Final answer:
The size of the tip used when gas welding steel is determined by factors such as the thickness of the steel, the type of gas being used, and the welding technique.
Step-by-step explanation:
The size of tip used when gas welding steel is determined by factors such as the thickness of the steel, the type of gas being used, and the welding technique being employed.
Thicker steel requires a larger tip size to generate enough heat for proper fusion. For example, a tip size of 4 to 6mm may be suitable for welding steel with a thickness of 3-6mm.
The type of gas used also affects the tip size. Different gases have different heat capacities and heat transfer rates. For instance, acetylene gas produces a hotter flame compared to propane, so a smaller tip size may be sufficient when using acetylene.
Lastly, the welding technique being used can also influence the size of the tip. For example, if a high-speed welding technique is used, a smaller tip size may be employed to ensure precise control of the weld pool.