CN108723638B

CN108723638B - Sintered flux for niobium-titanium-containing stainless steel welding wire and preparation method and application thereof

Info

Publication number: CN108723638B
Application number: CN201810386117.6A
Authority: CN
Inventors: 王效莲; 王青云
Original assignee: 725th Research Institute of CSIC
Current assignee: 725th Research Institute of CSIC
Priority date: 2018-04-26
Filing date: 2018-04-26
Publication date: 2021-07-02
Anticipated expiration: 2038-04-26
Also published as: CN108723638A

Abstract

The invention belongs to the technical field of welding materials, and particularly relates to a sintered flux for a niobium-titanium-containing stainless steel welding wire, and a preparation method and application thereof. The sintered flux for the niobium-titanium-containing stainless steel welding wire comprises the following components in parts by mass: CaF₂51-53 parts; al (Al)₂O₃40-42 parts; CaSiO₃0.5-2 parts; k₃AlF₆1-2 parts; KMnO₄0.8-1.2 parts; 28-30 parts of water glass; the sintered flux is prepared by the steps of batching, dry mixing, wet mixing, granulating, drying, sintering, sieving and the like, is matched with submerged arc welding wires conforming to AWS A5.9 ER321 and ER347, and has good weld bead deslagging, forming and deposited metal performances. The flux has simple components and lower cost, and has larger market popularization prospect and good economic benefit along with the continuous expansion of the application field of the austenitic stainless steel intergranular corrosion resistance.

Description

Sintered flux for niobium-titanium-containing stainless steel welding wire and preparation method and application thereof

Technical Field

The invention belongs to the technical field of welding materials, and particularly relates to a sintered flux for a niobium-titanium-containing stainless steel welding wire, and a preparation method and application thereof.

Background

In order to improve the intergranular corrosion resistance of austenitic stainless steel, the prior mature technology is to add 8C-1.0% of Nb or (C-0.02) multiplied by 5-0.8% of Ti into austenitic stainless steel, because the Nb or the Ti can be more easily combined with C element than Cr element to generate more stable carbide NbC or TiC, thereby reducing carbon-chromium compounds (Cr, Fe) in the stainless steel₇C₃And (C, Fe)₂₃C₆The generation and the precipitation of the chromium-poor area of the crystal boundary are avoided, and the intergranular corrosion is further prevented.

The more widely used Nb-containing submerged arc welding wire listed in AWS a5.9 "stainless steel bare wire and filler wire standard" is ER347, and the Ti-containing submerged arc welding wire is ER 321. Because Nb and Ti are more active and are easily oxidized into NbO and TiO in the welding process, and the lattice size of the NbO and TiO is closer to the lattice size of alpha-Fe than FeO, the NbO and TiO are more easily connected with the alpha-Fe lattice, so that the submerged arc welding deslagging performance of the welding wire or the base metal containing Nb and Ti is poor.

At present, a sintered flux with excellent slag removal performance matched with the ER347 welding wire containing Nb and the ER321 welding wire containing Ti is difficult to find in the market. The literature and the patent are searched, some sintered fluxes for stainless steel strip electrode surfacing and wire electrode submerged arc welding are detected, but few sintered fluxes are related to matching welding wires and welding strips containing Nb and Ti elements, and even if the sintered fluxes are related, the components, the application range and the key technical route of the fluxes are different from those described in the patent.

Disclosure of Invention

In order to overcome the disadvantages and shortcomings of the prior art, the primary object of the present invention is to provide a sintered flux for a niobium-titanium-containing stainless steel welding wire, which uses CaF₂-Al₂O₃Slag system by precise control of the total SiO of the flux₂The content of the welding flux is 7.55-8.15%, the low oxidizability of the welding flux is ensured, the burning loss of Nb and Ti elements and the generation of NbO and TiO by the welding flux are reduced, the welding flux is matched with Nb and Ti-containing stainless steel welding wires such as ER321, ER347 and the like, the submerged arc welding deslagging, the forming and the welding seam metal performance are good, the welding flux is simple in component and low in cost, and the welding flux has a wide market popularization prospect and good economic benefits along with the continuous expansion of the application field of intergranular corrosion resistance of austenitic stainless steel.

