AWS D17.1 Endorsement cheat sheet

AWS D17.1 governs fusion welding of aerospace components in aluminum, titanium, steel, nickel, cobalt, and magnesium alloys; it is a specification of requirements rather than a how-to guide.

D17.1 classifies welds by inspection class: Class A (critical), Class B (semi-critical), and Class C (non-critical); acceptance criteria for porosity, undercut, and profile tighten from C to A.

Three weld categories drive qualification: manual, semi-automatic, and automatic/machine; welder performance qualification is required for manual and semi-automatic welding only.

Welding procedure specifications must be qualified by procedure qualification records using mechanical testing (tension, bend, or radiographic) per the applicable base-metal group.

Base metals are grouped by composition and weldability; a procedure qualified on one alloy may extend to other alloys within the same group under stated thickness and joint limits.

Preheat and interpass temperature limits are specified by alloy family; titanium and some aluminum alloys require controlled interpass temperature and clean-room-level contamination control.

Visual examination is mandatory on all completed welds; Class A welds additionally require liquid penetrant and radiographic examination unless otherwise specified by the contract.

Welder qualification remains valid provided the welder stays continuously employed in the qualified process; a lapse beyond six months requires requalification.

A welder performance qualification test is welded to a qualified WPS; the test coupon joint type, position, and thickness set the range of production work the welder may perform.

Position qualification follows the standard rule that qualifying in the most difficult position (typically vertical or overhead) extends to easier positions such as flat.

Thickness qualification: a test coupon qualifies production thickness ranges that bracket the coupon thickness per the specification's table, not an unlimited range.

Essential variables for procedure qualification include base-metal group, filler-metal classification, joint design, welding process, position, and preheat/interpass range.

A change from manual to automatic welding is a new process condition requiring separate qualification; automatic welding is qualified by the machine and procedure, not by welder skill.

Filler metals must conform to the applicable AWS filler-metal specification and be stored and handled per manufacturer instructions; expired or contaminated filler is nonconforming.

Qualification records must be retained and traceable to the welder, the WPS, and the test results; records are subject to audit by the cognizant engineering authority.

Discontinuity acceptance limits are class-dependent: porosity size and cumulative length, undercut depth, incomplete fusion, and crack indications are all evaluated against Class A, B, or C criteria.

Cracks of any kind are rejectable in Classes A and B; certain limited indications may be evaluated for repair or rejection under Class C criteria.

Radiographic examination acceptance uses a reference severity standard; the inspector compares the production radiograph to the standard and accepts only indications at or below the class limit.

Liquid penetrant examination applies to surface-breaking discontinuities on nonporous materials; penetrant inspection of rough or as-welded surfaces can produce false indications.

Weld repairs require a repair procedure qualified to the same rules as the original weld; repeated repair cycles are limited by the specification and by engineering approval.

Post-weld heat treatment, when required, must be performed per the qualified procedure and documented; heat-treat condition of the base metal affects the procedure.

Inspection personnel must be qualified to a recognized certification scheme (for example, NAS 410 or an equivalent employer program) for the method they perform.

Documentation package typically includes the WPS, procedure qualification record, welder qualification record, inspection reports, and material certifications, all traceable to the part.