Is it PSF27 or D2?
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Nathan the Machinist
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The HDFK marked D2 is PSF27
PSF27 is D2
The EDC I've made that are marked D2 are Crucible D2, but the non-particle metallurgy version. CPM D2 carbide is small and rounded and does not enhance edge retention or create a toothy edge like conventional D2, and it is a little more "mushy" and does not respond well to pre-quenching so overall it does not have the edge stability potential (given an optimized HT) or edge retention of their regular D2 though I expect it is very good in tool and die.
D2 can be cheapass Chinese import with impurities, alloy banding and mixed microstructure (this is frequently sold as American D2 because it was cutup and ground here)
It can be high end cross rolled very clean electroslag remelt
It can be spray formed to reduce issues with aggregating alloy and carbide (PSF27) this actually has some advantages over CPM
It can be one of the foreign equivalents with tungsten replacing vanadium and some Chinese maker is calling it D2
edit to add:
The amount of vanadium can vary widely from maker to maker and this greatly effects pre-quenching response. You might find a higher chrome lower vanadium and moly blend that works great in tool and die or reacts well to induction hardening that doesn't play well in a knife edge or increased carbon versions tweaked for drawing dies rather than stamping tools or a lower carbon made to use for injection molding abrasive corrosive plastics like PVC. Some D2 has no manganese and added moly and has a better secondary hardening response and reduced pitting and is used to extrude vinyl siding. D2 is like hotdogs with many makers using different ingredients. Many flavors.
PSF27 is D2
D2 might be my personal favorite steel but I don't use it much because other people value other properties differently than I do and there isn't much demand for it. Also, it was frustrating having one batch behave differently than the next. 3V does so much of what D2 does and does it with much better toughness, and better corrosion resistance and edge stability too that I work in 3V almost exclusively now, and from a manufacturing point of view it is wonderful ordering 3V custom rolled and getting an entire ingot of it with consistent chemistry and microstructure. People tend to think of me as a 3V guy, but I was a D2 person first.
PSF27 is D2
The EDC I've made that are marked D2 are Crucible D2, but the non-particle metallurgy version. CPM D2 carbide is small and rounded and does not enhance edge retention or create a toothy edge like conventional D2, and it is a little more "mushy" and does not respond well to pre-quenching so overall it does not have the edge stability potential (given an optimized HT) or edge retention of their regular D2 though I expect it is very good in tool and die.
D2 can be cheapass Chinese import with impurities, alloy banding and mixed microstructure (this is frequently sold as American D2 because it was cutup and ground here)
It can be high end cross rolled very clean electroslag remelt
It can be spray formed to reduce issues with aggregating alloy and carbide (PSF27) this actually has some advantages over CPM
It can be one of the foreign equivalents with tungsten replacing vanadium and some Chinese maker is calling it D2
edit to add:
The amount of vanadium can vary widely from maker to maker and this greatly effects pre-quenching response. You might find a higher chrome lower vanadium and moly blend that works great in tool and die or reacts well to induction hardening that doesn't play well in a knife edge or increased carbon versions tweaked for drawing dies rather than stamping tools or a lower carbon made to use for injection molding abrasive corrosive plastics like PVC. Some D2 has no manganese and added moly and has a better secondary hardening response and reduced pitting and is used to extrude vinyl siding. D2 is like hotdogs with many makers using different ingredients. Many flavors.
PSF27 is D2
D2 might be my personal favorite steel but I don't use it much because other people value other properties differently than I do and there isn't much demand for it. Also, it was frustrating having one batch behave differently than the next. 3V does so much of what D2 does and does it with much better toughness, and better corrosion resistance and edge stability too that I work in 3V almost exclusively now, and from a manufacturing point of view it is wonderful ordering 3V custom rolled and getting an entire ingot of it with consistent chemistry and microstructure. People tend to think of me as a 3V guy, but I was a D2 person first.
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