Preparation method and application of low-hydrogen anti-cracking flux-cored wire

Abstract

The invention belongs to the field of welding, and particularly discloses a preparation method and application of a low-hydrogen anti-cracking flux-cored wire, the low-hydrogen anti-cracking flux-cored wire comprises a steel belt and powder, and the powder comprises, by weight, 100 parts of metal powder, 20-40 parts of a deoxidizing agent, 10-20 parts of a slag former, 10-20 parts of an arc stabilizer and 5-10 parts of a plasticizer. The composition and the content of the metal powder are adjusted according to welding requirements and base metal components; the powder accounts for 10-20wt% of the mass of the welding wire; the invention further discloses a preparation method of the low-hydrogen welding wire. The low-hydrogen welding wire has the advantages of being low in welding crack sensitivity, good in mechanical property, high in welding smoothness, few in generated air holes and the like.

Description

[0001] This application is a divisional application of the patent with the application date of July 3, 2024, application number CN202410883590.0, and invention title 'Composition of a Low-Hydrogen Crack-Resistant Flux-Cored Wire and Its Preparation Method'. Technical Field

[0002] The present invention belongs to the field of welding, and specifically discloses a preparation method and application of a low-hydrogen crack-resistant flux-cored wire. Background Art

[0003] In recent years, with the continuous development of welding technology, low-hydrogen crack-resistant flux-cored wires, as a kind of efficient and high-quality welding materials, have been widely used and developed. Low-hydrogen crack-resistant flux-cored wires mainly aim at improving the problems of easy crack generation under conditions such as base metals with relatively high carbon equivalent, narrow welds of thick plates, and high-restraint assembled plates. By reducing the content of low-melting-point elements and compounds in the deposited metal and the diffusible hydrogen content of welding materials, the welding quality and crack resistance are effectively improved. At present, this kind of wire has been widely used in ship and offshore platform engineering, and domestic flux-cored wires already account for the vast majority of the share in the shipbuilding market. However, the existing low-hydrogen crack-resistant flux-cored wires still have the following disadvantages and limitations.

[0004] 1. Influence on welding finish: Gases are generated during welding of the flux core, and these gases will affect the welding finish, thus affecting its mechanical properties and appearance quality. In addition, the gases may also cause defects such as pores, further affecting the welding quality.

[0005] 2. Prone to porosity: Due to the existence of the flux core, the electrode is prone to porosity during welding, affecting the welding quality. This may lead to a decrease in mechanical properties such as the strength and toughness of the weld.

[0006] 3. Preheating requirement: To solve the crack problem, preheating before welding is currently mostly adopted. However, the preheating temperature is proportional to the diffusible hydrogen content in the weld, the weld strength, and the base metal thickness, which may lead to an increase in the customer's money and time costs. At the same time, preheating may also result in a decrease in welding efficiency and an extension of working hours.

[0007] In summary, low-hydrogen crack-resistant flux-cored wires have significant advantages in improving welding quality and crack resistance, but there are disadvantages and limitations in welding finish, porosity generation, preheating requirements, etc. Summary of the Invention

[0008] Based on the deficiencies existing in the prior art, the present invention discloses a preparation method and application of a low-hydrogen crack-resistant flux-cored wire to overcome the above-mentioned disadvantages and limitations of poor welding finish, easy porosity generation, high preheating requirements, etc. existing in the existing low-hydrogen crack-resistant flux-cored wires.

[0009] The present invention includes the following technical solutions:

[0010] A component of a low-hydrogen crack-resistant flux-cored welding wire comprises a steel strip and powder, wherein the powder comprises the following components by weight:

[0011]

[0012] The composition and content of the metal powder are adjusted according to welding requirements and base material composition;

[0013] The powder accounts for 10-20wt% of the welding wire mass.

[0014] Furthermore, the metal powder of the above-mentioned low-hydrogen crack-resistant flux-cored welding wire comprises the following components:

[0015]

[0016] The low-hydrogen crack-resistant flux-cored welding wire is used in welding of steel materials.

[0017] Furthermore, in the above-mentioned component of the low-hydrogen crack-resistant flux-cored welding wire, the deoxidizer is silicon carbide.

[0018] Furthermore, the components of the above-mentioned low-hydrogen crack-resistant flux-cored welding wire, the slag-forming agent, calculated by weight, includes the following components:

[0019] Calcium fluoride 5-15 parts

[0020] Aluminum fluoride 2-4 parts.

[0021] Furthermore, the components of the above-mentioned low-hydrogen crack-resistant flux-cored welding wire, the arc stabilizer, calculated by weight, includes the following components:

[0022] Rutile 5-10 parts

[0023] 3-6 parts potassium carbonate

[0024] 3-6 parts of feldspar.

[0025] Furthermore, the components of the above-mentioned low-hydrogen crack-resistant flux-cored welding wire, the plasticizer, calculated by weight, includes the following components:

[0026] 4-8 parts of triethyl borate

[0027] 2-4 parts of dioctyl phthalate.

