600mpa grade high toughness ultra-low hydrogen electrode

Abstract

The application relates to the technical field of welding materials, and discloses a 600MPa-grade high-toughness ultra-low-hydrogen welding rod, which comprises a welding core and a coating arranged on the surface of the welding core, and the coating raw material comprises the following components in parts by weight: 22-32 parts of marble, 16-24 parts of feldspar, 8-12 parts of fluorite, 10-15 parts of titanium white, 4-8 parts of medium-carbon manganese iron, 1.2-3.0 parts of low-carbon silicon iron and 6-12 parts of titanium trioxide. Through the technical scheme, the problems of high weld crack rate and high diffusible hydrogen content in the related art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of welding material, in particular to a 600MPa grade high toughness ultra-low hydrogen welding rod. BACKGROUND

[0002] With the rapid development of the national economy, the trend of large-scale steel structure manufacturing is becoming more and more obvious, and the strength grade of the steel used is getting higher and higher. In the welding structure manufacturing of water and electricity, engineering machinery, storage tank, submarine, etc., the tensile strength of 600MPa has become the main steel grade. Stick arc welding still plays an important role in these structure manufacturing.

[0003] 600MPa steel has high strength and toughness, and has a certain crack sensitivity due to high alloy content. The welding rod matched with 600MPa steel also requires high strength and toughness, and more importantly, it requires strong welding adaptability, low diffusible hydrogen content and low crack sensitivity.

[0004] The main technical means to obtain high toughness is to add metal Ni, which can reduce the ductile-brittle transition temperature of the material and improve the toughness of the material. However, Ni is an expensive metal, and the cost of adding Ni is high.

[0005] Hydrogen is one of the important factors that cause cold cracks in welds. During the cooling process of welding, hydrogen atoms will diffuse and accumulate in the stress concentration areas or weak areas of the weld. When the hydrogen content reaches a certain level and there is enough restraint stress and sensitive microstructure, cold cracks may occur. Cold cracks usually occur after a period of time after welding, which is delayed and not easy to be found, so it has great potential danger. Such cracks can seriously reduce the toughness and strength of the weld, making the weld prone to brittle fracture during use, which poses a great threat to the safety of the structure. At the same time, excessive hydrogen will be dissolved in the crystal lattice of the weld metal, causing distortion of the crystal lattice and internal stress, thereby reducing the toughness and plasticity of the weld metal. This means that the weld is more likely to break when subjected to dynamic loads such as impact or vibration, reducing the fatigue resistance and reliability of the welded structure. For example, in the welding of some mechanical parts that bear cyclic loads, high hydrogen content may cause the weld to develop fatigue cracks prematurely, shortening the service life of the parts. The main way to reduce the diffusible hydrogen content is to add fluorite (CaF2), which can reduce the hydrogen content in the weld through the metallurgical reaction CaF2+2H=Ca+2HF. Although the addition of fluorite reduces the diffusible hydrogen content, it also deteriorates the operating performance of the welding rod.

[0006] In summary, there is a need for a high toughness welding rod that does not add noble metal elements such as Ni, reduces the amount of fluorite, and reduces the diffusible hydrogen content and weld crack rate, in order to be suitable for welding steel with a tensile strength of 600MPa. SUMMARY

[0007] The application provides a 600MPa high-toughness ultra-low-hydrogen welding rod, and solves the problems of high weld crack rate and high diffusible hydrogen content in the prior art.

[0008] The technical scheme of the application is as follows:

[0009] The application provides a 600MPa high-toughness ultra-low-hydrogen welding rod, which comprises a welding core and a coating arranged on the surface of the welding core, and the coating raw material comprises the following components in parts by weight: 22-32 parts of marble, 16-24 parts of feldspar, 8-12 parts of fluorite, 10-15 parts of titanium white, 4-8 parts of medium-carbon manganese iron, 1.2-3.0 parts of low-carbon silicon iron and 6-12 parts of titanium trioxide.

[0010] In the application, the low-carbon silicon iron in the coating contains silicon elements, which can play a role of solid solution strengthening and deoxidation in the weld, and when manganese-silicon exists simultaneously, the deoxidation product can float up, and the weld metal can be purified.

