One of the most commonly used methods of joining parts in the production of mass and small-scale products is welding. With its help, you can assemble almost any pairing of elements - tee, corner, end and lap. Over time, the technological methods by which welding of metal structures is carried out improve, becoming more efficient.
Classic Welding Methods
Standard methods for welding metal elements involve the use of two main sources of energy: a gas flame or an electric arc.
Gas and arc welding can be automatic, semi-automatic and fully manual. The latter option involves the formation of a welding seam only with the master's own hands. In addition, manual arc (RD) welding of metal structures includes both manual control of the processes of supplying an electrode, or filler wire, and the process of welding parts.
Manual mode is most effective only in domestic conditions. When itin use, they mainly use submerged arc welding, brazing with a gas welding machine or the classic method of electric arc welding.
The first option - automatic welding - is based on the process of applying a seam to a section without direct human participation. All work is done by a special mechanism that is pre-configured. Naturally, this unit has a very limited range of functions, but this significantly reduces the cost of finished products, making it very popular in large-scale production.
Assembly of metal structures, welding in automatic mode allows the use of contact technology, including heating and pressure testing of elements, electric shock welding and other "manual" methods. The only difference is that it is not the master who runs everything, but a specially created and programmed robot.
Semi-automatic mode implies the application of a welding seam by a foreman, however, electrodes or wire are fed into the work area automatically, which significantly increases the productivity of work on the site.
In this mode, almost any technology for welding metal structures is used, using infusible electrodes, gas fluxes and automated feeding of filler wire into the heating zone. In everyday life and small-scale production, semi-automatic welding of metal structures is the most profitable and efficient option for the technical process.
Technological innovations
In modern welding for joiningmetal parts, not only superheated gas flames and electric arcs are used, but also the thermal effect of friction, laser energy, ultrasound, and even the power of electron beams.
Simply put, welding technology itself is constantly improving. Quite regularly, new ways of implementing this technical process are invented. These innovations include the following types of welding - plasma, thermite and electron beam.
By thermite technology, critical metal structures are welded, the components of which are melted along the seam during the combustion of a special mixture introduced into the joint. Thermite is also used to repair defects and cracks in pre-fabricated metal structures by "flowing" the metal.
Plasma welding is carried out under the conditions of passing ionized gas through two electrodes. The latter acts as an electric arc, but its efficiency is much higher. Superheated gas is used not only for metal welding, but also for metal cutting, so that an automatic and multifunctional welding system can be created around the plasma generator.
With the help of electron beam technology, deep seams up to 20 centimeters are welded, while the width of such a seam will not exceed one centimeter. The only disadvantage of such a generator is that it can only be operated in a complete vacuum. Accordingly, such technology is used only in highly specialized areas.
For the assembly of small-sized metal structures, it is most effective to use gas or electric arc manual welding. The semi-automatic device pays off when working with small-scale objects. Modern welding technologies, respectively, are used only in mass production.
Structure welding: features
Welding technology is used not only when working with metal, but also with various polymers. The whole process is heating and deformation of surfaces, which are then combined into one.
All welding work consists of two main stages: assembly and connection.
The first stage is the most time-consuming and difficult. The reliability and strength of the structure largely depends on compliance with all requirements. More than half of the time falls on the assembly of components.
Ensuring correct assembly of steel structures
High quality, strength and reliability of the final result is ensured by compliance with certain requirements.
- When choosing parts, you must strictly adhere to the dimensions laid down in the project.
- The gaps must be of a certain size - if they increase, the strength of the finished product will decrease significantly.
- Angles are measured and controlled using special tools. It is important that they fully comply with those specified in the project, otherwise there will be a risk of collapse of the entire structure.
Benefitswelding
In addition to the fact that welding of metal structures significantly saves time for all work, and the seam is of high quality, the process has other characteristics:
- The mass of the finished soldering does not change, since only two main parts are used, which saves material.
- No restrictions on metal thickness.
- The ability to control and adjust the shapes of metal structures.
- Availability of welding equipment.
- The ability to use welding for repair and reconstruction.
- High tightness and strength of joints.
Additional points
In order for the resulting design to be of high quality and reliable, it is necessary to comply with all technological requirements.
Properly selected materials, components and equipment allow you to get high quality seams. Otherwise, the finished design not only loses its presentation, but also its performance.
Weld defects
To obtain accurate dimensions and simplify work, a jig is used when creating a metal structure. Despite this, RD welding of metal structures, cranes can result in certain defects during the process - sagging, cracks, burns, porosity, burns, undercuts and others.
Causes of defects
Sags are formed on metal structures as a result of leakage of molten metal. Most often, such a defect is characteristic ofcarrying out work on the creation of horizontal seams. Remove them with a hammer, and then check the product for lack of penetration.
The causes of burn-through may be poor-quality processing of the edges of structures, an increase in the gap, low speed of work and low flame power. Eliminate it by cutting and welding the seam.
The most dangerous type of defect is lack of penetration, since it adversely affects the reliability and strength of the weld. Such areas are completely eliminated, metal structures are cleaned and re-welded.