The invention also aims to provide a preparation method of the sintered flux for the niobium-titanium-containing stainless steel welding wire.

Still another object of the present invention is to provide the use of the sintered flux for a niobium-titanium-containing stainless steel welding wire as described above.

The purpose of the invention is realized by the following technical scheme:

a sintered flux for a niobium-titanium-containing stainless steel welding wire comprises the following components in parts by mass:

the components of the sintered flux for the niobium-titanium-containing stainless steel welding wire are preferably added in the following modes:

CaF₂in the form of fluorite, Al₂O₃In the form of alpha-alumina, CaSiO₃In the form of wollastonite, potassium fluoroaluminate (K)₃AlF₆) And potassium permanganate (KMnO)₄) The sodium silicate is a chemically pure product, and the sodium silicate is in a potassium-sodium 1:1 sodium silicate form;

the fluorite preferably has a particle size of less than or equal to 80 meshes, and the chemical component of the fluorite is CaF₂≥95.0wt％，SiO₂≤1.00wt％，S≤0.010wt％，P≤0.010wt％；

The grain size of the alpha-alumina is preferably less than or equal to 120 meshes, and the chemical component of the alpha-alumina is preferably Al₂O₃≥98wt％，S≤0.035wt％，P≤0.035wt％；

The CaSiO₃The particle size of (B) is preferably 120 meshes or less, and the chemical composition thereof is preferably SiO₂≥40wt％，CaO≥42wt％，S≤0.040wt％，P≤0.040wt％；

The granularity of the potassium fluoroaluminate is preferably less than or equal to 120 meshes, and the chemical components of the potassium fluoroaluminate are preferably less than or equal to 48wt% and less than or equal to 53wt% of F, less than or equal to 15wt% and less than or equal to 20wt% of Al, less than or equal to 25wt% and less than or equal to 33wt% of K, less than or equal to 0.050wt% of S and less than or equal to 0.050;

the granularity of the potassium permanganate is preferably less than or equal to 60 meshes, and the chemical component of the potassium permanganate is preferably KMnO₄≥97wt％；

The chemical composition of the potassium-sodium 1:1 water glass is preferably SiO₂≥25wt％，K₂O≥5.5wt％，Na₂O is more than or equal to 5.5wt%, S is less than or equal to 0.050wt%, P is less than or equal to 0.050wt%, modulus M is more than or equal to 2.9 and less than or equal to 3.1, and density is 1.394-1.422 g/cm at 20 DEG C³；

The preparation method of the sintered flux for the niobium-titanium-containing stainless steel welding wire comprises the following steps of:

(1) preparing and dry-mixing components of a sintered flux for the niobium-titanium-containing stainless steel welding wire except water glass to obtain a mixture;

(2) wet mixing the mixture prepared in the step (1) with water glass uniformly to obtain a wet mixed material;

(3) granulating the wet mixed material prepared in the step (2), drying, sintering at high temperature for forming, and screening to obtain a sintered flux for the niobium-titanium-containing stainless steel welding wire;

the granulation in step (3) is preferably carried out in a granulation tray;

the drying temperature in the step (3) is preferably 300-400 ℃ for drying;

the temperature of the high-temperature sintering in the step (3) is preferably 630-730 ℃;

the sintered flux for the niobium-titanium-containing stainless steel welding wire can be further packaged and put in storage;

the granularity of the sintered flux for the niobium-titanium-containing stainless steel welding wire is preferably 12-60 meshes, wherein the welding process is unstable due to the excessively large particle size, and adverse effects such as poor air permeability and easiness in moisture absorption are caused on the welding process under the working condition due to the excessively small particle size.

