If the material is A 516 Gr 70 plate, chances are (great chances, I'd say) that it'll be used to make a pressure vessel. In this case, the applicable Code is ASME VIII. Depending on the pressure, it'll be Division I, II or III. If it's required impact at -29C, it means that the vessel will work at less than zero C temperatures. 
If the thickness is 35 mm, it'll definetely require preheat. I don't have the Code at hand, but I'd guess (guess, I repeat) that the preheat temperature will be about 150 C.
Now, mujibali, are you sure that a carbon steel plate 35 mm thick doesn't require PWHT? If I were you, I'd check and double check the Code.
Giovanni S. Crisi

i think that PWHT has relation with p number (read b31.3 table PWHT° AFTER YOU CAN REFER TO  ASTM (ACORDONG YOUR MATERIAL° FOR DETRMINING  all what you need
don't forget asme section II  (SFA....) for determinig interpass temperature
and notion of carbon equivalent eq= c%+.......5FOR DETERMINIG T.PREHEATING BY USING CURVES)
i think that i give you key

As Professor Crisi indicates, it will be your constructing code that will specify both the preheat (either recommendation OR requirement) and PWHT, if required or exempted based on elevated preheat, in some cases.