Welding demand in offshore and marine applications is increased with the increasing in oil and gas activities as well as increasing in the marine transportation and industrial applications. Applications of underwater welding well be increased in Kuwait in the coming years due to the strategic directive of the country toward starting the offshore oil and gas exploration and production, and the increase in marine transportation projects. Therefore, there is a need to understand the concept of underwater welding and different techniques used in the market. In this paper, a brief description of the different commercial underwater techniques will be presented taking into account showing detailed description of a few advanced welding techniques.
Underwater welding is an important technique used for underwater fabrication. There are two main types: wet welding, where welding is performed directly under water using a special electrode, and dry welding, where an enclosed chamber is used to displace water and allow welding in a dry environment filled with gas. Wet welding is more common due to greater freedom of movement but has higher risks, while dry welding has higher costs but lower risks. Underwater welding requires higher currents than air welding due to water cooling the weld. It is used in offshore construction, ship repair, and salvage operations. Underwater welders require commercial diving certification and welding qualifications.
This document discusses underwater welding, including its need, requirements, processes, equipment, classifications, advantages, disadvantages, applications, risks, and developments. Specifically, it outlines the differences between normal welding and underwater welding, describes wet and dry welding processes, and discusses the risks and difficulties of underwater welding including electric shock and gas explosions.
This document discusses underwater welding techniques. It begins by providing background on welding in general and how underwater welding arose during World War II to salvage sunk vessels. There are two main types of underwater welding: wet welding, where welding is done directly in water, and dry welding, which uses an enclosed positive pressure environment. Wet welding is the most common as it provides freedom of movement and is efficient and economical for repair work. The document then provides details on a specific wet welding project to repair submarine ballast tanks and the equipment and procedures used.
Professional Subsea Service is a professional diving service company that has operated for over 20 years, specializing in subsea technical and civil engineering projects on offshore oil and gas infrastructure. They perform underwater welding in all positions, including the difficult 6G position, and have extensive experience with over 2100 meters of welded joints completed. Their wet welding allows work in locations that dry welding cannot access, though it has limitations in non-destructive testing and weld quality.
Underwater welding can be classified as dry welding, which uses sealed chambers, or wet welding, which is performed directly in water. Dry welding produces higher quality welds but requires more complex and expensive equipment. Wet welding is more economical but results in lower weld quality due to water's quenching effect. The underwater environment affects welds by introducing hydrogen that causes embrittlement and oxygen that increases porosity. Weld quality declines with increasing depth due to higher pressures. Proper welding equipment and techniques can help reduce these negative impacts.
Underwater welding is used for pipelines, ships and vessels, and mining operations. It can be done through wet welding, which involves welding directly in water using special electrodes, or dry welding inside a sealed chamber. Wet welding is faster and cheaper but has risks of electric shock and poor visibility in water, while dry welding allows for higher quality welds and safety inspections but is more expensive. Proper equipment, training, and precautions are needed to address risks like pressure changes and shark attacks when welding underwater.
this is the best presentation to get the clear idea and knowledge about Under Water Welding. this the best way to get to know about this topic. and this presentation is from Army institute of Technology pune.
Underwater welding is used for repairing offshore structures like oil rigs and pipelines. There are two main types: wet welding, where welding occurs directly in water using techniques like MMA; and dry welding, where a chamber is created to weld in a dry environment, with techniques like GTAW and GMAW. Wet welding is cheaper but results in poorer weld quality due to quenching, while dry welding produces higher quality welds but requires more complex and expensive equipment like hyperbaric chambers. Proper insulation and ventilation are needed to address risks like electric shock and gas accumulation. Underwater welding is an important but challenging field with ongoing research into deeper diving capabilities.
Underwater welding is an important technique used for underwater fabrication. There are two main types: wet welding, where welding is performed directly under water using a special electrode, and dry welding, where an enclosed chamber is used to displace water and allow welding in a dry environment filled with gas. Wet welding is more common due to greater freedom of movement but has higher risks, while dry welding has higher costs but lower risks. Underwater welding requires higher currents than air welding due to water cooling the weld. It is used in offshore construction, ship repair, and salvage operations. Underwater welders require commercial diving certification and welding qualifications.
This document discusses underwater welding, including its need, requirements, processes, equipment, classifications, advantages, disadvantages, applications, risks, and developments. Specifically, it outlines the differences between normal welding and underwater welding, describes wet and dry welding processes, and discusses the risks and difficulties of underwater welding including electric shock and gas explosions.
This document discusses underwater welding techniques. It begins by providing background on welding in general and how underwater welding arose during World War II to salvage sunk vessels. There are two main types of underwater welding: wet welding, where welding is done directly in water, and dry welding, which uses an enclosed positive pressure environment. Wet welding is the most common as it provides freedom of movement and is efficient and economical for repair work. The document then provides details on a specific wet welding project to repair submarine ballast tanks and the equipment and procedures used.
Professional Subsea Service is a professional diving service company that has operated for over 20 years, specializing in subsea technical and civil engineering projects on offshore oil and gas infrastructure. They perform underwater welding in all positions, including the difficult 6G position, and have extensive experience with over 2100 meters of welded joints completed. Their wet welding allows work in locations that dry welding cannot access, though it has limitations in non-destructive testing and weld quality.
Underwater welding can be classified as dry welding, which uses sealed chambers, or wet welding, which is performed directly in water. Dry welding produces higher quality welds but requires more complex and expensive equipment. Wet welding is more economical but results in lower weld quality due to water's quenching effect. The underwater environment affects welds by introducing hydrogen that causes embrittlement and oxygen that increases porosity. Weld quality declines with increasing depth due to higher pressures. Proper welding equipment and techniques can help reduce these negative impacts.
