Horrendous electricity and gas bills, increasingly expensive food, unaffordable repair services ... the current situation is the number one topic of conversation with neighbours and in the media. As citizens, you save wherever you can and do without many things that used to be a matter of course. In industry, people are constantly looking for cost-cutting measures that must not, however, restrict production. Welding companies and other manufacturing companies that employ skilled welders are not exempt from this. Where can savings be made in welding if the quality of the products must not suffer under any circumstances? There is one approach that is often not recognised as a savings potential: shielding gas.
Gas mixtures of argon and CO2 are predominantly used for gas-shielded metal arc welding. Although these are not fossil gases like natural gas, which is used for heating and reaches Europe via pipelines, electricity is needed to produce them. Due to the massive increase in the price of electricity, shielding gases have also become significantly more expensive.
The most common process for producing argon is the so-called air liquefaction, also known as the Linde process. This technical method of gas separation was developed and patented by Carl von Linde in 1895. In order for air to be liquefied to extract the individual atmospheric gases such as oxygen, nitrogen, argon as well as other noble gases, it must be cooled down considerably from room temperature. A lot of electricity is needed for this very high extraction of energy. The production of argon is therefore only feasible with very high electricity consumption.
Another shielding gas used in gas metal arc welding is helium, which is used for TIG welding and plasma welding, for example. Among the welding processes, however, these are rather niche processes. Currently, helium is only available in very limited quantities – and thus there is also a price increase. Therefore, it makes sense to take a closer look at shielding gas consumption and see where gas can be saved.
Every company is searching for potential to reduce costs. A look at the total costs of a gas-shielded welding process shows whether gas is worthwhile as a savings potential: the largest share, about 80 %, consists of personnel costs. As an average, shielding gas causes 10–15 % of the total costs, the rest of the costs are distributed among filler materials and the energy for the welding process itself.
Shielding gas indeed represents a noticeable savings potential that has not yet been recognised as such for the most part.
In practice, shielding gas is really wasted. One cause of this is the "the more the better" attitude that is common among welders. The weld must be protected from oxidation, because too little gas coverage leads to pore formation. The welded joint is weakened, the component has to be expensively reworked or is scrap. If the weld seam is not sufficiently protected against oxygen ingress when welding stainless steel – which is very popular where appearance plays a decisive role – this will result in unsightly tarnishing, which should also be avoided. Instead of risking insufficient shielding gas coverage, many welding specialists or operators of robot welding systems tend to set the flow rate of shielding gas too high.
For each welding process, there is a recommended shielding gas flow rate as a guideline. This means that depending on the set amperage and also depending on the gas nozzle diameter, a certain shielding gas flow rate in litres per minute is recommended. For example, if the recommendation is 15–20 litres per minute, the flow rate is often preset to 20 litres per minute. This fact represents the real waste.
At least not exceeding the recommended flow rate of shielding gas already offers a lot of potential for saving gas. But no welding specialist will take a closer look at this if sufficient gas coverage can be ensured with "the more the better" approach. A solution to save gas that is accepted by practitioners must be simpler.
Shielding gas cylinders for gas-shielded welding have an immense pressure. A full 20-litre bottle of shielding gas is subject to a pressure of 200 bar at approx. 20 °C air temperature. This pressure is regulated down to approx. 20 bar by a pressure reducer installed between the gas cylinder outlet valve and the gas hose of the connected welding device or power source. These 20 bar weighs on the solenoid valve that is installed in the welding device and ensures that the gas supply opens and closes during welding.
Every time a welding process is started, the solenoid valve at the power source is opened and the 20 bar want to escape. At the moment of opening, this creates an initial gas emission – also called initial peak – which already allows a lot of shielding gas to escape without serving the process. This gas loss can be avoided by installing a mechanical gas-saving system, for example. With this, savings of 10 to a maximum of 20 percent can already be achieved.
When welding a complex component, different welding seams usually have to be made. There are welds that have to be welded with 300 amperes, for example, while 150 amperes are sufficient for others. For manual welding, this means that you should also set the shielding gas to match the amperage if you want to save shielding gas. In practice, however, the shielding gas for all welds is set to the highest amperage right from the start.
If you want to use this technology for robot welding, it means that you have to programme the welding robot for each seam. This is done sometimes, but it takes a lot of time. In this context, too, gas can only be saved with an automated solution to make it as easy as possible for manufacturing companies.
When welding components with several weld seams, where the welding torch is repeatedly set down and stopped in between, the solenoid valve on the power source naturally also closes and the shielding gas stops flowing. However, this is a delayed process, which means that even then there is still some shielding gas flowing. If you want to save gas here too, use an electronic valve that opens and closes very quickly.
In view of rising energy prices, companies must find new ways to save energy. Significantly reduced or completely eliminated initial gas emission, current-dependent shielding gas quantity and very fast closing of the gas valve are therefore starting points for saving gas during gas-shielded welding. An elegant solution for all three approaches to saving gas for both manual welding and robotic welding are gas management systems – like the EWR 2 from ABICOR BINZEL. EWR stands for Electronic Welding Regulator and that is exactly what this system does: it electronically regulates gas consumption by simply being installed in the gas circuit between the solenoid valve of the power source and the welding torch.
The EWR 2 gas management system is a current-dependent gas control and a patented technology that makes it possible to reduce gas costs in welding by 50 to 60 percent.
The EWR 2 gas management system uses a measuring shunt on the cable assembly to measure the current strength and sends this signal to the system. The electronic valve is able to react extremely quickly to the current and opens or closes accordingly. The initial gas surge as well as the gas overrun are avoided.
Anyone who wants to document their gas consumption and retrieve this data can also use the EWR 2 gas management system. The EWR 2 can be connected to a computer with a jack plug connection. The service software installed allows to display and document the recorded data from the welding process.
The data determined during welding can also be made available to other workstations if required – with the EWR 2 Net. For example, a welding engineer always has the gas flow of his system in view. Different systems can be linked with each other, and the individual gas consumptions can be compared with each other. Since the EWR 2 Net can also be connected to a cloud, the data can also be made available on the internet. This gives the user the option of having the data evaluated by the manufacturer of the gas management system in order to further optimise the welding processes.
The payback period of the gas management system EWR 2/EWR 2 Net from ABICOR BINZEL is between six months and two years, depending on the conditions of use and the gas price. With rising gas prices, the amortisation period is therefore shortened – and the more interesting the acquisition of such a system becomes.
The quickest way to find out whether the purchase of an EWR 2 is worthwhile for your production process is to use the EWR 2 calculator from ABICOR BINZEL. With only a few entries such as shielding gas consumption per day, daily working time per shift, gas type, etc., this calculator determines your current gas consumption and your possible savings potential for shielding gas and CO2. In addition, the amortisation period is shown.
Saving gas when welding can be so simple. A small device integrated into your welding process, and you can reduce your gas costs by up to 60 percent. At the same time, CO2 emissions are reduced due to less transport traffic on the road, which has an additional positive side effect on our environment and carbon footprint. Every welding workplace should be equipped with such a gas management system – and not only in times of rising gas prices.
Happy welding!