What is SCH 80 Carbon Steel Pipe?

SCH 80 Pipe

SCH 80 pipe is a type of piping widely used for conveying high-pressure fluids and gases. Its core characteristic is its thicker wall thickness, making it one of the internationally recognized pipe wall thickness standards (Schedules).

This system, defined by ANSI/ASME B36.10 (carbon and alloy steels) and B36.19 (stainless steel), uses a "Schedule number" to distinguish different wall thickness grades.

Generally speaking, for the same nominal pipe diameter (NPS), a higher Schedule number indicates a thicker wall thickness and greater pressure-carrying capacity.

Manufacturing Standards for SCH 80 Carbon Steel Pipe

SCH 80 carbon steel pipe is typically manufactured using standards such as ASTM A106 Grade B (seamless carbon steel pipe for high-temperature service), ASTM A53 Grade B (welded and seamless steel pipe), or API 5L Grade B (line pipe). ASTM A106 Grade B is suitable for high-temperature environments with a maximum operating temperature not exceeding 425°C.

Manufacturing Process for SCH 80 Carbon Steel Pipe

Pipe with an NPS of ≤ 1.5 inches can be formed by hot rolling or cold drawing. Cold-drawn pipe requires normalizing to relieve internal stresses.

Larger-sized pipe is typically manufactured using hot working and generally does not require additional heat treatment.

Chemical Composition of SCH 80 Carbon Steel Pipe

Example: Chemical Composition of ASTM A106 Grade B

C: ≤0.30%

Mn: 0.29-1.06%

P & S: ≤0.035%

Si: ≥0.10%

Also contains trace elements such as Cu, Ni, Cr, Mo, and V. The total amount of residual elements does not exceed 1%.

Features of SCH 80 Carbon Steel Pipe

1. High Strength

Schedule 80 pipes have increased wall thickness, resulting in higher mechanical strength than pipes with lower wall thicknesses.

2. Resistance to Harsh Conditions

SCH 80 carbon steel pipes are known for their excellent performance in harsh environments, including high temperatures, high pressures, or corrosive media.

3. Suitable for High-Pressure Systems

These pipes are ideal for applications involving the transmission of high-pressure fluids or gases, such as industrial processes or systems where maintaining high pressure is critical.

4. Weldability

Carbon steel, including SCH 80 pipe, is renowned for its excellent weldability, enabling easy and safe connections during installation and maintenance.

5. Cost-Effectiveness

While SCH 80 carbon steel pipe is more expensive than lower-spec pipe, it is a cost-effective solution for applications requiring a robust and reliable piping system.

SCH 80 Carbon Steel Pipe Specifications: Size/Wall Thickness/Weight

Note: For complete dimensions, please refer to ASME B36.10. Weights are for reference only; actual weights may vary slightly due to material and manufacturing tolerances.

Pressure Ratings for SCH 80 Pipe

The actual maximum allowable working pressure (MAWP) of a pipe depends on the material, operating temperature, and design criteria. The following are estimated pressure ratings for SCH 80 CS pipe at room temperature (based on the ASME B31.3 Process Piping Code):

Applications of SCH 80 Carbon Steel Pipe

1. Industrial Processing

SCH 80 carbon steel pipe is commonly used in manufacturing equipment, robotics, and heavy machinery where high-pressure fluids must be transported.

2. High-Pressure Systems

These SCH 80 carbon steel pipes are suitable for cleaning equipment, steam heating, and power systems where erosion resistance and pressure resistance are required.

3. Oil and Gas Industry

In the oil and gas industry, SCH 80 carbon steel pipe is used for oil and gas gathering and transportation, drilling platform pipelines, and high-pressure processes in refineries.

4. Power Generation

In power plants, SCH 80 CS pipe is used for high-pressure steam piping, water supply systems, heat exchangers, and condensing units.

5. Chemical Processing

Due to its corrosion resistance and high-pressure properties, SCH 80 carbon steel pipe is widely used for conveying corrosive media and high-temperature, high-pressure reaction fluids. It is commonly found in reactor inlets and outlets, and in heat exchange systems.

FAQ

Q1: Which is Better, SCH 80 or SCH 40 Carbon Steel Pipe?

A: There's no such thing as "better," only "more suitable."

SCH 40: Suitable for low-pressure, general applications (such as building plumbing and low-pressure air systems), with lower cost and lighter weight.

SCH 80: Suitable for high-pressure, high-temperature applications with mechanical impact risk or harsh operating conditions (such as process piping, high-pressure steam, and hydraulic systems).

Q2: How to Buy SCH 80 Carbon Steel Pipe That Meets The Standards?

A: Choose a reputable, professional steel pipe supplier or manufacturer.

When purchasing, be sure to specifically request products that meet standards such as ASTM A106 (seamless) or ASTM A53 (welded/seamless).

Request a material certificate (MTC/MTR) to ensure that the material's chemical composition and mechanical properties fully meet the specifications.

Read more: Carbon Steel Pipe Schedules