Schedule 80 seamless steel pipe

The steel pipe wall thickness series comes from the British metrology unit, and the score is used to express the size. The wall thickness of the seamless pipe is made up of the Schedule series (40, 60, 80, 120) and is connected to the weight series (STD, XS, XXS). These values are converted to millimeters as part of the tube wall thickness series.

Specifications of SCH series seamless steel pipes

The specifications of SCH series seamless steel pipes mainly include nominal diameter (DN), outer diameter (Outer Diameter), nominal wall thickness (T), etc. The following are some common specifications listed according to different nominal diameters:

Material of SCH 80 pipe

SCH 80 does not refer to a specific material, but one of the pipe wall thickness grades defined by the American standard (ASME B36.10/B36.19), representing "Schedule 80". ASTM No. 80 seamless carbon steel pipe has high compressive strength, high precision, no deformation during cold bending, no crack flattening, no oxide scale, good tensile and impact resistance. The material selection depends on the specific application requirements, and common types include:

1. Carbon steel (such as ASTM A106)

Used in high temperature and high pressure environments, tensile strength ≥415 MPa, yield strength ≥240 MPa (refer to ASTM A106 standard).

2. Stainless steel (such as ASTM A312 304/316)

It has strong corrosion resistance. The molybdenum content of 316L stainless steel reaches 2%-3%, which is suitable for chemical and marine environments.

3. Alloy steel (such as ASTM A335 P11/P22)

It contains elements such as chromium and molybdenum, is resistant to high temperature and high pressure, and is often used in power station boiler pipes.

The larger the number after SCH, the thicker the wall thickness. For example, the wall thickness of SCH 80 carbon steel pipe is about 30%-50% thicker than that of SCH40, and the pressure bearing capacity is stronger (taking DN50 pipe as an example, the wall thickness of SCH 80 is 5.54mm, and that of SCH40 is 3.91mm).

Typical application scenarios of SCH 80 pipes

1. Chemical industry

For the transportation of corrosive media (such as acids and alkalis), stainless steel SCH 80 is preferred.

2. Oil and gas

High-pressure wellhead pipelines mostly use alloy steel SCH 80, such as ASTM A335 P91 (temperature resistance up to 600℃).

3. Building water supply and drainage

SCH 80 PVC pipes can be used in high impact demand scenarios, and their bursting pressure is ≥3.5 MPa (refer to ASTM D1785).

Difference Between SCH 40 and SCH 80 Steel pipe

Pipes with Schedule 40 come with standard weight, and pipes with schedule 80 come with extra strength. The materials used for making Schedule 40 and Schedule 80 come from the same material.

Schedule 80 pipes have a thicker wall than Schedule 40 pipes. As such, Schedule 80 pipes are stronger than Schedule 40 pipes. Though both pipes are used in construction work, Schedule 40 is used more often. But if a stronger pipe was needed, then the engineers would go for Schedule 80 pipes. Schedule 80 pipes are used where the pipes have to be exposed. But if there is no need for any extra strength, Schedule 40 pipes are sufficient.