Schedule 40 Stainless Steel Pipe

1.Schedule 40 stainless steel pipe meaning

Schedule 40 stainless steel pipe is categorized based on its wall thickness and pressure rating. “Schedule 40” (SCH 40) is part of a wall thickness designation system established by the American National Standards Institute (ANSI) and the American Society for Testing and Materials (ASTM).

Typically made from low-carbon stainless steel (such as SS 304), SCH 40 pipes consist of chromium, nickel, and other metal elements. These components provide the pipe with excellent corrosion resistance, oxidation resistance, and mechanical strength, making it suitable for harsh chemical and physical environments. For instance, the low carbon content in SS 304 enhances its weldability and ensures high resistance to cracking in chloride-rich environments.

Moreover, SCH 40 stainless steel pipes can undergo additional treatments, such as online galvanizing or hot-dip galvanizing, to improve their corrosion resistance. Hot-dip galvanizing, in particular, forms a robust protective layer on the surface, effectively preventing rust.

2.Dimensional Classifications of SCH 40 Stainless Steel Pipe

SCH 40 stainless steel pipes are available in various nominal pipe sizes (NPS), ranging from 1/8 inch to 12 inches, with each size featuring different wall thicknesses and internal diameters. These variations in dimensions and wall thicknesses make them suitable for diverse pressure and flow requirements.
For example:
1-inch SCH 40 pipe: Outer diameter of 33.4 mm, wall thickness of 2.77 mm.
4-inch SCH 40 pipe: Outer diameter of 114.3 mm, wall thickness of 6.02 mm, and an internal diameter of approximately 102.26 mm.
24-inch SCH 40 pipe: Wall thickness up to 9.525 mm.
As the schedule number increases, so does the wall thickness, enabling the pipe to withstand higher pressures and more demanding operating conditions.

SCH 40 Stainless Steel Pipe Size Chart

Nominal size [inches]	Outside diameter [inches]	Outside diameter [mm]	Wall thickness [inches]	Wall thickness [mm]	Weight [lb/ft]	Weight [kg/m]
1/2 Inches	0.84	21.3	0.065	1.65	0.54	0.8
3/4 Inches	1.05	26.7	0.065	1.65	0.69	1.03
1 Inches	1.315	33.4	0.065	1.65	0.87	1.3
1 1/4 Inches	1.66	42.2	0.065	1.65	1.12	1.66
1 1/2 Inches	1.9	48.3	0.065	1.65	1.28	1.91
2 Inches	2.375	60.3	0.065	1.65	1.61	2.4
2 1/2 Inches	2.875	73	0.083	2.11	2.49	3.71
3 Inches	3.5	88.9	0.083	2.11	3.05	4.54
3 1/2 Inches	4	101.6	0.083	2.11	3.5	5.21
4 Inches	4.5	114.3	0.083	2.11	3.95	5.88
5 Inches	5.563	141.3	0.109	2.77	6.4	9.52
6 Inches	6.625	168.3	0.109	2.77	7.65	11.38
8 Inches	8.625	219.1	0.109	2.77	9.99	14.87
10 Inches	10.75	273.1	0.134	3.4	15.29	22.76
12 Inches	12.75	323.9	0.156	3.96	21.13	31.44
14 Inches	14	355.6	0.156	3.96	23.22	34.56
16 Inches	16	406.4	0.165	4.19	28.11	41.83
18 Inches	18	457	0.165	4.19	31.64	47.09
20 Inches	20	508	0.188	4.78	40.12	59.7
22 Inches	22	559	0.188	4.78	44.18	65.75
24 Inches	24	610	0.218	5.54	55.85	83.11
30 Inches	30	762	0.25	6.35	80.02	119.09

3.Seamless and welded types of SCH 40 stainless steel pipes

SCH 40 stainless steel pipes are divided into seamless pipes and welded pipes. Seamless pipes have higher strength and pressure resistance due to their uniform structure and weld-free design, and are suitable for high-pressure fluid transportation scenarios. Stainless Welded pipes have lower manufacturing costs and high production efficiency, making them more economical in medium and low pressure applications.
In actual use, the choice of seamless or welded pipes depends on specific pressure, flow and environmental conditions. For example:
In harsh chemical processing or high temperature environments, seamless pipes are more suitable.
In more conventional construction or low-pressure fluid transportation, welded pipes are an economical and efficient choice.

4.Application areas of SCH 40 stainless steel pipe

Due to its high performance and economical performance, SCH 40 stainless steel pipe has been widely used in many industries:

4.1Oil and gas
In the oil and gas industry, No. 40 stainless steel pipe is used to transport liquid and gaseous media, especially in corrosive environments.

4.2 Chemical industry
Chemical plants need pipes that can withstand high pressure and chemical corrosion, and the corrosion resistance of SCH 40 pipe makes it very suitable.

4.3 Construction and infrastructure
In the construction industry, No. 40 stainless steel pipe is used for pipes, railings and structural supports. Its beautiful surface and corrosion resistance increase its service life.

4.4 Food and pharmaceutical
Since stainless steel does not contaminate fluids or produce harmful substances, SCH 40 pipe is widely used in food processing and pharmaceutical industries.

5.Schedule 40 stainless steel pipe thickness

(1)Standard thickness specifications
Schedule 40 stainless steel pipes adhere to standardized thickness specifications set forth by industry standards organizations such as ANSI and ASTM. The nominal wall thickness for Schedule 40 pipes varies depending on the nominal pipe size (NPS).

For example:
For NPS 1/8 to 10, the nominal wall thickness is 0.068 inches (1.73 mm).For NPS 12 and above, the nominal wall thickness is 0.406 inches (10.31 mm).These thickness specifications ensure consistency and uniformity in pipe dimensions, facilitating seamless integration into piping systems and compatibility with various fittings and connectors.

Schedule 40 stainless steel pipe weight per foot

The weight per foot of a Schedule 40 stainless steel pipe refers to the mass of the pipe per linear foot of its length. It is determined by the pipe's dimensions (such as diameter and wall thickness) and the density of stainless steel, typically around 0.29 pounds per cubic inch (lb/in³) for austenitic stainless steels commonly used in piping applications.

6.Tips for Choosing SCH 40 Stainless Steel Pipe

When selecting SCH 40 stainless steel pipes, consider the following factors:
Pressure Ratings: Choose the appropriate wall thickness based on the pressure requirements of your system.
Dimensional Compatibility: Ensure the pipe dimensions match the system's fittings and connections.
Corrosion Resistance Needs: For pipes exposed to highly corrosive environments, opt for hot-dip galvanized or higher-grade stainless steel materials.
Additionally, sourcing high-quality stainless steel pipes from reputable suppliers ensures compliance with ASTM or ANSI standards, delivering consistent performance and durability.