Well, first it burns hot. Very hot. Combine acetylene with oxygen, and it creates a flame temperature of approx. 3150 C. This, together with its low moisture levels and lack of oxidation, makes it highly suitable for welding high-strength materials such as steel. It’s also ideal for rapid metal preheating and cutting. Yet, paradoxically, when you use acetylene, the precisely concentrated heat distribution reduces distortion and potential thermal damage to the metal being cut, an impressive bonus considering the heat acetylene operates at.
In addition, only acetylene can produce the flame temperature and output to melt and weld steel with a neutral setting, which is critical when welding steel in particular, to avoid undesirable reactions in the molten pool.
Then there’s the versatility. Just change the attachment on your torch and you can switch from welding to cutting or pre-heating metal in a matter of minutes, without having to change gases, ideal for smaller businesses running on a restricted budget. And it can remove rust and make paint and coatings bond better to metal.