Upward vertical position

Physicochemical Mechanism of Action

The vertical-up position allows the weld metal to penetrate deeper into the workpiece. This increases the hardness and strength of the weld.

Metallurgical Relevance & Welding Risks

Too fast root penetration can cause hot cracking because the material shrinks too much before fully cooling. Too slow root penetration can lead to insufficient hardness and toughness of the weld.

Shop Practice & Instructions

Use vertical-up for thick plates to achieve sufficient root penetration. Make sure penetration speed and cooling are controlled. Typical penetration speed is 1-2 mm/s.