[0028] Furthermore, the components of the low-hydrogen crack-resistant flux-cored welding wire include a steel strip and powder, and the powder includes the following components by weight:

[0029]

[0030] The low-hydrogen crack-resistant flux-cored wire is used in the welding of steel.

[0031] The flux accounts for 10-20 wt% of the wire mass.

[0032] Preferably, the components of a low-hydrogen crack-resistant flux-cored wire include a steel strip and a flux. The flux, by weight, includes the following components:

[0033]

[0034]

[0035] The low-hydrogen crack-resistant flux-cored wire is used in the welding of steel.

[0036] The flux accounts for 15 wt% of the wire mass.

[0037] Furthermore, the present invention discloses a preparation method of the above low-hydrogen crack-resistant flux-cored wire, including the following steps:

[0038] Low-temperature drying is performed on the deoxidizer, slag former, arc stabilizing agent, and plasticizer in the wire flux components. The low-temperature drying temperature is 60-100 °C, and the drying time is 2-4 h; high-temperature drying is performed on the metal powder in the wire flux components. The high-temperature drying temperature is 400-500 °C, and the drying time is 3-6 h;

[0039] After the above fluxes are dried, they are mixed evenly, ground, and sieved. Fine powder with a mesh size of 200 or more is taken and wrapped with a steel strip. The flux filling ratio is 10-20%, and then it is drawn to form a finished wire.

[0040] Compared with the prior art, the present invention has the following outstanding beneficial effects:

[0041] The present invention discloses a preparation method and application of a low-hydrogen crack-resistant flux-cored wire. Compared with traditional wires, the low-hydrogen crack-resistant flux-cored wire in the present invention can produce a smoother and more uniform weld during welding. This not only improves the appearance quality of the welded joint but also reduces the workload of subsequent grinding and treatment, thereby improving work efficiency; due to the characteristics of the low-hydrogen design, the probability of porosity generation during welding of this wire is extremely low. Porosity is one of the important factors affecting welding quality. A low porosity rate means that the mechanical properties and sealing performance of the welded joint are more reliable, reducing potential safety hazards; in the welding of steel, preheating is a necessary step, but excessive preheating requirements not only increase energy consumption but also may have an adverse impact on the base metal. The low-hydrogen crack-resistant flux-cored wire disclosed in the present invention has low preheating requirements during welding, which not only reduces energy consumption but also expands the application range of the wire, enabling it to be used in more types of steel and welding environments. Description of the Drawings

[0042] Figure 1 ; Example 1-3 and Comparative Example 1-4 groove welding test crack rate (%);

[0043] Figure 2 : Porosity of welds of Examples 1-3 and Comparative Examples 1-4 (%);

[0044] Figure 3 : Surface roughness (μm) of Examples 1-3 and Comparative Examples 1-4. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention are 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.

[0046] Example 1

[0047] A component of a low-hydrogen crack-resistant flux-cored welding wire comprises a steel strip and powder, wherein the powder comprises the following components by weight:

[0048]

[0049] The low-hydrogen crack-resistant flux-cored welding wire is used for welding high-carbon steel materials.

[0050] The powder accounts for 15wt% of the welding wire mass.

[0051] The method for preparing the low-hydrogen crack-resistant flux-cored welding wire is characterized by comprising the following steps:

[0052] The deoxidizer, slag-forming agent, arc stabilizer and plasticizer in the welding wire powder component are dried at low temperature, the low temperature drying temperature is 80°C, and the drying time is 3 hours; the metal powder in the welding wire powder component is dried at high temperature, the high temperature drying temperature is 450°C, and the drying time is 5 hours;

[0053] The above powders are dried and mixed evenly, ground and sieved, and fine powders above 200 mesh are taken and wrapped with steel belts with a powder filling ratio of 15%. The finished welding wires are then drawn.

[0054] Example 2

[0055] A component of a low-hydrogen crack-resistant flux-cored welding wire comprises a steel strip and powder, wherein the powder comprises the following components by weight:

[0056]

[0057] The low-hydrogen crack-resistant flux-cored wire is used for welding high-carbon steel.

[0058] The powder accounts for 15 wt% of the wire mass.

[0059] The preparation method of the above low-hydrogen crack-resistant flux-cored wire is characterized by including the following steps:

[0060] The deoxidizer, slag former, arc stabilizing agent, and plasticizer in the wire powder components are dried at a low temperature. The low-temperature drying temperature is 80 °C and the drying time is 3 h; the metal powder in the wire powder components is dried at a high temperature. The high-temperature drying temperature is 450 °C and the drying time is 5 h.

[0061] After the above powders are dried, they are mixed evenly, ground, sieved, and the fine powder above 200 mesh is taken. It is wrapped with a steel strip, the powder filling ratio is 15%, and then it is drawn to make a finished wire.

