a conveyor belt for baking. Different specifications are baked at different temperatures, and the baking time is 35 minutes; (5) The baked welding rods are sent to the fully automatic packaging machine through a conveyor belt, automatically weighed and packaged, and the packaged welding rods are sent to the robot for automatic pallet packaging.

[0019] The present invention will be further described below by means of specific embodiments: Embodiment 1 S1 welding core selection The chemical components of the welding core are calculated by weight percentage: C: 0.07%; Mn: 0.65%; Si: 0.03%; S: 0.015%; P: 0.020%, the balance is Te. The welding core is preheated at 150℃ for 1h and slowly cooled to 30℃; S2 coating selection The powder components of the selected medicine coating are as follows by weight percentage: Rutile 3%; Reduced ilmenite 40%; Wood powder 3%; Marble 2%; Mica 8%; Feldspar 12%; Medium carbon ferromanganese 4%; Attapulgite 4%; S3 Forming Add 10% water glass by weight to all the coating powders and stir evenly for 50 minutes, knead into a ball, put into a pressure powder coating molding machine and extrude into the welding core which is slowly cooled to 30°C in step S1; S4 Drying After the welding rod is formed, it is naturally dried at 20°C for 24 hours, baked at 330°C for 30 minutes and then taken out to obtain the welding rod.

[0020] Embodiment 2 S1 welding core selection The chemical components of the welding core are calculated by weight percentage: C: 0.07%; Mn: 0.65%; Si: 0.03%; S: 0.015%; P: 0.020%, the balance is Te. The welding core is preheated at 150°C for 1 hour and slowly cooled to 30°C; S2 coating selection The powder components of the selected medicine coating are as follows by weight percentage: Rutile 15%; Reduced ilmenite 55%; Wood powder 9%; Marble 9%; Mica 15%; Feldspar 18%; Medium carbon ferromanganese 9%; Attapulgite 13%; S3 Forming Add 10% water glass by weight to all the coating powders and stir evenly for 50 minutes, knead into a ball, put into a pressure powder coating molding machine and extrude into the welding core which is slowly cooled to 30°C in step S1; S4 Drying After the welding rod is formed, it is naturally dried at 20°C for 24 hours, baked at 330°C for 30 minutes and then taken out to obtain the welding rod.

[0021] Embodiment 3 S1 welding core selection The chemical components of the welding core are calculated by weight percentage: C: 0.07%; Mn: 0.65%; Si: 0.03%; S: 0.015%; P: 0.020%, the balance is Te. The welding core is preheated at 150°C for 1 hour and slowly cooled to 30°C; S2 coating selection The powder components of the selected medicine coating are as follows by weight percentage: Rutile 9%; Reduced ilmenite 48%; Wood powder 6%; Marble 6%; Mica 12%; Feldspar 15%; Medium carbon ferromanganese 7%; Attapulgite 9%; S3 Forming Add 10% water glass by weight to all the coating powders and stir evenly for 50 minutes, knead into a ball, put into a pressure powder coating molding machine and extrude into the welding core which is slowly cooled to 30°C in step S1; S4 Drying After the welding rod is formed, it is naturally dried at 20°C for 24 hours, baked at 330°C for 30 minutes and then taken out to obtain the welding rod.

[0022] Embodiment 4 S1 welding core selection The chemical components of the welding core are calculated by weight percentage: C: 0.04%; Mn: 0.5%; Si: 0.02%; S: 0.012%; P: 0.015%, the balance is Te. The welding core is preheated at 150°C for 1 hour and slowly cooled to 30°C; S2 coating selection The powder components of the selected medicine coating are as follows by weight percentage: Rutile 9%; Reduced ilmenite 48%; Wood powder 6%; Marble 6%; Mica 12%; Feldspar 15%; Medium carbon ferromanganese 7%; Attapulgite 9%; S3 Forming Add 10% water glass by weight to all the coating powders and stir evenly for 50 minutes, knead into a ball, put into a pressure powder coating molding machine and extrude into the welding core which is slowly cooled to 30°C in step S1; S4 Drying After the welding rod is formed, it is naturally dried at 20°C for 24 hours, baked at 330°C for 30 minutes and then taken out to obtain the welding rod.

[0023] Embodiment 5 S1 welding core selection The chemical components of the welding core are calculated by weight percentage: C: 0.02%; Mn: 0.4%; Si: 0.01%; S: 0.01%; P: 0.01%, the balance is Te element. The welding core is preheated at 150℃ for 1h and slowly cooled to 30℃; S2 coating selection The powder components of the selected medicine coating are as follows by weight percentage: Rutile 9%; Reduced ilmenite 48%; Wood powder 6%; Marble 6%; Mica 12%; Feldspar 15%; Medium carbon ferromanganese 7%; Attapulgite 9%; S3 Forming Add 10% water glass by weight to all the coating powders and stir evenly for 50 minutes, knead into a ball, put into a pressure powder coating molding machine and extrude into the welding core which is slowly cooled to 30°C in step S1; S4 Drying After the welding rod is formed, it is naturally dried at 20°C for 24 hours, baked at 330°C for 30 minutes and then taken out to obtain the welding rod.

