> Chromium is produced
Brearley steel debuted in 1915. The question is not how it is produced in 2025 but how it was produced in 1915.
Wikipedia partly agrees with GP:
“Also in the late 1890s, German chemist Hans Goldschmidt developed an aluminothermic (thermite) process for producing carbon-free chromium.[29] Between 1904 and 1911, several researchers, particularly Leon Guillet of France, prepared alloys that would later be considered stainless steel.[29][30]”
Though it points out a host of household names that knew of iron chrome alloys, including Faraday and Bunsen. Chrome steel existed for 75 years before Brearley came along but seems to have been used for things like canons, which are a lot more dear than cutlery. I wonder how they got their chrome 50 years before Goldschmidt.
Ferrochrome was first produced in electric arc furnaces in 1893, two decades before stainless steel.
The first ferrochrome produced thus had very high carbon content.
The only kind of stainless steel that could have had any chances of being made with such a ferrochrome would have been a martensitic stainless steel for knife blades.
In any case that kind of ferrochrome was not suitable for researching the properties of chromium alloys. The acceptable compositions for alloys like stellite or various kinds of stainless steels have all been discovered, after many experiments, only by using relatively pure aluminothermic chromium, which was a strictly necessary ingredient for enabling chromium alloy research.
Only after the required composition of a kind of stainless steel was understood and only if it was determined that such a composition can be reached by mixing ferrochrome with iron, the manufacturing process was adjusted for using cheaper ferrochrome instead of pure chromium.
Today there exists low-carbon ferrochrome, which is suitable for making most kinds of stainless steels, but even now the low-carbon ferrochrome is much more expensive than the high-carbon ferrochrome from which only martensitic stainless steel can be made.
Chromite was mined in the US back in 1811.
Ferrochrome is used to make Chrome steel and later stainless steel, but Chrome steel is significantly older.
The kinds of chrome steel used in the 19th century were very fragile, due to high content of carbon and of other impurities.
Their possible uses were very limited in comparison with the ductile stainless steels discovered in the 20th century.
Also the chemical resistance of the first chrome steels was modest, because it was not known which is the minimum content of chromium for avoiding rusting and also their composition was not well controlled.
Chromite was being mined then for use in chemicals, particularly for tanning, IIRC.