Exam Question
(a) What is the principle of gas cutting? (4)
(b) Describe how gas cutting is carried out with Oxygen and Acetylene flame? (8)
(c) State the pressure levels for Acetylene & Oxy cylinders for gas cutting operations (4)
Class 4 (4th Engineer)
MEP
📅 May 2023
Reference Answer
### (a) Principle of Gas Cutting (4 Marks)
Gas cutting, more accurately termed 'Oxy-fuel cutting', is a chemical process primarily used for cutting ferrous metals, such as low-carbon and mild steels. The principle is not based on melting the metal, but on its rapid, controlled, exothermic oxidation.
The process involves two key stages:
1. **Pre-heating**: The metal surface is heated to its 'kindling' or 'ignition' temperature, which is approximately 870°C (1600°F). This is achieved using a pre-heating flame from an oxy-fuel gas mixture (e.g., oxy-acetylene). At this temperature, the steel glows a bright cherry red but remains in a solid state, as it is well below its melting point of approximately 1535°C.
Gas cutting, more accurately termed 'Oxy-fuel cutting', is a chemical process primarily used for cutting ferrous metals, such as low-carbon and mild steels. The principle is not based on melting the metal, but on its rapid, controlled, exothermic oxidation.
The process involves two key stages:
1. **Pre-heating**: The metal surface is heated to its 'kindling' or 'ignition' temperature, which is approximately 870°C (1600°F). This is achieved using a pre-heating flame from an oxy-fuel gas mixture (e.g., oxy-acetylene). At this temperature, the steel glows a bright cherry red but remains in a solid state, as it is well below its melting point of approximately 1535°C.
Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.
Prepare on Android — MeoMock on Google Play