409 Chapter 15 Oxyfuel Gas Cutting cutting (OFC) is one process in a larger group of ther- mal cutting processes referred to as oxygen cutting (OC) processes. Nonstandard Terminology Oxyfuel gas cutting is sometimes referred to by the non- standard term flame cutting. Oxyfuel gas cutting is particularly useful for shape-cutting metal parts. It can be done with great accuracy and leaves the edges smooth enough to satisfy most fi nished job requirements. Also, it can be done much faster than machine saw cutting. Oxyfuel gas cutting is used in many industries. It is used in factories and on construction and fabrica- tion sites. 15.1 The Heat of Combustion of Steel In cutting, burning is the rapid oxidation of a material. Virtually all materials burn if they are fi rst heated to their ignition temperature in the presence of oxygen. Ignition temperature (or kindling point) is the lowest temperature in a normal atmosphere at which a given material will ignite spontaneously without any exter- nal spark or fl ame. Steel is a combustible material, since it burns (oxidizes). Thermadyne Industries, Inc. Learning Objectives After studying this chapter, you will be able to: • Explain the oxyfuel gas cutting process. • Describe the function of each component of an oxyfuel gas cutting outfi t. • Select the proper cutting tip and working pressures for cutting a particular thickness of steel. • Light and adjust the fl ame on an oxyacetylene cutting torch and shut down a cutting torch. • Cut base metal (plate and pipe) with an oxyacetylene cutting torch. • Distinguish between a well cut surface and a poorly cut surface, and be able to adjust where necessary to perform a good cut. • Pierce and cut holes in both plate and pipe and cut a bevel on the end of steel pipe. • Describe the gouging process and its applications. • Perform semiautomatic cutting using an OFC torch mounted on a motorized carriage. • Recall safe practices and procedures for oxyfuel gas cutting or gouging. In oxyfuel gas cutting of metal, an oxyfuel gas fl ame is used to heat the metal and an oxygen jet, a pres- surized stream of pure oxygen delivered through the center orifi ce of the cutting tip, cuts it. Oxyfuel gas