Hard-face flux-cored wire with grain refinement effect and preparation technology of hard-face flux-cored wire

Abstract

The invention discloses a hard-face flux-cored wire with a grain refining effect and a preparation process thereof, the hard-face flux-cored wire comprises a low-carbon steel sheath and a flux core filled in the low-carbon steel sheath, and the flux core comprises the following components in percentage by mass: 60-85wt% of high-carbon ferrochrome alloy powder, 10-15wt% of high-carbon ferrochrome alloy powder, 10-15wt% of high-carbon ferrochrome alloy powder and 10-15wt% of high-carbon ferrochrome alloy powder; 1 to 5 weight percent of potassium manganese titanate KMnTiO4; 1-5 wt% of electrolytic manganese powder; 1-5 wt% of rare earth ferrosilicon; 3 to 10 weight percent of graphite powder; and the balance of iron powder and inevitable impurities. In this way, grain refinement and deoxidation are achieved, the electric arc stability is improved, the mechanical property of weld metal is improved, the mechanical property of deposited metal is improved, and the crack resistance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of welding materials, in particular to a hard-faced flux-cored welding wire with grain refinement effect and a preparation process thereof. Background Art

[0002] During the high-carbon and high-chromium open arc welding hardfacing process, the weld layer is prone to the following problems: (1) Increased brittleness and reduced impact resistance: Especially when the carbon content exceeds 3% and the chromium content exceeds 20%, the weld layer will form a large amount of coarse initial carbides, causing the hard surface layer to become brittle and not resistant to impact; (2) Poor welding quality: The high alloy content makes the arc less stable and prone to spattering, affecting the welding quality; (3) Coarse grains affect performance: The grains and carbides of the weld layer are coarse, which will further reduce the hardness and wear resistance.

[0003] Based on the above defects and deficiencies, it is necessary to improve the existing technology and design a hard-surface flux-cored welding wire with grain refinement effect and its preparation process. Summary of the Invention

[0004] The main technical problem solved by the present invention is to provide a hard-faced flux-cored welding wire with grain refining effect and its preparation process, which refines the grains, improves arc stability through deoxidation, improves the mechanical properties of the weld metal, improves the mechanical properties of the deposited metal, and improves crack resistance.

[0005] To solve the above technical problems, the present invention adopts a technical solution: providing a hard-faced flux-cored welding wire with a grain refining effect, comprising a low-carbon steel outer sheath and a flux core filled in the low-carbon steel outer sheath, wherein the flux core comprises the following components:

[0006] High carbon ferrochromium alloy powder: the mass percentage of the flux core is 60-85wt%, providing basic hardness and wear resistance of the welding material;

[0007] Potassium manganese titanate KMnTiO4: The mass percentage of KMnTiO4 in the flux core is 1-5wt%, which acts as an arc stabilizer and grain refiner to improve arc stability and refine grains;

[0008] Electrolytic manganese powder: The mass percentage of the flux core is 1-5wt%, which improves the mechanical properties of the weld metal and enhances crack resistance;

[0009] Rare earth ferrosilicon: The mass percentage of the rare earth ferrosilicon in the flux core is 1-5wt%, which refines the grains, deoxidizes, and improves the mechanical properties of the deposited metal;

[0010] Graphite powder: The mass percentage of graphite powder in the core is 3-10wt%, which increases the carbon content and improves the hardness;

[0011] The remainder is iron powder and inevitable impurities.

[0012] Preferably, the filling rate of the drug core is 40-55%.

[0013] A process for preparing a hard-faced flux-cored welding wire with a grain refining effect comprises the following steps:

[0014] S1, according to the mass percentage of each of the corresponding high carbon ferrochromium alloy powder in the core, 60-85 wt% of potassium manganese titanate KMnTiO4, 1-5 wt% of electrolytic manganese powder, 1-5 wt% of rare earth ferrosilicon and 3-10 wt% of graphite powder, uniformly mix to obtain a mixture;

[0015] S2. Filling the mixture into the outer sheath of a flux-cored welding wire made of low carbon steel at a filling ratio of 40-55%;

[0016] S3. Flux-cored welding wire is made through extrusion, drawing and other processes.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] Improve arc stability: Potassium manganese titanate effectively improves arc stability and reduces spatter during welding. The strong deoxidation effect of silicon in rare earth ferrosilicon effectively removes oxygen impurities during welding, improving welding efficiency and weld quality.

