4th Class Absa Exam Part A Practice Practice For Anatomy And Physiology Ii|942 Q&a Latest 2024

Cavitation {Ans: The sudden vapour cavity formation, growth, and subsequent collapse, that occurs in a saturated liquid. Cavitation is caused by local pressure fluctuations.}Post weld heat treatment (PWHT) {Ans: Any heat treatment after welding, which serves to restore desirable mechanical properties to the welded part and parent metal.}Voltage Measurement {Ans: With a voltmeter, or more commonly with a DMM Has a high resistance. Becomes an additional load to circuit. If wrong current is selected, then it may show a wrong reading, making the user believe there is no current, which is dangerous.}Premix burner {Ans: Mixes fuel and air in the pipe before it leaves the nozzles. Also called atmospheric burner because furnace pressure is at or near atmosphere pressure.}Firetube boiler tube attachment {Ans: Tube expanders expand the tubes onto the tube sheet to lock it into place, protect it from heat, etc.}Categories of welding {Ans: Non-fusion welding - does not involve melting the parent metal; only the filler metal melts. Soldering and brazing are both forms of non-fusion welding. Fusion welding: The melting together of filler metal and base metal, or of base metal only to produce a weld.}