Argon-hydrogen mixture

You use argon-hydrogen mixtures when you want to bring more heat into the arc than with pure argon. The hydrogen makes the arc hotter and more aggressive, making welding faster and the seam cleaner. But watch out: too much hydrogen in the mixture makes the seam porous and can lead to cracks. For most cases, a small hydrogen content is enough; the exact mixture depends on the material and the job. The gas protects the weld from oxidation, but you must ensure that the hydrogen doesn't burn into the seam, otherwise the result becomes brittle.