REVISION AND PRACTICE E 4 U L These are the most important words you have met in this module. M O D UNIT 1 adhesive bonding assembly blowpipe bolt bond brazing combustible dielectric welding electric arc equipment fastener filler fusion fusion bonding hose hot-gas welding induction welding joint liquid state welding maintenance mechanical fastening nozzle nut pressure regulator release rivet valve screw self-tapping shank slotted solder soldering soldering iron solid state welding solvent bonding threaded ultrasonic welding unthreaded vibration welding washer VOCABULARY UNIT 2 exit route fire extinguisher flammable gloves goggles hard hat harmful high voltage overall respirator toxic welding helmet work boots Now use some of them to fill in the blanks. a. Machinery needs continuous ........................... to be kept at the same good working standard. b. Welding processes which involve partial melting of the metals to be joined are classified as c. ........................... ones. ........................... are small rods used to drop metal in a ........................... and make it stronger. d. A ........................... is a long plastic pipe which can be bent and used to direct water or other substances. e. The ........................... regulates the flow of gas in gas welding. f. The ........................... is the continuous helical rib around the length of bolts or screws. g. ........................... fasteners form an internal thread in a hole. h. The most common non-threaded fasteners are ........................... . i. Mechanical ........................... (screws, rivets, pins, sheet-metal nuts) are the most common plastic joining method. j. In ........................... pulses are transmitted to the part by a resonant vibrating tool called a horn. k. ........................... joins thermoplastics such as polyethylene, polypropylene, and ABS. l. With the technique of ........................... , plastics are softened by a coat of solvent, then pressed together. m. ........................... is a method of joining metal parts using a filler material, the ........................... which has a melting temperature below 450°. n. The surfaces are then heated with a hot metal tool called a ........................... . o. ........................... differs from ordinary soldering only in the temperature of the operation. p. Contact with ........................... substances must be avoided. q. All employees must refer to the floor plan to locate the nearest ........................... . Complete the following sentences. a. In oxycetylene welding, flame and pressure can be varied according to ................................... . b. Forge, friction and ultrasonic welding are examples of ................................... . c. Electric arc welding is widely employed because it allows obtaining ................................... and avoiding ................................... . d. Gas welding equipment includes ................................... . 164