An underwater electrode and a method of making the same

Abstract

This invention discloses an underwater welding electrode, belonging to the field of welding materials technology. The electrode comprises a core and a coating. The coating is made from the following raw materials in weight percentages: rutile 30-44%, fluorite 5-10%, reduced iron powder 3-8%, potassium feldspar 4-10%, ferrosilicon 1.5-5%, manganese powder 2.5-5%, cellulose 3-8%, rare earth ferrosilicon alloy 1.5-5%, sepiolite 1.5-5%, AlSi12 1.5-5%, and water glass 20-30%. This invention also discloses a method for preparing this underwater welding electrode. The welding electrode of this invention provides easy arc ignition, stable arc combustion, strong resistance to porosity, and excellent welding process performance, meeting the welding requirements of humid and underwater environments.

Description

Technical Field

[0001] This invention relates to the field of metal welding technology, and more particularly to an underwater welding electrode and its preparation method, suitable for welding in underwater and extremely humid environments. Background Technology

[0002] Underwater welding technology is widely used in offshore oil extraction, ship repair, and marine facility construction. However, due to the unique underwater environment, the welding process faces challenges such as high hydrogen content and rapid cooling, making the weld highly susceptible to defects such as porosity, cracks, and insufficient strength. Existing underwater welding electrodes still cannot adequately meet the needs of practical engineering in terms of flux formulation, welding process performance, and weld strength and toughness. Therefore, developing a new type of underwater welding electrode that is easy to ignite, has a stable arc, is low in hydrogen and waterproof, and possesses excellent mechanical properties is of great significance for ensuring the construction safety and welding quality of marine facilities. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides an underwater welding electrode with good waterproof performance, easy arc ignition, stable combustion, strong resistance to porosity, and excellent welding process performance, which can meet the higher operational requirements of humid and underwater environments. This invention also provides a method for preparing the underwater welding electrode.

[0004] To solve the above technical problems, the present invention is achieved through the following technical solution:

[0005] This invention provides an underwater welding electrode, comprising a core and a coating, the coating being made from the following raw materials in weight percentages: rutile 30-44%, fluorite 5-10%, reduced iron powder 3-8%, potassium feldspar 4-10%, ferrosilicon 1.5-5%, manganese powder 2.5-5%, cellulose 3-8%, rare earth ferrosilicon alloy 1.5-5%, sepiolite 1.5-5%, AlSi 12 1.5-5%, water glass 20-30%.

[0006] Preferably, the coating is made from the following raw materials in weight percentage: According to claim 1, the underwater welding electrode is characterized in that the coating is made from the following raw materials in weight percentage: rutile 32-44%, fluorite 6-10%, reduced iron powder 5-8%, potassium feldspar 5-10%, ferrosilicon 1.5-3%, manganese powder 2.5-5%, cellulose 3-6%, rare earth ferrosilicon alloy 1.5-4%, sepiolite 1.5-4%, AlSi12 1.5-4%, and water glass 25-30%.

[0007] Preferably, the welding core material is of grade E410-16.

[0008] The functions of each raw material are as follows:

[0009] Rutile: mainly TiO2. TiO2 is covalent with low bond energy, which can reduce the surface tension of the slag (its surface tension increases rapidly during cooling, constraining weld formation) and ensuring weld quality.

[0010] Fluorite: The main component of fluorite is CaF2, which is mainly used in basic slag systems for slag formation and to improve the physicochemical properties of the slag. It can lower the melting point, viscosity, and surface tension of basic slag, increase its fluidity, and help reduce gaseous impurities in the weld metal. An appropriate amount of CaF2 can improve the protective effect of the slag on the liquid metal, thus reducing the amount of hydrogen absorbed by the liquid metal. However, excessive CaF2 will affect the stability of the welding arc, increase the diameter of the molten droplets during welding, increase spatter, lengthen the short-circuit time, worsen the melting performance of the electrode coating, and reduce the coverage of the weld metal by the slag.

[0011] Reduced iron powder: Reduced iron powder can improve welding efficiency, purify the molten pool, refine grains, improve weld impact toughness, and improve the re-arc striking ability of welding electrodes underwater.

[0012] Potassium feldspar: mainly used for slag formation, it can reduce the basicity of molten slag, refine molten slag particles, and improve the stability of the electrode arc.

[0013] Ferrosilicon: It is mainly used as a deoxidizer and alloying agent. Excessive content of ferrosilicon will increase splashing and reduce toughness.

[0014] Manganese powder: mainly used as a deoxidizer, alloying agent and desulfurizer. Excessive content of manganese powder will increase splashing.

