Das Schweißen ist in einer Vielzahl von Branchen von entscheidender Bedeutung, einschließlich Industrie, Automobil, and construction. Galvanized steel, which is composed of an exterior layer of zinc, is typically used when there is a significant demand for the material’s resistance to corrosion or rust. Even if it’s obvious that welding galvanized steel is feasible, the question still arises because of how difficult it is.
Understanding Galvanized Steel
Was ist verzinkter Stahl?
Galvanized steel can be described as steel that has been metallic coated with zinc. This one is done through different practices including hot-dip galvanization or electro-galvanization to improve on the safeguard on the steel from rust and corrosive contents. It is also known as corrosion-resistant steel, mainly because of the additional coat that makes it ideal for construction, car parts, outdoor products and many others.
Why Weld Galvanized Steel?
Whether it is fixing a fence or pillar or building construction or the manufacturing of some automobile parts, welding makes sure that the linkage does not break. Trotzdem, the use of the zinc coating poses characteristics that are difficult while welding the surface.
Challenges of Welding Galvanized Steel
Zinc Fumes
Since zinc is one of the main ingredients of galvanized steel, the burning of this material produces dangerous vaporous clouds. These fumes are dangerous to human health and can cause such diseases as metal fume fever and respiratory diseases. These risks require adequate ventilation as well as protective clothing and other gear.
Zinc Weldment
Zinc weldment is the situation where a combination of zinc-iron compounds makes the weld joint to be brittle. These compounds can cause undermine the strength of the weld, as well as increase its liability to develop cracks. Zinc weldment is a severe factor to consider because it thins the cross-section, reduces the mechanical properties of the material, and in essence weakens the weld.
Arc Strikes and Crater Pipes
Arc strikes and crater pipes are the defects that can be found on the galvanized coatings that happen during welding. These defects may result in the poor-quality welds and even a reduced strength of the structure.
Preparing to Weld Galvanized Steel
Sicherheit zuerst
Before undertaking welding of galvanized steel, ensure the following:
Ventilation: Ventilate the environment where welding is being done to reduce the accumulation of zinc fumes. When welding it is recommended to use exhaust fans or fume extractors if you are welding inside the house.
Protective Gear: Personal protective equipment for this practice entails a welding helmet, safety goggles and face shield, and masks that are able to protect the worker from fumes and sparks; rusty curved gloves; long sleeve cotton or leather aprons.
Oberflächenvorbereitung
The following preparations should be made to ensure that the weld is successful:
Wash off Zinc Coating: The zinc coating needs to be removed from the area where welding is to be done, by using a grinder, sander or chemical solution. This eliminates the risk of zinc fumes and also the formation of brittle weldment in the weldment during the welding process.
Treat the Surface: Ensure that the surface has no oil, grease or rust which could may affect the weld joint.
Techniques for Welding Galvanized Steel
Auswählen der richtigen Methode
When welding, the process of joining that is used when making galvanized steel varies and depends on one’s preference.
The following are some approaches that could be used:
Shielded Metal Arc Welding: Otherwise referred to as stick welding, SMAW is a popular method of welding galvanized steel since it is versatile. Employ a low content hydrogen electrode and it is important to remove the zinc coating at the welding spot.
Gas Metal Arc Welding (GMAW): Also known as MIG welding, this is also quite famous. The zinc should be the removed and the right shielding gases such as argon or carbon dioxide mixtures needs to be used.
Tungsten Inert Gas (TIG) Schweißen: TIG welding offers rather tight control and can be used for the thinner thickness of the galvanized steel. Like other methods, there is the necessity to remove zinc coating first.
Welding Techniques
To avoid having defects and weak welds, especial concern needs to be taken in the following aspect:
Preheat and Interpass Temperature: the means of having the steel on before the first weld pass helps in minimizing the reactions that create zinc weldment. The peak’s interpass temperature should remain more or less constant to reduce thermal stresses and distortion.
Prevent Skin Melting: By controlling the heat input, this may be avoided because the skin will melt if it receives too much heat. Heat can be effectively managed by avoiding cubic or weaving and controlling travel speed.
Post-Welding Considerations
Jedoch, after the weld on galvanized steel, there is always an additional process needed to be taken for the weld steadiness and durability:
Inspect the Weld
Examine welded parts for any signs of any imperfection like cracks, porosity and below threshold fusion. In case of welds, use methods such as ultrasonic examination or radiography examination in order to meet quality inspection checks.
Reapply Zinc Coating
To ensure the protection of the galvanized steel, renew the zinc coating especially on the areas that have been welded. Restore the protective layer by methods such as hot-dip galvanizing and thermal spraying.
Final Cleaning
Tidy up for any droppings, splatter, and other residues which are part of the welding operation. Check the welded structure for the presence of any contaminants that may have a detrimental effect on it.