The sintered flux for the niobium-titanium-containing stainless steel welding wire is applied to the field of welding;

the principle of the invention is as follows:

the sintered flux for the niobium-titanium-containing stainless steel welding wire provided by the invention is a fluorine-alkali type sintered flux which is CaF₂-Al₂O₃A slag system; wherein:

CaF₂is an alkaline fluoride which is a main component of slag and belongs to a slag former and a diluent in the flux. CaF in molten state₂The fluidity is good, the melting point, the viscosity and the surface tension of the slag can be reduced, and the fluidity of the slag is improved. The experimental result shows that CaF₂The content of (b) is not less than 51 parts by mass, and an excessively low content is liable to cause unfavorable spreading; CaF₂Not more than 53 parts by mass, and CaF is excessively high₂The content of (b) will make the arc unstable, resulting in poor bead formation and poor skull formation.

Al₂O₃Is a neutral oxide and is the main component of the slag. Among the fluxes, Al is an important vitreous slag former₂O₃The slag viscosity regulator can regulate the fluidity of slag and has the function of increasing the surface tension of slag. The experimental result of the invention shows that Al₂O₃Not more than 42 parts by mass, and excessive Al₂O₃Can cause pores and pockmarks in the weld joint, but Al₂O₃Not less than 40 parts by mass and excessively low Al₂O₃The uneven surface of the welding line can influence the welding line forming.

CaSiO₃Is a silicate with CaO and SiO₂The function of the method is to stabilize the arc, desulfurize, balance the pH value of the welding flux and improve the weld formation. The experimental result of the invention shows that CaSiO₃The content of (A) is not more than 2 parts by mass, and exceeding of the total tends to cause the total SiO content of the flux₂The content exceeds 8.15 percent, thereby increasing the slag sticking tendency of submerged arc welding matched with the ER321 and ER347 welding wires; CaSiO₃The content of (B) is not less than 0.5 parts by mass, and when too low, the arc is unstable and the bead formation is not good.

Potassium fluoroaluminate (K)₃AlF₆) The composite material is a chemical product, has the functions of reducing melting point, thinning slag and stabilizing arc, and can improve the wetting effect of weld metal and parent metal. The experimental result of the invention shows that K₃AlF₆The content of (b) is not more than 2 parts by mass, and when the content is too large, the slag is too thin, and the surface ripple of the welding seam is thick; but K₃AlF₆The content of (B) is not less than 1 part by mass, and when too low, fluidity of flux slag is deteriorated and bead bulge occurs.

Potassium permanganate (KMnO)₄) Is a chemical product which is heated and decomposed to generate K in the sintering or welding process₂O、MnO₂MnO, etc. K₂O has good arc stabilizing and melting point lowering effects, and can supplement K which is less added due to reduction of water glass consumption₂O。MnO₂MnO also has good arc stabilization and slag thinning effects, the gas permeability of slag can be enhanced, and gas indentations on the surface of a welding seam and gas holes on the back of a slag shell are effectively eliminated. The experimental result of the invention shows that KMnO₄The content of (b) is not more than 1.2 parts by mass, and when too much, the melting point of the flux is too low, and the slag shell formation is poor; KMnO₄The content of (b) is not less than 0.8 parts by mass, and when too low, the arc stability of the flux is insufficient, the weld formation becomes poor, and pores are easily left on the back surface of the skull.

One of the functions of the potassium-sodium 1:1 water glass is to bind the powder, and the two functions are due to the influence of its composition on the performance of the solder. Wherein the low-melting point alkaline component K₂O、Na₂O has the functions of stabilizing arc and reducing melting point, and has the functions of balancing the pH value of the flux, improving the fluidity of slag and optimizing the formation of the surface of a welding seam. In order to avoid introducing too much SiO into the flux₂Resulting in matching ER321 and ER347 submerged arcsWhen welding, the slag is adhered, and the addition amount of the water glass is reduced as much as possible on the premise of ensuring good granulation and welding manufacturability of the welding flux. The experimental result of the invention shows that when the adding amount of the potassium-sodium 1:1 water glass exceeds 30 parts by mass, the total SiO of the flux is easily caused₂The content exceeds 8.15 percent, thereby increasing the slag sticking tendency of submerged arc welding matched with the ER321 and ER347 welding wires; when the amount of potassium-sodium 1:1 water glass added is less than 28 parts by mass, the flux total SiO is easily caused₂When the content is less than 7.55%, the electric arc is unstable in the welding process, the welding bead bulges, and the spreading straightness of the welding bead is poor.

