Stainless steel electrode and its use and welding method

Abstract

The application provides a stainless steel electrode and application and welding mode thereof, and particularly relates to the field of welding materials. The stainless steel electrode comprises a steel core and a coating, the coating is coated on the outer surface of the steel core, and the coating comprises the following components and the weight fractions of the components are as follows: 10-15 parts of metallic chromium, 13-18 parts of micro-carbon chromium iron, 1-5 parts of titanium concentrate, 20-30 parts of rutile, 4-8 parts of fluoride, 5-10 parts of feldspar, 1-5 parts of fluorite, 3-8 parts of marble, 1-5 parts of potassium titanate, 1-5 parts of metallic manganese, 8-13 parts of mica, 0.1-0.5 parts of bismuth oxide, 0.1-1 parts of zirconium sand, 0.1-1 parts of carboxymethyl cellulose and 20-25 parts of water glass. The stainless steel electrode has the characteristics of good welding process, high strength, excellent corrosion resistance and crack resistance, and is suitable for the welding of high-carbon steel, tool steel, high-temperature steel and dissimilar steel.

Description

Technical Field

[0001] This invention relates to the field of welding materials, specifically to a stainless steel welding electrode and its uses and welding methods. Background Technology

[0002] With the rapid development of modern industrial technology, the requirements for structures and equipment are constantly increasing, leading to a proliferation of specialized metallic materials, such as high-strength steel, spring steel, forged steel, high-alloy steel, and tool steel, which are being used more and more widely. These special-purpose metallic materials are generally characterized by a wide variety, high performance requirements, and poor weldability. Therefore, the development of corresponding welding materials is quite difficult, and mass production is not feasible, making it hard to achieve good economic benefits. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the present invention provides a stainless steel welding electrode to improve the problems of difficulty in developing welding materials for special metal materials and difficulty in mass production.

[0004] To achieve the above and other related objectives, the present invention provides a stainless steel welding electrode, comprising a steel core and a coating, wherein the coating covers the outer surface of the steel core, and the coating comprises the following components and the following weight parts of each component: 10-15 parts of metallic chromium, 13-18 parts of micro-carbon ferrochrome, 1-5 parts of titanium concentrate, 20-30 parts of rutile, 4-8 parts of fluoride, 5-10 parts of feldspar, 1-5 parts of fluorite, 3-8 parts of marble, 1-5 parts of potassium titanate, 1-5 parts of metallic manganese, 8-13 parts of mica, 0.1-0.5 parts of bismuth oxide, 0.1-1 part of zircon sand, 0.1-1 part of carboxymethyl cellulose, and 20-25 parts of water glass.

[0005] In one example of the present invention, the metallic chromium contains ≥99 wt% chromium; the micro-carbon ferrochrome contains ≥70 wt% Cr and ≤0.06 wt% carbon; the titanium concentrate contains ≥55 wt% TiO2; the rutile contains ≥85 wt% TiO2; the feldspar contains 63–73 wt% SiO2 and 15–22 wt% Al2O3; the fluorite contains ≥95 wt% CaF2; the marble contains ≥96 wt% CaCO3; the potassium titanate contains ≥65 wt% TiO2; the metallic manganese contains ≥99.80 wt% Mn; the mica contains 44–52 wt% SiO2; the bismuth oxide contains ≥95 wt% Bi2O3; and the zircon sand contains ≥66 wt% ZrO2.

[0006] In one example of the present invention, the steel core is made of Cr. 26 Ni9 steel core, the diameter of which is 6.5mm.

[0007] In one example of the present invention, the weight of the coating is 40-45% of the total weight of the stainless steel welding electrode.

[0008] In one example of the present invention, the water glass used in the welding electrode is a 1:1 potassium-sodium water glass.

[0009] In one example of the present invention, the diameter of the stainless steel welding rod is 2.5 mm to 4.0 mm.

[0010] In one example of the present invention, the chemical composition of the weld metal deposited by the stainless steel welding electrode is: C≤0.15wt%, Mn0.5~2.5wt%, Si≤1.00wt%, P≤0.004wt%, S≤0.003wt%, Cr 28.0~32.0wt%, Ni 8.0~10.05wt%, Mo≤0.75wt%, Cu≤0.75wt%.

[0011] In one example of the present invention, the mechanical properties of the stainless steel welding electrode deposited metal are: tensile strength ≥660MPa, elongation after fracture ≥15%.

[0012] The present invention also provides an application of stainless steel welding rods, which are used for welding high carbon steel, tool steel, high temperature steel, armor steel, and dissimilar steels.