[0019] Refinement of grains and carbides: TiO2 particles generated by the decomposition of potassium manganese titanate form heterogeneous nucleation points in the hard surface layer, effectively refining grains and carbides, improving hardness and toughness. Rare earth elements significantly refine grains and improve the microstructure of the weld layer.

[0020] Improved mechanical properties: High-carbon ferrochromium alloy powder provides the basic hardness and wear resistance of the welding material, and the hardness, wear resistance and impact resistance of the weld layer are significantly improved;

[0021] Improve the properties of deposited metal: Rare earth elements improve the organizational structure of deposited metal, increase toughness and crack resistance, and extend service life. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described in detail below so that the advantages and features of the invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0023] The embodiments of the present invention include:

[0024] A hard-faced flux-cored welding wire with a grain-refining effect comprises a low-carbon steel outer sheath and a flux core filled in the low-carbon steel outer sheath. The flux core components and their mass percentages in the flux core are as follows: high-carbon ferrochromium alloy powder: 60-85wt%; potassium manganese titanate KMnTiO4: 1-5wt%; electrolytic manganese powder: 1-5wt%; rare earth ferrosilicon: 1-5wt%; graphite powder: 3-10wt%; the remainder being iron powder and unavoidable impurities.

[0025] High carbon ferrochromium alloy powder provides basic hardness and wear resistance for welding materials. The hardness, wear resistance and impact resistance of the weld layer are significantly improved, thus extending the service life.

[0026] Compared with potassium titanate, potassium manganese titanate has an additional deoxidation and degassing effect. During the arc welding process of flux-cored welding wire, potassium manganese titanate is decomposed into manganese ions by the arc. Manganese ions have a high binding ability with oxygen. Potassium manganese titanate effectively improves arc stability, reduces spatter during welding, and improves welding efficiency and weld quality.

[0027] The TiO2 particles produced by the decomposition of potassium manganese titanate form heterogeneous nucleation points in the hard surface layer, effectively refining the grains and carbides, and improving the hardness and toughness.

[0028] Compared with potassium titanate plus electrolytic manganese, electrolytic manganese first needs to be made by electrolysis, and because it is made by electrolysis, electrolytic manganese has the problem of high gas content. In addition, manganese in alloy or metallic state and manganese ions in potassium manganese titanate (KMnTiO4) do have significant differences in properties. These differences are mainly reflected in the following aspects:

[0029] Different oxidation states: Manganese in metallic or alloyed states is usually in a zero-valent (Mn^0) or low-valent state, while in potassium manganese titanate, manganese is generally in a higher oxidation state (such as Mn^3+ or Mn^4+). This difference in oxidation state makes the reaction characteristics and chemical stability of manganese ions in potassium manganese titanate similar to those of metallic manganese. High-valent manganese ions are more active and easily react with other elements, thus more effectively forming stable compounds or precipitates during grain refinement, which inhibits grain growth.

[0030] Chemical activity and interfacial behavior: Highly oxidized manganese ions are more active in the molten pool than metallic manganese, especially when they coexist with elements such as titanium and potassium. They are more likely to generate complex oxides or nitrides. These compounds act as refiners and can form tiny crystal nuclei in the molten pool, which helps to evenly distribute them in the weld metal and promote grain refinement. In addition, high-valent manganese ions are prone to interfacial reactions with other active elements, further enhancing the refinement effect.

[0031] Rare earth ferrosilicon has the following functions:

[0032] Grain refinement: Rare earth elements significantly refine grains and improve the microstructure of the weld layer;

[0033] Deoxidation: The strong deoxidation effect of silicon element effectively removes oxygen impurities during welding and improves the quality of welds;

[0034] Improve the properties of deposited metal: Rare earth elements improve the organizational structure of deposited metal, and increase its toughness and crack resistance.

