What two factors determine the amount of heat delivered by a gas welding torch?

The amount of heat delivered by a gas welding torch is primarily influenced by the size of the torch tip and the gas pressure. The size of the torch tip controls the flow of gas and the diameter of the flame; a larger tip can deliver more gas, resulting in a larger and hotter flame that can transfer more heat to the workpiece. On the other hand, gas pressure affects the speed at which the gas exits the torch. Higher pressure generally leads to a more vigorous flame, further increasing the heat output.

When these two factors are optimized, they ensure that the welding process can efficiently melt the base metal and filler material for effective joining, making it crucial for achieving strong welds. Other options do not directly influence the heat output in the same way, as factors such as filler material or torch angles primarily affect the welding technique and quality but not the quantifiable heat delivery.