Expansion alloy (GB/T14985-1994)
Expansion alloy is an important metal material widely used in our daily life. It is a material composed of metal base and special alloy elements, which has the effect of thermal expansion. Generally speaking, expansion alloy is a kind of alloy with good thermal expansion performance, which is obtained by adding rare earth, transition element and other alloy elements into metal base, such as iron and nickel. Expansion alloy is also an alloy which has special expansion characteristics due to the added alloy elements.
Expansion alloy made of corrosion resistant material have been widely used in petrochemical and chemical industry, because of its high melting point, good corrosion resistance and low chlorine content. Besides, expansion alloy has been developed in antifreeze, heat storage and other fields due to its thermal expansion and good thermal conductivity. Expansion alloy is also used in metallurgy, nuclear power, aerospace and radar, which is of great help for our modern society.
GB/T 14985-1994, the “Expansion Alloy” standard, is an important specification for expansion alloy, covering the requirements and test procedures of this product. According to this standard, the dimension and accuracy of expansion alloy should be in accordance with Table I below, which lists the dimension and accuracy of expansion alloy for different materials.
The expansion alloy should also meet the requirements for thermal expansion. The allowable deviation should be between 6 and 45, depending on the material under test. Moreover, it should also meet the hardness requirements, and the average hardness should be 500HV. Besides, the allowable deviation of Vickers hardness should be more than 150 HV.
Additionally, the expansion alloy should meet the requirement of chemical composition. The content of alloy elements should be controlled within reasonable scope under the premise of ensuring the quality and performance of the expansion alloy. Moreover, the microstructure shall be uniform and the composition should be balanced, which should be reflected in the uniform color and surface structure of the sample.
It should be emphasized that the expansion alloy should meet the requirements of the relevant national standard to guarantee its quality. Therefore, before using the product, we should make sure to read the relevant national standard and make sure that the product meets all the required requirements. The requirements for performance, dimension and accuracy should be reasonable, and the production process should also follow the national standard strictly. Thus, good quality expansion alloy products can be provided for use in today’s society.