Underwater welding is used for pipelines, ships and vessels, and mining operations. It can be done through wet welding, which involves welding directly in water using special electrodes, or dry welding inside a sealed chamber. Wet welding is faster and cheaper but has risks of electric shock and poor visibility in water, while dry welding allows for higher quality welds and safety inspections but is more expensive. Proper equipment, training, and precautions are needed to address risks like pressure changes and shark attacks when welding underwater.
this is the best presentation to get the clear idea and knowledge about Under Water Welding. this the best way to get to know about this topic. and this presentation is from Army institute of Technology pune.
Underwater welding is used for repairing offshore structures like oil rigs and pipelines. There are two main types: wet welding, where welding occurs directly in water using techniques like MMA; and dry welding, where a chamber is created to weld in a dry environment, with techniques like GTAW and GMAW. Wet welding is cheaper but results in poorer weld quality due to quenching, while dry welding produces higher quality welds but requires more complex and expensive equipment like hyperbaric chambers. Proper insulation and ventilation are needed to address risks like electric shock and gas accumulation. Underwater welding is an important but challenging field with ongoing research into deeper diving capabilities.
Welding processes have become increasingly important in almost all manufacturing industries and for structural application. Although a large number of techniques are available for welding in atmosphere, many of these techniques cannot be applied in offshore and marine application where presence of water is of major concern. In this regard, it is relevant to note that a great majority of offshore repairing and surfacing work is carried out at a relatively shallow depth, in the region intermittently covered by the water known as the splash zone. Though numerically, most ship repair and welding jobs are carried out at a shallow depth, the most technologically challenging task is repair at greater depths, especially in pipelines and repair of accidental failure. The advantages of underwater welding are largely of an economic nature, because underwater-welding for marine maintenance and repair jobs by passes the need to pull the structure out of the sea and saves valuable time and dry docking costs. It is also an important technique for emergency repairs which allow the damaged structure to be safely transported to dry facilities for permanent repair or scrapping. Underwater welding is applied in both inland and offshore environments, though seasonal weather inhibits offshore underwater welding during winter. In either location, surface supplied air is the most common diving method for underwater welders. Underwater welding is an important tool for underwater fabrication works.
Underwater hyperbaric welding was invented by the Russian metallurgist Konstantin Khrenov in 1932.
Hyperbaric welding is the process of welding at elevated pressures, normally underwater. Hyperbaric welding can either take place wet in the water itself or dry inside a specially constructed positive pressure enclosure and hence a dry environment. It is predominantly referred to as "hyperbaric welding" when used in a dry environment, and "underwater welding" when in a wet environment. The applications of hyperbaric welding are diverse—it is often used to repair ships, offshore oil platforms, and pipelines. Steel is the most common material welded.
Underwater welding is used for repairing offshore structures like oil rigs and pipelines. There are two types: wet welding, where welding occurs directly in water; and dry welding, where a chamber is created to keep water out. Wet welding uses manual metal arc welding and is cheaper but results in poorer quality welds due to quenching from water. Dry welding produces higher quality welds using gas tungsten or metal arc welding inside a pressurized chamber, but is more expensive. Precautions must be taken to prevent electric shocks and gas explosions when welding underwater. Research continues on welding deeper underwater through robotic technologies.
It is the welding process done under the water with the help of two methods : Dry Welding and Wet Welding. The presentation provides basic knowledge on the underwater welding and it's respective techniques.
Water Interactive Wet Welding Consulting - Len Andersen 914-536-7101 knows underwater welding and is known in the industry! The product for the Hurricane damaged platforms and pipelines. These wet welding stick and flux Core can be four time more productive than the old 3.2 mm slow wet weld. You can put in the weldment with 6.5 mm 450 mm electrodes and get production. There is 8018-C3 like stick to let your do higher strength steels! It is a patented proven wet welding process developed by Wet Welding to improve the profitability and potential of wet welding through a dry gelling agent and weld enhancers coating on ARC welding consumables which wets and activates near the ARC forming a gelatinous shielding envelope. The Resulting wet welding being done with as greater or greater ease (operability) than surface welding and a lessening of the cooling rate of the weldment such that 2T bends are obtainable.
Water Interactive Wet Welding Uses
• Pipelines • Sheet Steel Piling
• Offshore Platforms • Docks
• Ships and Barges • Dams and Canals
• US Navy Warships • Marine Salvage
Underwater welding can be classified as either wet or dry welding. Wet welding is performed directly in water and allows for increased freedom of movement but has poorer quality welds than dry welding. Dry welding takes place inside a pressurized chamber near the work area and produces higher quality welds, most commonly using gas tungsten arc welding or gas metal arc welding processes. Underwater welding requires specialized equipment including powerful power supplies, gas manifolds, and pressurized chambers. It is used for applications like pipeline construction and repair, ship construction and maintenance, and offshore oil rig installation and repair.
Unit 4 OTHER WELDING PROCESS (MECHANICAL ELECTIVE COURSE)LearnMech
The document discusses various welding processes including thermit welding, electron beam welding, laser beam welding, friction stir welding, and underwater welding. Thermit welding uses an exothermic reaction to generate heat and join metals. Electron beam welding uses a concentrated beam of electrons to melt materials in a vacuum. Laser beam welding focuses intense laser light to join metals. Friction stir welding is a solid-state process that uses a rotating pin to plasticize and join metals without melting. Underwater welding can be done wet using shielded metal arc welding or dry using gas tungsten arc welding inside a pressurized chamber.
This document provides an overview of underwater welding, including a brief history, the two main types (wet and dry welding), advantages and disadvantages of each, applications, risks involved, safety rules, and future developments. It discusses how underwater welding was pioneered in the 1930s in Russia and how the techniques have evolved. Wet welding is done directly in water while dry welding uses an enclosed chamber. Underwater welding is used to repair ships, offshore platforms, and pipelines and allows construction in underwater environments. Safety is important due to risks like electric shock and gas explosions. The future of underwater welding may include increased automation and new techniques like friction welding.