[0015] Cellulose: The main function of cellulose is to increase lubrication and improve the coating performance of welding electrodes. It also has a certain gas-generating function.

[0016] Rare earth ferrosilicon: used to refine grains and improve the low-temperature impact toughness of weld metal.

[0017] Sepiolite: Primarily used as an arc stabilizer to improve the stability, adsorption, and processability of the welding process, while ensuring welding quality.

[0018] AlSi12 is mainly used as a deoxidizer and alloying agent to reduce the oxygen content in the weld, refine the weld grains, and improve the weld strength and toughness.

[0019] Water glass: mainly used as a binder to firmly bond the coating material to the core, which helps to improve the electrode's process performance and welding quality.

[0020] This invention provides a method for preparing the above-mentioned underwater welding electrode, comprising the following steps:

[0021] (1) Mix the raw materials of the drug coating, stir evenly, add binder, continue stirring, and obtain drug coating after uniform mixing;

[0022] (2) The welding core is cleaned by removing oil and rust, and then the obtained flux coating is applied to the outside of the welding core, rolled, and then baked and dried to obtain the welding rod blank;

[0023] (3) Apply a waterproof layer to the surface of the obtained welding electrode blank to obtain the underwater welding electrode of the present invention.

[0024] Preferably, the adhesion thickness of the coating can be adjusted between 1 and 3 mm according to the core diameter and actual usage requirements and working conditions.

[0025] Preferably, the adhesive is mainly water glass with a modulus of 2.4 to 2.7 and a specific gravity of 1.39 to 1.59.

[0026] Preferably, the waterproof layer is any one of paint, resin, tung oil or paraffin.

[0027] The present invention has the following positive and beneficial effects:

[0028] The underwater welding electrode of this invention is easy to ignite, has a stable arc, strong resistance to porosity, produces a complete and beautiful weld, and has good welding process performance. Attached Figure Description

[0029] Figure 1 This is a flowchart of the preparation method of the underwater welding electrode of the present invention. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0031]

Example 1

[0032] An underwater welding electrode includes a core and a coating. The core has a diameter of 3.2 mm and is composed of C: 0.08%, Si: 1.0%, Mn: 1.0%, P: 0.04%, S: 0.03%, Ni: 0.6%, Cr: 11.5-13.5%, with the balance being Fe. The coating is 1.5 mm thick and is made from the following raw materials in weight percentages: rutile 40%, fluorite 8%, reduced iron powder 5%, potassium feldspar 4%, ferrosilicon 1.5%, manganese powder 2.5%, cellulose 4%, rare earth ferrosilicon alloy 3%, sepiolite 2.5%, AlSi12 2.5%, and water glass 27%.

[0033] Its preparation method is as follows Figure 1 As shown, the specific steps include:

[0034] (1) Mix the raw materials of each drug coating, stir evenly, add water glass as a binder, continue stirring, and obtain the drug coating after it is evenly mixed;

[0035] (2) The welding core is cleaned by removing oil and rust, and then the obtained flux coating is applied to the outside of the welding core, rolled, and then baked and dried to obtain the welding rod blank;

[0036] (3) Apply a waterproof layer to the surface of the obtained welding electrode blank to obtain the underwater welding electrode of the present invention.

[0037] In this embodiment, the underwater welding process is stable, with no porosity in the weld. The diffusible hydrogen content is measured to be 6.5 ml / 100g, which meets the national standard requirement of ≤8 ml / 100g and can satisfy the requirements of various underwater welding conditions.

[0038]

Example 2

[0039] An underwater welding electrode includes a core and a coating. The core has a diameter of 4.0 mm and is grade H08E. The coating has a thickness of 2.0 mm and is made from the following raw materials in weight percentages: rutile 40%, fluorite 6%, reduced iron powder 5%, potassium feldspar 5%, ferrosilicon 2%, manganese powder 3%, cellulose 4%, rare earth ferrosilicon alloy 2%, sepiolite 3%, AlSi12 3%, and water glass 30%.

[0040] Except for the following, the preparation method is basically the same as in Example 1: Step (1) Add water glass as a binder.

[0041] In this embodiment, the underwater welding process is stable, no porosity appears in the weld, and the diffusible hydrogen content is measured to be 6.7 ml / 100g, which meets the national standard requirement of ≤8 ml / 100g and can meet the requirements of various underwater welding conditions.