[0013] The present invention also provides a welding method for stainless steel welding rods, wherein the stainless steel welding rods are AC or DC reverse polarity, and the welding position is all-position.

[0014] The stainless steel welding electrode provided by this invention is a titanium-calcium type coated duplex stainless steel welding electrode. The deposited metal has a ferrite-austenite duplex structure, with a ferrite content as high as about 50%. The coefficient of thermal expansion of the stainless steel welding electrode is between that of carbon steel and austenitic steel. When used for dissimilar steel welds, it has a high absorption capacity for both iron and carbon, and will not form a pure austenitic or martensitic weld structure. Therefore, it has good crack resistance, excellent welding process, and is suitable for welding high-carbon steel, tool steel, high-temperature steel, dissimilar steel, etc. Detailed Implementation

[0015] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0016] Please note that in this instruction manual, "wt%" represents weight percentage and "parts" represents weight parts.

[0017] This invention provides a stainless steel welding electrode comprising a steel core and a flux coating. The flux coating covers the outer surface of the steel core and comprises the following components in the following weight proportions: 10-15 parts metallic chromium, 13-18 parts micro-carbon ferrochrome, 1-5 parts titanium concentrate, 20-30 parts rutile, 4-8 parts fluoride, 5-10 parts feldspar, 1-5 parts fluorite, 3-8 parts marble, 1-5 parts potassium titanate, 1-5 parts metallic manganese, 8-13 parts mica, 0.1-0.5 parts bismuth oxide, 0.1-1 parts zircon sand, 0.1-1 parts carboxymethyl cellulose (CMC), and 20-25 parts water glass. The coefficient of thermal expansion of this stainless steel welding electrode is between that of carbon steel and austenitic steel. When used for dissimilar steel welds, it exhibits high absorption capacity for both iron and carbon, preventing the formation of pure austenitic or martensitic weld structures. Therefore, it possesses excellent crack resistance and superior welding performance.

[0018] The functions of each component in the coating of stainless steel welding electrodes are as follows:

[0019] Metallic chromium: Chromium is introduced into the weld to improve the strength and corrosion resistance of the deposited metal. However, if the chromium content in the electrode is too high, the toughness of the deposited metal will decrease significantly. Therefore, the weight percentage of metallic chromium in this invention is 10 to 15 parts. For example, the weight percentage of metallic chromium can be any value within the range of 10 parts, 13 parts, or 15 parts.

[0020] Micro-carbon ferrochrome: This material introduces chromium into the weld, acting as an alloying agent and providing corrosion and oxidation protection. Simultaneously, the carbon content helps refine the molten droplets. In this invention, the weight percentage of micro-carbon ferrochrome is 13–18 parts. For example, the weight percentage of micro-carbon ferrochrome can be any value within the range of 13, 15, or 18 parts.

[0021] Titanium concentrate: It can refine molten droplets, promote fine and bright weld formation, and facilitate slag removal; however, excessive titanium concentrate is detrimental to directional welding, easily causing porosity and spatter. Therefore, the weight percentage of titanium concentrate in this invention is 1 to 5 parts, for example, any value within the above range such as 1 part, 3 parts, or 5 parts.

[0022] Rutile: It plays a role in stabilizing the arc and forming slag, regulating the fluidity of the molten slag, improving weld formation, and reducing spatter. In this invention, the weight percentage of rutile is 20 to 30 parts, for example, any value within the range of 20, 24, 26, or 30 parts by weight.

[0023] Feldspar: It has the functions of stabilizing the arc and refining the grains, and increases the fluidity of the slag. In this invention, the weight part of feldspar is 5 to 10 parts, for example, any value within the above range such as 5 parts, 8 parts, or 10 parts by weight of feldspar.

[0024] Fluorides: They dilute welding slag, enhance its fluidity, and facilitate the escape of gas from the weld; they also enhance the stability of the electric arc. In this invention, the weight percentage of fluoride is 4 to 8 parts, for example, any value within the range of 4, 6, or 8 parts by weight.

[0025] Fluorite: Its main component is CaF2, which acts as a slag-forming agent. It can reduce the hydrogen content in the weld and improve the physical properties of the slag, as well as its viscosity and solidification rate. However, excessive fluorite can reduce arc stability. Therefore, the weight percentage of fluorite in this invention is 1 to 5 parts. For example, the weight percentage of fluorite can be any value within the above range, such as 1 part, 3 parts, or 5 parts.

