Despite decades of standards, many shops still weld without a written welding procedure specification (WPS). A common misconception is that if the parameters used meet the conditions for prequalified status, no written procedure is needed. This is not true. The AWS D1.1 Structural Welding Code – Steel explicitly requires written WPSs for all fabrication—whether prequalified or qualified by test.

The WPS is as a Communication Tool

he WPS is the primary means of communication between the welding engineer, the supervisor, the inspector, and the welder.
It tells everyone exactly how a weld is to be made—process, base metal, preheat, amperage, polarity, shielding gas, and more.

For communication to be effective, welidng procedures must be readily available:

• Some fabricators issue each welder a personal set of WPSs.
• Others list parameters on shop drawings or post them on bulletin boards.
• Whatever the method, WPSs must be accessible to those authorized to use them.

When WPSs are missing or unavailable, quality suffers and productivity declines.

Quality and Productivity Depend on Conformance

A well-written WPS sets the safe, efficient operating window for each process and material combination. This means: 

• Correct polarity must be used for each electrode.
• Proper shielding gas ensures stable arcs and sound welds.
• Amperage and voltage must match the electrode size and base-metal thickness.
• Required preheat depends on steel grade, material thickness, and electrode type.

Failure to follow these parameters can produce welds that do not meet code or contract quality requirements.
Repairing such welds can raise the cost of a weldment by a factor of up to ten—a direct hit to project profitability.

The Economic Impact of Procedure Control

It is important to note that welding cost is inversely proportional to deposition rate, which depends on wire-feed speed for wire processes such as GMAW and FCAW and amperage for SMAW.
For example, if a weld can be made at 200 ipm but is performed at 160 ipm, the cost may rise ≈ 25% for that same joint.
Adhering to WPS values ensures welding is performed within the optimum range for both quality and cost.

Beyond Minimum Code Requirements

Codes define the minimum acceptable limits—but minimums aren’t always sufficient.
Contract specifications or critical service conditions often require tighter controls.
Those additional requirements should also be communicated through the WPS so every stakeholder understands what must be done and why.

Key Points to Remember

1. Written WPSs are mandatory — prequalified does not mean exempt from documentation.
2. Communication is the core function of a WPS.
3. Availability matters — make sure welders, supervisors, and inspectors can access the current procedures.  Many shops simply store the procedures on a file folder or binder that is not in the welder’s station.  
4. Quality and cost control start with procedure conformance.
5. Codes set minimums; your welding procedure can go beyond that if necessary.

A welding procedures specification (WPS) should not be senn as just paperwork—it’s the language of quality welding.
It tells every team member how to perform safely, efficiently, and consistently.
Clear written procedures prevent rework, reduce cost, and build the foundation for weld integrity.

Reference:

“The National Steel Construction Conference Proceedings,” AISC (1997) – Duane K. Miller, Sc.D., P.E.,