[0062] Example 3

[0063] The composition of a low-hydrogen crack-resistant flux-cored wire includes a steel strip and powder. The powder includes the following components by weight:

[0064]

[0065]

[0066] The low-hydrogen crack-resistant flux-cored wire is used for welding high-carbon steel.

[0067] The powder accounts for 15 wt% of the wire mass.

[0068] The preparation method of the above low-hydrogen crack-resistant flux-cored wire is characterized by including the following steps:

[0069] The deoxidizer, slag former, arc stabilizing agent, and plasticizer in the wire powder components are dried at a low temperature. The low-temperature drying temperature is 80 °C and the drying time is 3 h; the metal powder in the wire powder components is dried at a high temperature. The high-temperature drying temperature is 450 °C and the drying time is 5 h.

[0070] After the above powders are dried, they are mixed evenly, ground, sieved, and the fine powder above 200 mesh is taken. It is wrapped with a steel strip, the powder filling ratio is 15%, and then it is drawn to make a finished wire.

[0071] Comparative Example 1

[0072] It does not contain molybdenum powder, and the rest is the same as in Example 2.

[0073] Comparative Example 2

[0074] It does not contain titanium powder, and the rest is the same as in Example 2.

[0075] Comparative Example 3

[0076] It contains neither molybdenum powder nor titanium powder, and the rest is the same as in Example 2.

[0077] Comparative Example 4

[0078] It contains neither calcium fluoride nor aluminum fluoride, and the rest is the same as in Example 2.

[0079] Test Example 1

[0080] The low-hydrogen crack-resistant flux-cored wires prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The wire diameter was 1.2 mm, and the chemical composition of the steel strip in the wire was:

[0081] C ≤ 0.04%, Mn: 0.15 - 0.35%, Si ≤ 0.040%, S ≤ 0.008%, P ≤ 0.012%. The welded base metal was high-carbon steel of grade 60. The manual welding parameters were as follows: welding current 250 A, welding arc voltage 29 V, welding speed 10 cm / min, no high-temperature preheating, welding wind speed not greater than 2 m / s, and relative humidity not greater than 90%.

[0082] The diffusible hydrogen content (mercury method mL / 100g), welding tensile strength Mpa, crack rate % of groove welding experiment, porosity % of weld, and surface smoothness (measured using roughness (μm)) in the above welding were detected. The results are shown in Table 1 and Figures 1-3 .

[0083] Table 1 Measurement Results of Welding Parameters

[0084]

[0085] As can be seen from the data in Table 1 above, the present invention discloses a composition of a low-hydrogen crack-resistant flux-cored wire and its preparation method. Compared with traditional wires, the low-hydrogen crack-resistant flux-cored wire in the present invention can produce a smoother and more uniform weld during welding. This not only improves the appearance quality of the welded joint but also reduces the workload of subsequent grinding and treatment, thus improving work efficiency. Due to the characteristics of low-hydrogen design, the probability of gas pores generated during welding of this wire is extremely low. Gas pores are one of the important factors affecting welding quality. A low porosity means that the mechanical properties and sealing performance of the welded joint are more reliable, reducing potential safety hazards. In steel welding, preheating is a necessary step, but excessive preheating requirements not only increase energy consumption but may also have an adverse impact on the base metal. The low-hydrogen crack-resistant flux-cored wire disclosed in the present invention has low preheating requirements during welding, which not only reduces energy consumption but also expands the application range of the wire, enabling it to be used in more types of steels and welding environments.

[0086] The above are only several limited preferred embodiments of the present invention, and the description thereof is relatively specific and detailed. However, it should not be construed as a limitation to the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A method for preparing a low-hydrogen crack-resistant flux-cored welding wire, characterized in that: The components of the low-hydrogen crack-resistant flux-cored welding wire include a steel strip and powder, and the powder includes the following components by weight: 30 portions of iron powder Nickel powder 25 parts Chromium powder 20 parts Molybdenum powder 15 parts Titanium powder 10 parts Silicon carbide 20 parts Calcium fluoride 5 parts 2 parts of aluminum fluoride 5 parts of rutile 3 parts potassium carbonate 3 parts of feldspar 4 parts of triethyl borate 2 parts of dioctyl phthalate The powder accounts for 15wt% of the welding wire mass; The method for preparing the low-hydrogen crack-resistant flux-cored welding wire comprises the following steps: The silicon carbide, calcium fluoride, aluminum fluoride, rutile, potassium carbonate, feldspar, triethyl borate and dioctyl phthalate in the welding wire powder components are subjected to low-temperature drying at 80°C for 3 hours; the metal powder in the welding wire powder components is subjected to high-temperature drying at 450°C for 5 hours; the above powders are dried and mixed evenly, ground and sieved, fine powder above 200 mesh is taken, wrapped by a steel belt, the powder filling ratio is 15%, and then drawn to make a finished welding wire.

2. Use of the preparation method of the low hydrogen crack resistant flux cored welding wire as claimed in claim 1 in welding of high carbon steel.

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