STEEL PLATES AND WELDING TYPES
The basis for successful welding of sheet steel is good preparation. Cutting, punching, bending and sheet breaking quality strongly influences the welding process. to have a good one consistency, an accurate and stable device is essential when welding steel sheets.
Steel sheet welding technologies
Sheet metal welding technology has a direct influence on seam design and the risk of sheet damage. Welding thin sheet metal, i.e. up to about 3 mm ( cold rolled ), up to 4 mm ( hot rolled ) is one of the most common sheet metal working methods, but also one of the most difficult. The risk of sheet deformation is greater due to its thickness. Something that doesn't happen in Chapas Grossas .
Spot weldingis one of the most common technologies in the industry. It is mainly used for steel sheet welding, such as resistance welding. Its competitors are riveted and glued joints, but sheet welding still holds its place and does not lose importance. Modern welding equipment solves major problems such as low productivity, high costs and health and safety requirements at work.
Welding generally retains its popularity among hobbyists. The fact that welding technologies are getting cheaper and easier to use has a strong influence.
The beginnings of modern sheet metal welding can be traced back, perhaps a little, to the 16th century. Humans started using a hydrogen flame to bond the weld metal. At the time of the Industrial Revolution in the 19th and 20th centuries, when industrial production of calcium carbide started, it boosted sheet metal welding to leaps and bounds.
New methods look to the old gas welding, which, while still used in many industries today, tends to go backwards from the standpoint. Among these technologies are, for example, arc welding, resistance welding, pin welding, spot welding and welding in a protective atmosphere.
Types of welding on steel sheets according to CSN
- 311 flames
- 111 arc coated electrode
- 114 Arc-filled electrode without shielding gas
- 131 Arc welding with MIG inert gas fusion electrode
- 135 Arc welding with fusion electrode in active gas MAG
- 136 Arc welding with tubular wire electrode in active gas
- 137 Arc welding with tubular wire electrode in inert gas
- 141 Arc welding with non-consumable electrode in TIG inert gas
- 12 below concentration
- 15 Plasma welding and material cutting
The basic division regarding welding technology is fusion welding and pressure welding. We are mainly involved in sheet steel welding and therefore we have selected two of these areas as the most used technologies for sheet steel welding.
Welding Resistance Point in Steel Sheets
Anyone who has ever worked in the field of sheet steel welding definitely remembers at least two concepts: spot welding and resistance welding. Both concepts will essentially penetrate, as spot welding is the most common method of resistance welding. In contrast, here is resistance seam welding of the sheets.
Resistance welding is used to weld two overlapping materials together. This is very common with products made from sheet steel or fabric. These metals are welded by copper electrodes, as there is great resistance between them (contact resistance in welding materials) and therefore also significant heating, which brings together the welding of sheet steel parts. With simultaneous pressure effect, this leads to spot welding.
For these good quality welds and to be stable, a high pressure force is required on the two plates (up to 10,000 N). To produce a sufficient temperature, the current value of electricity flow can reach up to 100 kA.
Resistance spot welding is spot welding close to stable electrodes. In resistance seam welding, on the other hand, sheets are welded together with long seams as the electrodes move.
Electrodes for spot welding plates are usually made of copper. But cobalt and cadmium alloys or copper and silver alloys can also be used.
Perhaps the biggest advantage of resistance welding is the possibility of application both in automated mass production and in manual adjustments and corrections in garages, for example.
Another method of welding steel sheets is arc welding with a consumable electrode. This is a type of fusion welding and, unlike resistance welding, is rarely used forsheet steel products .
It is basically a fusion of welding wire (or a steel supplied through a tube) in a protective atmosphere (gas out of the tank) by means of a welding torch, it is supplied by a high performance power source. The melting of the metal creates a so-called fusion pool.
Welding gases prevent chemical reactions at the weld point, which could lead to a reduction in the quality of the joints. Another function is current device protection.
It is often distinguished between MIG and MAG welding processes. Sheet metal welding using MIG uses a protective atmosphere of inert gases (argon and helium) and MAG of active gases involved in metallurgy (carbon dioxide).
A related method is the so-called MOG welding, which, however, does not use a shielding gas atmosphere.
MIG/MAG inert gas welding is mainly used in steel construction and larger mechanical parts in mechanical engineering. Previously, it was purely manual activity and quite expensive, but nowadays, robotic welding is also being used successfully.
In welding of steel sheets, we must mention a similar process, TIG. It is also an inert gas welding, but in this case only with inert gases and a non-consumable electrode.
As protective gases, helium and argon are commonly used. Sometimes mixtures with hydrogen or nitrogen are used.
It is mainly used for manual welding of various materials and is very demanding on the welder, combining the handling with the torch and the welding material. Its effectiveness is much lower compared to MIG/MAG. On the other hand, the biggest advantage is the low cost (especially for equipment) and the ability to weld a wide variety of materials.