Védgázként

Védgázként is a Hungarian term that translates to "shielding gas" in English. It refers to an inert or semi-inert gas used in welding processes to protect the molten weld pool from atmospheric contamination. This contamination can lead to defects in the weld, such as porosity, lack of fusion, and embrittlement, which compromise the strength and integrity of the joint.

The primary function of a shielding gas is to displace the surrounding air, which contains oxygen and nitrogen. Oxygen can cause oxidation of the molten metal, leading to oxides that reduce the weld's mechanical properties. Nitrogen can dissolve into the molten metal and form nitrides, also causing embrittlement.

Common shielding gases used in welding include argon, helium, carbon dioxide, and mixtures of these. Argon is widely used due to its inert nature and effectiveness in most arc welding processes like Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW). Helium, being lighter and more conductive, is often used for thicker materials or to achieve higher welding speeds. Carbon dioxide is a reactive gas that can be used as a less expensive alternative, often in mixtures with argon, for certain steel welding applications. The specific choice of shielding gas depends on the type of metal being welded, the welding process, the desired weld quality, and economic considerations. The proper selection and application of a védgázként are crucial for achieving sound and high-quality welds.