Grain refinement by vanadium

Vanadium acts as a grain refiner in steel. It forms fine carbides or nitrides that slow grain growth during heating. This keeps the structure fine and the steel tougher.

When welding, you need to be careful not to get too much vanadium. If the content is too high, the steel becomes hard and brittle, and you get cracks. The exact amount is in the material certificate.

Aim for controlled cooling after welding. If you cool too quickly, you won't get a fine grain. Don't let the part get too hot, and don't quench it with water, or you'll ruin the structure.