In: Mechanical Engineering
1)The welding process with highest power density is: a) Electron beam welding. b) Plasma welding. c) Excimer laser welding. d) Shielded metal arc welding.
2) Welding 1015 and 1010 steels using CO2 laser: a) It is harder to weld the 1010 because of its low hardness. b) It is harder to weld the 1015 because of its low hardness. c) It is harder to weld the 1010 because of less prone for cracking. d) It is harder to weld the 1015 because of more prone for cracking.
3) Find the incorrect sentence from: a) Weldment melts and joins in fusion welding. b) Weldment melts and joins in solid state welding. c) Weldment melts and joins in brazing. d) Weldment melts and joins in friction welding.
4) When welding thin aluminum sheets with laser, the weldment should be: a) Positive b) Negative c) Either positive or negative d) None of the above
5) When using YAG laser to produce a lap joint of two steel sheets, the melt starts at: a) Top of the sheets. b) Between the sheets. c) Bottom of the sheets. d) None of the above.
6) In brazing, the base metals melt at temperatures above 840F (450C) while in soldering they melt at 840F (450C) or below a) true b) false
7) Which one of the following AW processes uses an electrode consisting of continuous consumable tubing containing flux and other ingredients in its core a) FCAW b) GMAW c) GTAW d) SMAW
8) Which one of the following arc welding processes uses a non-consumable electrode a) FCAW b) GMAW c) GTAW d) SMAW
9) "Stick" welding is a term sometimes applied when referring to a) FCAW b) GMAW c) GTAW d) SMAW
10) For metallurgical reasons, it is desirable to melt the weld metal with minimum energy input. Which one of the following heat sources is most consistent with this objective: a) high power b) high power density c) low power d) low power density
1.( c) Excimer laser welding
Explanation: Power density (kW/m^2) is highest in laser welding process beacuse it can be focused over very less area.
2. (d) It is harder to weld the 1015 because of more prone for cracking.
Explanation:Carbon percentage in 1015 is more than 1010 steel
3.(c) Weldment melts and joins in brazing.
Explanation:In brazaing workpieces does not melt ,filler metal melt and fill the gap of adjoining metals.
4(a) Positive
5.(c) Bottom of the sheets.
6.(6)True
Brazing is high tempreture joining process .
7.( a) FCAW : Flux Cored arc welding process uses an electrode consisting of continuous consumable tubing containing flux and other ingredients in its core.
8.(c) GTAW :Gas tungsten arc welding process consist of tungsten as a non-consumable electrode.
9.( d) SMAW:Shielded Metal Arc welding process also konwn as stick welding.
10.( b) High power density i.e more power in less area.