JPS58500111A - Methods, fluxes and equipment for electroslag welding - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Methods, fluxes and equipment for electroslag welding Technical field The present invention relates to welding technology, and in particular to light welding technology having a density lower than that of slag. Elect of metals and light alloys.

Slag welding method, based on alkali metal halides and alkaline earth metal halides. The present invention relates to a welding flux and an apparatus for performing the welding method.

Background technology The present invention applies to aluminum, magnesium, titanium, their alloys, and other light materials. Can be used for welding metals. The present invention is applicable to non-ferrous metallurgy, chemical industry, electrical industry and other Particularly useful for welding aluminum busbars in the engineering field.

Establish a slag bath, melt the welding rod and both edges to be welded, and electroslag of metal, which involves filling the gap between both ends of the metal with molten metal. The welding method is known (ElektroshlakovaJa 5varka , Ed, by B, E, Paton, Moscow-Klev, “Mashg. lz″l　/Rijri, pp.

ri0-/geta).

Electroslag welding of light metals and light alloys using conventional fluxes During the process, the gas content in the weld metal increases as the thickness of the workpieces to be welded increases. It is also known to increase.

For example, fluxes intended for electroslag welding of light metals and light alloys. So...contains alkali metal halides and alkaline earth metal halides, and A flux with the following composition (% by weight) is proposed (USSR Inventor's Certificate No. 626. No. 73, March 1977 2r Strontium fluoride /3-77 Magnesium fluoride 10~/g Lithium fluoride /4-. 20 Potassium fluoride ('1M thick aqueous solution) 3J-4ZF Gas content in weld metal The above flux in the process of welding without using known techniques for reducing Welds produced using this method are defective due to increased gas content; The increase in quantity intensely treats the mechanical properties of the weld joint. Furthermore, the above flux is It is extremely hygroscopic (because its composition includes a concentrated aqueous solution of potassium fluoride); This is due to the welding pool being splattered during electroslag welding. Seth's stability can be disrupted.

The above electroslag welding method is used to weld the bottom plate, molding shoe, run It uses equipment consisting of an on-plate and welding rod.

Using methods, fluxes, and equipment as described above features increased gas content In order to improve the weld quality in terms of the weld critical structure, Additional processing operations are required.

Adequate degassing of the weld metal in the above method requires additional preheating operations of the weld metal, as well as carrying out preheating and subsequent heating operations (this necessitates the use of additional complex equipment); by suppressing the crystallization process of the weld metal (which can only be achieved by It can be achieved.

In addition, the above method may include additional compounds that can fix the gas-generating components into stable compounds. chemical elements must be introduced into the weld metal during the welding process, and the weld area must be inert. Requires further protection from toxic gases.

The methods, fluxes, and equipment described above may be utilized in conjunction with additional processing steps described above. greatly increases labor costs and the cost of the welding process.

Composition (wt%) Potassium chloride μ Sodium chloride 27 Sodium cryolite (3NBF-, It/F3) 22 Lithium chloride 6 Establish a slag bath (pool) in which the welding rod and both parts to be welded are The process involves melting the metal and filling the gap between the two edges with trap metal. A vertical welding method for minium (U.S. Patent No. 3.j♂j, 34tJ) has also been proposed. .

The above fluxes allow the implementation of stable electroslag welding methods and The oxide film on the workpiece is fully reduced by using the weld metal degassing technique described above. Otherwise, it will not be possible to ensure strong welding.

10 Re methods include metal molds, graphite moldings/knees, and conductive members. , and a solid-section welding rod by means of a gas that twists and rotates the welding rod in a slag bath. This device uses a device that includes an Idbut/Yu, and its conductive member is connected to the welding pool. located outside.

The graph shows that degassing of the weld zone during the welding process reduces the heat removal from the weld pool. The use of molded ink cartridges made of nitrates and the rotation of welding rods in slag baths caused by rotation.

Due to the high crystallization rate of the weld metal and the rotation of the welding rod during the welding process, Because of the mechanical effects on the slag bath, this prior art method does not sufficiently remove the weld metal. cannot be degassed.

The electroslag welding method using the above flux and equipment is Adjusting the placement of the welding rod at (!l-washing) ensures the stability of the process. requires complex follow-up equipment, which makes the process complicated; This increases the cost and furthermore, due to the low melting point of the flux, the weld metal cannot crystallize. Gas cannot be removed sufficiently from the weld metal.

