Name: TAPAR, JOHN JERRIEL D. Score:_________________________ Course/Section: ES1A1 Date:__________________________ Test I. Multiple Choice: Choose from among the choices the letter of the best answer. Answers must be written on the spaces provided before each number. _________1.What determines oxy-acetylene cutting tip size? A. Material composition C. Material thickness B. Material formation D. Material texture _________2.When cutting a ¼” mild carbon steel bar, what are the oxygen and acetylene required pressure? A. Acetylene 5, Oxygen 25 C. Acetylene 15, Oxygen 30 B. Acetylene 25, Oxygen 5 D. Acetylene 30, Oxygen 15 __________3. What are the colors of oxygen hoses? A. Black C. Red B. Green D. White __________4. What gas does the long lever on an oxy-acetylene cutting torch control? A. Acetylene cutting gas C. Oxygen cutting gas B. Acetylene preheat gas D. Oxygen preheat gas __________5. How far should you turn on the bottle valve on an oxygen cylinder? A. All the way C. ¼ turn B. Half way D. ¾ turn Test II. Essay: Discuss the following words with your own ideas. (5pts each). (Write your answers on the spaces provided below). 1. Acetylene Acetylene uses for many major applications. It is the only fuel gas that can be used for welding. It is also ideal for brazing, cutting, flame gouging, spot heating, hardening, texturing, cleaning, and thermal spraying many materials. Acetylene appears as a colorless gas with a faint garlic-like odor. Easily ignited and burns with a sooty flame. Gas is lighter than air. Flame may flash back to the source of a leak very easily. 2. Oxygen Oxygen is now considered to be one of welding industry's raw materials. For cutting metals, Oxygen flame has no rival. It cuts metal plates. Heat required for welding cutting. Brazing may be obtained by combustion of suitable fuel gases in conjunction with oxygen which is essential for all forms of combustion. Oxygen is used in small amounts as an addition to other gases typically as 2–5% addition to argon. It enhances arc stability and reduces the surface tension of the molten metal, increasing wetting of the solid metal. It is used for spray transfer welding of mild carbon steels, low alloy and stainless steels 3. Hydro carbon Hydrocarbons are the simplest organic compounds and contain only carbon and hydrogen but they can be straight chain or branched chain with the same empirical formula but showing differences in properties. Chemical change results in the hydrocarbon yielding a product that may be entirely different in composition to the starting hydrocarbon the exception is the isomerization reaction where a straightchain hydrocarbon is converted to a branched-chain hydrocarbon. Chemical properties of hydrocarbons describe the potential of hydrocarbons to undergo chemical change or reaction by virtue of the hydrocarbon structure. Physical properties can be observed or measured without changing the composition of matter. Physical properties are used to observe and describe matter. 4. Neutral flame The neutral flame has a one-to-one ratio of acetylene and oxygen. It obtains additional oxygen from the air and provides combustion. It is generally preferred for welding. The neutral flame has a clear, welldefined, or luminous cone indicating that combustion is complete.
