There's two issues here that are difficult to deal with independently, much less at the same time. The degree to which these factors interact with one another will determine the most suitable wear material to provide.

First, alloy steels lose their toughness ability as temperatures fall. The -40 degree F figure is a plenty hostile environment! Alloy steels become less resistant to breakage in temperatures this low.

Second, the compressive strength value of the material being reduced is also a consideration, as well as the noted abrasiveness. If the compressive strength of the crushed material is low -- less than 20k p.s.i. -- a medium hardness (400 bh) high nickel carbon steel may possibly be in order. If the impact resistance is higher than the noted 20k p.s.i., then manganese steel may be more suitable.

Manganese has a better ability to maintain its toughness in cold temperatures than do carbon steels. However, manganese would be less resistant to abrasion wear. You could use a silica content factor of + .4 to determine degree of abrasive wear resistance as a lower limit wear ability factor.

The long and short of it -- if you're crushing a highly friable and highly abrasive material, use the carbon steel. If the material is both high in compressive strength and possesses a moderate to high silica content, use the higher carbon value premium manganese steel. The governing issue at hand is the compressive strength value of the material being reduced. If it's hard, abrasive and located somewhere that cold, it had better be of high value, as it's going to be difficult to produce. Sizing considerations and type of crushing equipment add to the considerations in selecting the least detrimental wear material choice.