Sager made axes for the professional lumberjack, this is the regular double bitted head. The Chemical part of the name referred to the chemicals that the head was quenched in during the manufacturing process, which resulted in a gun blue-type finish. The difference in colour of the hardened blade area versus the body is apparent. Stamping the manufacture year is also unusual. I need to find out more on these things!
Update: Yesteryears tools has what seems to be the only history of the Sager process and axes. It turns out there was a Canadian branch of the company, the Canadian Warren Axe & Tool Co. located in St. Catherines.