What are the common materials for tees? How to choose?

Question: What are the common materials for tees? How to choose?

A tee is a commonly used branch fitting in piping systems, and the choice of its material directly affects the safety and service life of the piping system.

I. Classification of Common Materials

1. Carbon Steel Tee: Common grades include 20#, Q235, A105, and Q345 (16Mn). It features high strength, good toughness, excellent weldability, and cost-effectiveness, making it suitable for general media such as water, steam, air, and oil, with a temperature range of -20 to 425 degrees.

2. Stainless Steel Tee: Commonly used grades are 304, 304L, 316, and 316L. It offers excellent corrosion resistance; 316/316L, which contains molybdenum, provides better pitting corrosion resistance and is suitable for chemical corrosive media, sanitary-grade pipelines in the food and pharmaceutical industries, and seawater desalination.

3. Alloy Steel Tee: Commonly used grades include 15CrMo, 12Cr1MoV, P91, and P92. They offer high-temperature strength and excellent creep resistance, making them suitable for power plant boilers, high-temperature steam pipelines, and high-temperature process pipelines in the petrochemical industry.

4. Duplex Steel Tee: Commonly used grades are 2205 and 2507. It features high strength and excellent resistance to pitting and stress corrosion, making it suitable for seawater treatment and chemical environments with high chloride ion content.

II. Principles of Material Selection

1. Selection based on medium corrosivity: carbon steel for general media, 304 for weakly corrosive media, and 316L or duplex steel for highly corrosive media or those containing chloride ions.

2. Selection based on operating temperature: carbon steel for ambient to 350°C, chromium-molybdenum alloy steel for 350°C to 550°C, and P91/P92 for temperatures above 550°C.

3. Selection based on working pressure: Q235 can be selected for medium and low pressures, 20# or A105 for medium and high pressures, and alloy steel or thick-walled carbon steel for high pressures.

4. Selection based on hygiene requirements: The food and pharmaceutical industries must use 304 or 316L stainless steel.

5. Selection based on economy: Prioritize the use of carbon steel, provided that the usage requirements are met.

III. Precautions

1. When welding different materials, matching welding consumables must be selected; a dedicated procedure is required for dissimilar steel welding;

2. When transporting and storing stainless steel tees, avoid contact with carbon steel to prevent iron ion contamination;

3. Alloy steel tees shall be heat-treated in accordance with the specifications after welding;

4. The material must be accompanied by a quality certificate, and spectral analysis re-inspection shall be conducted when necessary.

Cangzhou Kairuifeng Pipeline Equipment Co., Ltd. can produce tee products of various materials, with a full range of specifications and customization support. We welcome your inquiries and purchases.