WO2023134149A1 - Tc4 titanium alloy submerged arc welding flux, a preparation method therefor and application thereof - Google Patents

Abstract

A TC4 titanium alloy submerged arc welding flux, prepared from an adhesive and powder, wherein the powder is formed by mixing, by mass fraction, 4.5% to 5.5% of BaCl₂, 1.8% to 2.1% of LiF, 4.8% to 5.1% of NaF, and the remainder being CAF₂. The preparation method for the TC4 titanium alloy submerged arc welding flux comprises: mixing and dry-stirring raw material powder according to a powder proportion, then adding an adhesive and continue stirring to obtain a mixture; and drying the obtained mixture at a low temperature, then sintering same at a high temperature, cooling same to room temperature, and sieving same to obtain the TC4 titanium alloy submerged arc welding flux. According to the welding flux, the proportion of each component of the welding flux is set, the viscosity, surface tension and fluidity of molten slag are optimized, and when the welding flux is used in conjunction with a TC4 titanium alloy submerged arc welding wire for submerged arc welding, good welding process performance and mechanical performance are achieved. The present invention also relates to an application of the submerged arc welding flux.

Description

A kind of TC4 titanium alloy submerged arc welding flux and its preparation method and application

This application claims the priority of the Chinese patent application submitted to the China Patent Office on January 11, 2022, with the application number 202210025891.0, and the title of the invention is "a TC4 titanium alloy submerged arc welding flux and its preparation method and application", the entire content of which Incorporated in this application by reference.

technical field

The invention belongs to the technical field of welding materials, and in particular relates to a TC4 titanium alloy submerged arc welding flux and a preparation method and application thereof.

Background technique

TC4 titanium alloy is an important structural material, because of its excellent comprehensive properties (low density, high specific strength, stable corrosion resistance and high temperature resistance, etc.), it is widely used in aerospace, deep submersibles and weaponry and other fields . At present, the filling welding of TC4 titanium alloy thick-walled components mostly adopts MIG shielded welding and laser wire filling welding. The multi-layer welding process not only restricts the substantial improvement of its efficiency, but also increases the probability of welding defects due to the multi-pass filling during the welding process, and at the same time, repeated heating will also cause the grain coarsening of the structure. In addition, ultra-narrow gap welding technology will also cause defects such as poor fusion of side walls, pore slag inclusions, etc., and put forward higher requirements for welding equipment and processes. Therefore, it is urgent to find a welding material that is simple and efficient, has a low probability of defect occurrence, and has high reliability to solve the technical problems in the field of welding thick-walled titanium alloys.

Contents of the invention

In order to solve the above technical problems, the present invention provides a TC4 titanium alloy submerged arc welding flux and its preparation method and application.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides a TC4 titanium alloy submerged arc welding flux, which is prepared from a binder and powder, and the powder is composed of BaCl ₂ : 4.5%-5.5%, LiF: 1.8%-2.1%, NaF : 4.8% ~ 5.1% and the balance of CaF ₂ mixed.

It is further defined that the binder is high modulus potassium sodium water glass with a modulus of 2.8-3.1 and a potassium-sodium ratio of 3:1.

It is further defined that the mass fraction of the binder in the flux is 3%-5%.

It is further defined that the powder is formed by mixing BaCl ₂ : 5%, LiF : 2%, NaF : 5% and the balance of CaF ₂ in mass fraction.

It is further defined that the mass percentage of H in the powder is ≤0.003%, the mass percentage of N is ≤0.005%, the mass percentage of O is ≤0.010%, the mass percentage of S is ≤0.003%, and the mass percentage of P is ≤ 0.003%.

The present invention provides the preparation method of TC4 titanium alloy submerged arc welding flux described in the above scheme, which is carried out in the following steps:

Step 1: Mix and dry mix the raw material powders according to the powder ratio for 3 minutes to 5 minutes, then add the binder and continue stirring for 4 minutes to 6 minutes to obtain the mixture;

Step 2: drying the mixture obtained in step 1 at low temperature, then sintering at high temperature, cooling to room temperature and then sieving to obtain TC4 titanium alloy submerged arc welding flux.

