Which factors influence the amount of heat delivered by a gas welding torch?

The amount of heat delivered by a gas welding torch is largely influenced by the size of the torch tip and the gas pressure. A larger torch tip allows for a greater volume of gas and oxygen mixture to flow through, which results in a more intense and hotter flame. Additionally, higher gas pressure can increase the flow rate, further enhancing the flame characteristics.

This interplay between tip size and gas pressure determines the ultimate heat output, which is crucial for effectively melting the base metals and filler materials during welding. Adjusting these parameters appropriately enables welders to achieve the desired heat input for different materials and thicknesses.

While other factors listed in the options have their own roles in welding procedures, they do not directly affect the torch's heat output in the same fundamental way as tip size and gas pressure. For instance, the type of gas can influence flame characteristics but not the primary heat output mechanism. Similarly, welding technique and duration may impact the final weld quality but do not alter the heat generated by the torch itself.