In this lecture on Practical & Lab Demonstration: Gas Welding and Gas Cutting of Steel - Characteristics of Cut Edge, we cover the key components and techniques involved in gas welding and cutting. The session covers the welding torch nozzle, development of different types of gas flames, and live demonstration of welding and cutting processes. It also focuses on analyzing the structure and properties of the cut edge, including drag, roughness, microstructure, hardness, and composition.