[0026] Marble: Its main component is calcium carbonate, which acts as a slag-forming and gas-generating agent, and also plays a role in stabilizing the arc and desulfurizing. However, excessive marble content can lead to rough weld formation and porosity within the weld. Therefore, the marble content in the coating of this invention is 3 to 8 parts by weight. For example, the marble content can be any value within the above range, such as 3 parts, 5 parts, or 8 parts by weight.

[0027] Potassium titanate: Primarily enhances the stability of the electric arc. The potassium titanate in the coating of this invention comprises 1 to 5 parts by weight. For example, the potassium titanate may be 1 part, 2 parts, 3 parts, or 5 parts by weight, or any value within the above range.

[0028] Metallic manganese: It functions as a deoxidizer, desulfurizer, and alloyer, and provides solid solution strengthening to the weld. The coating of this invention contains 1 to 5 parts by weight of metallic manganese. For example, the weight of metallic manganese can be any value within the range of 1, 2, 4, or 5 parts.

[0029] Mica: It can increase the elasticity and plasticity of the electrode coating, improve the electrode coating performance, and also reduce the sensitivity of the porosity surface, acting as a slag-forming agent. The weight part of mica in the coating of this invention is 8 to 13 parts. For example, the weight part of mica is any value within the above range, such as 8 parts, 10 parts, 11 parts, or 13 parts.

[0030] Bismuth oxide: Improves the slag removal properties of weld metal. The coating of this invention contains 0.1 to 0.5 parts by weight of bismuth oxide. For example, the weight of bismuth oxide can be any value within the above range, such as 0.1, 0.2, 0.3, or 0.5 parts.

[0031] Zircon sand: can increase the corrosion resistance of the welded surface. The zircon sand in the coating of this invention is 0.1 to 1 part by weight. For example, the zircon sand is any value within the above range, such as 0.1 parts, 0.4 parts, 0.7 parts, or 1 part by weight.

[0032] Carboxymethyl cellulose: It can improve the pressure coating performance of welding electrodes, resulting in stable pressure, non-eccentricity, smooth surface, and good grinding head and tail properties; its thermal decomposition properties can improve arc blowing force and arc ignition performance. The weight percentage of carboxymethyl cellulose in the coating of this invention is 0.1 to 1 part. For example, the weight percentage of carboxymethyl cellulose can be any value within the above range, such as 0.1 part, 0.5 part, 0.7 part, or 1 part.

[0033] Water glass acts as a binder, firmly adhering the coating to the steel core, thus giving the dried stainless steel welding electrode coating a certain strength and preventing any harmful effects on the molten pool and weld metal during the welding process. In this invention, the weight fraction of water glass in the coating is 20-25 parts; for example, the weight fraction of water glass can be any value within the range of 20, 23, or 25 parts. In one embodiment, a 1:1 potassium-sodium water glass is used.

[0034] In one embodiment, the chromium content in metallic chromium is ≥99 wt%; the Cr content in micro-carbon ferrochrome is ≥70 wt% and the carbon content is ≤0.06 wt%; the TiO2 content in titanium concentrate is ≥55 wt%; the TiO2 content in rutile is ≥85 wt%; the SiO2 content in feldspar is 63–73 wt% and the Al2O3 content is 15–22 wt%; the CaF2 content in fluorite is ≥95 wt%; the CaCO3 content in marble is ≥96 wt%; the TiO2 content in potassium titanate is ≥65 wt%; the Mn content in metallic manganese is ≥99.80 wt%; the SiO2 content in mica is 44–52 wt%; the Bi2O3 content in bismuth oxide is ≥95 wt%; and the ZrO2 content in zircon sand is ≥66 wt%.

[0035] In this invention, the steel core can be made of materials commonly used in the art. In one embodiment, the steel core is made of Cr. 26Ni9 steel core. In other embodiments, steel cores of other materials may be selected according to the requirements of the stainless steel welding rod.

[0036] In this invention, the steel core is selected from conventional sizes in the art. In one embodiment, the diameter of the steel core is 6.5 mm. In other embodiments, steel cores of other sizes can be selected according to the required size of the stainless steel welding rod. The stainless steel welding rod in this invention is obtained using conventional techniques in the art: powder is mixed evenly according to the above proportions, water glass is added to the powder and stirred evenly to form a flux mixture, the flux mixture is evenly pressed onto the surface of the steel core, and after drying, a stainless steel welding rod is obtained. The weight of the flux in the obtained stainless steel welding rod is 40-45% of the total weight of the stainless steel welding rod, for example, 40%, 43%, or 45%. Before use, the steel core needs to be drawn, and the diameter of the steel core after drawing is adjusted according to the usage requirements. The diameter of the stainless steel welding rod obtained by this invention is 2.5 mm to 4.0 mm. For example, the diameter of the stainless steel welding rod can be any value within the above range, such as 2.5 mm, 3.0 mm, 3.5 mm, or 4.0 mm. The diameter of the stainless steel welding rod is the diameter of the steel core after drawing.

