A netizen commented under the video, asking, “Isn’t it said that DC53 has a high chromium content and better rust resistance?”
This statement is incorrect.
DC53 has a carbon content of 1.0%. Although its chromium (Cr) content is 8.0%, the carbon-to-chromium ratio is low, so it cannot form a rust-resistant passivation layer. Therefore, DC53 is not stainless steel.
In DC53, both chromium (Cr) and carbon (C) form a very hard carbide structure—not a chromium-rich structure—which gives it excellent wear resistance. Therefore, DC53 is a cold-work tool steel with good wear resistance, but it does not possess rust-resistant properties.
For steel to provide rust protection, it must have a high carbon-to-chromium ratio. Generally, the carbon (C) content must not exceed 4.0%, and the chromium (Cr) content must be at least 13% to form a passivation layer approximately 1 mm thick on the mold surface, thereby providing rust protection. Furthermore, the thickness of this passivation layer increases with higher chromium (Cr) content. Stainless steels typically have very high chromium (Cr) content and very low carbon (C) content.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.