Gas bump online store UK: Shielding Gas for Gas Metal Arc Welding: For GMAW the additions of helium range from around 25% helium up to 75% helium in argon. By adjusting the composition of the shielding gas, we can influence the distribution of heat to the weld. This, in turn, can influence the shape of the weld metal cross section and the speed of welding. The increase in welding speed can be substantial, and as labor costs make up a considerable amount of our overall welding costs, this can relate to a potential for significant savings. The weld metal cross section can also be of some consequence in certain applications.
Overall, argon is a standard, low cost but high-quality choice of shielding to use when welding. Although its odourless and colourless properties make it a convenient gas to use, it can also be dangerous if leaks or overexposure when welding occurs. Never forget that you are dealing with a potentially hazardous element, so entrust installation to a specialist gas installer who knows what they are doing.
The shielding gas does more than protect the finished weld from the effects of oxygen and nitrogen in the atmosphere. It affects the weld’s bead shape and size and its porosity and fusion, as well as the welding speed and amount of spatter. Choose your gas wisely and you’ll achieve strong, tough and corrosion-resistant welds; select poorly and you affect performance: delivering welds that are never quite good enough. Read extra details on Span Gas Cylinder.
The normal gas for TIG welding is argon (Ar). Helium (He) can be added to increase penetration and fluidity of the weld pool. Argon or argon/helium mixtures can be used for welding all grades. In some cases, nitrogen (N2) and/or hydrogen (H2) can be added to achieve special properties. For instance, the addition of hydrogen gives a similar, but much stronger, effect as adding helium. However, hydrogen additions should not be used for welding martensitic, ferritic or duplex grades. Alternatively, if nitrogen is added, the weld deposit properties of nitrogen alloyed grades can be improved. Oxidizing additions are not used because these destroy the tungsten electrode. Zero calibration gas is a gas that does not contain flammable gas. You will need this gas in the calibration of analyser’s or gas detectors. Span calibration gases are a more advanced type of calibration gas. They contain a more precise total make up of detectable gases.
The symptoms of over-exposure may not be apparent for several hours after the cutting activity has ceased. Severe over-exposure may lead to an accumulation of water in the lungs which impairs oxygen supply to the blood and may lead to death. Welding generates only small amounts of nitrous gases so exposure to nitrous gases during welding does not present a problem. Exposure problems may arise during cutting activities, particularly if the cutting is hand-held, as this places the operator closer to the emissions. Hotter flames generate higher concentrations of nitrous gases, so using acetylene generates more nitrous gases than using propane or natural gas. Source: https://www.weldingsuppliesdirect.co.uk/.