Lesson Notes By Weeks and Term v4 - SHS 3
WELDING TECHNOLOGY
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WELDING TECHNOLOGY
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Subject: Applied Technology
Class: SHS 3
Term: 1st Term
Week: 14
Grade code: 3.2.2.LI.6
Strand code: 2
Sub-strand code: 2
Content standard code: 3.2.2.CS.1
Indicator code: 3.2.2.LI.6
Theme: METAL TECHNOLOGY
Subtheme: WELDING TECHNOLOGY
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This lesson explores the highly specialized and critical field of welding within Ghana's vibrant oil and gas industry. We will move beyond basic welding techniques to understand the advanced processes required to build and maintain the massive infrastructure like the FPSO Kwame Nkrumah, underwater pipelines in the Jubilee and TEN fields, and storage facilities at the Tema Oil Refinery (TOR). The safety, environmental protection, and economic success of this industry depend heavily on the quality and integrity of these specialized welds. Understanding these techniques opens doors to high-skill careers and a deeper appreciation of modern engineering.
A. Why "Special" Welding Techniques are Necessary
The oil and gas environment is one of the most demanding for any engineered structure. Standard welding techniques are often inadequate due to a combination of factors: Extreme Pressures: Oil and gas are transported through pipelines at very high pressures. A weak weld could lead to a catastrophic failure. Corrosive Environments: Crude oil, natural gas, and saltwater are highly corrosive. Welds must be resistant to this chemical attack to prevent leaks. Extreme Temperatures: Materials can be exposed to very low or very high temperatures, which can affect the properties of the metal and the weld. Difficult Locations: Much of the work is done offshore, deep underwater (subsea), or in remote, windy locations. This requires processes that are reliable in challenging conditions. Zero-Failure Tolerance: A single failed weld on a subsea pipeline can cost millions of cedis to repair and cause significant environmental damage. The quality standards are therefore exceptionally high.
These challenges mean the industry relies on welding processes that offer superior strength, consistency, speed, and the ability to be performed in difficult conditions. B. Key Special Welding Techniques
Here are some of the most important special welding techniques used in the oil and gas industry. Orbital Welding What it is: An automated welding process where the welding torch rotates 360 degrees around a stationary pipe or tube. The entire process is controlled by a computer. How it Works (Simplified): The two pipe ends are carefully prepared and clamped into position with a precise gap. An "orbital head," which contains the welding torch, is clamped onto the pipe. A pre-written computer program controls all welding parameters: current, voltage, travel speed, and shielding gas flow. The operator initiates the process, and the torch travels perfectly around the pipe joint, creating a flawless, continuous weld. It often uses the Gas Tungsten Arc Welding (GTAW/TIG) process for its high quality. Why it's used in Oil & Gas: Consistency & Quality: Every weld is identical and of extremely high quality, removing the risk of human error. Speed: It is much faster than manual welding for repetitive pipeline joints. Documentation: The computer can record the exact parameters of every single weld, which is crucial for quality control and inspection records. Application Example: Laying the long-distance pipelines that bring oil and gas from offshore fields like Jubilee to the processing facility at Atuabo.