Welding in Marine Engineering

1953 ◽  
Vol 167 (1) ◽  
pp. 48-61
Author(s):  
H. N. Pemberton
Keyword(s):  
Gas Turbines ◽  
Good Practice ◽  
Land Plant ◽  
General Interest ◽  
Repair Work ◽  
Welding Equipment ◽  
New Construction ◽  
Marine Engineering ◽  
Welding Processes ◽  
Marine Engineers

This lecture comprises a survey and commentary on the use of welding for the construction and repair of marine machinery for main propelling and ancillary purposes. The history of welding in relation to marine engineering is traced from the hammer welding of boiler seams in 1870 up to the present day, when welds made by modern processes are accepted for highly stressed components. Descriptions of welding processes are omitted since the lecture deals with welding applications rather than welding technique. Numerous examples are given and illustrated, and many of them relate to design details which are typical of good practice and are accepted by ship classification authorities. The lecture is divided under two main heads, namely, “New Construction” and “Repairs”. A further subdivision is made under “New Construction”, so that boilers, pipe-work, machinery components, turbines, gearing, electrical propulsion, refrigerating plant, and dredging craft are dealt with in that order. Also included in this section are some remarks of general interest on the subject of residual stresses and their relief by thermal treatment. Problems concerning the welding of alloy steels for gas turbines are discussed. There is need for research into the weldability of these steels, bearing in mind that not only the welds should be free from micro-cracks to start with, but they should also be equivalent to the parent metal in resistance to metallurgical and physical deterioration whilst operating at high temperatures over long periods. A field of welding which is always of interest to marine engineers is in repair work. Unlike land plant for which complete resources for repairs are usually available, marine machinery may be involved in mishaps and breakdown on the high seas and in remote parts of the world when repair facilities might be primitive, or even non-existent. Many ships now carry electric welding equipment, and sea-going marine engineers include welding in their many manual accomplishments. Several interesting examples of weld repairs are described, which in some cases have enabled ships to complete their voyages carrying valuable cargoes with a minimum of delay. Other examples are given which emphasize the discrimination that is necessary in deciding whether or not a welded repair is desirable. Unfortunate consequences have followed the ill-advised use of welding in some cases.

Failures Related to Welding

2021 ◽  
pp. 266-306
Author(s):  
Jorge J. Perdomo ◽  
Luis A. Ganhao
Keyword(s):  
Base Metal ◽  
Nondestructive Inspection ◽  
Incomplete Fusion ◽  
Service Failures ◽  
Critical Flaw ◽  
Weld Porosity ◽  
New Construction ◽  
Construction Inspection ◽  
Welding Processes

Abstract This article describes some of the welding discontinuities and flaws characterized by nondestructive examinations. It focuses on nondestructive inspection methods used in the welding industry. The sources of weld discontinuities and defects as they relate to service failures or rejection in new construction inspection are also discussed. The article discusses the types of base metal cracks and metallurgical weld cracking. The article discusses the processes involved in the analysis of in-service weld failures. It briefly reviews the general types of process-related discontinuities of arc welds. Mechanical and environmental failure origins related to other types of welding processes are also described. The article explains the cause and effects of process-related discontinuities including weld porosity, inclusions, incomplete fusion, and incomplete penetration. Different fitness-for-service assessment methodologies for calculating allowable or critical flaw sizes are also discussed.

U.S. Navy World War II War Damage Reports

2012 ◽  
Vol 46 (6) ◽  
pp. 49-60
Author(s):  
Philip Sims
Keyword(s):  
World War Ii ◽  
Damage Control ◽  
Good Practice ◽  
Lessons Learned ◽  
Physical Evidence ◽  
Des Moines ◽  
The Pacific ◽  
New Construction ◽  
Extent Of Damage ◽  
High Level

AbstractThe damaged and sunken ships of Pearl Harbor contained information on the response of ships and their damage control teams to modern weapons. As they were raised to be repaired, the physical evidence of damaged areas was carefully recorded. The Navy’s ship design organization, the Bureau of Ships (Buships), combined the physical evidence with crew action reports to determine what worked and what did not. Buships published the results in almost 70 War Damage Reports, which were illustrated with photographs and newly prepared extent-of-damage drawings. This paper is a high-level introduction to that massive body of work.The customers of the reports were the damage control schools, the operational fleet (needing to ruthlessly remove flammable materials), the naval repair yards (installing ship alterations to overcome deficiencies), and the designers of new construction warships. The report series was continued covering ships damaged or lost in the Pacific battles. Modern warship features that are now thought of as “good practice,” such as ring fire mains with one line high and the other low on the opposite side of the ship, are a result of “lessons learned” from the war damage surveys. The paper compares the 1938 design Iowa class battleships and the war design Des Moines class heavy cruisers, which incorporated the lessons learned. The differences in compartmentation and damage control fittings of the two classes are described.

