Preheating can produce many beneficial effects;however, without a working knowledge of the fundamentals involved one risks wasting money, or even worse, degrading the integrity of the weldment.

• 但是，如果没有一个工作知识的基本面牵涉其中的风险在浪费钱，或者更糟的是，有辱人格的完整的焊缝。