By controlling the content of each component, the prepared sintered flux for the niobium-titanium-containing stainless steel welding wire has the following characteristics:

(1) using CaF of high basicity₂-Al₂O₃Slag system, by controlling the SiO content of wollastonite, water glass and the like₂Ingredient flux raw material adding amount, and accurately controlling total SiO in flux₂The content is 7.55-8.15%, so that good weld forming can be guaranteed, and the welding wires (ER321 and ER347 welding wires) containing Nb and Ti can be matched for submerged arc welding without slag adhesion. Total SiO of the solder of the invention₂There are three sources: one is containing SiO₂The flux raw material powder wollastonite and the water glass which plays a role in bonding; third, SiO in fluorite powder₂Impurities. Total SiO in flux₂Content (wt%) calculation method: (SiO contained in the respective components of the flux)₂The sum of the weights is divided by the weight of the flux after sintering) x 100%;

(2) by using potassium permanganate KMnO₄Product K of thermal decomposition₂O to supplement K which is added little by controlling the amount of water glass₂O, using potassium permanganate KMnO₄MnO product of thermal decomposition₂MnO to stabilize the arc and increase slag permeability.

Compared with the prior art, the invention has the following advantages and effects:

(1) the sintered flux for the niobium-titanium-containing stainless steel welding wire is matched with ER347 and ER321 welding wires for submerged arc welding, the welding arc is stable, the slag removal performance is excellent, the width of a welding bead is narrow and uniform, the stacking height is moderate, the transition is smooth, and the surface of the welding bead has no defects of gas indentation, cracks, slag adhesion and the like. The content of the deposited metal Ti of the ER321 welding wire meets the requirement of (C-0.02) multiplied by 5-0.8%, and the content of the deposited metal Nb of the ER347 welding wire meets the requirement of 8C-1.0%, so that the two deposited metals have good intergranular corrosion resistance, and other chemical components and mechanical properties are good.

(2) Compared with the similar sintered flux, the sintered flux for the niobium-titanium-containing stainless steel welding wire provided by the invention has the advantages of simple components, good granulation effect, low sintering temperature and excellent production adaptability, and is beneficial to simplifying quality management and process control in production, thereby being more beneficial to reducing cost and ensuring the stability of product quality.

Drawings

FIG. 1 is a graph showing analysis of bead results after submerged arc welding with two welding wires, ER321 and ER347, of flux matching prepared in examples 1-3; wherein, A: the flux prepared in example 1 matches the weld bead after ER321 application; b: the flux prepared in example 2 matches the weld bead after ER321 application; c: the flux prepared in example 3 matched the weld bead after ER347 application; d: the flux prepared in example 3 matched the weld bead after ER321 application; e: the flux prepared in comparative example 1 matches the weld bead after ER321 application; f: the flux prepared in comparative example 2 matched the weld bead after ER321 application.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

Example 1

(1) removing potassium and sodium 1:1, preparing materials outside water glass, and putting the materials into a stirrer for full dry mixing to obtain a mixture;

(3) and (3) putting the wet mixed material prepared in the step (2) into a granulator for granulation, drying the prepared granules in a rotary drying furnace at 300-330 ℃ for 30min, drying, then conveying the dried granules into a rotary sintering furnace for high-temperature sintering, wherein the sintering temperature is 630-640 ℃, the sintering time is 30min, taking out the granules from the rotary sintering furnace for cooling, screening out granules with 12-60 meshes, packaging, inspecting and warehousing after passing, thus obtaining the finished sintered flux for the niobium-titanium-containing stainless steel welding wire.