This document provides an overview of underwater welding, including its history, classifications, working principles, advantages, disadvantages, and applications. Underwater welding can be classified as either wet welding, where the welder works directly in water, or dry welding, where welding occurs inside a pressurized chamber. While wet welding is faster and cheaper, it produces lower quality welds compared to dry welding. Underwater welding is used for repairs of ships and structures and construction of pipelines and offshore oil rigs.
Underwater welding includes a lot of different processes that join metals on offshore oil platforms, pipelines & ships .It is the process of welding under water using various techniques under various conditions.....etc.!!!
Underwater welding is a specialized welding process that involves welding at depths below the surface of water. It can be classified as wet welding, where welding is done directly in water, or dry welding, where a dry chamber is created to perform the welding. Wet welding uses manual metal arc welding with direct current power and special electrodes. It allows for work in difficult to reach areas but results in lower quality welds due to quenching from the water. Dry welding produces higher quality welds by working in a pressurized chamber, but requires more complex and expensive equipment. Underwater welding is used for offshore construction, ship repair, and pipeline maintenance.
Underwater welding can be classified as wet welding or dry welding. Wet welding is performed directly in water using manual arc welding, which has advantages of lower cost but risks of cracking and poor visibility. Dry welding uses a chamber near the work area and gas metal arc welding for better quality welds and welder safety, but requires more complex equipment and has higher costs. Underwater welding is used for ship repair and construction, offshore energy structures, and other underwater fabrication work, but poses electric shock and explosion risks that require inspections.
This document provides an overview of underwater welding. It discusses two main types: wet welding, which is performed directly in water using specialized electrodes, and dry welding, where a chamber is created to allow welding in a dry environment. Wet welding is cheaper and faster but results in lower quality welds due to poor visibility and rapid cooling in water. Dry welding allows for higher quality welds but is more expensive due to specialized equipment needs. Underwater welding has applications in offshore construction, ship repair, and salvage operations where it provides a means for metal fabrication and joining underwater.
under water welding-s.saravanakumar,ice,srptcSaravana Yadav
Underwater welding is an important technique for fabrication and repair of marine structures. It was developed in 1946 when special waterproof electrodes were created in Holland. There are two main types of underwater welding: welding performed directly in water and hyperbaric welding which is done inside a pressurized chamber. Manual metal arc welding is commonly used for repairs of offshore platforms due to its versatility and low cost. Research continues on techniques like hyperbaric welding to enable welding at depths of 500 to 1000 meters. Underwater welding is used for offshore construction, ship repair and maintenance, and construction of large ships.
This document discusses various methods of underwater welding. It begins by classifying underwater welding into dry welding and wet welding. Dry welding involves welding inside a chamber that is sealed around the structure, while wet welding is performed directly under water. The document then describes the processes and equipment used for dry welding methods like hyperbaric and cavity welding. It also covers the principles, advantages, and disadvantages of wet welding. The document concludes by discussing applications of underwater welding, the effects of the wet environment on welds, and providing a graph showing the relationship between porosity and water pressure during welding.
Underwater welding involves joining steel structures underwater, such as on offshore oil platforms and ships. It can be done using wet or dry welding methods. Wet welding is done entirely underwater using a special electrode and manual welding similar to open-air welding. Dry welding is done inside a pressurized chamber flooded with a breathing gas like heliox to protect the welder from water pressure. Underwater welding faces risks like electric shock, gas explosions, and decompression sickness which require safety precautions during the process. It is used in offshore construction, ship repair, and salvaging sunken vessels.
This document discusses underwater welding. It begins with an introduction stating that underwater welding allows for the assembly or repair of structures underwater. It then discusses the origin of underwater welding in the 1930s by a Russian metallurgist. There are two main types: dry welding using an enclosed chamber with elevated gas pressure, and wet welding directly exposed to water using special electrodes. Advantages include safety for dry welding and versatility for wet welding. Applications include offshore construction, shipbuilding, pipelines, salvaging sunken vessels, and oil refineries. The document concludes by discussing future areas of automation, mechanization, inspection techniques, and new welding methods.
Hyperbaric welding is the process in which a chamber is sealed around the structure to be welded and is filled with a gas ( He and Oxygen) at the prevailing pressure.
1) Underwater welding is used to repair structures like ships, oil rigs, and pipelines. It can be done wet in water or dry within a pressurized chamber.
2) Wet welding is simpler but produces lower quality welds due to quenching from water and hydrogen embrittlement. Dry welding allows better control but requires more complex equipment.
3) Advances include developing automated dry welding robots and testing friction and explosive welding at deeper depths. Ongoing research aims to improve welding quality and safety at high pressures.
The document discusses two methods for underwater welding: wet welding and dry welding. Wet welding involves welding directly in water and has advantages such as being the cheapest and fastest method, but disadvantages such as poor visibility and risk of hydrogen embrittlement. Dry welding involves welding in a pressurized chamber and has advantages like better weld quality and worker safety, but higher costs associated with the complex equipment required. The document compares the pros and cons of each welding method.
This document discusses underwater welding. It begins by noting the first underwater welds done by the British Admiralty in the 1940s. It then covers the two main types of underwater welding - wet welding, where welding is done directly in the water, and dry welding, where a chamber is created to keep the area dry. The document discusses the equipment, materials, and safety considerations for underwater welding. It notes challenges like hydrogen embrittlement and reduced visibility. Overall, the document provides an introduction to the process and challenges of underwater welding.
