The standard for big-end and small-end specifications in China mainly includes the Electric Power Department standards, National standards, Mechanical Department standards, Petrochemical Department standards, Chemical Industry Department standards, and for imports and exports, American and British standards.

The reduction forging process involves placing a billet with the same diameter as the larger end of the pipe into a mold, and then compressing it along the axis of the billet. During the movement, it is reduced to the smaller end. According to customer requirements, either a single or multiple forming steps can be chosen.

The sizing process requires a billet smaller than the size of the pipe elbow, allowing the mandrel to expand the interior of the billet, thereby solving the issue of oversized tees that are difficult to pass through the sizing process.