The tee is mainly used to change the direction of the fluid, and is used at the branch pipe of the main pipeline. Tee is a kind of chemical pipe fittings with three holes, namely one inlet and two outlets; or two inlets and one outlet. There are T-shaped and Y-shaped, with equal diameter nozzles and reducing nozzles, used for Where three identical or different pipelines meet. The production methods are mainly topping, pressing, forging and casting.