[0011] In the application, the medium-carbon manganese iron in the coating contains manganese elements, and with the increase of the content of manganese, the yield strength and tensile strength of the weld metal can be greatly improved.

[0012] In the application, the marble is added in the coating, and the marble is an important gas and slag forming agent in the low-hydrogen welding rod.

[0013] In the application, the feldspar is added in the coating, and the feldspar is also an important slag forming agent.

[0014] In the application, the fluorite is added in the coating, and the fluorite is an important dehydrogenation component.

[0015] In the present application, titanium white powder is added to the coating, which is a forming agent and a plasticizer for the welding rod.

[0016] As a further technical solution, the welding core is H08A welding wire.

[0017] As a further technical solution, the H08A welding wire is composed of the following components by mass percentage: C 0.04%~0.10%, Si ≤0.03%, Mn 0.4%~0.65%, S 0.002%~0.015%, P ≤0.030%, and the balance is iron and unavoidable impurities.

[0018] As a further technical solution, according to the test method specified in GB / T 2652-2022 "Metallic Materials Weld Breakdown Test Transverse Tensile Test", the tensile strength of the 600MPa high toughness ultra-low hydrogen welding rod is 600~700MPa.

[0019] As a further technical solution, the average particle size of titanium trioxide is 0.5~3μm.

[0020] In the present application, the average particle size of titanium trioxide is controlled to be 0.5~3μm. If it exceeds this particle size, the induction of ferrite will be poor.

[0021] The present application also proposes a preparation method of the 600MPa high toughness ultra-low hydrogen welding rod, comprising the following steps:

[0022] S1, the H08A welding wire rod is drawn, cut, and the welding core is obtained;

[0023] S2, the components of the coating raw material are mixed with water glass uniformly to obtain a coating;

[0024] S3, the coating is pressed and coated on the welding core, and dried to obtain a 600MPa high toughness ultra-low hydrogen welding rod.

[0025] As a further technical solution, the length of the welding core is 350~400mm, and the diameter is 3.2~4.0mm.

[0026] As a further technical solution, the specific gravity of the water glass is 1.67~1.92.

[0027] As a further technical solution, the mass of the water glass is 16%~24% of the mass of the coating.

[0028] As a further technical solution, the mass ratio of the coating to the welding core is 0.4~0.6:1.

[0029] As a further technical solution, the temperature of the drying is 370-390 DEG C, and the time is 1.5-2.5 h.

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

[0031] In the present application, the titanium trioxide is added to the coating raw material, and 10wt%-25wt% of the titanium trioxide added to the coating will directly transition into the molten pool. Since the weld metal structure is mainly reticular grain boundary ferrite and intracrystalline lath bainite, the grain boundary ferrite is very developed and forms a reticular structure to become a brittle phase. The lath bainite is composed of fine ferrite and M-A components between the ferrite, and the brittle M-A components become the crack source under impact load, and the ferrite lath forms a rapid channel for crack propagation, which greatly reduces the toughness. The titanium trioxide transitioned into the molten pool becomes a spontaneous nucleation core, inhibits the nucleation of grain boundary ferrite, promotes the rapid nucleation and growth of intracrystalline ferrite. Since the titanium trioxide is dispersedly distributed and the number is large, the distance between adjacent titanium trioxides is very small, and the adjacent intracrystalline nucleated ferrites intersect with each other to form a closed structure. The titanium trioxide makes the effective grain size of the induced precipitated intracrystalline ferrite very small, which limits the crack propagation. Therefore, the addition of the titanium trioxide in the coating improves the impact toughness and reduces the crack rate.

[0032] Another function of the titanium trioxide is to act as a hydrogen trap to hinder the diffusion of hydrogen atoms in the weld, thereby reducing the crack sensitivity. Due to the addition of the titanium trioxide, a smaller amount of fluorite can be used to reduce the diffusible hydrogen content to below 4 mL / 100 g. When the titanium trioxide content in the coating raw material is less than 6 parts, the effect of improving the toughness and reducing the diffusible hydrogen content is not significant, and when the content is greater than 12 parts, a large amount of powder will enter the molten slag. Therefore, the present application controls the titanium trioxide content to be 6-12 parts to reduce the diffusible hydrogen content. DETAILED DESCRIPTION

[0033] 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 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 also fall within the scope of protection of the present application.