Further defined, the parameters of the low-temperature drying in step 2 are: the temperature is 180-230° C., and the time is 35 minutes-60 minutes.

Further defined, the parameters of the high-temperature sintering in step 2 are: the temperature is 700-900° C., and the time is 50 min-70 min.

It is further defined that the size of the sieve in step 2 is 10-80 mesh.

The present invention provides the application of the TC4 titanium alloy submerged arc welding flux described in the above scheme for TC4 titanium alloy submerged arc welding.

It is further defined that the TC4 titanium alloy submerged arc welding flux is used in conjunction with the TC4 titanium alloy submerged arc welding wire.

Further limit, TC4 titanium alloy submerged arc welding flux and TC4 titanium alloy submerged arc welding wire are used together to carry out the chemical composition and content of weld deposit metal after TC4 titanium alloy submerged arc welding: C: ≤ 0.04wt%, Al: 5.20wt %～5.45wt%, V: 4.20wt%～4.80wt%, Fe: 0.10wt%～0.20wt%, Li: 0.15wt%～0.20wt%, Mn: ≤0.015wt%, P≤0.01wt%, S ≤0.02wt%, N: ≤0.02wt%, the balance is Ti.

Advantages of the present invention compared to prior art:

The main core means of regulating the structure and properties of titanium alloy submerged arc welding joints is to adjust the microstructure by changing the composition of submerged arc welding wire and flux, so as to optimize the mechanical properties of welded joints. The invention proposes a TC4 titanium alloy submerged arc flux, which supplements the burning loss of elements in the welding process, adds beneficial elements to the weld seam, uses submerged arc welding technology to perform high-efficiency and high-quality welding of thick-walled titanium alloy components, and realizes welding joints The control of tissue performance finally obtains high-quality welded joints. The invention scientifically adjusts the proportions of components of the flux, and optimizes the viscosity, surface tension and fluidity of molten slag. When welding with TC4 titanium alloy submerged arc welding wire, the arc is stable during the welding process, the smoke is less, the slag is easy to remove, the weld shape is beautiful, and it has good welding process performance and mechanical properties. The specific advantages are as follows:

1) In the present invention, _CaF2 is mainly used to suppress the transition of harmful elements such as H, O, N to the weld, control the content of S and P in the weld, which is beneficial to reduce the melting point of the flux, and ensure the purity of the weld metal and the process performance of the flux ; At the same time, CaF ₂ can also increase the gas permeability of slag, reduce the viscosity of slag, and make the slag _removal performance better; The fluidity of the slag is improved, and the weld pool is isolated and protected in time; but too much CaF ₂ will cause the electrical conductivity to be too high and the viscosity of the slag to decrease, which will affect the stability of the slag formation process, thereby affecting the weld formation.

2) The welding slag generated by adding BaCl ₂ to the flux can evenly cover the surface of the weld metal, reduce the cooling rate of the weld metal, control the content of α' martensite, and obtain good weld formation. An appropriate content of _BaCl2 can ensure that the slag has an appropriate melting point and density, and can remove harmful impurities such as sulfur and phosphorus in the weld to ensure the purity of the weld, thereby ensuring the impact toughness of the weld. In addition, BaCl ₂ has a lower melting point than BaF ₂ , which can reduce the welding heat input during the welding process, thereby ensuring the refinement of the weld microstructure. At the same time, the addition of _BaCl2 significantly reduces the content of O and N in the weld, thus ensuring the impact toughness of the weld.

3) Adding LiF to the flux can also reduce the melting point of the flux and improve the process performance of the flux; in addition, by strictly controlling the content of metal Li in the flux, the transformation temperature of the β phase in the weld metal can be significantly increased, and the residual β phase can be refined. Thereby, the ductility and toughness of the weld metal can be improved.

