What is the largest charge for carbon steel pressure pipe with exothermic welding?

The largest charge for carbon steel pressure pipe with exothermic welding is typically specified to be 15 grams. Exothermic welding, also known as thermite welding, is a process that involves a chemical reaction that generates heat to melt metals, allowing them to fuse together. The charge size is crucial as it directly affects the heat generated during the process, ensuring that the joint is strong and durable.

Using a charge that is too large can lead to excessive heat and molten metal, which may cause damage to the weld area or surrounding materials. Conversely, a charge that is too small may not produce enough heat for proper fusion, resulting in a weak joint. Therefore, the specification of 15 grams strikes the right balance for joining carbon steel pressure pipes, making it the correct answer.

Options for larger or smaller charges may not meet the necessary requirements for effective bonding, ultimately compromising the integrity of the welded joint.