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
1 Continued on next page... OXYGEN AND ACETYLENE This chapter will deal with the two gases which, burned together, produce the oxy-acetylene flame. It will cover their properties, their production, their commercial distribution, the containers in which they are stored and distributed, and the precautions which should be observed when using the gases or handling and storing the containers. Oxygen Oxygen, which makes up about 21 percent of the air we normally breathe, as well as about 90 percent by weight of all the water on earth, may be considered the most important element in the universe. Without it, there would be no life as we know it. Every living animal ”burns” oxygen with carbon and hydrogen to produce the energy that it needs in order to live, grow, and move. Fortunately for the animal kingdom, all green plants produce more oxygen than they consume, so that the reservoir of oxygen in our atmosphere remains at a constant level from century to century. Oxygen not only combines with carbon and hydrogen to produce energy (heat), but combines with most of the other elements found in the universe, including all metals. Fortunately, its reaction with most elements and compounds takes place very slowly or not at all at normal temperatures. However, almost everything made up predominantly of carbon and hydrogen (coal, wood, petroleum products) has a ”kindling temperature”. Once that temperature is reached, ”oxidation” suddenly becomes ”burning”, which then proceeds to produce enough heat to maintain the reaction until the supply of oxygen or fuel runs out, or until other influences produce enough cooling effect to quench the fire. It’s perhaps fortunate we have only 21 percent oxygen in our atmosphere, and that 78 percent is made up of nitrogen, which won’t combine with oxygen at any temperature normally reached by the burning of other materials. We don’t often think of it in that way, but the nitrogen acts as a cooling agent. A good part of the energy produced by the burning of carbon and hydrogen in air is used up in heating the nitrogen. In an atmosphere of 100 percent oxygen, burning takes place at a greatly accelerated rate. Given such an atmosphere, a wooden house that caught