What can excessive slag on the cut edge indicate?

Excessive slag on the cut edge is primarily indicative of an improperly adjusted flame. When the flame is not adjusted correctly, either it can be too carburizing or too oxidizing, leading to poor combustion and incomplete oxidation of the metal. This results in the formation of excess slag, which is the molten material that does not properly separate from the cut piece.

A well-adjusted flame is crucial for optimal cutting as it ensures that the right balance of oxygen and fuel gas is present. This balance allows for efficient heating of the metal to its ignition temperature, followed by adequate oxidation, which helps in producing clean cuts with minimal slag.

In contrast, metal thickness or cutting speed alone may influence the quality of the cut, but they are not the primary factors leading to excessive slag formation. If the gas used was incorrect, it could affect performance, but an improperly adjusted flame is the most direct cause of excessive slag on the edge, as it directly relates to the combustion process and how effectively the cutting torch is working.