Displaying of Digital Clock through digital circuits and through Assembly Lan...IJERA Editor
With a view to display a Digital Clock through digital circuits using modulo-n (mod-n) counters, a circuit diagram was designed and implemented it through multi simulation software. In the similar manner the time digits were displayed on seven segment displays at 8255 programmable peripheral interface (PPI) ports through 8051 microcontroller, the time digits (hours, minutes and seconds) were connected to the first 8255 PPI and the date digits (Years, months and days) were connected to second 8255 PPI. The detailed circuit diagram was given to understand the construction details of the circuit. The loop in a loop technique of assembly language program was used to display date and time. After displaying a year, month and day on the date displays through main program, it calls 1day subroutine to display time in 24 hours clock. The 1day subroutine calls 1second delay subroutine to change the digits in seconds display. After completion of 24 hours time, the digit will be changed in the days display to indicate the next date. After completion of 31 days in the first month, the main program calls month subroutine to change the digit in the months display. Precautions were taken to change the digits in months display for January 31 days, February 28 days, March 31 days, April 30 days, May 31 days, June 30 days, July 31 days, August 31 days, September 30 days, October 31 days, November 30 days and December 31 days. After completion of a month, there will be a change in years digit and this process will be repeated continuously.
Comparative Analysis of Pso-Pid and Hu-PidIJERA Editor
PID control is an important ingredient of a distributed control system. The controllers are also embedded in many special purpose control systems. PID control is often combined with logic, sequential functions, selectors, and simple function blocks to build the complicated automation systems used for energy production, transportation, and manufacturing. Many sophisticated control strategies, such as model predictive control, are also organized hierarchically. PID control is used at the lowest level; the multivariable controller gives the set points to the controllers at the lower level. The PID controller can thus be said to be the “bread and butter‟ of power system engineering. It is an important component in every control engineer‟s tool box. PID controllers have survived many changes in technology, from mechanics and pneumatics to microprocessors via electronic tubes, transistors, integrated circuits. The microprocessor has had a dramatic influence on the PID controller
Welding processes have become increasingly important in almost all manufacturing industries and for structural application. Although a large number of techniques are available for welding in atmosphere, many of these techniques cannot be applied in offshore and marine application where presence of water is of major concern. In this regard, it is relevant to note that a great majority of offshore repairing and surfacing work is carried out at a relatively shallow depth, in the region intermittently covered by the water known as the splash zone. Though numerically, most ship repair and welding jobs are carried out at a shallow depth, the most technologically challenging task is repair at greater depths, especially in pipelines and repair of accidental failure. The advantages of underwater welding are largely of an economic nature, because underwater-welding for marine maintenance and repair jobs by passes the need to pull the structure out of the sea and saves valuable time and dry docking costs. It is also an important technique for emergency repairs which allow the damaged structure to be safely transported to dry facilities for permanent repair or scrapping. Underwater welding is applied in both inland and offshore environments, though seasonal weather inhibits offshore underwater welding during winter. In either location, surface supplied air is the most common diving method for underwater welders. Underwater welding is an important tool for underwater fabrication works.
Underwater hyperbaric welding was invented by the Russian metallurgist Konstantin Khrenov in 1932.
Hyperbaric welding is the process of welding at elevated pressures, normally underwater. Hyperbaric welding can either take place wet in the water itself or dry inside a specially constructed positive pressure enclosure and hence a dry environment. It is predominantly referred to as "hyperbaric welding" when used in a dry environment, and "underwater welding" when in a wet environment. The applications of hyperbaric welding are diverse—it is often used to repair ships, offshore oil platforms, and pipelines. Steel is the most common material welded.
Underwater welding is used for repairing offshore structures like oil rigs and pipelines. There are two types: wet welding, where welding occurs directly in water; and dry welding, where a chamber is created to keep water out. Wet welding uses manual metal arc welding and is cheaper but results in poorer quality welds due to quenching from water. Dry welding produces higher quality welds using gas tungsten or metal arc welding inside a pressurized chamber, but is more expensive. Precautions must be taken to prevent electric shocks and gas explosions when welding underwater. Research continues on welding deeper underwater through robotic technologies.
It is the welding process done under the water with the help of two methods : Dry Welding and Wet Welding. The presentation provides basic knowledge on the underwater welding and it's respective techniques.
Water Interactive Wet Welding Consulting - Len Andersen 914-536-7101 knows underwater welding and is known in the industry! The product for the Hurricane damaged platforms and pipelines. These wet welding stick and flux Core can be four time more productive than the old 3.2 mm slow wet weld. You can put in the weldment with 6.5 mm 450 mm electrodes and get production. There is 8018-C3 like stick to let your do higher strength steels! It is a patented proven wet welding process developed by Wet Welding to improve the profitability and potential of wet welding through a dry gelling agent and weld enhancers coating on ARC welding consumables which wets and activates near the ARC forming a gelatinous shielding envelope. The Resulting wet welding being done with as greater or greater ease (operability) than surface welding and a lessening of the cooling rate of the weldment such that 2T bends are obtainable.
Water Interactive Wet Welding Uses
• Pipelines • Sheet Steel Piling
• Offshore Platforms • Docks
• Ships and Barges • Dams and Canals
• US Navy Warships • Marine Salvage
Underwater welding can be classified as either wet or dry welding. Wet welding is performed directly in water and allows for increased freedom of movement but has poorer quality welds than dry welding. Dry welding takes place inside a pressurized chamber near the work area and produces higher quality welds, most commonly using gas tungsten arc welding or gas metal arc welding processes. Underwater welding requires specialized equipment including powerful power supplies, gas manifolds, and pressurized chambers. It is used for applications like pipeline construction and repair, ship construction and maintenance, and offshore oil rig installation and repair.
Unit 4 OTHER WELDING PROCESS (MECHANICAL ELECTIVE COURSE)LearnMech
The document discusses various welding processes including thermit welding, electron beam welding, laser beam welding, friction stir welding, and underwater welding. Thermit welding uses an exothermic reaction to generate heat and join metals. Electron beam welding uses a concentrated beam of electrons to melt materials in a vacuum. Laser beam welding focuses intense laser light to join metals. Friction stir welding is a solid-state process that uses a rotating pin to plasticize and join metals without melting. Underwater welding can be done wet using shielded metal arc welding or dry using gas tungsten arc welding inside a pressurized chamber.
