Abstract
The authors studied the effect of aluminum, chromium and titanium on the properties of Fe-Cr-Al electric resistor alloys. The ingots were made by a special consumable electrode arc melting. The compositions of specimens were varied from 4 to 9%Al, from 5 to 36%Cr and from 0 to 0.8%Ti. After being forged and hot-rolled,the specimens were drawn for test pieces. Electric resistivity and heat durability were improved with increase of aluminum and chromium contents, though the ductility was lowered by increase of those elements. Aluminum was more effective than chromium,and addition of small amount of titanium was not only effective upon heat durability but also upon ductility. As is well known, the electric resistivity of the conventional alloys which contain comparatively lower contents of aluminum and chromium has a positive temperature coefficient and the ohm-resistance is increased with increasing temperature. As compared with those conventional alloys, the which contained substantially large contents of aluminum and chromium showed an extraordinary behaviour in changes of electric resistivity with changing temperature, and the ohm-resistance was reversely decreased with increasing temperature, which has the advantage of preventing the heat resistor from being locally heated and guarantees longer life. The temperature coefficient can be controled by changing the contents of aluminum and chromium.