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第四章工程定位设备的准则(二) 热膨胀——当温度变化时,不同材料之间膨胀系数的差别是很大的。铝 12.3青铜 9.9钢 6.2铸铁 6.0碳化钨(硬质合金) 3.3因钢 1.5温度每变化华氏一度时,材料每时长度(25.4毫米)的线值膨胀量(以微时计,1微时=0.025微米)。热膨胀的重要性可以通过下面的例子得到验证:一个10时长的钢块规,在温度上升10°F时,其伸长量将大于万分之五时,这说明,这类变化在精密测量中确实是不容忽视的。
Chapter 4 Guidelines for Engineering Positioning Equipment (2) Thermal Expansion - When the temperature changes, the difference between the expansion coefficients of different materials is very large. Aluminum 12.3 Bronze 9.9 Steel 6.2 Cast iron 6.0 Tungsten carbide (cemented carbide) 3.3 Linear expansion of material per length (25.4 mm) at temperature of one degree Fahrenheit for steel 1.5 temperature (micrometers, 1 microsecond = 0.025 Micron). The importance of thermal expansion can be verified by the following example: A 10-gauge steel gauge will elongate by more than ten thousandths of an hour at a 10 ° F temperature, indicating that such changes are significant in precision measurements Really can not be ignored.