This document provides an overview of underwater welding, including a brief history, the two main types (wet and dry welding), advantages and disadvantages of each, applications, risks involved, safety rules, and future developments. It discusses how underwater welding was pioneered in the 1930s in Russia and how the techniques have evolved. Wet welding is done directly in water while dry welding uses an enclosed chamber. Underwater welding is used to repair ships, offshore platforms, and pipelines and allows construction in underwater environments. Safety is important due to risks like electric shock and gas explosions. The future of underwater welding may include increased automation and new techniques like friction welding.
This document provides an overview of underwater welding, including its history, classifications, working principles, advantages, disadvantages, and applications. Underwater welding can be classified as either wet welding, where the welder works directly in water, or dry welding, where welding occurs inside a pressurized chamber. While wet welding is faster and cheaper, it produces lower quality welds compared to dry welding. Underwater welding is used for repairs of ships and structures and construction of pipelines and offshore oil rigs.
Underwater welding includes a lot of different processes that join metals on offshore oil platforms, pipelines & ships .It is the process of welding under water using various techniques under various conditions.....etc.!!!
Underwater welding is a specialized welding process that involves welding at depths below the surface of water. It can be classified as wet welding, where welding is done directly in water, or dry welding, where a dry chamber is created to perform the welding. Wet welding uses manual metal arc welding with direct current power and special electrodes. It allows for work in difficult to reach areas but results in lower quality welds due to quenching from the water. Dry welding produces higher quality welds by working in a pressurized chamber, but requires more complex and expensive equipment. Underwater welding is used for offshore construction, ship repair, and pipeline maintenance.
Underwater welding can be classified as wet welding or dry welding. Wet welding is performed directly in water using manual arc welding, which has advantages of lower cost but risks of cracking and poor visibility. Dry welding uses a chamber near the work area and gas metal arc welding for better quality welds and welder safety, but requires more complex equipment and has higher costs. Underwater welding is used for ship repair and construction, offshore energy structures, and other underwater fabrication work, but poses electric shock and explosion risks that require inspections.
This document provides an overview of underwater welding. It discusses two main types: wet welding, which is performed directly in water using specialized electrodes, and dry welding, where a chamber is created to allow welding in a dry environment. Wet welding is cheaper and faster but results in lower quality welds due to poor visibility and rapid cooling in water. Dry welding allows for higher quality welds but is more expensive due to specialized equipment needs. Underwater welding has applications in offshore construction, ship repair, and salvage operations where it provides a means for metal fabrication and joining underwater.
under water welding-s.saravanakumar,ice,srptcSaravana Yadav
Underwater welding is an important technique for fabrication and repair of marine structures. It was developed in 1946 when special waterproof electrodes were created in Holland. There are two main types of underwater welding: welding performed directly in water and hyperbaric welding which is done inside a pressurized chamber. Manual metal arc welding is commonly used for repairs of offshore platforms due to its versatility and low cost. Research continues on techniques like hyperbaric welding to enable welding at depths of 500 to 1000 meters. Underwater welding is used for offshore construction, ship repair and maintenance, and construction of large ships.
This document discusses various methods of underwater welding. It begins by classifying underwater welding into dry welding and wet welding. Dry welding involves welding inside a chamber that is sealed around the structure, while wet welding is performed directly under water. The document then describes the processes and equipment used for dry welding methods like hyperbaric and cavity welding. It also covers the principles, advantages, and disadvantages of wet welding. The document concludes by discussing applications of underwater welding, the effects of the wet environment on welds, and providing a graph showing the relationship between porosity and water pressure during welding.
Underwater welding involves joining steel structures underwater, such as on offshore oil platforms and ships. It can be done using wet or dry welding methods. Wet welding is done entirely underwater using a special electrode and manual welding similar to open-air welding. Dry welding is done inside a pressurized chamber flooded with a breathing gas like heliox to protect the welder from water pressure. Underwater welding faces risks like electric shock, gas explosions, and decompression sickness which require safety precautions during the process. It is used in offshore construction, ship repair, and salvaging sunken vessels.
This document discusses underwater welding. It begins with an introduction stating that underwater welding allows for the assembly or repair of structures underwater. It then discusses the origin of underwater welding in the 1930s by a Russian metallurgist. There are two main types: dry welding using an enclosed chamber with elevated gas pressure, and wet welding directly exposed to water using special electrodes. Advantages include safety for dry welding and versatility for wet welding. Applications include offshore construction, shipbuilding, pipelines, salvaging sunken vessels, and oil refineries. The document concludes by discussing future areas of automation, mechanization, inspection techniques, and new welding methods.
Hyperbaric welding is the process in which a chamber is sealed around the structure to be welded and is filled with a gas ( He and Oxygen) at the prevailing pressure.
1) Underwater welding is used to repair structures like ships, oil rigs, and pipelines. It can be done wet in water or dry within a pressurized chamber.
2) Wet welding is simpler but produces lower quality welds due to quenching from water and hydrogen embrittlement. Dry welding allows better control but requires more complex equipment.
3) Advances include developing automated dry welding robots and testing friction and explosive welding at deeper depths. Ongoing research aims to improve welding quality and safety at high pressures.
The document discusses two methods for underwater welding: wet welding and dry welding. Wet welding involves welding directly in water and has advantages such as being the cheapest and fastest method, but disadvantages such as poor visibility and risk of hydrogen embrittlement. Dry welding involves welding in a pressurized chamber and has advantages like better weld quality and worker safety, but higher costs associated with the complex equipment required. The document compares the pros and cons of each welding method.