[0034] In the following comparative examples and examples, the calcium carbonate content in the marble is 94wt%, the particle size is 200 mesh, the silicon dioxide content in the feldspar is 84wt%, the particle size is 200 mesh, the calcium fluoride content in the fluorite is 95wt%, the particle size is 200 mesh, the titanium dioxide content in the titanium white powder is 98wt%, the particle size is 300 mesh, the carbon content in the medium-carbon manganese iron is 2.0wt%, the manganese content is 78wt%, and the silicon content in the silicon iron is 75wt%.

[0035] Embodiment 1

[0036] A 600MPa high toughness ultra-low hydrogen electrode, comprising a welding core and a coating arranged on the surface of the welding core, the coating raw material comprising the following components by weight: 24 parts of marble, 21 parts of feldspar, 11 parts of fluorite, 12 parts of titanium white powder, 5.5 parts of medium carbon ferromanganese, 2.6 parts of low carbon ferrosilicon, and 10 parts of titanium trioxide;

[0037] The welding core is H08A welding wire; the H08A welding wire is composed of the following components by mass percentage: C 0.072%, Si 0.02%, Mn 0.52%, S 0.006%, P 0.013%, and the balance being iron and unavoidable impurities;

[0038] The average particle size of the titanium trioxide is 1.76μm;

[0039] A preparation method of the 600MPa high toughness ultra-low hydrogen electrode, comprising the following steps:

[0040] S1, drawing, cutting the H08A welding wire rod to obtain the welding core;

[0041] S2, uniformly mixing the components of the coating raw material with water glass to obtain the coating;

[0042] S3, pressing the coating on the welding core, and drying to obtain the 600MPa high toughness ultra-low hydrogen electrode;

[0043] The length of the welding core is 400mm, and the diameter is 4.0mm;

[0044] The specific gravity of the water glass is 1.85;

[0045] The mass of the water glass is 17.5% of the mass of the coating;

[0046] The mass ratio of the coating to the welding core is 0.46:1;

[0047] The drying temperature is 380℃, and the time is 2h.

[0048] Embodiment 2

[0049] The difference between this embodiment and embodiment 1 is that the coating raw material of this embodiment comprises the following components by weight: 25 parts of marble, 20 parts of feldspar, 10 parts of fluorite, 11 parts of titanium white powder, 5.0 parts of medium carbon ferromanganese, 2.2 parts of low carbon ferrosilicon, and 9 parts of titanium trioxide;

[0050] The average particle size of the titanium trioxide is 2.65μm.

[0051] Embodiment 3

[0052] The difference between the embodiment and embodiment 1 is that the coating raw material of the embodiment comprises the following components by weight: marble 28 parts, feldspar 20.5 parts, fluorite 11.5 parts, titanium white 9.5 parts, medium-carbon manganese iron 4.8 parts, low-carbon silicon iron 2.4 parts, and titanium trioxide 11 parts;

[0053] The average particle size of the titanium trioxide is 2.31 μm.

[0054] Embodiment 4

[0055] The difference between the embodiment and embodiment 1 is that the coating raw material of the embodiment comprises the following components by weight: marble 23 parts, feldspar 17 parts, fluorite 12 parts, titanium white 11 parts, medium-carbon manganese iron 5.3 parts, low-carbon silicon iron 2.0 parts, and titanium trioxide 9 parts;

[0056] The average particle size of the titanium trioxide is 1.83 μm.

[0057] Embodiment 5

[0058] The difference between the embodiment and embodiment 3 is that the average particle size of the titanium trioxide of the embodiment is 4.72 μm.