[0037] In one embodiment, the chemical composition of the weld metal deposited by the stainless steel welding electrode is: C≤0.15wt%, Mn0.5~2.5wt%, Si≤1.00wt%, P≤0.004wt%, S≤0.003wt%, Cr28.0~32.0wt%, Ni8.0~10.05wt%, Mo≤0.75wt%, Cu≤0.75wt%.

[0038] In one embodiment, the mechanical properties of the weld metal deposited by the stainless steel welding electrode are: tensile strength ≥660MPa, elongation after fracture ≥15%.

[0039] The present invention also provides applications for stainless steel welding electrodes. Because the stainless steel welding electrodes of the present invention have the characteristics of good welding processability, high strength, corrosion resistance and excellent crack resistance, they are suitable for welding high carbon steel, tool steel, high temperature steel, dissimilar steel and the like.

[0040] This invention also provides a welding method for stainless steel welding electrodes. When welding with stainless steel electrodes, AC or DC reverse polarity is used, and the welding position is all-position. When using AC welding, the polarity of the arc welding machine alternates. When using DC arc welding, there is the issue of positive and reverse polarity connection. DC reverse polarity means that the workpiece is connected to the negative terminal of the power supply, and the stainless steel welding electrode is connected to the positive terminal. Using DC reverse polarity results in a relatively stable arc. All-position welding refers to a technique that can be performed in all positions, including horizontal, flat, and ceiling positions. All-position welding produces high-quality welds, ensuring strong and dense weld points, and is suitable for welding various materials, including steel, iron, copper, aluminum, and zinc.

[0041] The technical solution of the present invention will be described in detail below through several specific embodiments. Unless otherwise stated, the raw materials and reagents used in the following embodiments are all commercially available products, or can be prepared by conventional methods in the art, and the instruments used in the embodiments are all commercially available.

[0042] Example 1

[0043] In this embodiment, the coating of the stainless steel welding electrode comprises the following components by weight: 10 parts metallic chromium, 18 parts micro-carbon ferrochrome, 1 part titanium concentrate, 30 parts rutile, 8 parts fluoride, 5 parts feldspar, 3 parts fluorite, 8 parts marble, 5 parts potassium titanate, 1 part metallic manganese, 8 parts mica, 0.5 parts bismuth oxide, 1 part zircon sand, 0.5 parts carboxymethyl cellulose, and 25 parts water glass. The water glass is added to the powder and stirred evenly before being uniformly coated onto the Cr... 26 The surface of the Ni9 steel core is dried to obtain a stainless steel welding rod with a diameter of 4.0 mm.

[0044] Example 2

[0045] In this embodiment, the coating of the stainless steel welding electrode comprises the following components by weight: 13 parts metallic chromium, 16 parts micro-carbon ferrochrome, 3 parts titanium concentrate, 25 parts rutile, 6 parts fluoride, 8 parts feldspar, 1 part fluorite, 5 parts marble, 3 parts potassium titanate, 3 parts metallic manganese, 10 parts mica, 0.1 parts bismuth oxide, 0.5 parts zircon sand, 0.1 parts carboxymethyl cellulose, and 22 parts water glass. The water glass is added to the powder and stirred evenly before being uniformly coated onto the Cr... 26 The surface of the Ni9 steel core is dried to obtain a stainless steel welding rod with a diameter of 3.2 mm.

[0046] Example 3

[0047] In this embodiment, the coating of the stainless steel welding electrode comprises the following components by weight: 15 parts metallic chromium, 13 parts micro-carbon ferrochrome, 5 parts titanium concentrate, 20 parts rutile, 4 parts fluoride, 10 parts feldspar, 5 parts fluorite, 3 parts marble, 1 part potassium titanate, 5 parts metallic manganese, 13 parts mica, 0.3 parts bismuth oxide, 0.1 parts zircon sand, 1 part carboxymethyl cellulose, and 20 parts water glass. The water glass is added to the powder and stirred evenly before being uniformly coated onto the Cr... 26 The surface of the Ni9 steel core is dried to obtain a stainless steel welding rod with a diameter of 2.5 mm.