Failure Mechanisms on Exhaust Systems of Naval Gas Turbines

2008 ◽  
Vol 587-588 ◽  
pp. 946-950 ◽  
Author(s):  
Rui F. Martins ◽  
Carlos M. Branco ◽  
António M. Gonçalves-Coelho ◽  
Edgar C. Gomes
Keyword(s):  
Crack Propagation ◽  
Gas Turbines ◽  
Failure Mechanisms ◽  
Plate Thickness ◽  
Exhaust System ◽  
System Structure ◽  
Surface Finishing ◽  
Thin Wall ◽  
Welding Processes ◽  
Exhaust Systems

Some exhaust systems of naval gas turbines have been periodically repaired due to thermal-fatigue crack propagation after entering into service. Those structures were made of austenitic stainless steel grade AISI 316L in thin wall plates, which were bent in rolling machines and welded with longitudinal and circumferential joints by means of shielded metal arc, TIG or MIG/MAG welding processes. The plate thickness is about 3.7 mm and the temperature on the exhaust system is approximately 500°C and 350°C in the critical zones, which are located in the lower and intermediate regions of the exhaust system.Several cracks were detected at the critical regions, near the weld toe of butt and T-welded joints. The stress concentration factors induced by the weld angle, toe radius and rolled surface finishing diminishes the fatigue life strength. Some cracked material samples were taken out from the exhaust system structure and were analysed with a Scanning Electron Microscope (SEM/EDS), in order to determine the failure mechanisms involved in the crack propagation process. Those results are presented in the paper. Several high temperature fatigue and creep tests were performed with CT specimens. The mechanisms of crack propagation on the CT specimens were studied by SEM and compared with the fracture surfaces obtained from the samples taken out from the structure. The carbide precipitation on the grain boundaries was also studied.

The Society of Naval Architects and Marine Engineers and the Conquest of Innerspace

1970 ◽  
Vol 7 (01) ◽  
pp. 1-9
Author(s):  
E. M. MacCutcheon
Keyword(s):  
International Collaboration ◽  
Advisory Group ◽  
Ocean Engineering ◽  
Naval Architecture ◽  
Engineering Problems ◽  
The Future ◽  
Marine Engineering ◽  
And Control ◽  
Marine Engineers

National planners are developing programs for surveying and exploiting the oceans. A decade of international collaboration is contemplated for the 1970's. The focus is on exploitation as contrasted to research, so the major problems will be engineering problems. The disciplines of naval architecture and marine engineering, and the technologies of ship designing, shipbuilding and ship operating will feature in this future national-international exploitation of the world's oceans. The Society of Naval Architects and Marine Engineers has espoused the broader domain of ocean engineering for the future scope of the Society's activities. Policies and plans have been completed. Problem areas and possible SNAME activities have been identified and assigned for action. An Ocean Engineering Advisory Group has been operating for two years in carrying out this work and will continue to maintain and control an active SNAME participation in ocean engineering. This paper summarizes the aforementioned plans and activities and mentions 19 interesting ocean engineering focal projects which might be useful to advance our capabilities for exploitation of the ocean resources.

Gas Turbine Training in the Royal Navy

1988 ◽  
Author(s):  
T. J. Meadows
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Royal Navy ◽  
Career Training ◽  
Enlisted Men ◽  
Marine Engineering ◽  
New Generation

This paper discusses the training given to the personnel of the Marine Engineering Branch of the Royal Navy to enable them to maintain and operate the main propulsion gas turbines fitted in the new generation of warships. Concentrating on the aspects appertaining to gas turbines, the paper describes the training given to both officers and enlisted men during their initial career training both ashore and at sea, and also outlines the training undertaken by personnel to prepare them for appointments to specific ships. Finally, the methods of validating this training to ensure that it meets the requirements of the Fleet are described.

Developing Additive Manufacturing Technology for Burner Repair

2016 ◽  
Author(s):  
Olov Andersson ◽  
Andreas Graichen ◽  
Håkan Brodin ◽  
Vladimir Navrotsky
Keyword(s):  
Additive Manufacturing ◽  
Gas Turbines ◽  
Research Work ◽  
Manufacturing Technology ◽  
Heat Radiation ◽  
Original Design ◽  
Repair Work ◽  
Additive Manufacturing Technology ◽  
Low Emission ◽  
Industrial Gas Turbines

Low emission combustion is one of the most important requirements for Industrial gas turbines. Siemens Industrial gas turbines SGT-800 and SGT-700 use DLE (Dry Low Emission) technology and are equipped with 3rd generation of DLE burners. These burners demonstrate high performance and reliable operation for the duration of their design lifetime. The design and shape of the burner tip is of great importance in order to achieve a good fuel/ air mixture and at the same time a resistance to the fatigue created by heat radiation input. This gives a requirement for a tip structure with delicate internal channels combined with thicker structure for load carrying and production reasons. It was found that the extension of the burner lifetime beyond the original design life could be accomplished by means of repair of the burner tip. Initially the tip repair has been done by conventional methods — i.e. cutting off the tip and replacing it with a premanufactured one. Due to the sophisticated internal structure of the burner the cuts have to be made fairly high upstream to avoid having the weld in the delicate channel area. Through the use of AM (Additive Manufacturing) technology it has been possible to simplify the repair and only replace the damaged part of the tip. Special processes have been developed for AM repair procedure, including: a) machining off of the damaged and oxidized tip, b) positioning the sintered model on the burner face, c) sintering a new tip in place, d) quality assurance and inspection methods, e) powder handling, f) material qualification including bonding zone, g) development of methods for mechanical integrity calculation, h) qualification of the whole repair process. This paper describes how we have developed and qualified SGT-800 and SGT-700 DLE burners repair with the help of additive manufacturing technology and our research work performed. In addition, this paper highlights the challenges we faced during design, materials qualification and repair work shop set-up.

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