The image at left was made at 100X, and the image below it was made at 500X. Both used a Nital etch.
Specimen 2 is a gas-carburized steel.
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Here we have a free machining steel (B1144) which failed to
induction harden properly because of the banded structure. The image at left was made at 100X, and the image below it was made at 500X. Both used a Nital etch. |
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The ferrite formed first next to the manganese sulfide (MnS)
stringers because the manganese was depleted there in the process of
becoming combined with the sulfur. The brown areas are tempered
martensite, and the blue areas are pearlite. Specimen 2 is a gas-carburized steel.
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