B_edward

Earth engaging steel would need to be 0.5 to 0.8 carbon to get the abrasion resistance. Large mower blades are made from low carbon steel heat treated to a bainite structure. This structure is much tougher than tempered martensite thus safer (less likely to shatter and throw schrapnel out the deck)

The ASM course is well worth the efort if you are in the steel business. You will receive several printed topic's. Each topic has a question and answer section at the back to test your knowledge. The advantage of the course is the structured learning. The book of the same title is also a good resource.If you can conceptualize the atomic structure learning heat treat is simple. Phase diagrams are self explanitory when you catch on to BCC, FCC and BCT.....