4) Adding NaF and LiF to the flux can combine with H in the weld to form HF gas overflow, which is beneficial to reduce the partial pressure of H in the arc atmosphere, thereby dehydrogenating and reducing the generation of hydrogen-induced cracks.

5) Adding an appropriate amount of high modulus potassium sodium water glass to the flux can improve the arc stability and increase the alkalinity of the flux. When the content of high modulus potassium sodium water glass in water glass is greater than 5%, the hydrogen content in the weld tends to increase significantly, so the mass fraction of high modulus potassium sodium water glass in the flux is controlled at 3% to 5%.

Detailed ways

The present invention will be further described below in conjunction with the embodiments and accompanying drawings.

Example 1:

A kind of TC4 titanium alloy submerged arc welding flux of the present embodiment is prepared from binder and powder, wherein powder is composed of BaCl ₂ : 4.5%, LiF: 2.0%, NaF: 4.9% and the CaF of balance ₂ mixed, the binder is high modulus potassium sodium water glass, the modulus is 2.8 to 3.1, the potassium-sodium ratio is 3:1, the mass fraction of the binder in the flux is 4%, and the powder The mass percentage content of H in the material is ≤0.003%, the mass percentage content of N is ≤0.005%, the mass percentage content of O is ≤0.010%, the mass percentage content of S is ≤0.003%, and the mass percentage content of P is ≤0.003%.

Described flux preparation method is carried out as follows:

Step 1: Mix and dry mix the raw material powders according to the powder ratio for 4 minutes, then add the binder and continue stirring for 5 minutes to obtain the mixture;

Step 2: Dry the mixture obtained in step 1 at low temperature at 200°C for 45 minutes, then sinter at 800°C for 60 minutes at high temperature, cool to room temperature and pass through an 80-mesh sieve to obtain TC4 titanium alloy submerged arc welding flux.

Example 2:

A kind of TC4 titanium alloy submerged arc welding flux of the present embodiment is prepared from binder and powder, wherein the powder consists of BaCl ₂ : 5%, LiF: 2.1%, NaF: 5.1% and the CaF of the balance ₂ mixed, the binder is high modulus potassium sodium water glass, the modulus is 2.8 to 3.1, the potassium-sodium ratio is 3:1, the mass fraction of the binder in the flux is 4%, and the powder The mass percentage content of H in the material is ≤0.003%, the mass percentage content of N is ≤0.005%, the mass percentage content of O is ≤0.010%, the mass percentage content of S is ≤0.003%, and the mass percentage content of P is ≤0.003%.

Described flux preparation method is carried out as follows:

Step 1: Mix and dry mix the raw material powders according to the powder ratio for 4 minutes, then add the binder and continue stirring for 5 minutes to obtain the mixture;

Step 2: Dry the mixture obtained in step 1 at low temperature at 200°C for 45 minutes, then sinter at 800°C for 60 minutes at high temperature, cool to room temperature and pass through an 80-mesh sieve to obtain TC4 titanium alloy submerged arc welding flux.

Application example 1:

The TC4 titanium alloy submerged arc welding flux of Embodiment 1～2 is used for TC4 titanium alloy submerged arc welding, and the specific process is as follows:

The TC4 titanium alloy submerged arc welding flux of Examples 1-2 is used in conjunction with the TC4 titanium alloy submerged arc welding wire with a diameter of 4.0mm for multi-layer multilayer submerged arc welding. The base material is a TC4 titanium alloy plate with a specification of 300mm×200mm× 30mm, process V-shaped groove, single-side groove angle is 30°, groove blunt edge is 5mm, groove root gap is 10mm, a total of 12 weldings are completed to complete the test plate welding, and the interlayer temperature is controlled within 100°C. AC welding power supply, Table 1 is the welding process parameters, Table 2 is the chemical composition of the weld deposited metal, and Table 3 is the test results of the mechanical properties of the welded joint.

