Detailed Explanation of the Manufacturing Process and Execution Standards for Steel Tees

I. Overview of Three-Way Valves

A tee is an important pipe fitting used for branch connections in piping systems, widely applied in industries such as petroleum, chemical, power, metallurgy, and shipbuilding. Steel tees can be classified into two main categories based on manufacturing processes: seamless tees and welded tees. Based on shape, they can be divided into equal-diameter tees and unequal-diameter tees.

II. Manufacturing Process

1. Hydraulic Bulging Process: The hydraulic bulging of seamless tees is a forming process in which the branch pipe is bulged out through the axial compensation of the metal material. The process involves using a dedicated hydraulic press to inject liquid into a pipe blank with a diameter equal to that of the tee. The two horizontal side cylinders of the hydraulic press synchronously squeeze the pipe blank. After being squeezed, the volume of the pipe blank decreases, and the pressure of the liquid inside the pipe blank increases as its volume decreases. When the pressure required to bulge out the branch pipe of the tee is reached, the metal material flows along the inner cavity of the mold under the dual action of the side cylinders and the liquid pressure inside the pipe blank, thereby bulging out the branch pipe.

2. Hot Pressing Forming Process: Hot-pressed tees are formed by heating the pipe blank and placing it in a die, where a press applies pressure to shape the blank within the die. Hot pressing forming is suitable for manufacturing large-diameter, thick-walled tees, particularly for materials such as low-alloy steel and stainless steel.

III. Execution Standards

Commonly used domestic standards: GB/T 12459 "Steel Butt-Welding Seamless Pipe Fittings", GB/T 13401 "Steel Plate Butt-Welding Pipe Fittings", SH/T 3408 "Steel Butt-Welding Seamless Pipe Fittings", HG/T 21635 "Carbon Steel and Low Alloy Steel Seamless Butt-Welding Pipe Fittings".

Commonly used international standards: ANSI/ASME B16.9 "Welding Fittings of Steel for Factory Manufacture", DIN 2615 "Steel Welding Fittings - Tees", JIS B2311 "Steel Welding Fittings".

IV. Common Materials

Carbon steel: 20#, Q235, A105; Stainless steel: 304, 304L, 316, 316L; Alloy steel: 16Mn, 15CrMo, 12Cr1MoV, P91, P92, etc.

V. Quality Inspection

Finished tees shall undergo appearance inspection, dimensional measurement, wall thickness testing, non-destructive testing (radiographic testing, ultrasonic testing), hydrostatic testing, and spectral analysis to ensure that the product quality meets the requirements of the applicable standards.

Cangzhou Kairuifeng Pipeline Equipment Co., Ltd. specializes in the production of various steel tee products, offering a full range of specifications and customization options. We welcome your inquiries and purchases.