[0059] Embodiment 6

[0060] A 600 MPa high-toughness ultra-low-hydrogen welding rod comprises a welding core and a coating arranged on the surface of the welding core, and the coating raw material comprises the following components by weight: marble 22 parts, feldspar 16 parts, fluorite 8 parts, titanium white 15 parts, medium-carbon manganese iron 4 parts, low-carbon silicon iron 1.2 parts, and titanium trioxide 6 parts;

[0061] The welding core is an H08A welding wire; the H08A welding wire is composed of the following components by mass percentage: C 0.04%, Si 0.03%, Mn 0.4%, S 0.015%, P 0.013%, and the balance is iron and inevitable impurities;

[0062] The average particle size of the titanium trioxide is 0.5 μm.

[0063] A preparation method of a 600 MPa high-toughness ultra-low-hydrogen welding rod comprises the following steps:

[0064] S1, drawing, cutting the H08A welding wire rod to obtain a welding core;

[0065] S2, mixing the components of the coating raw material with water glass uniformly to obtain a coating;

[0066] S3, pressing the coating on the welding core and drying to obtain a 600 MPa high-toughness ultra-low-hydrogen welding rod;

[0067] The length of the welding core is 350 mm, and the diameter is 3.2 mm;

[0068] The specific gravity of the water glass is 1.67;

[0069] The mass of the water glass is 16% of the mass of the coating;

[0070] The mass ratio of the coating to the welding core is 0.4:1;

[0071] The temperature of the drying is 370 DEG C, and the time is 2.5h.

[0072] Example 7

[0073] A 600MPa high toughness ultra-low hydrogen electrode, comprising a welding core and a coating arranged on the surface of the welding core, the coating raw material comprising the following components by weight: 32 parts of marble, 24 parts of feldspar, 12 parts of fluorite, 15 parts of titanium white powder, 8 parts of medium-carbon ferromanganese, 3 parts of low-carbon ferrosilicon, and 12 parts of titanium trioxide;

[0074] The welding core is H08A welding wire; the H08A welding wire is composed of the following components by mass percentage: C 0.1%, Si 0.01%, Mn 0.65%, S 0.002%, P 0.03%, and the balance being iron and unavoidable impurities;

[0075] The average particle size of the titanium trioxide is 3μm;

[0076] A preparation method of a 600MPa high toughness ultra-low hydrogen electrode, comprising the following steps:

[0077] S1, drawing, cutting the H08A welding wire rod to obtain a welding core;

[0078] S2, mixing the components of the coating raw material with water glass uniformly to obtain a coating;

[0079] S3, pressing the coating on the welding core, drying to obtain a 600MPa high toughness ultra-low hydrogen electrode;

[0080] The length of the welding core is 400mm, and the diameter is 4.0mm;

[0081] The specific gravity of the water glass is 1.92;

[0082] The mass of the water glass is 24% of the mass of the coating;

[0083] The mass ratio of the coating to the welding core is 0.6:1;

[0084] The temperature of the drying is 390 DEG C, and the time is 2.5h.

[0085] Comparative Example 1

[0086] A welding rod comprises a welding core and a coating arranged on the surface of the welding core, and the coating raw material comprises the following components by weight: 42 parts of marble, 13 parts of feldspar, 19 parts of fluorite, 5 parts of titanium white powder, 5.0 parts of medium-carbon manganese iron, 2.3 parts of low-carbon silicon iron, and 2.1 parts of nickel powder;

[0087] The welding core is H08A welding wire;

[0088] A preparation method of the welding rod comprises the following steps:

[0089] S1, drawing and cutting the H08A welding wire rod to obtain the welding core;

[0090] S2, uniformly mixing the components of the coating raw material with water glass to obtain the coating;

[0091] S3, pressing the coating on the welding core and drying to obtain the welding rod;

[0092] The length of the welding core is 400 mm, and the diameter is 4.0 mm;

[0093] The specific gravity of the water glass is 1.85;

[0094] The mass of the water glass is 17.5% of the mass of the coating;

[0095] The mass ratio of the coating to the welding core is 0.46:1;

[0096] The drying temperature is 380 DEG C, and the time is 2 h.