This document discusses underwater welding. It begins by noting the first underwater welds done by the British Admiralty in the 1940s. It then covers the two main types of underwater welding - wet welding, where welding is done directly in the water, and dry welding, where a chamber is created to keep the area dry. The document discusses the equipment, materials, and safety considerations for underwater welding. It notes challenges like hydrogen embrittlement and reduced visibility. Overall, the document provides an introduction to the process and challenges of underwater welding.
Displaying of Digital Clock through digital circuits and through Assembly Lan...IJERA Editor
With a view to display a Digital Clock through digital circuits using modulo-n (mod-n) counters, a circuit diagram was designed and implemented it through multi simulation software. In the similar manner the time digits were displayed on seven segment displays at 8255 programmable peripheral interface (PPI) ports through 8051 microcontroller, the time digits (hours, minutes and seconds) were connected to the first 8255 PPI and the date digits (Years, months and days) were connected to second 8255 PPI. The detailed circuit diagram was given to understand the construction details of the circuit. The loop in a loop technique of assembly language program was used to display date and time. After displaying a year, month and day on the date displays through main program, it calls 1day subroutine to display time in 24 hours clock. The 1day subroutine calls 1second delay subroutine to change the digits in seconds display. After completion of 24 hours time, the digit will be changed in the days display to indicate the next date. After completion of 31 days in the first month, the main program calls month subroutine to change the digit in the months display. Precautions were taken to change the digits in months display for January 31 days, February 28 days, March 31 days, April 30 days, May 31 days, June 30 days, July 31 days, August 31 days, September 30 days, October 31 days, November 30 days and December 31 days. After completion of a month, there will be a change in years digit and this process will be repeated continuously.
Comparative Analysis of Pso-Pid and Hu-PidIJERA Editor
PID control is an important ingredient of a distributed control system. The controllers are also embedded in many special purpose control systems. PID control is often combined with logic, sequential functions, selectors, and simple function blocks to build the complicated automation systems used for energy production, transportation, and manufacturing. Many sophisticated control strategies, such as model predictive control, are also organized hierarchically. PID control is used at the lowest level; the multivariable controller gives the set points to the controllers at the lower level. The PID controller can thus be said to be the “bread and butter‟ of power system engineering. It is an important component in every control engineer‟s tool box. PID controllers have survived many changes in technology, from mechanics and pneumatics to microprocessors via electronic tubes, transistors, integrated circuits. The microprocessor has had a dramatic influence on the PID controller
Electrochemical Supercapacitive Performance of Sprayed Co3O4 ElectrodesIJERA Editor
Nanocrystalline cobalt oxide (Co3O4) thin film electrodes were fabricated by spray pyrolysis method on conducting fluorine doped tin oxide (FTO) substrates using ammonia complexed with cobalt chloride (CoCl2. 6H2O) solution. The structural and morphological properties of Co3O4electrodes were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM).The surface morphology study showed the film formation of porous surface with clusters. The electrochemical supercapacitive properties ofCo3O4 electrodes were evaluated using cyclic voltammetry and galvanostatic charge-discharge method. The Co3O4electrodes showed maximum specific capacitance of 168 F/g in 1 M aqueous KOH electrolyte at the scan rate of 20 mV/s. The maximum specific energy and specific power of the cell are 2.2Wh/kg and 0.23 kW/kg, respectively.
A stochastic modeling of biological systems is crucial to effectively and efficiently developing treatments for medical conditions that plague humanity. The study of challenge tests designed to evaluate serotoninergic pathways have widely used intravenous citalopram. Oral citalopram has also been used, but unsatisfactory results were obtained with a dose of 20 mg. We evaluated cortisol, growth hormone and prolactin levels and determine whether a higher oral dose would reproduce similar to those described for intravenous administration. Under the assumption that the threshold level of cortisol is a random variable follows exponentiated modified weibull distribution. The survival function of cortisol and its p.d.f are derived.
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Press tool components play an important role in every aspects of modern word. There are different types of press tools are available, in this progressive tools are more influence the automobile industry for mass production. The operation of a progressive die involves the series of sheet metal operations at two or more stations during each press stroke for developing the complete work piece. The strip must move from the first station through each succeeding station and perform one or more distinct die operations at each working station. One or more idle stations may be incorporated in the die. In this paper we use software CATIA V5 for modeling a progressive tool to manufacture a washer for M12 bolt. In earlier design there is no primary stopper for first station and there are no accurate location like pilots for further station. In this design we provide primary stopper for first station, pilots for further stations and also we replace the die block with die buttons. For this any damage occurs on die button simply we can replace that particular die button instead of replacement of entire die block this will reduce the material cost, machining time and die maintenance.
Cost Aware Expansion Planning with Renewable DGs using Particle Swarm Optimiz...IJERA Editor
This Paper is an attempt to develop the expansion-planning algorithm using meta heuristics algorithms. Expansion Planning is always needed as the power demand is increasing every now and then. Thus for a better expansion planning the meta heuristic methods are needed. The cost efficient Expansion planning is desired in the proposed work. Recently distributed generation is widely researched to implement in future energy needs as it is pollution free and capability of installing it in rural places. In this paper, optimal distributed generation expansion planning with Particle Swarm Optimization (PSO) and Cuckoo Search Algorithm (CSA) for identifying the location, size and type of distributed generator for future demand is predicted with lowest cost as the constraints. Here the objective function is to minimize the total cost including installation and operating cost of the renewable DGs. MATLAB based `simulation using M-file program is used for the implementation and Indian distribution system is used for testing the results.
Welding demand in offshore and marine applications is increased with the increasing in oil and gas activities as
well as increasing in the marine transportation and industrial applications. In this paper, a brief description of the
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of a few advanced welding techniques
Underwater welding can be classified as wet welding, where welding is performed directly in water, or dry welding, where a dry chamber is created for welding. Wet welding uses manual metal arc welding with direct current and negative electrode polarity. It is a versatile and economical method but produces welds of lower quality due to quenching and hydrogen embrittlement risks. Dry welding produces higher quality welds but requires more complex and expensive equipment. Developments aim to improve wet welding quality and automate dry welding processes.