[0042]

Example 3

[0043] An underwater welding electrode includes a core and a coating. The core has a diameter of 2.5 mm and is grade E410-16. The coating has a thickness of 1.0 mm and is made from the following raw materials in weight percentages: rutile 35%, fluorite 10%, reduced iron powder 8%, potassium feldspar 3%, ferrosilicon 2%, manganese powder 1.5%, cellulose 3%, rare earth ferrosilicon alloy 1.5%, sepiolite 5%, AlSi 123%, and water glass 28%.

[0044] Except for the following, the preparation method is basically the same as in Example 1: Step (1) Add water glass as a binder.

[0045] In this embodiment, the underwater welding process is stable, with no porosity in the weld. The diffusible hydrogen content is measured to be 6.5 ml / 100g, which meets the national standard requirement of ≤8 ml / 100g and can satisfy the requirements of various underwater welding conditions.

[0046]

Example 4

[0047] An underwater welding electrode includes a core and a coating. The core has a diameter of 6.0 mm and is grade E410-16. The coating has a thickness of 3.0 mm and is made from the following raw materials in weight percentages: rutile 38%, fluorite 8%, reduced iron powder 7%, potassium feldspar 5%, ferrosilicon 1.5%, manganese powder 1.5%, cellulose 3%, rare earth ferrosilicon alloy 3%, sepiolite 5%, AlSi 123%, and water glass 26.5%.

[0048] Except for the following, the preparation method is basically the same as in Example 1: Step (1) add 6% of the total weight of the raw materials as binder (92 wt% water glass and 8 wt% potassium permanganate).

[0049] The underwater welding process of this embodiment is stable, with no porosity in the weld. The diffusible hydrogen content is measured at 6.4 ml / 100g, which meets the national standard requirement of ≤8 ml / 100g, and can meet the requirements of various underwater welding conditions. After the underwater welding electrode in the above embodiment was placed at 100cm underwater for 4 hours, there was no change in weight before and after placement, while commercially available underwater welding electrodes showed a weight gain of 0.2 to 0.5 mg, indicating that the underwater welding electrode of this invention has a better waterproof effect. This invention is not limited to the specific embodiments described above. Those skilled in the art can make various changes accordingly, but any changes that are equivalent to or similar to this invention should be covered within the scope of the claims of this invention.

Claims

1. An underwater welding electrode, comprising a core and a coating, characterized in that: The coating is made from the following raw materials by weight percentage: rutile 30-44%, fluorite 5-10%, reduced iron powder 3-8%, potassium feldspar 4-10%, ferrosilicon 1.5-5%, manganese powder 2.5-5%, cellulose 3-8%, rare earth ferrosilicon alloy 1.5-5%, sepiolite 1.5-5%, AlSi12 1.5-5%, and water glass 20-30%.

2. The underwater welding electrode according to claim 1, characterized in that: The coating is made from the following raw materials in weight percentage: rutile 32-44%, fluorite 6-10%, reduced iron powder 5-8%, potassium feldspar 5-10%, ferrosilicon 1.5-3%, manganese powder 2.5-5%, cellulose 3-6%, rare earth ferrosilicon alloy 1.5-4%, sepiolite 1.5-4%, AlSi12 1.5-4%, and water glass 25-30%.

3. The underwater welding electrode according to claim 1, characterized in that: The welding core is made of the following raw materials in weight percentage: C: 0.08, Si: 1.0, Mn: 1.0, P: 0.04, S: 0.03, Ni: 0.6, Cr: 11.5-13.5, with the balance being Fe.

4. A method for preparing an underwater welding electrode, characterized in that, Includes the following steps: (1) Prepare the raw material for the coating according to claim 1 or 2, mix and stir evenly, add 5 to 10% of the total weight of the raw material as a binder, continue stirring, and obtain the coating after uniform mixing; (2) The welding core is cleaned by removing oil and rust, and then the obtained flux coating is applied to the outside of the welding core, rolled, and then baked and dried to obtain the welding rod blank; (3) Apply a waterproof layer to the surface of the obtained welding electrode blank to obtain the underwater welding electrode of the present invention.

5. The method for preparing underwater welding electrodes according to claim 4, characterized in that: The coating thickness is 1–3 mm.

6. The method for preparing underwater welding electrodes according to claim 4, characterized in that: The binder is mainly water glass with a modulus of 2.4 to 2.7 and a specific gravity of 1.39 to 1.

59.

7. The method for preparing underwater welding electrodes according to claim 6, characterized in that: The binder consists of 90-98 wt% water glass and 2-10 wt% potassium permanganate.

8. The method for preparing underwater welding electrodes according to claim 4, characterized in that: The waterproof layer is any one of paint, resin, tung oil or paraffin.

Images