Example 2

(3) and (3) putting the wet mixed material prepared in the step (2) into a granulator for granulation, sending the prepared granules into a rotary drying furnace at 340-360 ℃ for drying for 40min, sending the dried granules into a rotary sintering furnace for high-temperature sintering at 660-670 ℃ for 40min, taking the granules out of the rotary sintering furnace for cooling, screening out granules with 12-60 meshes, packaging, inspecting and warehousing after qualification, and obtaining the finished sintered flux for the niobium-titanium-containing stainless steel welding wire.

Example 3

(3) and (3) putting the wet mixed material prepared in the step (2) into a granulator for granulation, drying the prepared granules in a rotary drying furnace at 380-400 ℃ for 50min, drying, then conveying the dried granules into a rotary sintering furnace for high-temperature sintering, wherein the sintering temperature is 720-730 ℃, the sintering time is 50min, taking out the granules from the rotary sintering furnace for cooling, screening out granules with 12-60 meshes, packaging, inspecting, and warehousing after passing, thus obtaining the finished sintered flux for the niobium-titanium-containing stainless steel welding wire.

Comparative example 1

The sintered flux comprises the following components in parts by mass:

the preparation method of the sintered flux comprises the following steps:

(1) removing potassium and sodium from the components of the sintered flux by 1:1, preparing materials outside water glass, and putting the materials into a stirrer for full dry mixing to obtain a mixture;

(3) and (3) putting the wet mixed material prepared in the step (2) into a granulator for granulation, drying the prepared granules in a rotary drying furnace at 380-400 ℃ for 50min, drying, then conveying the dried granules into a rotary sintering furnace for high-temperature sintering, wherein the sintering temperature is 720-730 ℃, the sintering time is 50min, taking out of the rotary sintering furnace for cooling, screening out granules with 12-60 meshes, packaging, inspecting, and warehousing to obtain the finished sintered flux.

Comparative example 2

The sintered flux comprises the following components in parts by mass:

the preparation method of the sintered flux comprises the following steps:

Effects of the embodiment

The chemical composition requirements of each raw material component of the fluxes obtained in examples 1 to 3 and comparative examples 1 to 2 are shown in table 1.

TABLE 1 chemical composition requirements for the raw material components of the fluxes

The welding fluxes prepared in the examples 1 to 3 and the comparative examples 1 to 2 were tested and matched with two welding wires, namely ER321 and ER347, for submerged arc welding, wherein the specifications of the welding wires and the welding specifications are shown in Table 2.

TABLE 2 welding wire Specifications and welding Specifications

(1) Post-weld bead analysis

FIG. 1 shows the welding beads formed by submerged arc welding of the welding fluxes prepared in examples 1 to 3 and comparative examples 1 to 2 with two welding wires, namely ER321 and ER347, wherein the welding fluxes in examples 1 to 3 within the range of formula design have good slag removal performance and good welding bead spreading; the comparative example 1 outside the formulation design range has unstable arc and no straight spreading of the welding bead due to the flux matched with ER321 welding wire; the flux of comparative example 2 outside the range of the formula design is matched with the ER321 welding wire, the slag removal is not good, and the slag is adhered on the surface of the welding bead.

(2) Mechanical properties

Table 3 shows the mechanical properties of the deposited metal obtained by matching the flux obtained in example 3 with the two welding wires ER347 and ER 321.

TABLE 3 mechanical Properties of deposited metals

Sample number and reference standard	Rp_0.2/Mpa	Rm/Mpa	A/％	Z/％	KV₂/(J，-196℃)
						Example 3+ ER347	367	585	40.0	63	39. 38, 42 mean value 39.7
Example 3+ ER321	401	639	43.0	69	43. 48, 48 mean 46.3

(3) Chemical composition

Table 4 shows that the flux obtained in example 3 matches the chemical compositions of deposited metals obtained from two types of welding wires, ER347 and ER321, and that the flux causes less impurity elements such as S, P to be incorporated into the weld metal. The content of the ER347 welding wire deposited metal Nb meets the requirement of 8C-1.0%, and the content of the ER321 welding wire deposited metal Ti meets the requirement of (C-0.02) x 5-0.8%.

