Zero calibration gas online store UK: Helium / argon mixtures are sometimes used for their higher heat characteristics. Gas mixtures, usually 25% helium and 75% argon are sometimes used and can help to increase travel speeds when AC – gas tungsten arc welding. Mixtures of more than 25% helium for AC – gas tungsten arc welding are used, but not often, as they can tend to produce instability, under certain circumstances, in the AC arc. Pure helium or high percentages of helium (He-90%, Ar-10%) shielding gas are used primarily for gas tungsten arc machine welding with direct current electrode negative (DCEN). Often designed as seam welders, the combination of GTAW – DCEN and the high heat input from the gas used can provide fast welding speeds and outstanding penetration. This configuration is sometimes used to produce full penetration butt welds, welded from one side only, onto temporary baking with no vee-groove preparation, just a square edged plate.
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.
And for hobby welders and small businesses without the space to spare for a standard-sized cylinder, there’s even the choice of a more practically sized lightweight 2-litre Argoshield Light that takes up less space at home or in a van. Argoshield Universal contains the same amount of oxygen as Argoshield Light but slightly less argon and more CO2. It produces smooth, flat welds with fewer weld defects and with its low spatter performance reduces the need for rework. It’s best used when productivity and low levels of distortion are important – such as semi-automatic, automatic and robotic applications in the automotive industry. See more info at Calibration Gas Suppliers UK.
A perfect welding result, without impairment of corrosion resistance and mechanical properties, can only be obtained when using a backing gas with very low oxygen content. For best results, a maximum of 20 ppm O2 at the root side can be tolerated. This can be achieved with a purging setup and can be controlled with a modern oxygen meter. Pure argon is by far the most common gas for root protection of stainless steels. Formier gas (N2 + 5 – 12% H2) is an excellent alternative for conventional austenitic steels. The gas contains an active component, H2, which brings down the oxygen level in the weld area. 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.
Many of the gases fall within the scope of the Control of Substances Hazardous to Health Regulations (COSHH) 2002 (Amendment) 2004, which require that exposure to them is maintained below concentrations known as Workplace Exposure Limits (WELs). WEL values are given in Guidance Note EH40 from the Health and Safety Executive (HSE), which is usually updated annually. Source: www.weldingsuppliesdirect.co.uk.