The purpose of the present invention is to optimize the gas content in the weld metal by self-adjusting the welding rod melting rate. Ensures a small and stable welding process, and even improves both the welding process and solidification. Removal of gas from the welding pool during the process and quantitative and determination of the flux used For electroslag welding of light metals and their alloys, ensuring a change in their composition. An object of the present invention is to provide a method, a welding flux, and an apparatus for welding.

These and other purposes establish a slag bath.

Melt the welding rod and both edges to be welded, and then fill the gap between the two edges. Electroslag welding of light metals and light alloys, including filling the molten metal In accordance with the present invention, the weld metal remains in a liquid state even after the welding current is turned off. the weld metal is held, the heat capacity is jointly increased and the weld metal is The weld metal shall be kept in a liquid state for a period of 70~/j% longer than the sufficient degassing time of the weld metal. This is achieved by being held.

By the method described above, a welded joint with strong weld metal can be obtained.

According to the invention, the heat capacity of the slag bath is increased by increasing the volume of the slag bath. can be increased. This reduces the cooling rate of the weld metal during the welding process. .

According to the invention to increase the heat capacity of the slag bath.

The following composition (wt%) of flux is used: barium fluoride to, o to ri, o.

Calcium fluoride jr, 0~/! r, Q lithium fluoride /, 0~! ,θ Sodium fluoride i, o~10.0 Potassium fluoride /, 0~/3.0 When barium fluoride is mixed into a flux in the above specified amount, the flux The density is much higher than that of the metal being welded, so the process of electroslag welding The separation of the molten metal from the slag becomes easier and the stability of the process is achieved. will be accomplished.

When the barium fluoride content in the flux is lower than the lower limit mentioned above, the welding process The separation of molten metal from the slag at the Deteriorate. On the other hand, if the amount exceeds the above upper limit, the activity of the flux decreases, and so The reduction of the edges to be welded and joined becomes poor, resulting in weld defects.

When calcium fluoride is mixed into the flux composition in the above specified amount, the flux This increases the activity of the slag and reduces the surface tension at the interface between the slag and the metal. During the electroslag welding process, individual metal droplets coalesce into seven metal pools. be promoted. The calcium fluoride content in the flux composition is as specified above. When it becomes less than or more than the range, the activity of the flux decreases.

Lithium fluoride, sodium fluoride and Potassium fluoride also enhances flux activity.

With the above percentages of flux composition, the melting point of the flux will be the melting point of the metal to be welded. This means that the gap between the two edges to be welded together will be higher than K. Crystallization of the molten metal is suppressed, making the weld metal more highly degassed and stronger. A weld is obtained. The above benefits of said fluxes improve the quality and quality of welded joints. and operational reliability are greatly enhanced.

Increasing the heat capacity of the slag bath and increasing the weld metal to its full potential according to the method of the invention Retaining the liquid state until sufficient degassing is achieved by using a metal mold with a bottom plate, An apparatus comprising a closing shoe, a conductive member and a welding rod, the apparatus comprising: The welding rod is installed through the hole in the center of the bottom plate and has a low resistance conductive part. This is achieved using a device in which the material is placed in the welding rod melting zone.

The above arrangement stabilizes the welding process by self-adjusting the melting rate of the welding rod. You can get sex. This is because the welding rod end melts below the top surface of the conductive member. Then, the arc generation site moves from the welding rod to the conductive member, which means that the welding rod melts more than the trap. This is because the melting rate decreases.

According to the present invention, the conductive member installed in the welding rod melting zone trap has a melting point higher than the welding temperature. Can be made of either solid substances whose boiling points exceed the welding temperature or liquid substances whose boiling points exceed the welding temperature. Ru.

With this selection, the conductive member material will not be destroyed during welding.

If a liquid substance is selected as the conductive member, the substance should be.

According to the invention, the substance is liquid so that its density exceeds that of the slag bath. It is selected so that it will not mix with or dissolve in the weld metal.

By selecting the material as described above, the weld metal can be made of conductive material during the welding process. will no longer be contaminated.

The welding rod has an internal passageway disposed along and across the welding rod; The channels are filled with a gas transmitting substance and are connected to the same channel in the bottom plate of the metal mold. Modification of electroslag welding equipment is preferred, consisting of communication with various passages. Yes.

By providing a passage as described above, gas can be removed from the welding pool during the welding process. can be removed, while its passageway is filled with a gas-transmitting substance so that the solution This prevents the contact pool from flowing out through the gap between the two edges that are welded together. .

