Pressure Vessel Welds
Friction Stir and Fusion Weld Joint System
Pressure vessel weld systems, utilizing solid-state friction stir welding and fusion methods with ER2319 filler wire, join structural shell and head sections into complete pressure boundaries. Primary boundary seams require full-penetration joints, typically delivering joint efficiencies between 0.85 and 1.0 depending on the welding process and inspection level. In the lunar operational environment, maintaining structural integrity depends on managing fatigue crack growth under NASA-STD-5019 fracture mechanics standards, using post-weld heat treatment to relieve residual stresses. Long-term reliability also requires continuous physical access for periodic in-service examination via ultrasonic and radiographic equipment, alongside specialized welding procedures for dissimilar metal joints between aluminum-lithium shells and titanium penetrations.
Weld joints assembling pressure vessel shell and head sections into complete vessels
Purpose
Weld joints assembling pressure vessel shell and head sections into complete vessels
Context
Child of L2-STR-PRES
Principles
- ▸Friction stir welding produces solid-state joints with superior fatigue properties
- ▸Weld joint efficiency typically 0.85-1.0 depending on process and inspection level
- ▸Full-penetration welds required for all primary pressure boundary joints
- ▸Post-weld heat treatment relieves residual stresses improving fatigue life
Typical implementations
- ▸NASA Marshall Space Flight Center FSW for SLS core stage
- ▸Orion crew module friction stir welded pressure vessel
- ▸AWS D17.1 aerospace welding standards
Lunar considerations
- ▸Weld inspection access must be maintained for periodic in-service examination
- ▸Fatigue crack growth analysis at welds uses fracture mechanics (NASA-STD-5019)
- ▸Dissimilar metal welds (Al to Ti) at penetrations require special procedures
Specifications
Functional
| primary function | Weld joints assembling pressure vessel shell and head sections into complete vessels |
Physical
| materials | FSW process parameters for Al-Li, ER2319 filler wire for fusion welds, NDE equipment for ultrasonic/radiographic inspection |
Interfaces
Provides
- Pressure boundary integrity at all joints
Requires
- Weld inspection and crack monitoring data
Cite this entry
Lunar Ark Codex. "Pressure Vessel Welds" (L3-STR-PRES-WELD). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-STR-PRES-WELD
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.