Gas bump online shopping 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.
Of course the right shielding gas is not the only consideration – your safety when using high-pressure cylinders is also paramount. It’s important to go to a reputable company to rent your shielding gases, so you can be sure strict standards are met and cylinders comply with regulations. Renting a cylinder from WSD (weldingsuppliesdirect.co.uk) gives you peace of mind. You know it is well maintained and renting can also be more cost effective. Find out why it’s good to rent. It’s also a priority to use the right safety equipment such as helmets and gloves, which you can also find through WSD (weldingsuppliesdirect.co.uk). Read extra details on Zero Calibration gas.
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.
Ozone can be generated by reaction between UV light from the arc and oxygen in the air. The exposure limit for ozone is 0.2ppm for a 15-minute reference period. At the levels of exposure to ozone found in welding the main concern is irritation of the upper airways, characterised by coughing and tightness in the chest, but uncontrolled exposure may lead to more severe effects, including lung damage. MIG welding of aluminium alloys with an aluminium/silicon filler wire generates by far the highest concentrations of ozone. Using an aluminium filler wire generates substantially less ozone, and using an aluminium/magnesium filler wire generates the least ozone when MIG welding aluminium alloys. Other process/material combinations that may generate hygienically significant concentrations of ozone are MAG/mild steel, MAG/Stainless steel and TIG/stainless steel. Source: https://www.weldingsuppliesdirect.co.uk/.