Welding Procedure Specifications WPSs

D1.8 Seismic Supplement Welding Manual

Welding Procedure Specifications (WPSs)

A welding procedure specification is “a document providing the required welding variables for a specific application to assure repeatability by properly trained welders and welding operators” according to AWS A3.0 Standard Terms and Definitions. AWS D1.1 requires WPSs to be documented (see D1.1 subclause 3.1, 4.6). Under D1.1, WPSs may be either prequalified or qualified by test, and both types of WPSs may be used under D1.8 as well.

In addition to meeting the requirements of D1.1, D1.8 mandates additional WPS requirements. Under D1.8, WPSs must list the filler metal manufacturer as well as the filler metal trade name (such as Lincoln Electric’s Innershield® NR®-233) as opposed to showing only the AWS classification (in this case, E71T-8). D1.8 mandates a variety of other filler metal requirements that are addressed in the next section of this manual. See D1.8, clause 6.1(1).

WPSs must also list one or more combinations of welding variables that produce heat inputs within the limits of the tests performed on the specific filler metal (this will be discussed in greater detail under “Filler Metals”). Heat input is determined from the following equation:

Heat Input (H) = (60 x E x I)

	1000 S
Where: H =	Heat input in KJ/in (KJ/mm)
E =	Arc voltage in volts
I =	Current in amps
S =	Travel speed in inches per minute (mm per minute)

The values for E, I and S as shown on the WPS must result in a heat input within the high and low heat input limits for the specific electrode being used. See D1.8, clause 6.1(2).

The welding process shown on the WPS may be SMAW, GMAW (except for short circuit transfer), FCAW (either self-shielded or gas-shielded) or SAW. Other processes are permitted under specific conditions. See D1.8, clause 6.2.1.

The maximum interpass temperature to be shown on the WPS shall not exceed 300°C (550°F), unless an alternative temperature (either higher or lower) has been established by test. See D1.8, clause 6.5.

Filler Metals – General

Filler metals acceptable for use on D1.8 projects are subject to a variety of requirements beyond those imposed by D1.1. Some requirements apply to all welds governed by D1.8 while other provisions are mandated only for the Demand Critical (DC) welds. If the weld is not on or part of the seismic force resisting system, only D1.1 requirements apply. See D1.8, clause 6.3.