Butt weld tee dimensions introduction

　　Shengtian Group has been specializing in the production and sales of ASME B16.9 standard weld neck fittings for many years. We provide customers with one-stop services including production, sales, transportation, and export. ASME B16.9 weld neck tees are one of our key products, characterized by their robustness, durability, and excellent sealing performance, making them widely used in various industrial piping systems.

　　I. What is a Welded Butt Tee?

　　A welded butt tee is T-shaped, consisting of a main pipe and a branch pipe connected perpendicularly to it. The English word "Tee" aptly describes its appearance.

　　The ends require beveling to facilitate welding to the pipe. The fitting surface typically requires sandblasting or shot blasting; carbon steel fittings require rust-preventive paint or other anti-corrosion treatments. The internal transition area is smooth to reduce fluid resistance and prevent eddies and scale buildup.

　　II. Types, Dimensions, and Weights of Welded Butt Tees in ASME B16.9

　　ASME B16.9, published by the American Society of Mechanical Engineers, is the internationally recognized standard for the production of welded butt tees, specifically for "factory-made forged steel welded pipe fittings." This standard ensures the interchangeability, safety, and performance consistency of welded butt tees.

　　1. Types of Steel Welded Butt Tees

　　Equal Diameter Tees: The main pipe and branch pipe have the same outer diameter. Suitable for applications requiring equal flow distribution, resulting in a relatively uniform flow field.

　　Reducing tee: The outer diameter of the branch pipe is smaller than that of the main pipe. It is commonly used in situations where a smaller flow rate line needs to branch off. The notation is "Main pipe diameter × Branch pipe diameter".

　　2. ASME B16.9 Butt-welded tee dimensional parameters

　　ASME B16.9 specifies a series of dimensions for butt-welded tees, mainly including:

　　Nominal pipe diameter: Covering from NPS 1/2″ to NPS 48″ (DN15 to DN1200).

　　Dimensional tolerances: Strictly specifying the permissible deviations for the port's outer diameter, inner diameter, bevel angle, and center-to-end distance (e.g., the C dimension of an equal-diameter tee), ensuring the accuracy of the weld joint.

　　Wall thickness: Usually matched to the wall thickness of the connected pipe. Standard tees have "Standard Wall Thickness" (STD) and "Extra Thickness" (XS) series to meet different pressure rating requirements.

　　The butt-welded tee conforming to ASME B16.9 is fully compatible with pipes, valves and other fittings of the same standard, achieving standardized design and installation of the system.

　　3. Theoretical Weight Table

　　4. Tolerance range for butt welded pipe fittings according to ASME B16.9

Nominal  Size

All Fittings

45°&90° Elbows & Tees, Crosses

3D Radius Elbows

180 °  Elbow Returns

Caps

Reducers & Lap Joint Stub Ends

Lap Joint  Stub Ends

DN

NPS

OD 3) 4)

ID 3)

A   B   C   M

A   B

O

K

U

E,  E1

H   F

G

R

t

15-65

1/2 -21/2

+1.6 -0.8

± 0.8

± 2

± 3

± 6

± 6

±  1

± 3

± 2

0     -1

0     -1

+1.6 0

80-90

3-31/2

± 1.6

± 1.6

± 2

± 3

± 6

± 6

±  1

± 3

± 2

0     -1

0     -1

+1.6 0

100

4

± 1.6

± 1.6

± 2

± 3

± 6

± 6

±  1

± 3

± 2

0     -1

0     -2

+1.6 0

125-200

5-8

+2.4 -1.6

± 1.6

± 2

± 3

± 6

± 6

±  1

± 6

± 2

0     -1

0     -2

+1.6 0

250-450

10-18

+4.0 -3.2

± 3.2

± 2

± 3

± 10

± 6

± 2

± 6

± 2

0     -2

0     -2

+3.2 0

500-600

20-24

+6.4 -4.8

± 4.8

± 2

± 3

± 10

± 6

± 2

± 6

± 2

0     -2

0     -2

+3.2 0

650-750

26-30

+6.4 -4.8

± 4.8

± 3

± 6

---

---

---

± 10

± 5

---

---

---

800-1200

32-48

+6.4 -4.8

± 4.8

± 5

± 6

---

---

---

± 10

± 5

---

---

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　　III. Common Materials for Steel Welded Butt Tees

       The choice of material for a welded butt tee directly determines its applicable media, temperature, and pressure environments. Common materials include:

　　1. Carbon Steel Welded Butt Tees:

　　A106 Gr.B: The most commonly used carbon steel material, with good weldability and mechanical properties, suitable for general water, steam, oil, and other media, with a wide temperature range.

　　Q235B: A commonly used carbon steel in Chinese standards, offering high cost-effectiveness, used in low-pressure general fluid systems.

　　2. Stainless Steel ASME B16.9 Tees:

　　304/304L: General-purpose austenitic stainless steel, with excellent corrosion resistance and formability, suitable for food, chemical, and general corrosive environments.

　　316/316L: Contains molybdenum, with significantly better resistance to pitting and chloride corrosion than 304, suitable for more demanding conditions such as marine environments and chemical plants.

　　321: Contains titanium, with strong resistance to intergranular corrosion, suitable for high-temperature environments.

　　3. Alloy Steel BW Tees:

　　16Mn (Q345B/C/D): Low-alloy high-strength steel with superior comprehensive mechanical properties compared to ordinary carbon steel, commonly used in oil and gas pipelines with certain pressure requirements.

　　15CrMoG, P91, etc.: Heat-resistant alloy steels with excellent creep strength and oxidation resistance under high temperature and pressure, specifically used in power plant boilers, high-temperature steam pipelines, etc.

　　4. Other Special Materials:

　　Such as duplex stainless steel (2205), nickel-based alloys (Inconel 600/625), etc., used in extreme corrosive or high-temperature environments.

　　Material selection requires comprehensive consideration of design pressure, design temperature, fluid corrosivity, process requirements, and cost factors.

　　IV. Application Scope

        The superior performance of welded tees makes them play a core role in many industrial fields:

　　Oil and Gas Industry: Used for diversion, gathering, and process switching in long-distance pipelines for crude oil, natural gas, and refined oil, as well as in process pipelines of refineries and chemical plants.

　　Chemical and Petrochemical Industries: Connecting various reactors, towers, and heat exchangers, and transporting various chemical raw materials, intermediates, and products, the selection of corrosion-resistant materials is crucial.

　　Power Industry: High-quality alloy steel tees are indispensable in the steam and feedwater systems of thermal power plants and the auxiliary pipelines of nuclear power plants, especially in the main steam pipelines under high temperature and pressure.

　　Shipbuilding and Marine Engineering: Used in the power systems (fuel oil, lubricating oil), ballast water systems, and oil and gas handling and transportation systems of offshore platforms.

　　Municipal Construction: Used in the main and branch lines of centralized heating networks to achieve efficient heat distribution.

　　Food and Pharmaceutical Industries: Primarily using sanitary-grade stainless steel tees to meet the stringent requirements of sterility, residue-free operation, and easy cleaning in fluid transportation.

　　Other Fields: Also includes papermaking, metallurgy, air conditioning, and environmental engineering.

　　Welded tees, as a high-efficiency and reliable pipe fitting, ensure the safe, efficient, and long-term stable operation of modern industrial pipeline systems through their strict adherence to the ASME B16.9 standard, diverse material selection, and wide range of applications.