What is the difference between uphill and downhill vertical welding?

Vertical welding can be done in two ways, each with its advantages:

Downhill vertical welding:

• Direction: top to bottom
• Technique: the electrode or torch is tilted upward (push angle)
• Advantages: faster than uphill, less metal deposition, less penetration
• Ideal for: thin sheet, thin-wall pipe (pipeline), root passes
• Often uses E6010 electrodes for fast penetration

Uphill vertical welding:

• Direction: bottom to top
• Technique: the electrode or torch is tilted downward (drag angle)
• Advantages: Deeper penetration, better sidewall fusion, thicker metal deposition
• Ideal for: thick plates, structural frames, full penetration joints, fill passes
• Uses E7018 electrodes (low hydrogen) for mechanical strength

On qualification: the direction (uphill or downhill) and the position assessed are those prescribed by the body running the test or by the company's WPS — the platform publishes no exam rule. In pipelines, downhill welding procedures are governed by API 1104.