Brief description of the drawing The invention will be explained in more detail with reference to the accompanying drawings.

FIG. 1 shows the electric conduction of light metals and light alloys according to the present invention using solid conductive members. The loss lag welding method is illustrated.

Figure 2 is similar to Figure 1, but illustrates the case where a liquid conductive member is used. ing.

FIG. 3 shows liquid weld metal placed on a hot bed in accordance with the present invention after the welding current is turned off. It illustrates the process of retention. and Figure v shows the resulting weld after crystallization.

The invention will be illustrated by specific examples.

Example/ Electroslag of workpieces with equipment fabricated for welding by the following method: Welding was carried out.

To be welded together, cross section jQ x 100m, length so.

The aluminum test piece 2 (Fig. 7) was welded to the gap between the two edges to be welded together. It was placed on metal mold 1 so that AOm. Those specimens are the metal It was electrically disconnected from the mold.

A graphite run-on plate 3 was placed on top of the specimen 2. welded together The gap between both hems is electrically disconnected from the specimen 2 to be welded at its side. It was closed by a molding shoe 4 which was inserted.

An aluminum welding rod 6 with a cross section of 20'XlfiOm is inserted into the center hole of the bottom plate 5. It was inserted into the gap between the two edges to be welded together.

The above hole into which the welding rod 6 was inserted was sealed with asbestos cord T. then , a graphite conductive member 8 is attached to the bottom plate 5 around the welding rod 6 and the seal 1. was placed inside the metal mold 1.

The bottom plate 5 and welding rod 6 are provided with internal holes to release gas from the welding pool during the welding process. Sectional passages 11, 12, 13 are provided in which the weld pool is located. finely ground metal material and coarse frac to prevent it from escaping through these channels. It was filled with a mixture of 14.

The melting point of flux 14 for making the bath exceeds the melting point (gxOc) of the metal to be welded. The following flux composition (wt%) was selected considering that It's: barium fluoride.

Calcium fluoride lO, O Lithium fluoride S, O Sodium fluoride 70.0 Potassium fluoride 10. Q The density of Franks above is 3. /? /cm'' and the melting point was ooC.

The above flux 14 is applied to the upper part of the welding rod 6 into the gap between the test pieces 2 to be welded. is 10. It was filled so that it remained exposed and became a trap.

Run-on plate 3 and welding rod 6 are transformed into welding voltage by current supply cable 15 It was connected to the vessel 16.

Next, apply pre-melted flux to the gap between the two edges to be welded together. The flux l≠ filled in the middle was injected at an upper pressure.

Equipment for carrying out the electroslag welding process of workpieces is installed as described above for operation. It was adjusted.

Welding conditions were as follows: Power supply, no-load voltage 3vv Welding current Hiro JKA Upon completion of the welding electric circuit, the edge of the test piece 2 to be welded and the welding rod 6 are melted. A metal pool 1γ was formed while the flux melted to form a slag bath 18. So The metal pool 17 was protected from atmospheric influences by the inert gas argon.

During the welding process, welding is continued until the molten end of the welding rod 6 is below the top surface of the conductive member 8. The rod 6 is melted into a short ring, and the molten metal fills the gap between the two edges to be welded together. Filled the gap.

Since the welding rod is arranged as shown above, the arc generation position is conductive from the welding rod end. By moving to the upper surface of the member 8, the melting of the welding rod was reduced. As a result The end of the welding rod is above the upper surface of the conductive member 8, that is, the melting rate of the welding rod 6 during the welding process is degree of self-regulation occurred.

Gas generated from the welding pool during the welding process is removed from the welding rod 6 and the bottom plate 50 through the passage 11. ．． 12.13' & ran away.

After the gap between the edges of test piece 2 to be welded is filled with molten metal 1γ, The contact current was cut off.

The slag bath 18 solidified to form a hot bed 19 of the OOC.

The temperature of the bed 19 and the temperature of the liquid metal 1γ ranged from 00C for 5 minutes to the temperature of the gold to be welded. The solidification temperature of Group 2 was reduced by 110CK. During this time, the metal pool 17 is This facilitated maximum removal of gas from the weld metal. welding metal Degassing of the metal occurred in 2 minutes (the degassing time of the metal pool was determined experimentally before welding). It has been determined).

After the liquid metal solidified, a welded joint with strong weld metal was obtained.

The strength of the weld metal is 7Q to 22Q of the strength of the metal being welded, which is higher than conventional It went beyond similar characteristics for technical law.