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1. Esam F. Alajmi et al. Int. Journal of Engineering Research and Application www.ijera.com
ISSN : 2248-9622, Vol. 7, Issue 2, ( Part -3) February 2017, pp.14-17
www.ijera.com DOI: 10.9790/9622- 0702031417 14 | P a g e
Underwater Welding Techniques
Esam F. Alajmi *, Ahmad A. Alqenaei **
*( The Public Authority for Applied Education and Training , Email: esam81@outlook.com )
** (The Public Authority for Applied Education and Training, Email: ahmedany74@hotmail.com )
ABSTRACT
Welding demand in offshore and marine applications is increased with the increasing in oil and gas activities as
well as increasing in the marine transportation and industrial applications. Applications of underwater welding
well be increased in Kuwait in the coming years due to the strategic directive of the country toward starting the
offshore oil and gas exploration and production, and the increase in marine transportation projects. Therefore,
there is a need to understand the concept of underwater welding and different techniques used in the market.
In this paper, a brief description of the different commercial underwater techniques will be presented taking into
account showing detailed description of a few advanced welding techniques.
I. INTRODUCTION
The increasing demand for oil and gas has
led to increase the offshore oil and gas activities
and to move the exploration into the deep water.
The desire to build, maintain and repair offshore
structures has brought the need for underwater
welding. Underwater welding is the process of
welding at elevated pressures, normally
underwater. Underwater welding can either take
place wet in the water itself or dry inside a
specially constructed positive pressure enclosure
and hence a dry environment. It is predominantly
referred to as "hyperbaric welding" when used in a
dry environment, and "underwater welding" when
in a wet environment.
Principle of Operation
The welding circuit must include usually a
knife switch operated on the surface and
commanded by the welder and is used for safety
reasons. When DC is used with (+ve) polarity,
electrolysis will take place and cause rapid
deterioration of any metallic components in the
electrode holder. For wet welding AC is not used
because of electrical safety and difficulty in
maintaining an arc underwater.
Classification of Underwater Welding
Underwater welding can be divided into two main
types:
1. Wet Welding
2. Dry Welding
1. Wet Welding
Wet welding process is carried out at
ambient water pressure in which, the weld is
exposed to the water. This is carried out by a
special water-proof stick electrode, with no
physical barrier between water and welding arc.
The increased freedom of movement makes wet
welding the most effective, efficient and
economical method. Welding power supply is
located on the surface with connection to the
diver/welder via cables and hoses. When DC is
used with +ve polarity, electrolysis will take place
and cause rapid deterioration of any metallic
components in the electrode holder. Fig. 1, shows
the overall wet welding process diagram. For wet
welding AC is not used because of electrical safety
and difficulty in maintaining an arc underwater.
Figure 1: Schematic Diagram of Underwater Wet Welding Technique
RESEARCH ARTICLE OPEN ACCESS
2. Esam F. Alajmi et al. Int. Journal of Engineering Research and Application www.ijera.com
ISSN : 2248-9622, Vol. 7, Issue 2, ( Part -3) February 2017, pp.14-17
www.ijera.com DOI: 10.9790/9622- 0702031417 15 | P a g e
Equipment for underwater wet welding
The underwater wet welding equipment
has to meet all the safety aspects. Due to the
limited time spent under water, the diver-welder
has to be provided with satisfactory operating
conditions. Equipment has to be regularly
maintained according to stipulated regulations in
order insure its proper functioning. Main
equipment needed for wet underwater welding can
be summarized in the following:
Diving equipment
The diving equipment includes dry diving suit, dry
suit full-face mask, surface supply umbilical cord,
air tank on the surface with regulation manometer
and compressor for filling the air tank.
Welding power sources
Intensive dynamic behavior of the power source is
necessary to obtain a stable electric arc in greater
depths. Welding power source must be adjusted for
underwater wet welding, not only in the matter of
good arc behavior but also in the aspect of diver-
welder safety.
Safety switch
For safety reasons, the electrical circuit is fitted
with a safety switch, which interrupts or establishes
the flow of current necessary for underwater
welding or cutting as diver request or in case of
accident.
Communication system
For constant connection and coordination of works
between the surface and the diver, two-way
telephone communication system has to be applied
in order to facilitate the realization and
organization of underwater activities.
Welding cables, and welding and cutting
holders
Special cables with special insulation class have to
be used for underwater welding and cutting in
order to prevent breakthrough of electric current
into the water or to the platform structure, which
may cause safety problems and difficulties in
welding.
Mechanical tools system
Mechanical tools for underwater works may be
driven electrically, hydraulically and
pneumatically. Electric drive is avoided because of
safety problems, and mostly hydraulic and
pneumatic tools are used.
The advantages and disadvantages of wet underwater welding technique are indicated in Table 1.
Advantages
The versatility and low cost of wet welding makes this method highly desirable.
Fast method.
It is less costly compared to dry welding.
The welder can reach portions of offshore structures that could not be welded using other methods.
No enclosures are needed and no time is lost building.
Minimal equipment needed for mobilization.
Disadvantages
There is rapid quenching of the weld metal by the surrounding water. Although quenching increases the
tensile strength of the weld, it decreases the ductility and impact strength of the weldment and increases
porosity and hardness.
Hydrogen Embrittlement – Large amount of hydrogen is present in the weld region, resulting from the
dissociation of the water vapour in the arc region. The H
2
dissolves in the Heat Affected Zone (HAZ) and
the weld metal, which causes Embrittlement, cracks and microscopic fissures. Cracks can grow and may
result in catastrophic failure of the structure.
Another disadvantage is poor visibility. The welder sometimes is not able to weld properly.
