Oxyacetylene welding is the most widely used oxyfuel welding process because acetylene mixed with an equal volume of oxygen burns hotter than any other commercially available fuel:

Question

Quizplus · Accepted Answer

Acetylene, when mixed with an equal volume of oxygen, produces a flame with a temperature over 3,500 degrees Celsius (6,332 degrees Fahrenheit), making it the hottest burning common fuel gas, which is why oxyacetylene welding is widely used for various welding applications.

Oxyacetylene Welding Is the Most Widely Used Oxyfuel Welding Process