N211-070 TITLE: Lightweight Diver Handheld Underwater Hydraulic Friction Stud Welding System for 5000 Series Aluminum
RT&L FOCUS AREA(S): General Warfighting Requirements
TECHNOLOGY AREA(S): Materials / Processes
OBJECTIVE: Develop a lightweight diver handheld portable hydraulic friction stud welding system and welding procedures for 5000 series aluminum to support sustainment and readiness for underwater ship repairs and salvage on the Littoral Combat Ships (LCS).
DESCRIPTION: The Navy has a need to wet weld aluminum studs on aluminum hull vessels to support underwater ship husbandry and emergency ship damage control, specifically on the LCS. Current underwater friction stud welding technology has been limited to carbon steel studs welded to carbon steel base plate material. Underwater friction stud welding using aluminum studs and base material has not been achieved commercially or within the Government. The equipment, whether pneumatic or hydraulic, is heavy and not adequately designed for safe use by divers performing underwater ship husbandry. A lightweight, diver friendly system that does not require special training or qualifications, and which could be used by Navy divers and Navy diving services contractors worldwide, is preferred for use in the field and during emergency ship damage control.
Research and development is required to further this technology in order to fill the Navy�s current gap to perform underwater wet welding on aluminum hull vessels. Development of this technology will give the Navy the capability to wet weld aluminum studs to aluminum hulls, which can be used to perform underwater ship husbandry that would normally require dry-docking. This technology can also be used to attach cofferdams to perform underwater hull maintenance and repairs, something that is not possible currently. Performing repairs in the water significantly reduces overall maintenance and life cycle costs in comparison to dry-dock repairs. Additionally, the technology could be used to support emergency ship damage control efforts, such as patch attachments.
The concept design should allow for 1/2-inch minimum stud diameter and 3/8-inch minimum plate thickness. The weld head (actual equipment operated by the diver) should be as light as possible with a dry weight of approximately 25 pounds and be mechanically driven with no electrical or digital requirements to operate. The design concept should allow for the weld head to be operated by a 150ft minimum umbilical length attached to a hydraulic power unit (HPU). The HPU would be located on the surface and not be required subsea. The HPU can have electrical/digital requirements.
The technology, along with the welded stud coupons, will be tested against the qualification requirements of NAVSEA Technical Publication, S9074-AQ-GIB-010/248, Requirements for Welding and Brazing Procedure and Performance Qualification and Department of Defense Manufacturing Process Standard, MIL-STD-1689A, Fabrication, Welding, and Inspection of Ship Structure.
PHASE I: Develop a concept that will support fabrication of a prototype lightweight diver held hydraulic friction stud welding system capable of wet welding 5000 series aluminum (5086 stud to 5083 plate).
The feasibility of the concept shall be demonstrated as much as practicable by bread board bench testing and equipment prototyping. In addition, during this phase, the feasibility of welding 5086 studs to 5083 plate shall be demonstrated by welding coupons on a controlled environment and testing them by Non-Destructive and Destructive Test methods.
The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.
PHASE II: Based on the results of Phase I efforts and the Phase II Statement of Work (SOW), a prototype system shall be developed and delivered to the Government for final test and evaluation. The system shall include the weld head (diver operated part of the system), umbilical, and hydraulic power unit. Perform initial evaluation of the system, including diver safety and ability to operate the weld head in the flat, vertical, and overhead positions, which can be in a shop environment without requiring any diving services. The system will also go through preliminary qualification testing based on a test plan developed by the Government IAW NAVSEA Technical Publication, S9074-AQ-GIB-010/248 and MIL-STD-1689A. Final test and evaluation will take place at the Navy Experimental Diving Unit, Panama City, FL.
PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology to Navy use. Deliver an operational system to the Government for qualification testing in accordance with NAVSEA Technical Publication, S9074-AQ-GIB-010/248, Requirements for Welding and Brazing Procedure and Performance Qualification and Department of Defense Manufacturing Process Standard, MIL-STD-1689A, Fabrication, Welding, and Inspection of Ship Structure. Provide all studs and plate material required for qualification testing. Provide all required training to safely operate the system.
After successful qualification, deliver the systems to the Navy�s Emergency Ship Salvage Material (ESSM) program where they will be maintained ready for issue. Train ESSM personnel in the operation, maintenance, and overhaul of the entire system. Provide all drawings of the system to support fabrication, maintenance, and overhaul.
Not only will this technology fulfill the Navy�s gap for wet welding aluminum studs to aluminum hull vessels, the technology can be transitioned to industry for use wherever aluminum studs are required to be welded either on the surface or underwater.
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KEYWORDS: Underwater Welding; Friction Welding; Friction Stud Welding; Aluminum Welding; Aluminum Joining Processes; Underwater Ship Repair