Span gas online supplier 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.
Low cost, high quality: Argon is widely used because, like CO2, it is low cost. It is odourless, colourless, and known for not reacting to high levels of elements like oxygen or water. So why use it over CO2? As we mentioned, CO2 yields imperfect results, as it leaves openings for oxygen to compromise the weld. Argon, on the other hand, is much more stable and controllable. It keeps the molten weld from getting damaged, becoming brittle and breaking, and can be used with other gases such as helium to enhance the quality. The perfect choice would be a mix of argon and something else. Argon would always be the gas with the largest quantity though.
Ferric stainless steels used in the likes of exhausts and catalytic converters have high strength and good high-temperature properties, while martensitic stainless steels – used for vehicle chassis and under-carriage components of tractors – are more difficult to weld. A gas for every occasion: Specshield 2.5% CO2 is an excellent general-purpose gas for applications like MIG welding thin automotive parts, such as exhausts, using solid wire. Its mix of argon and 2.5% carbon dioxide gives a good wetting action and produces smooth welds with minimal spatter and low surface oxidation but its fusion is relatively low. See extra info on Calibration Gas Suppliers.
The primary task of a shielding gas is to protect the weld pool from the influence of the atmosphere, i.e. from oxidation and nitrogen absorption, and to stabilize the electric arc. The choice of shielding gas can also influence the characteristics of the weld penetration profile. The basic gas for MIG/MAG 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. However, small additions of oxygen (O2) or carbon dioxide (CO2) are usually needed to stabilize the arc, improve the fluidity and improve the quality of the weld deposit. For stainless steels there are also gases available containing small amounts of hydrogen (H2). Calibration gases are split into two categories. These are zero calibration gas and span calibration gas. Calibration gas is used to calibrate gas analyser’s. Calibration gas is in addition used to calibrate Gas detectors. These Gases will also be known as Span Gas and come in a Span Gas cylinder. This product has added one or more component(s).
Welding and cutting activities can generate gases that are hazardous to health. The gas or gases generated and their concentrations depend on the process used and the gas formation mechanisms. Gases, some of which may be hazardous, are inherent in some processes, either as a shielding gas to protect the molten weld pool against atmospheric contamination or, for flame processes, as a consumable that is burnt. Source: www.weldingsuppliesdirect.co.uk.