In recent memory, space exploration has found success with many accomplishments; just to name a few, the field has been responsible for discovering the closest ever potentially habitable planet, executing the flybys of Pluto and Saturn’s icy moon Enceladus, completing five years of the Mars Curiosity Rover’s expedition, and celebrating over 15 years of continuous human presence on the International Space Station (ISS) and over 25 years of the Hubble Space Telescope being in place. Down in the stratosphere, but still at elevations higher than human habitation, at any given time, there are 5,000 aircraft in the sky. Aerospace needs the best practices to make things fly.
Integral to this is the welding of the materials, components, and systems that are utilized in the aerospace industry. For guidance in this activity, AWS D17.1/D17.1M:2017 – Specification for Fusion Welding for Aerospace Applications has been revised.
Fusion welding refers to not a specific subset of welding, but it is more of a generic term for welding activities that incorporate melting as a way to join materials. Fusion welding for aerospace applications is simply a variant of these processes, but it serves an industry that is subject to some of the most stringent rules and practices to support its extreme demands. AWS D17.1/D17.1M:2017 contains guidelines for fusion welding and non-destructive examination (NDE) of aerospace flight hardware, as well as the welding and NDE of non-flight hardware.
When the AWS D17.1/D17.1M:2017 specification is stipulated in contract documents, conformance with all provisions of the specification is required. The document is broken up into 9 main clauses, with the earliest ones being devoted to general guidance, references, and background information, while the remainder address the design of welded connections, qualification for welding procedures and the welders performing them, fabrication when welding aerospace hardware, inspection, the repair of existing structures and nonflight hardware.
The AWS D17.1 standard originated in the 1990s, after a time when aviation welding specifications were primarily dependent on government standards for contract purposes. AWS D17.1/D17.1M:2017 is the third edition of the aerospace fusion welding specification, and it has undergone the following significant changes from the 2010 version:
- Removed Annex B for effective throat.
- Added Annex D for materials in Table 5.4 with cross-referenced UNS numbers to their proprietary tradenames.
- Added Annex G for samples of welding forms for WPSs, PQRs, and welder performing qualifications. These samples were removed from elsewhere in the standard.
- Added Annex H for qualified positions for production welding.
- Added Annex I for common acronyms that appear throughout the standard to ease compliance for the user.
- Added Figure 5.11C, “Condition of Surfaces Opposite Lap and T-Joint Fillet Welds—Melt Through in Fillet Welds”.
- Added Figure 5.11D, “Condition of Surfaces Opposite Lap and T-Joint Fillet Welds—Unacceptable Melt Through in Fillet Welds”.
- Separated Table B.3, “Bend Specimens for Groove Welds in Tube”, into B.3 and B.3M, one for U.S. Customary Units and one for the International System of Units, respectively.
- Conversion values were updated to reflect AWS A1.1:2016 – Metric Practice Guide for the Welding Industry.
Any other changes to the document are marked by underlined areas in the text.
AWS D17.1/D17.1M:2017 – Specification for Fusion Welding for Aerospace Applications is available on the ANSI Webstore.