碳钢管表: 施 40 与施 80 室壁厚度

碳钢管表: 施 40 与施 80 室壁厚度

Steel pipe “日程” (施 40, 施 80, 施 160) defines the wall thickness for a given nominal diameter, and it is one of the most frequently mis-specified parameters in piping. This guide explains what the numbers mean, how Sch 40 compares to Sch 80, and how to choose the right schedule for pressure service.

What Schedule Means

Schedule is a dimensionless number that determines wall thickness. For a given nominal pipe size (核动力源), higher schedule means thicker wall and smaller inside diameter. 施 40 is the standard wall for general plumbing, HVAC and low-pressure process piping. 施 80 has roughly twice the wall thickness, used for higher pressure or corrosive service. 施 160 is the extra-heavy wall for very high pressure. The outside diameter stays the same across schedules — only the inside diameter changes. 看看我们的 Q345D seamless pipe.

Why Wall Thickness Matters

Thicker wall handles higher internal pressure. For a given material, pressure rating scales with wall thickness divided by outside diameter. 施 80 pipe handles roughly 1.5× the pressure of Sch 40 at the same size. The trade-off is that thicker wall reduces inside diameter, which reduces flow capacity — a 2″ 施 80 pipe has about 15 % less internal flow area than a 2″ 施 40. For gravity flow or low-pressure water, 施 40 is sufficient; for steam, high-pressure oil or gas, 施 80 or higher is required by code.

购买建议

Never specify “1 英制管” without the schedule — suppliers default to Sch 40, which may not meet your pressure rating. For structural pipe (扶手, 栅栏柱), 施 40 or even STD is fine because pressure is not a concern. For process piping, always run the pressure calculation per ASME B31.3 and specify the schedule accordingly. Also note that “管道” 和 “管子” are different: pipe is specified by nominal diameter and schedule, while tube is specified by exact outside diameter and wall thickness.

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