No. 1 JR is an oxidation-resistant steel that offers excellent electrical resistance as well as resistance to scale. Because of its high specific electrical resistance and low temperature coefficient of resistance, this alloy has been used primarily as an electrical resistance material. Key benefits of this alloy include:
Three types of No. 1 JR are available with varying aluminum contents that provide different resistivities for greater adaptability to resistor design. Type 2 has nominal aluminum contents of 3.5%, respectively. The alloy 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.