The major source from chrome chemicals is in that region. I suspect that it affected exports as much as anything. I doubt that steel demands for war production were so severe that they consumed the available stocks.
Chromite and ferrochromium are the minerals from which chrome chemicals are derived. Those mineral deposits are found throughout Asia and Korea but none in North America.
While I have no evidence to prove this, my instincts are that the chrome shortages were the result of disruption of raw materials more than demand for steel production for war use.