[0097] Comparative Example 2

[0098] A welding rod comprises a welding core and a coating arranged on the surface of the welding core, and the coating raw material comprises the following components by weight: 42 parts of marble, 13 parts of feldspar, 19 parts of fluorite, 5 parts of titanium white powder, 5.0 parts of medium-carbon manganese iron, 2.3 parts of low-carbon silicon iron, and 2.1 parts of nickel powder;

[0099] The welding core is H08A welding wire;

[0100] A preparation method of the welding rod comprises the following steps:

[0101] S1, drawing and cutting the H08A welding wire rod to obtain the welding core;

[0102] S2, uniformly mixing the components of the coating raw material with water glass to obtain the coating;

[0103] S3, pressing the coating on the welding core and drying to obtain the welding rod;

[0104] The length of the welding core is 400 mm, and the diameter is 4.0 mm;

[0105] The specific gravity of the water glass is 1.85;

[0106] The quality of the water glass is 17.5% of the quality of the coating;

[0107] The mass ratio of the coating to the welding core is 0.48:1;

[0108] The temperature of the drying is 380 DEG C, and the time is 2h.

[0109] Comparative Example 3

[0110] A welding rod comprises a welding core and a coating arranged on the surface of the welding core, and the coating raw material comprises the following components by weight: 40 parts of marble, 20.5 parts of feldspar, 11.5 parts of fluorite, 9.5 parts of titanium white, 4.8 parts of medium-carbon manganese iron, 2.4 parts of low-carbon silicon iron, 2.0 parts of molybdenum iron, and 1.5 parts of nickel powder;

[0111] The welding core is H08A welding wire;

[0112] A preparation method of the welding rod comprises the following steps:

[0113] S1, the H08A welding wire rod is drawn, cut, and a welding core is obtained;

[0114] S2, the components of the coating raw material are mixed with water glass uniformly, and a coating is obtained;

[0115] S3, the coating is pressed and coated on the welding core, dried, and a welding rod is obtained;

[0116] The length of the welding core is 400 mm, and the diameter is 4.0 mm;

[0117] The specific gravity of the water glass is 1.85;

[0118] The quality of the water glass is 17.5% of the quality of the coating;

[0119] The mass ratio of the coating to the welding core is 0.5:1;

[0120] The temperature of the drying is 380 DEG C, and the time is 2h.

[0121] Comparative Example 4

[0122] The difference between the present comparative example and Example 3 is that the coating raw material in the present comparative example does not contain titanium trioxide.

[0123] Experimental Example 1

[0124] The 600 MPa high-toughness ultra-low-hydrogen welding rods or welding rods prepared in Examples 1-7 and Comparative Examples 1-3 are subjected to performance testing, and the testing method is as follows: a 40 mm steel plate is processed into a V-shaped groove, the welding current is 175 A, the voltage is 25 V, and the welding speed is 130-170 mm / min. The deposited metal is tested according to the method specified in CB / T 4364-2013 “Inclined Y-shaped groove welding crack test method”, and the test results are shown in Table 1.

[0125]

[0126] Compared with Comparative Examples 1-4, Examples 1-7 show that the addition of titanium trioxide in the coating raw material reduces the weld crack rate.

[0127] Experimental Example 2

[0128] The 600MPa high toughness ultra-low hydrogen electrode or welding rod prepared from Examples 1-7 and Comparative Examples 1-4 was tested for performance, and the test method was as follows: a 40mm steel plate was processed into a V-shaped groove, the welding current was 175A, the voltage was 25V, and the welding speed was 130-170mm / min. The yield strength (R p0.2 ), tensile strength (Rm), and elongation at break (A) of the deposited metal were tested according to the method specified in GB / T 2652-2022 "Metallic materials - Weld break test - Longitudinal tensile test of weld metal of fusion-welded joints", the absorbed energy at -40℃ was tested to characterize the low-temperature impact toughness according to the method specified in GB / T 229-2020 "Metallic materials - Charpy pendulum impact test method", and the diffusible hydrogen content was tested according to the method specified in GB / T 3965-2012 "Method for determination of diffusible hydrogen in deposited metal". The test results are shown in Table 2.

[0129]

[0130] Compared with Comparative Examples 1-4, Examples 1-7 show that the addition of titanium trioxide in the coating raw material reduces the diffusible hydrogen content of the deposited metal, and the 600MPa high toughness ultra-low hydrogen electrode of the present application is suitable for welding steel with a tensile strength of 600MPa.

