No. 1 JR® is an oxidation-resistant steel which offers excellent electrical resistance as well as resistance to scale with a low temperature coefficient of resistance. Three types of No. 1 JR alloys are available with varying aluminum contents that provide different resistivities for greater adaptability to resistor design. Type 1 has a nominal aluminum content of 3.5% and is stabilized with titanium to tie up carbon for protection against intergranular corrosion after heat treatment or welding. No. 1 JR has also been used as a magnetic core material in applications where resistance to oxidation and corrosion are required.