What is SCH 40 Steel Pipes
2025-03-10
What is SCH 40 Steel Pipes
1. What is a Steel Pipe Schedule?
A steel pipe schedule (SCH) refers to the standard measurement of a pipe's wall thickness.
Historically, metal fabricators relied on just three pipe categories — standard, extra strong, and double extra strong. However, these broad classifications were insufficient for precise specifications. To improve this, modern steel pipes are now available in 14 different schedule options.
Among these, schedule 40 is the most commonly used.
2. What is SCH 40 Steel Pipe?
SCH 40 steel pipe is one of the most widely used pipe schedules, valued for its balanced combination of durability and versatility. It can be galvanized for added corrosion resistance. This type of pipe is commonly found in water and gas pipelines, as well as in structural applications where additional support or decorative elements are needed.
Thanks to its reliable strength and adaptability, SCH 40 steel pipe is a preferred choice across various industries. Given its widespread use, let’s explore what makes it an ideal option for numerous projects.
3. What Does SCH 40 Mean?
The term "Schedule 40" does not refer to a specific measurement like 40 millimeters or 40 inches in diameter. Instead, pipe schedules are non-dimensional designations that indicate wall thickness. The standards for each schedule, including SCH 40, are established by ASME B36.10M, which governs the dimensions of both seamless and welded steel pipes. This standard defines the numerical values assigned to different pipe schedules, ensuring consistency in manufacturing and application.
4. Different Grades of SCH 40 Steel Pipe
Most SCH 40 steel pipes are made from mild steel, which contains approximately 0.2% to 0.25% carbon. This low carbon content keeps the alloy predominantly ferrous, making it easy to work with while maintaining good strength.
To enhance corrosion resistance, many manufacturers apply a galvanized coating, covering the pipe with a protective zinc layer. However, when galvanization is not suitable, stainless steel variants of SCH 40 pipes are also available.
Among the various grades, A53 steel pipe is the most commonly associated with schedule 40, though other grades are also available to meet different industry needs.
5. What is SCH 40 Steel Pipe Chart
| Nominal Dia (in) | Actual ID (in) | Actual OD (in) | Wt / Foot | Flange Dia (in) | Flange Thickness (in) | Bolt Cir Dia (in) | No of Bolts | Bolt Dia (in) | Bolt Length (in) |
| 1/8 | 0.269 | 0.405 | 0.25 | ||||||
| 1/4 | 0.364 | 0.54 | 0.43 | ||||||
| 3/8 | 0.493 | 0.675 | 0.57 | ||||||
| 1/2 | 0.622 | 0.84 | 0.86 | ||||||
| 3/4 | 0.824 | 1.05 | 1.14 | ||||||
| 1 | 1.049 | 1.315 | 1.68 | 4.25 | 0.438 | 3.125 | 4 | 0.5 | 1.75 |
| 1 1/4 | 1.38 | 1.66 | 2.28 | 4.625 | 0.5 | 3.5 | 4 | 0.5 | 2 |
| 1 1/2 | 1.61 | 1.9 | 2.72 | 5 | 0.563 | 3.875 | 4 | 0.5 | 2 |
| 2 | 2.067 | 2.375 | 3.66 | 6 | 0.625 | 4.75 | 4 | 0.625 | 2.25 |
| 2 1/2 | 2.469 | 2.875 | 5.8 | 7 | 0.688 | 5.5 | 4 | 0.625 | 2.5 |
| 3 | 3.068 | 3.5 | 7.58 | 7.5 | 0.75 | 6 | 4 | 0.625 | 2.5 |
| 3 1/2 | 3.548 | 4 | 9.11 | 8.5 | 0.813 | 7 | 8 | 0.625 | 2.75 |
| 4 | 4.029 | 4.5 | 10.8 | 9 | 0.938 | 7.5 | 8 | 0.625 | 3 |
| 5 | 5.047 | 5.563 | 14.7 | 10 | 0.938 | 8.5 | 8 | 0.75 | 3 |
| 6 | 6.065 | 6.625 | 19 | 11 | 1 | 9.5 | 8 | 0.75 | 3.25 |
| 8 | 7.981 | 8.625 | 28.6 | 13.5 | 1.125 | 11.75 | 8 | 0.75 | 3.5 |
| 10 | 10.02 | 10.75 | 40.5 | 16 | 1.188 | 14.25 | 12 | 0.875 | 3.75 |
| 12 | 11.938 | 12.75 | 53.6 | 19 | 1.25 | 17 | 12 | 0.875 | 3.75 |
| 14 | 13.126 | 14 | 63.3 | 21 | 1.375 | 18.75 | 12 | 1 | 4.25 |
| 16 | 15 | 16 | 82.8 | 23.5 | 1.438 | 21.25 | 16 | 1 | 4.5 |
| 18 | 16.876 | 18 | 105 | 25 | 1.563 | 22.75 | 16 | 1.125 | 4.75 |
| 20 | 18.814 | 20 | 123 | 27.5 | 1.688 | 25 | 20 | 1.125 | 5 |
| 24 | 22.626 | 24 | 171 | 32 | 1.875 | 29.5 | 20 | 1.25 | 5.5 |