[0131] Experimental Example 3

[0132] The 600MPa high toughness ultra-low hydrogen electrode or welding rod prepared from Examples 1-7 and Comparative Examples 1-4 was tested for performance, and the test method was as follows: a 40mm steel plate was processed into a V-shaped groove, the welding current was 175A, the voltage was 25V, and the welding speed was 130-170mm / min. The tensile strength (Rm) of the welded joint was tested according to the method specified in GB / T 2651-2023 "Metallic materials - Weld break test - Transverse tensile test", and the absorbed energy at -40℃ was tested to characterize the low-temperature impact toughness according to the method specified in GB / T 229-2020 "Metallic materials - Charpy pendulum impact test method". The experimental results are shown in Table 3.

[0133]

[0134] Compared with Comparative Examples 1-4, Examples 1-7 show that the impact toughness of the welded joint is improved by adding titanium trioxide with a particle size of 0.5-3 μm in the coating raw material, and the 600 MPa high toughness ultra-low hydrogen welding rod of the present application is suitable for welding of 600 MPa steel.

[0135] The above merely illustrates the preferred embodiments of the present application, but should not be used to limit the present application, and 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 600 MPa grade high toughness ultra-low hydrogen welding rod, characterized by, The welding core and the coating arranged on the surface of the welding core, the coating raw material comprises the following components by weight: 22-32 parts of marble, 16-24 parts of feldspar, 8-12 parts of fluorite, 10-15 parts of titanium white, 4-8 parts of medium-carbon ferromanganese, 1.2-3.0 parts of low-carbon ferrosilicon, and 6-12 parts of titanium trioxide; The welding core is H08A welding wire; The average particle size of the titanium trioxide is 0.5-3 μm; The calcium carbonate content in the marble is 94 wt%, the particle size is 200 mesh, the silicon dioxide content in the feldspar is 84 wt%, the particle size is 200 mesh, the calcium fluoride content in the fluorite is 95 wt%, the particle size is 200 mesh, the titanium dioxide content in the titanium white is 98 wt%, the particle size is 300 mesh, the carbon content in the medium-carbon ferromanganese is 2.0 wt%, the manganese content is 78 wt%, and the silicon content in the ferrosilicon is 75 wt%.

2. The 600 MPa grade high toughness ultra-low hydrogen electrode according to claim 1, characterized in that, According to the test method specified in GB / T2651-2023 "Metallic material weld destructive test Transverse tensile test", the tensile strength of the 600 MPa high-toughness ultra-low hydrogen welding rod is 634-665 MPa.

3. The method for preparing the 600MPa grade high toughness ultra-low hydrogen welding rod according to any one of claims 1-2, characterized in that, The method comprises the following steps: S1, drawing, cutting the H08A welding wire rod to obtain a welding core; S2, uniformly mixing the components of the coating raw material with water glass to obtain a coating; S3, pressing the coating on the welding core, drying to obtain a 600 MPa high-toughness ultra-low hydrogen welding rod.

4. The method for preparing a 600 MPa grade high toughness ultra-low hydrogen welding rod according to claim 3, characterized in that, The length of the welding core is 350-400 mm, and the diameter is 3.2-4.0 mm.

5. The method for preparing a 600MPa-grade high-toughness ultra-low hydrogen welding electrode according to claim 3, characterized in that, The specific gravity of the water glass is 1.67-1.

92.

6. The method for preparing a 600MPa-grade high-toughness ultra-low hydrogen welding electrode according to claim 3, characterized in that, The mass of the water glass is 16%-24% of the mass of the coating.

7. The method for preparing a 600MPa-grade high-toughness ultra-low hydrogen welding electrode according to claim 3, characterized in that, The mass ratio of the coating to the welding core is 0.4-0.6:

1.

8. The method for preparing a 600MPa-grade high-toughness ultra-low hydrogen welding electrode according to claim 3, characterized in that, The drying temperature is 370-390℃, and the time is 1.5-2.5 h.

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