Before opening the tank valve on an oxygen cylinder which is connected to an oxy-fuel cutting torch, you should turn the diaphragm screw a. all the way out. b. '/2 of the way out. c. /s of the way out. d. all the way in. a b g区 10. the primary purpose of peening as welding progresses is to a. condition the surface for further welding. b. relieve stresses.