Hard- Surfacing, Building Fusion Welding Carbon Welding Non-Ferrous Metals Heating & Heat Treating Braze Welding Welding Cast Iron Welding Ferrous Metals Brazing & Soldering Equipment Set-Up Operation Equipment For OXY-Acet Structure of Steel Mechanical Properties of Metals Oxygen & Acetylene OXY-Acet Flame Physical Properties of Metals How Steels Are Classified Expansion & Contraction Prep For Welding OXY-Acet Welding & Cutting Safety Practices Manual Cutting Oxygen Cutting By Machine Appendices Testing & Inspecting
5 Cutting. While oxy-acetylene welding may have ”taken a back seat” in industry (significant as it may be in repair work) the use of oxygen cutting has expanded in every decade since 1902. The cutting torch lives with and on steel, all the way from the primary steel mill to the scrap yard, where steel is reclaimed to be used in making more steel. Oxygen cutting is not now, and never has been, an exclusively oxy-acetylene process; other fuel gases are also widely used. However, more cutting torches are operated with acetylene than with all other fuel gases combined, for reasons which we’ll get into a bit deeper in Chapter 22. The amount of oxygen consumed in cutting operations exceeds by many times the amount consumed in gas welding. Steel Conditioning. It is a rather well-known fact that oxygen converters are rapidly taking the place of other types of furnaces (open-hearth, Bessemer) in the making of steel. Less well-known is the fact that long before the first oxygen converter went into service, steel mills were consuming many thousands of tons of oxygen for the removal of surface defects from steel blooms, billets, and slabs prior to rolling the steel to final plate or sheet form. The several types of operations covered by the term steel conditioning are all oxygen cutting processes; few of them today can be classified as oxy-acetylene, but all of them can be traced back to early use of oxy-acetylene cutting torches which were slightly modified so that they could groove steel rather than slice it. Fig. 2-3. This operator is removing surface defects from a steel slab, which will then be reheated and rolled into sheet. This is one of the operations covered by the general term ”steel conditioning”. A length of steel rod is advanced into the preheat flames, to speed up the start of the reaction between the oxygen jet and the plate surface, each time the operator depresses the cutting oxygen valve lever.