Pipe Welding Processes & Procedures
SMAW, GTAW welding, joint preparation, welding positions, electrode storage, preheat, and PWHT requirements.
- Compare SMAW and GTAW welding processes for pipe applications
- Describe proper joint preparation including bevel angles and root gaps
- Identify welding positions from 1G through 6G
- Explain preheat and post-weld heat treatment requirements
- Describe WPS content and welder qualification procedures
Leçon 1
SMAW, GTAW & Welding Process Selection
SMAW (Stick Welding)
SMAW (Shielded Metal Arc Welding) is the most common field welding process for pipe. An electrode (stick) with a flux coating melts to form the weld and the flux creates a shielding gas and slag to protect the molten metal. SMAW is versatile, portable, and works well in wind and outdoor conditions.
SMAW (Stick)
Most common field process
Works in wind and outdoors
Portable equipment
Higher deposition rate for fill passes
Slag must be cleaned between passes
GTAW (TIG)
Highest quality welds
Non-consumable tungsten electrode
Separate filler rod added by hand
Best for root passes and thin wall
Requires wind protection
GTAW (TIG Welding)
GTAW (Gas Tungsten Arc Welding) produces the highest quality welds with precise heat control. A non-consumable tungsten electrode creates the arc, and the welder manually adds filler metal with a separate rod. An inert gas (argon or helium) shields the weld pool. GTAW is the preferred process for root passes on high-pressure piping because it produces clean, defect-free roots.
Combination Welding
Many pipe welds use a combination: GTAW for the root pass and SMAW for fill and cap passes. This provides the quality root of TIG welding with the faster deposition rate of stick welding for the remaining passes.
Exam Tip - Root Pass Process
When the exam asks which process is preferred for the root pass on high-pressure piping, the answer is GTAW (TIG). It provides the best root quality with full penetration and minimal defects.
SMAW (stick) is the most common field process - portable and wind-tolerant. GTAW (TIG) produces the highest quality welds and is preferred for root passes. Many pipe welds use GTAW for the root and SMAW for fill and cap.