Table 1 Welding process parameters

Table 2 Results of chemical composition of weld deposited metal

Table 3 Mechanical property test results

The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (16)

1. A TC4 titanium alloy submerged arc welding flux is characterized in that it is prepared from a binder and powder, and the powder consists of BaCl ₂ : 4.5% to 5.5%, LiF: 1.8% to 2.1%, NaF : 4.8% ~ 5.1% and the balance of CaF ₂ mixed.
2. The TC4 titanium alloy submerged arc welding flux according to claim 1, wherein the binder is high modulus potassium sodium water glass, the modulus is 2.8-3.1, and the potassium-sodium ratio is 3:1.
3. The TC4 titanium alloy submerged arc welding flux according to claim 1 or 2, characterized in that the mass fraction of the binder in the flux is 3% to 5%.
4. The TC4 titanium alloy submerged arc welding flux according to claim 1, wherein the powder is mixed by mass fraction of BaCl ₂ : 5%, LiF: 2%, NaF: 5% and the remainder of CaF ₂ .
5. The TC4 titanium alloy submerged arc welding flux according to claim 1, wherein the powder is mixed by mass fraction of BaCl ₂ : 4.5%, LiF: 2.0%, NaF: 4.9% and the remainder of CaF ₂ .
6. The TC4 titanium alloy submerged arc welding flux according to claim 1, wherein the powder is mixed by mass fraction of BaCl ₂ : 5%, LiF: 2.1%, NaF: 5.1% and the remainder of CaF ₂ .
7. According to the TC4 titanium alloy submerged arc welding flux described in any one of claims 1 and 4 to 6, it is characterized in that, in the powder, H mass percentage content≤0.003%, N mass percentage content≤0.005%, O mass percentage content The percentage content is ≤0.010%, the S mass percentage content is ≤0.003%, and the P mass percentage content is ≤0.003%.
8. The preparation method of TC4 titanium alloy submerged arc welding flux described in any one of claims 1 to 7 is characterized in that, it is carried out according to the following steps:

   Step 1: Mix and dry mix the raw material powders according to the powder ratio for 3 minutes to 5 minutes, then add the binder and continue stirring for 4 minutes to 6 minutes to obtain the mixture;

   Step 2: drying the mixture obtained in step 1 at low temperature, then sintering at high temperature, cooling to room temperature and then sieving to obtain TC4 titanium alloy submerged arc welding flux.
9. The preparation method according to claim 8, characterized in that the parameters of the low-temperature drying in step 2 are: the temperature is 180-230° C., and the time is 35 minutes-60 minutes.
10. The preparation method according to claim 8, characterized in that the parameters of the high-temperature sintering in step 2 are: the temperature is 700-900°C, and the time is 50min-70min.
11. The preparation method according to claim 8, characterized in that the specification of sieving in step 2 is 10-80 mesh.
12. The application of the TC4 titanium alloy submerged arc welding flux described in any one of claims 1 to 7 or the TC4 titanium alloy submerged arc welding flux prepared by the preparation method described in any one of claims 8 to 11, is characterized in that the flux is used for TC4 titanium alloy submerged arc welding.
13. The application according to claim 12, characterized in that the TC4 titanium alloy submerged arc welding flux is used in conjunction with the TC4 titanium alloy submerged arc welding wire.
14. The application according to claim 12, characterized in that, the TC4 titanium alloy submerged arc welding flux is used in conjunction with the TC4 titanium alloy submerged arc welding wire to carry out the chemical composition and content of the weld deposit metal after TC4 titanium alloy submerged arc welding is as follows: : C: ≤0.04wt%, Al: 5.20wt%~5.45wt%, V: 4.20wt%~4.80wt%, Fe: 0.10wt%~0.20wt%, Li: 0.15wt%~0.20wt%, Mn: ≤0.015wt%, P≤0.01wt%, S≤0.02wt%, N: ≤0.02wt%, the balance being Ti.
15. The application according to claim 12, characterized in that the TC4 titanium alloy submerged arc welding is multi-pass multilayer submerged arc welding.
16. The application according to claim 12, characterized in that the wall thickness of the TC4 titanium alloy is 30mm.