90 degree tee

The 90 degree tee is also a kind of pipe fitting, generally there are two kinds. Equal diameter tee, with the same diameter at both ends, and the branch pipe with different diameter from the other two, is called reducing tee. The representation method is as follows: for equal diameter tees, for example, "T3" tees refer to equal diameter tees with an outer diameter of 3 inches. For reducing tee, such as "T4 × four × 3.5 "represents a reducing tee with the same diameter of four inches and the same diameter of 3.5 inches. The material is generally 10 # 20 # A3 Q23 20g 20G 16Mn ASTM A234 ASTM A105 ASTM A403, etc. Tee, the outer diameter range is 2.5 "- 60", from 26 "- 60" is welding tee. The wall thickness is 28-60mm. The pressure rating is Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80、Sch100、Sch120、Sch140、Sch160、XXS。

What is the cause of the three-way leakage

1. Tee leakage may be caused by stress

Tee is an important structural member in the pipeline system. Because its structure is more reliable, the wall thickness of different parts varies greatly, and it has high structural stress; In addition, in the actual use process, in addition to its own gravity, the pipe fittings also bear the tensile and compressive stresses imposed on the straight pipe due to the frequent changes in the external ambient temperature, as well as the bending, torsion and other external loads attached to the system such as the ground creep and earthquake in the area where the pipe passes. Therefore, the stress of the tee is much more complex than that of the straight pipe, so that we can have more corrosion pits and the bottom of the pull marks on the failed tee body, Many superficial cracks were found

2. The tee leaks, which may be caused by the production problem of the tee

During the cold extrusion forming process of tee, if the surface of the blank tube placed in the tee die has burrs or is poorly lubricated with the inner wall of the die, the metal on the blank surface will be mechanically blocked by the inner surface of the die during the forming flow process, and a metal pull mark will form on its surface. The pipe body pull mark defect will damage the integrity of the tee surface, not only reducing the strength of the metal, During the stress relief heat treatment of the tee with the draw mark defect, the metal structure near the draw mark will be oxidized and decarburized under the high temperature environment in the furnace, and the metal on the surface of the draw mark will be oxidized and form oxides, which will also cause stress concentration on the surface. During the water pressure process of the tee, it may become a crack source and cause the tee to crack

3. The tee is leaking. It may be that the tee missed inspection before delivery

We all know that the three-way pipe fittings need magnetic particle testing before leaving the factory. It can detect whether there are really invisible cracks in the three-way branch pipe to prevent leakage caused by cracks when the three-way pipe is in use. However, if the three-way pipe fittings are not tested before leaving the factory, they will be delivered to the customer directly. The customer has not tested before use, and the results are very obvious, Tees are prone to leakage

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