[0024] Comparative Example 1 S1 welding core selection The chemical components of the welding core are calculated by weight percentage: C: 0.1%; Mn: 0.8%; Si: 0.05%; S: 0.03%; P: 0.03%, the balance is Te. The welding core is preheated at 150°C for 1 hour and slowly cooled to 30°C; S2 coating selection The powder components of the selected medicine coating are as follows by weight percentage: Rutile 9%; Reduced ilmenite 48%; Wood powder 6%; Marble 6%; Mica 12%; Feldspar 15%; Medium carbon ferromanganese 7%; Attapulgite 9%; S3 Forming Add 10% water glass by weight to all the coating powders and stir evenly for 50 minutes, knead into a ball, put into a pressure powder coating molding machine and extrude into the welding core which is slowly cooled to 30°C in step S1; S4 Drying After the welding rod is formed, it is naturally dried at 20°C for 24 hours, baked at 330°C for 30 minutes and then taken out to obtain the welding rod.

[0025] Comparative Example 2 S1 welding core selection The chemical components of the welding core are calculated by weight percentage: C: 0.07%; Mn: 0.65%; Si: 0.03%; S: 0.015%; P: 0.020%, the balance is Te. The welding core is preheated at 150°C for 1 hour and slowly cooled to 30°C; S2 coating selection The powder components of the selected medicine coating are as follows by weight percentage: Rutile 20%; Reduced ilmenite 35%; Wood flour 15%; Marble 15%; Mica 20%; Feldspar 10%; Medium carbon ferromanganese 12%; Attapulgite 16%; S3 Forming Add 10% water glass by weight to all the coating powders and stir evenly for 50 minutes, knead into a ball, put into a pressure powder coating molding machine and extrude into the welding core which is slowly cooled to 30°C in step S1; S4 Drying After the welding rod is formed, it is naturally dried at 20°C for 24 hours, baked at 330°C for 30 minutes and then taken out to obtain the welding rod.

[0026] In the present invention, corresponding performance tests are performed on the above embodiments and comparative examples, and the specific test results are shown in the following table: Table 1 Performance test data of the welding electrodes prepared in Example 1 to Example 5 and Comparative Example 1 to Comparative Example 2 In summary, the present invention adjusts the chemical composition of the welding core of the welding rod, thereby reducing the content of harmful substances such as S and P in the welding core, improving the fluidity of the molten iron in the molten pool, and reducing welding spatter. Simultaneously, by adjusting the composition of the coating powder accordingly, the amount of reduced ilmenite used in the welding rod formula is increased, the amount of rutile used is reduced, the dependence on imported natural rutile is reduced, and the production cost of the welding rod is significantly reduced. At the same time, the amount of natural rutile used is saved, and the degree of dependence on it and damage to the environment are reduced. The welding rod prepared by the preparation method provided in the present invention can also perform good arc initiation under lower current and voltage conditions, and the corresponding welding current is lower than the current in the prior art.

[0027] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A welding rod, comprising a welding core and a coating covering the surface of the welding core, characterized in that: The chemical composition of the welding core is calculated by weight percentage as follows: C≤0.07%; Mn≤0.65%; Si≤0.03%; S≤0.015%; P≤0.020%; the remainder is Te element; The powder components in the medicine coating are calculated by weight percentage: Rutile 3~15%; reduced ilmenite 40~55%; wood powder 3~9%; marble 2~9%; mica 8~15%; feldspar 12~18%; medium carbon ferromanganese 4~9%; attapulgite 4~13%.

2. A welding rod according to claim 1, characterized in that: The rutile content is 87%.

3. The method for preparing a welding electrode according to claim 1, characterized in that: The following steps are involved: S1: Select the welding core wire rod according to the chemical composition and weight percentage of the welding core, compress and draw the welding core wire rod into the required specifications by using a roller die and a coating die, and then cut the welding core wire rod into welding cores of required length by a high-speed wire cutter, preheat the cut welding core for 1 to 1.5 hours, and slowly cool it to below 30°C before taking it out; S2: According to the powder components of the coating and their weight percentages, various raw materials are selected, crushed and sieved, and mixed evenly to obtain a coating mixed powder; S3: adding 8% to 10% of the total weight of water glass to the mixed powder of the coating in step S2, stirring evenly for 50 to 60 minutes to form a mass, and placing the mass in a press coater and the welding core which has been slowly cooled to below 30° C. in step S1 to form a mass; S4: After the welding rod is formed, it is baked to obtain the welding rod.

4. The method for preparing a welding rod according to claim 3, characterized in that: In step S3, the water glass is sodium water glass, potassium water glass or potassium sodium water glass.

5. The method for preparing a welding rod according to claim 4, characterized in that: The Baume concentrations of the sodium water glass, the potassium water glass and the potassium sodium water glass are 39-42˚Bé.

6. The method for preparing a welding rod according to claim 3, characterized in that: In step S4, the baking time is 35 minutes.

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