14-50. At ordinary temperatures, the carbon in steel exists in the form of iron carbide particles. These particles are known by what name? 1. Cordite 2. Ferrite 3. Pearlite 4. Austenite 14-51. In the heat-treatment process of steel,    the element that normally has the greatest influence is silicon. True False IN ANSWERING QUESTION 14-52, REFER TO TABLE 15-1 IN THE TEXTBOOK. 14-52. 14-53. 14-54. 14-55. What color is steel at 1,825°F? 1. Lemon 2. Salmon 3. Orange 4. Light lemon When water is used as a quenching medium for steel, the water bath should be held at what prescribed temperature? 1. 32°F 2. 48°F 3. 55°F 4. 65°F When steel is heated above its critical temperature and then slowly cooled, what is the final product called? Sorbite Pearlite Troostite Martensite After welding a ferrous metal, you should use the normalizing process of heat treatment for what reason? 1. To reduce its carbon content 2. To induce internal stresses 3. To remove all strains 4. To make it harder 14-56. Which of the following carburizing 14-57. 14-58. 14-59. methods produces only a thin case? Pack Gaseous Nitriding Cyaniding What prescribed temperature is required for nitriding steel parts? 1. 950°F 2. l,150°F 3. 1,300°F 4. 1,400°F Aluminum alloys should be heated by the use of which of the following methods? An air furnace A molten salt bath only An electric furnace only A molten salt bath or an electric furnace When a nonferrous part is quenched, what is the maximum recommended time between the part’s removal from the heat and immersion? 1. 10 sec 2. 15 sec 3. 20 sec 4. 25 sec 14-60. When annealing an aluminum part in a salt bath, you should use equal parts of which of the following chemicals? 1. Epsom salt and sodium nitrate 2. Epsom salt and silver nitrate 3. Potassium nitrate and baking soda 4. Potassium nitrate and sodium nitrate 78