Use ultra-low carbon austenitic stainless steels, including 304L and 316L, can decrease the formation of chromium carbide and decrease the probability of chromium-depleted envelope. Type 304 chrome steel is harder to machine than carbon metal and low alloy metal on account of its larger toughness and higher work hardening price. https://www.linkedin.com/pulse/inox-t%E1%BA%A5m-cu%E1%BB%99n-304-316-tr%E1%BA%A7n-trung-ngh%C4%A9a-xo2zf%C3%B4ng-ty-nh%C3%B4m-inox-nam-thu%E1%BA%ADn-l%E1%BB%A3i/t/c/0A6fd0w9chk