Aluminum is a light metal used in industry for many decades. During this period of time, it was found that cold welding for aluminum and its alloys is the only way to join billets.
What is cold welding?
Cold welding is a method of joining metal parts, which is performed without heating, under pressure. Bonding is carried out due to plastic deformation of the mass and its penetration into the welded surface. Cold welding for aluminum is widely available and does not require special preparation and sophisticated equipment. The process takes place directly in the room, at room temperature. No heat sources used by arc welding are required.
Composition and characteristics
Cold welding, in fact, is an adhesive for metals and can have a one-component or two-component composition, which includes:
- Epoxy resins that form the basis of welding and are responsible for the uniformity and ductility of the composition.
- Metal component as a filler.
- Additional substances and additives that improve adhesion, resistance to aggressive environments, temperature characteristics and so on.
Strength depends on its composition, proper use and quality of surface preparation.
Under suitable conditions, the joint can be even stronger than the metal being joined, but, as practice has shown, the seam after gluing is an order of magnitude less durable than with traditional welding. Therefore, it is recommended to use it only for a small repair.
Glue "Cold welding for aluminum" is found in almost every hardware store - a huge number of foreign and domestic manufacturers produce this composition, which differs from each other only in appearance.
Mastic, as a rule, is sold in the form of a two-layer bar, which resembles plasticine, or is placed in a cylindrical package for convenience.
Before welding, the required amount is cut off from the piece (strictly perpendicular). Welding elements after kneading with fingers are quickly applied to the desired area.
Deformation Welding Principle
Bonding of aluminum surfaces is due to plastic deformation.
During cold welding, the objects to be joined are compressed very tightly with each other, as a result of which the outer layer is destroyed, an intermolecular bond arises, forming a strong connection.
To ensure a better connection, it is advisable to degrease the parts in advance and remove dust.
Cold Welding Methods
The technology of joining aluminum in a cold way can be divided into 3 methods:
Butt welding
With this method, aluminum billets are placed and clamped in special jaws. Then, a force is applied to them, which is directed along the axis. As a result of this, the parts come together as closely as possible, and plastic deformation occurs.
This method has some disadvantages:
- to connect long parts is almost impossible, because their size is limited by the design of the clamping device;
- part of the workpieces located in the clamp sleeve is deformed;
- it is difficult to remove the parts from the clamps.
Spot welding
This method is used to overlap aluminum blanks. Special punches are used. The location of the pressed-in punch is called the weld point. Welded points are placed along the connection line at a certain interval.
The advantage of this method is the absence of the need for preliminary fixing of parts and low deformation of the metal in connected places. This is the most common cold welding for aluminum. It can be made without clamping or on fixed parts.
Seam welding
For the formation of a continuous seam with this welding method, rollers can be used between which connect the workpieces or ring-shaped punches.
Welding can be performed either with one rotating roller that presses the aluminum parts to the support, or with two rotating rollers that clamp the parts together.
Depending on the cross-section of the parts, the roller seam can be made on a milling or manual desktop machine.
With this method of joining, a seam without flanging is obtained, however, its drawback is the thinning of the section of the parts at the seam site, which leads to bending and bending of the workpieces in this place.
This drawback can be reduced by increasing the diameter of the working surface of the rollers. Or use of this method is best avoided.
Aluminum welding technology
Shear welding is a method of cold welding aluminum. It is performed by the method of compression with tangential displacement. As a result of this process, all oxide films are peeled off, forming bridges of the compound. This method is used in an industrial environment for connecting wiring and trolleybus wires, radio instrument housings, cable sheaths, different frames for household appliances. An excellent result is obtained when welding aluminum with its alloys (subject to the cleanliness of the surface of the workpieces). In the case of the slightest contamination, it is almost impossible to achieve a good quality compound.
In order to obtain a good quality of the joint, the sedimentary pressure should be applied so that the metal can flow freely from both sides of the weld point. Only the fulfillment of such a condition will allow achieving the correct displacement of the parts relative to each other.
A seam on sheet aluminum can be made:
- direct;
- circular;
- continuous (any length).
Application and Features
Before work, the surface should be cleaned with steel rotating brushes. Aluminum can be welded with various metals. Quite often, welding of aluminum pipes is used. In laboratory conditions, an attempt was made to carry out welding using aluminum and steel dies.
Cold welding has a great future. Despite the fact that new methods of using high-frequency current are being developed, such installations are quite expensive, and their efficiency is still quite low.
Welding and soldering can be performed under the influence of induced currents. When welding with direct current aluminum, you can proceed as follows: lower two rods into the alkali solution, then let direct current pass. As a result, a quick warming up of the negative rod will occur. Now you should remove the rods and make a draft.
This method is used in laboratories. He did not find his place in industry.
When cold welding is performed for aluminum, there is no external heating of the parts. This allows you to connect electrical insulation in the insulation, to carry out work in the flammable zone, to close up holes in the tank, which can not be heated. In addition, it is possible to combine aluminum with steel. When using cold welding on aluminum, metal waste can be reduced by almost 10 times. Using equipment for welding aluminum, copper and titanium, as well as other metals and alloys with ductility, are joined together. For welding aluminum, fluxes are not always necessary.
Spot welding can connect sheet metal up to 15 mm thick.
The joint method connects rods with a cross section of up to 30 mm and a wire of the same diameter. Cold welding for high-temperature aluminum is able to connect strips of copper with a cross section of 100 x 10 mm with a very strong seam.
Seam welding on sheet metal parts results in an airtight seam of absolutely any length
Cold welding of aluminum is designed for stationary conditions. The equipment may have a draft mechanism, hydraulic drive, a mechanism for clamping parts.
The composition of cold welding for domestic purposes includes fillers, epoxies, sulfur additives. The polymer composition has a bonding property that appears with little heat. It can be obtained by kneading a piece of the substance in the palms for several minutes. Then the mass can be applied to the junction of parts.
This type of welding is used when performing minor repairs of household appliances, plumbing, risers, radiators, windows, silencers, fuel tanks, etc.
After setting, the mass is able to take, if processed, any form. Full solidification occurs in 1-8 hours. Details can then be painted.
Cold welding for aluminum reviews of people who have repeatedly used it, received the most positive. After analyzing them, we can conclude that the durability and quality of the connection, as a rule, completely depend on the selected adhesive composition and the correct implementation of the technology.
Cold welding of aluminum in St. Petersburg is carried out both in specialized auto repair shops and independently at home. Material packaging costs from 38-40 rubles.
The best cold welding for aluminum
It is specially designed for the repair of aggregates and car parts made of aluminum, silumin and duralumin.
The quick-cure cold welding "Polymer-Aluminum", the formula of which was specially developed for better adhesion to aluminum and its alloys, makes it possible to carry out high-quality and reliable repair of aluminum parts, without the use of a welding machine.
Using this cold welding, you can efficiently and quickly repair:
- aluminum wings of the car;
- car radiators;
- pipelines made of aluminum or alloys;
- car cylinder heads;
- body panels and other car parts.
Cold welding for aluminum, the price of which depends on the packaging and starts at 40 rubles, specially contains a filler that provides the composition with enhanced adhesion specifically to aluminum and its alloys.
Now you do not need to bother with the welding machine - you can just take cold welding for aluminum, knead the composition with your hands and proceed with the repair.