Marine link
 
Articles - Ship Repair - History

Welding Technique Helps Navy Save Millions

When maintenance welding required cutting into the hull of a Navy submarine, John Bartly knew there had to be an easier way. Mr. Bartly supervises 15 welding engineers as a U.S. Navy employee on Mare Island in San Francisco Bay. A former president of the American Welding Society, he has decades of experience.

He and his engineers approached Hobart Lasers & Advanced Systems in May 1990 (formerly Martek) to create a multi-faceted program which would meet several welding challenges he faced in his assignment to repair Navy submarines and other seagoing vessels. To date, Hobart has evaluated equipment, developed accessories and conducted feasibility studies on a number of innovative processes for the Navy. Hobart's Application Development Centers provide an opportunity to test applications on state-of-the-art CW Nd: YAG lasers; Orbitig control systems; Viper tube-to-tube welding heads; HAWCS computer-controlled variable polarity plasma/gas tungsten arc systems; and other equipment. A challenge Mr. Bartly faced was the repair of deteriorated valve seats on the steam chest, which contains control valves to throttle the submarine's steam flow. Conventional welding processes in these applications are low yield and must be repaired several times. The low power density process required Mr. Bartly's welders to cut through the pressure hull of the sub, remove the item to be repaired, take it to the shop, preheat it, manually repair the item, post-weld heat it, machine it, return it to its original position, and repair the opened pressure hull. To cut down on this process, saving time and money, Hobart's engineers found that by using laser technology they could perform the repairs without having to remove the component, as the preheat and post heat are not required. "Because it has a 150-ft.

(45.7-m) fiber optic delivery system, our 2,400-watt CW Nd:YAG laser welding head can be brought internal to the vessel and locally tooled with accessories, potentially saving millions of taxpayer dollars," said Tim Webber, a Hobart Laser Applications manager.

In repairing the steam chests, old material must be machined off and replaced to a precise finish, size and polish. Currently, Hobart is developing a system with a small articulated gantry robot, small enough to get in the operator's lap. Using rotary motion, the robot welds a hardface alloy place from a small mechanical bridge. A pendant-like controller is used by the operator at the welding site to set up parameters as necessary. The laser generating equipment sits outside the vessel.

For more information on Hobart Lasers & Advanced Systems Circle 103 on Reader Service Card




Ship Repair History

ABB Turbocharger Repairs VTR..4 Turbine Blades
ABB Turbocharger: Renewed Focus On Quality, Customer Service
Agreement Finalized For Purchase And Cleanup Of Seattle Waterfront Property
Ailsa-Perth: from sunset to sunrise
Alaskan Oil Issue Lingers
ASRY Improves Performance In 1993
Astilleros Espanoles To Convert Tanker To FPSO
AWSC 1993 Annual Report
Consolidation Of Resources
Drew Ameroid Marine Forms CFC Conversion Alliance With York Marine Systems
Dutch Builders Enjoy Influx Of International Orders
frinity Acquires Plotter Yard In Houston
Getting To Where The Gouges Reside
Going Deep
Heightened Environmental Pressures, Rising Freight Rates Buoy Ship Repair Industry Announces New Contracts
HHI Starts ' 97 Strong Korean yard wins bulker contract from Norway's Bergesen to start year
Lisnave Reports Upbeat Quarter; Discusses Future Plans
NASSCO Invests In Technology To Capture Commercial Business
Norshipco Completes Work On Double-Hull Tanker Stena Concertina Acquire Air & Water Technologies Unit
Orkot Helps Repair Iceberg Damage To Tanker, Overseas Okie
Renovation Of Inland Service Tug Completed
Revenue And Profitability Gains Reported By ASRY
Ship Repair & Conversion '93
SHIP REPAIR & CONVERSION: Review of 1994
Ship Structure Committee Publishes Reports On Fatigue Curves And Underwater Repair Procedures
Shipbuilding in South Korea… Expansion Continues
Southwest Marine Inc. Expands Into New Market President And CEO
The Need To Rationalize Navy ship Maintenance Capacitu
Unitor Introduces Shipboard Polymer Repair System
Vietnam Government Approves Keppel/BaSon Joint Venture Shipyard
 
rss feeds | archive | privacy | history | articles | contributors | top news | contact us | about us | copyright