Table 1: Advantages and Disadvantages of Wet Underwater Welding Process
II. DRY UNDERWATER WELDING
Underwater wet welding is primarily used
at shallow depths when need for larger depths
emerge underwater dry welding procedures is first
choice. Moreover, usage of underwater dry welding
methods offers completion of full penetration
welds with mechanical properties adequate to
welding in normal conditions. Additionally, it is
possible to perform preheating or post weld heat
treatment in order to decrease hydrogen content
and improve weld properties.
Underwater welding in a dry environment
is carried out in chamber sealed around the
structure to be welded. The chamber is filled with a
gas (commonly helium containing 0.5 bar of
oxygen) at the prevailing pressure. The habitat is
sealed onto the pipeline and filled with a breathable
mixture of helium and oxygen, at or slightly above
3. Esam F. Alajmi et al. Int. Journal of Engineering Research and Application www.ijera.com
ISSN : 2248-9622, Vol. 7, Issue 2, ( Part -3) February 2017, pp.14-17
www.ijera.com DOI: 10.9790/9622- 0702031417 16 | P a g e
the ambient pressure at which the welding is to take
place.
This method produces high-quality weld
joints that meet X-ray and code requirements. The
gas tungsten arc welding process is employed for
this process. The area under the floor of the Habitat
is open to water. Thus the welding is done in the
dry but at the hydrostatic pressure of the sea water
surrounding the Habitat made possible by
encompassing the area to be welded with a physical
barrier (weld chamber) that excludes water. The
weld chamber is designed and custom built to
accommodate braces and other structural members
whose centerlines may intersect at or near the area
that is to be welded. The chamber is usually built of
steel, but plywood, rubberized canvas, or any other
suitable material can be used. Size and
configuration of the chamber are determined by
dimensions and geometry of the area that must be
encompassed and the number of welders that will
be working in the chamber at the same time.
There are different dry underwater welding
methods, it can be achieved by:
2-1 Dry Habitat Welding:
Using a chamber in ambient pressure (at
ambient water pressure) in a large chamber from
which water has been displaced, in an atmosphere
such that the welder/diver does not work in diving
gear. This technique may be addressed as dry
habitat welding. As shown in fig. 2, welders are
completely in dry environment and weld properties
are equivalent to one welded in normal conditions.
However, much more fit-up time is necessary to fix
the habitat and prepare it for welding.
Figure 2: Specially designed habitat
2-2 Dry Chamber Welding:
Welding at ambient water pressure in a simple
open-bottom dry chamber that accommodates the
head and shoulders of the welder/diver in full
diving gear as shown in Fig.3.
Figure 3: Dry welding in mini-habitat where the
diver-welder is partially immersed in water
2-3 Dry Spot Welding:
Welding at ambient water pressure in a small
transparent, gas filled enclosure with the
welder/diver in the water and no more than the
welder/diver’s arm in the enclosure.
The advantages and disadvantages of dry
underwater welding techniques are indicated in
Table 2.
Advantages
-
-
-
-
Better diver safety
Better quality welds
No build up of hydrogen and oxygen pockets
Allows for heat treatment before and after welding
Surface monitoring possible
Disadvantages
-
-
-
-
Requires large and complex equipment
Chamber has to be fabricated differently for different applications
Cost is very high and increases with depth
More energy requirement
Table 2: Advantages and Disadvantages of Dry Underwater Welding Process
4. Esam F. Alajmi et al. Int. Journal of Engineering Research and Application www.ijera.com
ISSN : 2248-9622, Vol. 7, Issue 2, ( Part -3) February 2017, pp.14-17
www.ijera.com DOI: 10.9790/9622- 0702031417 17 | P a g e
III. APPLICATION OF UNDERWATER
WELDING
The important applications of underwater welding
are:
• Offshore construction for tapping sea resources
• Temporary repair work caused by ships
collisions or unexpected accidents
• Salvaging vessels sunk in the sea
• Repair and maintenance of ships
• Construction of large ships beyond the
capacity of existing docks
• Repair and maintenance of underwater
pipelines
IV. FUTURE SCOPE FOR
UNDERWATER WELDING
Considerable industrial effort has been made to
improve process performance and control strategies
for the various underwater welding processes. For
future scope in underwater welding, the major
efforts on research and development should be
focused on the following topics:
• Automation of the underwater joining and
inspection of the welded structures
• Mechanized underwater welding for actual
usage of a very large floating structures
• Investigation of the potential of using a robot
manipulator for underwater ultrasonic testing
of welds in joints of complex geometry
• Application of advanced welding technique,
like friction, laser welding and understand the
behavior of materials after the welding and
process optimization
• Invention of new welding techniques and
explore the possibility of its application in
underwater welding
• Generation of research data book on weld
ability of materials during underwater welding
V. CONCLUSIONS AND REMARKS
Applications of Underwater Welding will
see increasing in demand in Kuwait due to the
country ambitious plans toward starting the
offshore oil and gas exploration and production,
increasing in marine projects such as Jaber Bridge
and establishing new marine ports. Therefore,
underwater welding will play vital roles in the
development and shaping of Kuwait future
industry. There is a big need to well understand
underwater techniques, secure the needed resources
and experts and develop the national capabilities to
be ready meet the country needs. Therefore,
preparation of the needed resources and
development plans to improve the skills in
underwater welding techniques need to be
considered in the country developments plans in
order to meet the requirements of the Kuwait future
industry trend.
REFERENCES
Amit Mukund Joshi, Underwater Welding,
Indian Institute of Technology.
Kralj, I. Garašić, Study of underwater
welding of the spud can on the Labin
platform 59, University of Zagreb, 2006
Habitat technology-innovative
underwater techniques,
www.hydrex.be,2006
Anand, A. and Khajuria, A., Welding
Processes in Marine Applications: A
Review, IJMERR, Vol. 2, No. 1, January
2013