[0048] The content of each component in the coating of the stainless steel welding electrodes in Examples 1-3 is shown in Table 1. The welding performance of the stainless steel welding electrodes in Examples 1-3 was tested according to relevant standards and specifications. The welding conditions and welding processability of the stainless steel welding electrodes are shown in Table 2, the chemical composition of the deposited metal is shown in Table 3, and the properties of the deposited metal are shown in Table 4.

[0049] Table 1: Content of coating components in stainless steel welding electrodes from Examples 1-3

[0050]

[0051]

[0052] Table 2: Welding process performance of stainless steel welding electrodes in Examples 1-3

[0053]

[0054] Table 3: Chemical composition of stainless steel welding electrode deposited metal in Examples 1-3

[0055]

[0056] Table 4: Properties of weld metal deposited from stainless steel welding electrodes in Examples 1-3

[0057]

[0058] The test results in Tables 2 to 4 show that the stainless steel welding electrode provided by this invention exhibits good welding processability, stable arc, beautiful weld formation, fine ripples, minimal welding spatter, and easy slag removal. The weld metal produced by the stainless steel welding electrode has good mechanical properties, with a tensile strength ≥775MPa and an elongation after fracture ≥26%.

[0059] The stainless steel welding electrode provided by this invention is a titanium-calcium type coated duplex stainless steel welding electrode. The deposited metal has a ferrite-austenite duplex structure, with a ferrite content as high as about 50%. The coefficient of thermal expansion of the stainless steel welding electrode is between that of carbon steel and austenitic steel. When used for dissimilar steel welds, it has a high absorption capacity for both iron and carbon, and will not form a pure austenitic or martensitic weld structure. Therefore, it has good crack resistance and excellent welding process, and is suitable for welding high-carbon steel, tool steel, high-temperature steel, dissimilar steel, etc. Therefore, this invention effectively overcomes some practical problems in the prior art, thus having high utilization value and application significance.

[0060] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A stainless steel welding rod, characterized by, The coating includes a steel core and a coating, the coating is coated on the outer surface of the steel core, wherein the coating is composed of the following components in parts by weight: 10-15 parts of metallic chromium, 16-18 parts of micro-carbon chromium iron, 1-5 parts of titanium concentrate, 20-25 parts of rutile, 4-8 parts of fluoride, 5-10 parts of feldspar, 1-5 parts of fluorite, 3-5 parts of marble, 1-5 parts of potassium titanate, 1-3 parts of metallic manganese, 10-13 parts of mica, 0.1-0.3 parts of bismuth oxide, 0.1-1 parts of zircon sand, 0.1-0.5 parts of carboxymethyl cellulose, and 20-25 parts of water glass.

2. The stainless steel electrode according to claim 1, characterized in that, The chromium content in the metallic chromium is ≥99wt%, the Cr content in the micro-carbon chromium iron is ≥70wt%, the carbon content is ≤0.06wt%, the TiO2 content in the titanium concentrate is ≥55wt%, the TiO2 content in the rutile is ≥85wt%, the SiO2 content in the feldspar is 63-73wt%, the Al2O3 content is 15-22wt%, the CaF2 content in the fluorite is ≥95wt%, the CaCO3 content in the marble is ≥96wt%, the TiO2 content in the potassium titanate is ≥65wt%, the Mn content in the metallic manganese is ≥99.80wt%, the SiO2 content in the mica is 44-52wt%, the Bi2O3 content in the bismuth oxide is ≥95wt%, and the ZrO2 content in the zircon sand is ≥66wt%.

3. The stainless steel electrode according to claim 1, characterized in that, The steel core is made of Cr 26 Ni9 steel core with a diameter of 6.5 mm.

4. The stainless steel electrode according to claim 1, characterized in that, The weight of the coating is 40-45% of the total weight of the stainless steel electrode.

5. The stainless steel electrode according to claim 1, characterized in that, The water glass is 1:1 potassium-sodium water glass.

6. The stainless steel electrode according to claim 1, characterized in that, The diameter of the stainless steel electrode is 2.5-4.0mm.

7. The stainless steel welding rod of claim 1 wherein, The mechanical properties of the deposited metal of the stainless steel electrode are: tensile strength ≥660MPa, and elongation after fracture ≥15%.

8. A welding method of the stainless steel electrode as set forth in any one of claims 1 to 7, characterized by, The stainless steel electrode adopts alternating current or direct current reverse connection, and the welding position is all-position.

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