Invar 36 and Kovar per ASTM F-15 - What is Invar? What is Kovar? скачать в хорошем качестве

Invar 36 and Kovar per ASTM F-15 - What is Invar? What is Kovar?

Our video today will introduce Invar and Kovar, well known  examples of alloys that are used for applications involving control of thermal expansion.  Both are  trademarks  of Carpenter Technology. Full transcript available here: https://www.michlinmetals.com/invar-3... So let's start with just a bit about expansion Metals generally expand with increasing temperature and it is expressed as the "Coefficient of Thermal Expansion"  (CTE for short) and in english units would be inches per inch per degree F x 10 to the minus 6 . Another way to say this is the CTE is how many millionths of an inch a one inch dimension changes for every degree of temperature change. Things are more complicated in that the CTE  also varies with temperature. To keep the math easier and for us to make better comparisons, the MEAN ( the average) CTE over a range of temperatures can be used.  Tables of data show the mean CTE for the temperature range of interest ...... With this data, we can compare two materials or we can make the calculation of how much a dimension will change with a change in temperature for an alloy. An ordinary steel  or aluminum alloy has a mean CTE of  about 12  ( x 10 to the minus 6) or point 000012 inch per inch  per degree in a temperature from  70 to 300 degrees F.   So if we have a one inch part at  a 70  degree F temperature and heat it to 170 degrees F  it would measure one point 0012 inches at 170 degrees. It grew by just over a thousandth of an inch.