A lot of these steels also contain tungsten (W). Chromium impacts creation of tungsten carbide. Would removing chromium possibly have some kind of benefits for performance of these steels?
High chromium leads to steel favoring a different tungsten carbide type, W6C rather than WC. W6C dissolves more readily so that more tungsten is in solution after austenitizing and quenching. This was indirectly discovered in the 1890s/1900s when they found that red hardness (hot hardness) was improved in high tungsten steel by adding ~3-5% chromium.
WC is harder than W6C so it is better for improving wear resistance than W6C. However, the vast majority of tool steels and high speed steels have tungsten added for hot hardness not wear resistance. It's the same reason why many steels have molybdenum additions. Both elements (Mo and W) contribute to hot hardness but you only have to use half as much Mo as W in terms of weight. Molybdenum is also better than tungsten for improving air hardening. Many tool steels have 1-2% Mo for that purpose, it makes the steel deeper hardening than if only using chromium. That allows the heat treatment of large dies, etc.
There are a few steels that have a significant addition of tungsten for wear resistance with low or no chromium. These are steels like Blue Super, F2, 1.2562, and ApexUltra. They are all water or oil hardening steels rather than air hardening like the 3-5% chromium tool steels and high speed steels we are discussing.
There are a couple air hardening steels that do not use high chromium, notably A4 and A6 tool steels. A6 uses a combination of high manganese (~2%) and molybdenum (~1.25%) and a small chromium addition (~1%). This was designed to be heat treated from lower temperatures than chromium die steels while also being air hardening.
There was also a rare steel called Hi Wear 64 that didn't take off that combined the non-chromium air hardening approach of A6 with 4% tungsten to make a completely different kind of air hardening die steel with high wear resistance from WC tungsten carbides.
However, tool steels that need high wear resistance more typically use chromium carbides (A2, D2, etc) and/or add vanadium to add vanadium carbide rather than tungsten to form tungsten carbide. That goes way back to when they were adding vanadium to high speed steels for higher wear resistance, leading to M2 (2% V) and M4 (4% V). They didn't try to reduce chromium to get more WC but instead added vanadium to get VC. Both VC and WC are among the hardest carbides that occur in steel.
Anyway, I can't explain all this in much detail on a forum. My book The Story of Knife Steel has a much more comprehensive look at the evolution of alloying in steel and why they are alloyed as they are.
