管子热膨胀量计算公式与举例
Pipes and Tubes - Temperature Expansion
Pipes expands when heated and contracts when cooled. The expansion of the pipes can be expressed with the expansion formula
管子有热胀冷缩的性质。

管子的热胀或冷缩量可以用公式表示
The temperature expansion of pipes depends on the start and final temperature of the pipe and the expansion coefficient of the piping material at the actual temperature. The general expansion formula can be expressed as:
管子随温度的膨胀或冷缩取决于起始温度和终了温度、实际温度下管子材质对应的膨胀系数。

其通用的膨胀公式也表达为：
dl = α Lo dt (1)
where 其中
dl = expansion 膨胀量 (m, inch)
Lo = length of pipe 管子原长(m, inch)
dt = temperature difference 温度差(℃, F)
α = linear expansion coefficient线膨胀系数(m/moK, inch/inch F)
Mean expansion coefficient may vary with temperature as:
平均膨胀系数会随温度的不同而不同
Mean Expansion Coefficient - α - (10-6 inch/inch F)
Material Temperature Range (oF)
- 32 32 - 212 32 - 400 32 - 600 32 - 750 32 - 900
32 -
1100
32 -
1300
Alloy Steel
(1% Cr. 1/2%
Mo)
7.7 8.0 8.4 8.8 9.2 9.6 9.8
Mild Steel
7.1 7.8 8.3 8.7 9.0 9.5 9.7
(0.1 - 0.2% C)
Stainless Steel
10.8 11.1 11.5 11.8 12.1 12.4 12.6 12.8
(18% Cr. 8% Ni)
Formula (1) can also be used with SI units. The expansion coefficient must be adjusted to ℃.
公式（1）也可以用SI单位表示，膨胀系数需要转化为℃。

下面是换算公式：
•T(℃) = 5/9[T(F) - 32]
• 1 in (inch) = 25.4 mm
• 1 ft (foot) = 0.3048 m
•Expansion coefficients for some common materials
Example - Thermal Expansion of Heated Alloy Steel
100 feet of alloy steel pipe is heated from 32 to 212 F. The expansion coefficient is 8 X10-6 (inch/inch F).。