[0035] Adding rare earth ferrosilicon and potassium manganese titanate to flux-cored wire generally produces better grain refinement than adding either material alone for the following reasons:

[0036] (1) Synergistic effect of multiple elements: rare earth elements and potassium manganese titanate can produce a synergistic effect during the welding process. Rare earth elements can effectively remove impurities and oxides in the weld and improve the purification effect of the molten pool, while potassium manganese titanate can provide a large number of fine crystal nuclei and promote grain refinement. Therefore, the combination of the two can more effectively control the grain growth rate and form finer grains.

[0037] (2) Improve the crystallization process: The rare earth elements in rare earth ferrosilicon help to lower the crystallization temperature of the weld metal, increase the supercooling of the weld, promote the formation of more crystal nuclei, and thus inhibit the formation of coarse grains. The titanium in potassium manganese titanate also helps to form stable fine precipitates, which act as crystal nuclei to help refine the grains. Therefore, the combination of the two can better control the cooling and solidification process of the molten pool, making the grain structure more uniform and fine.

[0038] (3) Improve element distribution: Rare earth elements can change the distribution of other elements (such as titanium, manganese, and potassium), making the diffusion and deposition of these elements in the weld more uniform. In this way, the titanium element in potassium manganese titanate is more likely to form uniformly distributed fine precipitates with the assistance of rare earth elements, further refining the grains;

[0039] (4) Anti-oxidation and anti-impurity effects: The rare earth elements in rare earth ferrosilicon have strong deoxidation and deimpurity capabilities, which can reduce the oxide and impurity content in the molten pool, thereby improving the effective effect of potassium manganese titanate. This effect enhances the effect of titanium and manganese as refiners, allowing them to more effectively generate fine precipitates and ultimately promote grain refinement.

[0040] A process for preparing a hard-faced flux-cored welding wire with a grain refining effect comprises the following steps:

[0041] S1, taking the corresponding high carbon ferrochrome alloy powder, potassium manganese titanate KMnTiO4, electrolytic manganese powder, rare earth ferrosilicon and graphite powder according to their respective mass percentages in the core, and uniformly mixing to obtain a mixture;

[0042] S2. Filling the mixture into the outer sheath of a flux-cored welding wire made of low carbon steel at a filling ratio of 40-55%;

[0043] S3. Flux-cored welding wire is made through extrusion, drawing and other processes.

[0044] The invention discloses a hard-face flux-cored welding wire with grain refining effect and a preparation process thereof, which refines grains, improves arc stability through deoxidation, improves the mechanical properties of weld metal, improves the mechanical properties of deposited metal, and improves crack resistance.

[0045] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A hard-faced flux-cored welding wire with grain refining effect, characterized in that: It comprises a low carbon steel outer skin and a core filled in the low carbon steel outer skin, wherein the core comprises the following components: High carbon ferrochrome alloy powder: the mass percentage of the powder in the flux core is 60-85wt%, providing basic hardness and wear resistance of the welding material; Potassium manganese titanate KMnTiO4: The mass percentage of KMnTiO4 in the flux core is 1-5wt%, which acts as an arc stabilizer and grain refiner to improve arc stability and refine grains; Electrolytic manganese powder: The mass percentage of the powder in the flux core is 1-5wt%, which improves the mechanical properties of the weld metal and increases crack resistance; Rare earth ferrosilicon: The mass percentage of the rare earth ferrosilicon in the flux core is 1-5wt%, which refines the grains, deoxidizes, and improves the mechanical properties of the deposited metal; Graphite powder: The mass percentage of graphite powder in the core is 3-10wt%, increasing the carbon content and improving the hardness; The remainder is iron powder and inevitable impurities.

2. The process for preparing a hard-surface flux-cored welding wire with grain refinement effect according to claim 1, characterized in that: The filling rate of the drug core is 40-55%.

3. A process for preparing a hard-faced flux-cored welding wire with a grain refining effect, characterized in that: The following steps are involved: S1, according to the mass percentage of each in the core, take 60-85wt% of high carbon ferrochrome alloy powder, 1-5wt% of potassium manganese titanate KMnTiO4, 1-5wt% of electrolytic manganese powder, 1-5wt% of rare earth ferrosilicon and 3-10wt% of graphite powder, mix them evenly to obtain a mixture; S2, filling the mixture into the outer sheath of a flux-cored welding wire made of low carbon steel at a filling ratio of 40-55%; S3. Flux-cored welding wire is made through extrusion, drawing and other processes.