TABLE 4 chemical composition of welding wire and deposited metal

(4) Intergranular corrosion resistance

Tests prove that the two deposited metals obtained by preparing ER347 in example 3 and preparing ER321 in example 3 are bent 180 degrees after being boiled in a slightly boiling sulfuric acid-copper sulfate solution for 16 hours according to GB/T4334-.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A sintered flux for a niobium-titanium-containing stainless steel welding wire is characterized by comprising the following components in parts by mass:

CaF₂51-53 parts;

Al₂O₃40-42 parts;

CaSiO₃0.5-2 parts;

1-2 parts of potassium fluoroaluminate;

0.8-1.2 parts of potassium permanganate;

28-30 parts of water glass;

accurate control of total SiO in flux₂The content is 7.55-8.15%.

2. The sintered flux for niobium-containing titanium stainless steel welding wire according to claim 1, characterized in that:

the sintered flux for the niobium-titanium-containing stainless steel welding wire comprises the following components in an adding mode:

CaF₂in the form of fluorite, Al₂O₃In the form of alpha-alumina, CaSiO₃In the form of wollastonite and the water glass in the form of potassium-sodium 1:1 water glass.

3. The sintered flux for niobium-containing titanium stainless steel welding wire according to claim 2, characterized in that:

the fluorite has a granularity of less than or equal to 80 meshes and contains CaF as a chemical component₂≥95.0wt%，SiO₂≤1.00wt%，S≤0.010wt%，P≤0.010wt%。

4. The sintered flux for niobium-containing titanium stainless steel welding wire according to claim 2, characterized in that:

the CaSiO₃The granularity of the material is less than or equal to 120 meshes, and the chemical component of the material is SiO₂≥40wt%，CaO≥42wt%，S≤0.040wt%，P≤0.040wt%。

5. The sintered flux for niobium-containing titanium stainless steel welding wire according to claim 1, characterized in that:

the granularity of the potassium fluoroaluminate is less than or equal to 120 meshes, and the potassium fluoroaluminate comprises the chemical components of less than or equal to 48wt% and less than or equal to 53wt% of F, less than or equal to 20wt% of Al, less than or equal to 15wt% and less than or equal to 33wt% of K, less than or equal to 0.050wt% of S and less than or equal to 0.050 wt%.

6. The sintered flux for niobium-containing titanium stainless steel welding wire according to claim 2, characterized in that:

the chemical component of the potassium-sodium 1:1 water glass is SiO₂≥25wt%，K₂O≥5.5wt%，Na₂O is more than or equal to 5.5wt%, S is less than or equal to 0.050wt%, P is less than or equal to 0.050wt%, modulus M is more than or equal to 2.9 and less than or equal to 3.1, and density is 1.394-1.422 g/cm at 20 DEG C³。

7. The method for preparing a sintered flux for a niobium-titanium-containing stainless steel welding wire according to any one of claims 1 to 6, characterized by comprising the steps of:

(3) and (3) granulating the wet mixed material prepared in the step (2), drying, sintering at a high temperature for forming, and screening to obtain the sintered flux for the niobium-titanium-containing stainless steel welding wire.

8. The method for preparing a sintered flux for a niobium-titanium-containing stainless steel welding wire according to claim 7, characterized in that:

the temperature of the high-temperature sintering in the step (3) is 630-730 ℃.

9. The method for preparing a sintered flux for a niobium-titanium-containing stainless steel welding wire according to claim 7, characterized in that:

the particle size of the sintered flux for the niobium-titanium-containing stainless steel welding wire is 12-60 meshes.

10. Use of the sintered flux for a niobium titanium stainless steel wire as claimed in any one of claims 1 to 6 in the field of welding.