奥氏体不锈钢低温热导率计算方法及验证

Computed method and validation of thermal conductivity of austenitic stainless steels in cryogenic temperature range

不锈钢在低温系统中应用广泛,但各种牌号的不锈钢材料在低温区间的热导率测试数据却很少。文献推荐的计算纯铁低温热导率的经验公式并不适用于不锈钢。在文献公式的基础上,提出了一种针对奥氏体不锈钢材料的低温热导率计算方法,可基于4K^20K温度区间内电阻率或热导率的单点测试数据,估算4K^300K温度区间的热导率,也可根据室温电阻率或热导率的测试数据,但计算精度比前者略低。计算方法通过了美标304、316、317、321牌号不锈钢实测数据的验证。基于该计算方法建立了奥氏体不锈钢低温热导率计算程序,估算了国产牌号1Cr18Ni9Ti不锈钢4~300K温度区间的热导率,并与文献中的测试数据进行了对比验证,相对计算误差能够满足工程设计需要。

Stainless steels are being used increasingly in cryogenic systems. However,cryogenic thermal conductivity measurements for many types of stainless steels are generally missing. The referenced equation for computing the thermal conductivity of pure iron is inadequate for austenitic stainless steels. This paper described a method of computing the thermal conductivity of austenitic stainless steels between the liquid helium temperature(approximately 4 K） and room temperature,based on a measurement of the thermal conductivity or electrical resistivity at a single temperature in cryogenic region(20 K and below）. Useful computing could also be made from room temperature measurements of electrical resistivity or thermal conductivity,but with reduced accuracy. The computing data agreed well with the measurements of stainless steels AISI 304,316,317 and 321. Recommended thermal conductivity values were presented for stainless steel type 1 Cr18 Ni9 Ti using the calculation procedure based on the computing method and validated by referenced data.