Welding of steel
An important feature of steel reinforcement is its weldability. EPSTAL steel, thanks to carefully controlled production process, has a chemical composition guaranteeing the full weldability of bars. In addition, welded EPSTAL steel joints have successfully passed laboratory tests.
EPSTAL steel was tested at the Welding Institute in Gliwice. The aim of this study was to design and test welded joints with the MAG method and the welded resistors on the cross. The scope of the study included: static stretch test, shear test and bending test.
The positive results, described in the Welding Institute's report, show that all tested joints had good strength and plastic properties:
- in the welded joint stretch tests, all the samples broke off beyond the weld point,
- in the cross-cutting tests, higher destructive forces were obtained than indicated by standard requirements,
- in the bend tests the joints showed good plasticity at the point of welding - all samples bent without cracks.
MIG/MAG welding (eng. Metal Inert Gas/Metal Active Gas) - MIG welding or active MAG welding. Protective gases are most commonly used argon, helium and mixtures of these gases. As active carbon dioxide or its mixture with argon. In the MIG / MAG method, the electric arc glows between the welded material and the electrode in the form of a wire. The arc and lagoon of liquid metal are protected by an inert or active gas stream. The method is suitable for welding most materials, selecting electrodes suitable for different metals.
Welding - a type of technology that permanently connects parts of devices or structures made of metal or plastic. It consists in heating the contact surfaces so that they become plastic and pressed them. Only a small volume at the interface is plasticized. Depending on the welding method used, pressure is applied first, then warming up, or vice versa, first heating and then pressing.
Resistance welding (electrical resistance) - is the most commonly used type of welding. It is divided into: face welding (spark), point welding (one and two-sided), linear (on the tab, linear-face) and projection welding. Electric resistance welding consists of 3 phases:
- Phase I - two (or more) connected components are subjected to the force of the electrodes, and after high pressure the high current electicity is applied. As a result of the current flow, heat is generated at the contact surface of the components, which have much greater electrical resistance than the resistance of the assembled components themselves. On heated surfaces (or points) begins to form a zone of molten plasticized metal called the coil core.
- Phase II - with the increase in the amount of heat generated, the weld nucleus is expanded. The welding process is designed so that the size of the weld nucleus ensures a sufficiently strong joint. The heated metal is plasticized and the force applied can cause its deformation, which is a normal side effect of this method. No distortion may imply an incorrect welded connection.
- Phase III - when the current is turned off, the weld nucleus reaches its maximum size, but the weld remains under the electrode clamp so that the metal (clay) of the weld can start to coagulate.