Bath welding of reinforcement is the most reliable method of connecting individual sections of metal structures made of high-strength alloy steel. The welding result is influenced by a number of factors, one of which is the alignment of the joined sections.
When carrying out conventional butt welding, the quality of the seam will be unreliable, the connection will break near the seam. Therefore, a solution has been developed for a more durable connection of the longitudinal and transverse sections of the reinforcing mesh - the pool welding method. Under significant loads during operation, the structure has sufficient rigidity, and the welding seam on the connection is small.
State standards
For this construction process, a GOST was developed called “Joints of welded reinforcement and embedded products of reinforced concrete structures.” The standard was introduced on July 1, 1992 under the number 14098-91.
Bath welding is a reliable and commonly used method. A distinctive feature of this process from all other types of welding is its continuity, which is very important for uniform melting. Thanks to this process, the metal melts much faster.
The welding method is used in the construction of various massive structures and buildings. The seam created using this welding is capable of withstanding moving loads without destroying the integrity of the structure and meets the requirements of GOST. If conventional butt welding is carried out, it can lead to failure of the joint near the seam, thus significantly degrading the quality of the weld.
Methods for connecting reinforcement
The production of reinforced concrete blocks for the construction of concrete houses, monolithic construction and the manufacture of foundations are the main places where reinforcement is used.
Possessing a low price and reliable material characteristics, the welding method satisfies all the requirements for the construction and installation of metal structures. Bath welding is also used to connect rails, shafts and other parts with a solid profile.
According to GOST standards - 14098 of 1991, for the manufacture of foundations, floor slabs and balconies, as well as other reinforced concrete products, it is allowed to weld sections of metal rods for reinforcement and reliable adhesion of concrete structures. In modern construction, several types of permanent connection of the reinforcing layer are used:
- using semi-automatic electroslag welding;
- bath-suture connection method;
- manual electric arc welding;
- contact;
- this connection method.
With the use of a special bath at the junction, permanent joint A500C and other brands and sizes, the process of execution and joining is greatly facilitated.
Process Highlights
The essence of the process is this: the ends of the reinforcement rods to be welded are located inside the bath, then they are melted one by one with electrodes. The electrode should touch the rod slightly , since welding is carried out at high current power.
Welding is carried out using one or more connected electrodes.
You can make the bracket-plate with your own hands or use existing molds that were produced in a factory by stamping. The manufactured form is welded to the electrodes to be welded.
Welding principle
The principle is as follows:
- the steel form should be welded to the reinforcement bars in the connection area;
- then the electrode forms a melt zone using the heat of the arc;
- since the ends melt from the heat of the bath metal, resulting in a liquid structure;
- As a result, upon cooling, a welded joint is formed.
The connecting rods can be positioned in any way: horizontally, vertically and in an inclined position. If the rods are located horizontally, then in this case the bath must be formed using a bracket, which is attached at the junction of the reinforcement blanks. Vertical joints are welded using a stamped form.
Basically, the bath welding process is used to connect rods with a large cross-section of 20-100 mm, since this size scale is most suitable for making a high-quality seam.
Types of bath welding:
- Manual arc welding.
- Semi-automatic electroslag.
- Bath-slag.
Methods of bath welding of reinforcement and their brief characteristics
The most common and most used are single-electrode and multi-electrode welding methods.
Single electrode method
Single-electrode arc welding can be performed with an arc powered by alternating or direct current. This method is used when assembling structures that are under the influence of stationary loads.
You must first prepare the surface. To do this, the ends of the steel reinforcement should be cleaned of various dirt, rust and dust; this can be done using iron brushes.
Bath welding begins from one side, gradually moving closer to the center. Select the correct angle of inclination for each position of the seam in space and type of joint. The further formation of the weld pool depends on the angle of inclination of the electrode. By choosing the correct angle of inclination, the cavity of the bath will be evenly filled, and the base metal will warm up.
When melting, the electrode is lowered, creating a particularly short arc. The metal, completely covering the fittings, rises to the upper edge of the bath. Thus, the welding is considered complete. The parts should be adjusted after the seam has cooled.
When stopping welding, it is imperative to beat off the slag and light an arc at the finished edge of the seam. It will be possible to reliably cover the place where the seam stops and breaks. The seam should be completed in the middle of the bath to prevent holes and voids. Such places must be cleaned of slag and this procedure must be repeated about five times.
Multi-electrode welding
The multi-electrode welding method operates on the same principle as the single-electrode method. It is best to finish the seam in the middle of the overlay.
This method guarantees high productivity of the process and the quality of the smelted metal, reduced penetration and distortion of parts, as well as a reduction in specific heat input.
Using baths
When preparing for work, you need to be able to choose the right bath. This can be done based on the visual features of the connection. Such baths are easy to find for sale in specialized stores. They can be produced by cast or stamped methods, but there will not be much difference in performance properties.
The baths can be used once or repeatedly. The first type is made of steel. In the process of performing tubular welding, reinforcement is welded to the rods, which increases the strength of the connection. The disadvantage of this option is the need to buy a new part each time.
Weld pool design Source burforum.ru
Reusable ones are made from copper or graphite. When using them, only the ends of the rods are welded to each other. The bath serves as a barrier that limits the spreading of molten substances. After finishing use and cooling, it is disconnected in order to use it later. Such a device is significantly more expensive compared to a disposable one, but it can be used up to 150 times.
Reusable parts when welding reinforcement using the bath method can be made in the form of an expanding socket or in the form of two symmetrical halves. In this case, it is necessary to seal the gaps between the bath and the rods so that the melt does not leak out during operation.
Joining reinforcement using trays Source uep.dn.ua
For bath welding of reinforcement and columns, you can make a sheet metal fixture yourself. To do this, just cut a piece of the desired size and bend it into a U-shape.
Elements with threaded connections can also be used. In these cases, the hut is cut on the rods. The surface of the bath is approximately three-quarters circular. It also has a thread inside. In this case, the parts can be securely fixed. This bath is disposable.
Reusable copper molds for welding Source partia-service.ru
The advantage of this option is the ease of connecting parts. The need for a thread can be considered as a disadvantage. If it is not there, then you will need to cut it.
Graphite baths for welding Source rynokdoma.ru
Equipment used
Welding of reinforcement can be carried out if the following equipment and materials are available:
- single-phase or three-phase welding machine 220 volts , providing direct current;
- trays (brackets) . They should be selected in accordance with the seam and the nature of the products being welded;
- limited volume cylinders with inert gas;
- consumable electrodes coated with various alloys;
- necessary special-purpose clothing to protect against UV rays and splashes of liquid metal. A protective mask is also required.
Approximate cost of welding machines on Yandex.market
Video description
Bathroom welding.
"West Ural Certification Center". ASOIC. Welding fittings using the hot tub method can be useful when carrying out apartment renovations. For example, such connections are in demand when installing screeds for the technical floor layer.
Baths for welding fittings Source svarkaipayka.ru
Advantages and disadvantages of the method
Bath welding has a number of advantages:
- Throughout the melt, the rods are uniformly heated;
- for each rod it is quite easy to choose shapes for its size , since they are available in a large assortment;
- Generally available welding equipment is used for work.;
- minimal costs for consumable materials;
- no need for edging structures;
- by using gamma radiation it is possible to check the quality of welding.
There are also some disadvantages:
- constant adherence to precise temperature conditions . It is necessary to ensure that the quality of the seam is not affected;
- high cost of copper baths that are used many times;
- Steel baths can only be used once;
- a large number of steel baths are consumed;
- mandatory preparatory stage , which takes a lot of time;
- Cooling must occur gradually so that a large amount of slag layer does not form.
