Photo AI
(a) Two resistance welding processes are illustrated at A and B below - Leaving Cert Engineering - Question Question 1 - 2009
Question Question 1
(a) Two resistance welding processes are illustrated at A and B below. (i) Name the two resistance welding processes. (ii) Describe the principles of operation for... show full transcript
Worked Solution & Example Answer:(a) Two resistance welding processes are illustrated at A and B below - Leaving Cert Engineering - Question Question 1 - 2009
Step 1
Step 2
Describe the principles of operation for any one of these resistance welding processes.
Answer
Principles of Operation for Resistance Spot Welding
Resistance Spot Welding involves placing the components to be joined between two electrodes. An electric current is passed through the electrodes to generate heat at the interface between the workpieces, which melts the metal and forms a weld nugget. The process is energy efficient, allowing for easy automation, and it does not require additional filler material, making it ideal for applications in sheet metal work.
Step 3
Distinguish clearly between the applications of MIG welding and the applications of TIG welding.
Answer
Applications of MIG Welding
MIG (Metal Inert Gas) welding is a versatile process, suitable for welding light metals as well as heavy plate. It is commonly used for manufacturing applications and can be automated for use with robots.
Applications of TIG Welding
TIG (Tungsten Inert Gas) welding is more specialized and is ideal for welding thin sections of stainless steel and non-ferrous metals like aluminum. It offers greater control and versatility, often used in industries requiring high-quality welds.
Step 4
State two functions of the electrode coating in manual metal arc welding.
Answer
- To generate a layer of shielding gas that protects the molten weld pool from atmospheric contamination by oxygen and nitrogen.
- To form a slag coating that helps protect the weld from oxidation and allows for a cooler, more controlled welding environment.
Step 5
Describe two factors to be considered when installing a welding station in a school workshop.
Answer
- Ventilation: A proper ventilation system must be in place to efficiently remove fumes and gases produced during welding processes to ensure a safe environment for students.
- Safety Measures: The welding station should be equipped with protective shields to guard against intense light and sparks, and personal safety gear must be easily accessible.
Step 6
Describe multi-run welding.
Answer
Multi-run welding is a technique where multiple passes are made over the same weld joint. This method produces a superior weld, as it allows for the heat from each weld to be controlled and refined. The result is a weld that is stronger and exhibits improved structural integrity compared to single run welds.
Step 7
Describe, with the aid of suitable diagrams, the main features of the transformer circuit used in manual metal arc welding.
Answer
Transformer Circuit in Manual Metal Arc Welding
A step-down transformer is used to convert 220V AC supply to a lower voltage suitable for welding, typically in the range of 80-100V. The transformer consists of:
- A primary coil that receives the high voltage.
- A secondary coil that provides the lower voltage output.
- Diodes in the rectifier convert the alternating current (AC) to direct current (DC), ensuring a smooth supply for welding operations.