Metallurgical microscopic analysis showed that the weld metal was pore-free.

The conductive member 8 of solid material may be replaced by a conductive member 20 of liquid material (FIG. 2). . The welding process in the latter case is similar to that in the above embodiment.

Example 2.3, ≠, j Examples λ, 3, g and j were similar to the method of Example/. In each of these examples The parameters for this are shown in the table below: Example Welding object Welding rod Flux composition (weight %) Material Substance BaF2 CaF2 LiF NaF KF2 Ti Ti Ta0. Oj, 0 2.0 2 ．． 0 /, 03 Mg Sai 7j, 0 10.0 3.0. 2.010.04 ’　N At　jO,020,0! , 0! ,0　2θ,Oj　N　At　taj ,0 2.0/,! r/, 0 0. Electros in Example λ and 3 In lag welding, the strength of the metal to be welded is 70.0% and 7! r, 0% strength A welded joint with a strong weld metal having a high strength was obtained.

Metallurgical microscopic analysis showed that the weld metal had no pores.

In Example G, the weld metal contained solidified slag inclusions. this is This is caused by a small difference between the density of the slag and the density of the metal to be welded. there were.

In Example J, there were areas where the weld metal and the edge to be welded were poorly fused. It was done. This was caused by inadequate activity of the flux.

From each of the above examples, it is clear that the method of the present invention was carried out using the flux composition and apparatus of the present invention. When electroslag welding is carried out according to It can be concluded that a hard weld metal is produced.

The above embodiments do not limit the range of metals to be welded. Because the present invention By the method of the present invention using the flux and equipment of This is because a strong welded joint can be obtained when welding metals with a smaller density.

Industrial applicability The present invention applies to aluminum, magnesium, titanium, their alloys, and other light materials. Used for welding metals. The present invention is applicable to nonferrous metallurgy, chemical industry, electrical industry, and other % useful for welding aluminum busbars in the engineering field.

F/l;, J FI5.4 international search report

Claims (1)

[Claims] l Establish a slag bath, melt the welding rod and both edges to be welded, and Light metals and light alloys, including filling the gap between both edges with the molten metal. In the electroslag welding method according to the present invention, even after the welding current is turned off, The weld metal is held in a liquid state, the heat capacity is jointly increased, and the weld metal is io~/j% longer than the experimentally determined sufficient degassing time of the weld metal before contact. A method characterized in that the method is maintained in a liquid state for a long period of time. λ The weld metal is in a liquid state for a period of time io~is% longer than the degassing time of the weld metal The method of claim 1, wherein the method is maintained at: 3. The heat capacity of the slag bath is increased by increasing its volume. The method described in item 1 of the scope of the request. q　The heat capacity of the slag bath is for a flux whose melting point exceeds the melting point of the metal to be welded. 2. The method of claim 1, wherein the method is enhanced by use. ! For carrying out the method described in claim 1. In fluxes containing lithium fluoride and sodium fluoride and potassium salts, It additionally contains barium fluoride and calcium fluoride, and the potassium salt is potassium fluoride. A flux characterized in that each component is used in the following ratio: Barium fluoride 4o, o-tao,. Calcium fluoride s, o~/! ,Q Lithium fluoride /・O～!・θ Sodium fluoride /, 0-10.0 Potassium fluoride 7.0~/θ, O t. A mold or model having a bottom plate for carrying out the method according to claim 1. In a loading shoe with a welding shoe, a welding rod, and a conductive member, the welding rod 6 is It is inserted through the hole in the center of the bottom plate 5, and is a conductive part with low electrical resistance. Apparatus characterized in that a material 8.20 is placed in the welding rod melting zone. 7. The conductive member 8 is made of a solid substance that has a melting point higher than the welding temperature. , the apparatus according to claim no. The conductive member 20 has a boiling point higher than the welding temperature and has a boiling point lower than the density of the slag bath 18. The liquid material of the conductive member 20 is made of a liquid material having a high density. and the welding material liquid metal are mutually immiscible and insoluble, according to claim 6. equipment. Interconnected internal passages 11.12.13 for gas evacuation are provided in the bottom plate of the metal mold. 5 and the welding rod 6 and filled with a gas-permeable material. The device according to item 6 of the scope of demand. 10 The internal passage 12 of the welding rod 6 is arranged along the welding rod 6, and the welding rod The welding rod passage 13 is arranged across the entire length of the weld 4m. Iruko 16 10. The device according to claim 9, characterized in that: 11) Table 58-500111 (2)