Crossword-Solution: PREHEATING 10 letters, 2 clues 🏆 scrabble score: 16

Tables, stands and special supports are provided for holding the work while being welded, and in order to handle the various metals and allow for their peculiarities while heated use is made of ovens and torches for preheating.

CHAPTER V OXY-ACETYLENE WELDING PRACTICE PREPARATION OF WORK _Preheating._--The practice of heating the metal around the weld before applying the torch flame is a desirable one for two reasons.

The work may be brought to a red heat in the forge if it is cast iron or steel; it may be heated in special ovens built for the purpose; it may be placed in a bed of charcoal while suitably supported; it may be heated by gas or gasoline preheating torches, and with very small work the outer flame of the welding torch automatically provides means to this end.

The temperature of the parts heated should be gradually raised in all cases, giving the entire mass of metal a chance to expand equally and to adjust itself to the strains imposed by the preheating.

The object in preheating the metal around the weld is to cause it to expand sufficiently to open the crack a distance equal to the contraction when cooling from the melting point.