The material of the valve Trim 8 is 410 and Hardfaced.
You should confirm the correct material codes of the valve trim with the vendor, and to ensure they are compatible with the API 600.
Looking at the original question, some manufacturers offer larger sized Valves with Cast Carbon Steel Closure (Wedge/Disc/Plug) with a 13%Cr Overlay to save cost. So it looks like you are comparing Solid 13% Cr Steel vs Cast WCB with 13%Cr overlay. Hardness should be much the same.
The Solid 13% Cr Trim may have better corrosion resistance over the WCB+13%Cr, but this is only used on Valves with a WCB Body so there is no real corrosion issue as the WCB is the weak link.
Refer to your first question
A216 WCB + 13%Cr meaning that the wedge of gate valve is originally cast carbon steel, which later (only) the contact area with seat ring were overlaid with 13%Cr. So the remaining wedge (apart from the seating surfaces) will still A216WCB. This is common practice for medium-bigger size gate valve since less surface should be overlay.
Not sure 13%CR alone meaning, but I assume that then the whole surface is overlay. Also quite common practice for smaller size
You will not find the word Stellite in any standard, since this is patented 'commercial' name. Having said that its hardness simply comply with API 600.
So yes, IMO, it is acceptable as per API 600.
for 316 (as per API 600) vs AISI 410 refer to your bill of material. AISI 410 usually used for more abrasive medium.
I assume your snip referred to a generic drawing.
In terms of hardness, as long as you choose the same material grade equivalent of 13%Cr, I don't think there is a difference in your case. A216 WCB + 13Cr means wedge material is A216 WCB with 13Cr overlay on the seating surface (the contact areas against the seat ring). And BVMan, there is equivalent solid 13Cr which is A217 CA15 (casting) and A182 F6a (Forging), like you said, A216 WCB is the weak link, I totally agree. So A216 WCB + 13Cr is the acceptance and wise choice in terms of cost-efficiency.
