That middle part is actually interesting, the "if you leave fracture high but drop yield" part. Because the current raws give all metals same impact (actually compressive) yield and fracture which would equate to something very brittle, like stone. Even bone yields before it reaches it's ultimate strength. I'm guessing that Toady just found "compressive strength" figures, just like I have, and used them for both. Metals should have lower yield than fracture across the board (ie. against every kind of stress). What kind of weapon were you using in the test case mentioned? Was it same material as the armor? Was the level of damage within realism? If yes, then making the impact figures realistic would actually give realistic preformance. Odd.
(Edit) It seems that the yield = fracture in impact resistance (and others too, actually) is all over the place. Including stuff like hair and skin. I think it is pretty safe to say that if a material isn't a type of rock, it should have lower yield than fracture. My recent testing with my own skin and hair revealed that they yield before they break. Okey, I didn't
really push my skin to the yield point. That would really hurt.
That being said, compressive figures are listed rather sporadically, possibly because they would only really matter for construction materials irl. I haven't found any kind of way to convert tensile strength to compressive. There seems to be some kind of correlation between toughness (ie. large margin between yield and fracture equates a tough material) and compressive strength though. Generally, tough (in terms of tensile resistance) materials have relatively smaller difference between tensile strength and compressive strength than brittle materials.
In other news, I found some godsent tools to approximately convert hardness to tensile strength (that would be ultimate strength, or fracture in this case). The first site requires registering after few tries.
http://www.efunda.com/units/hardness/convert_hardness.cfm?HD=HV&Cat=Steel#ConvIntohttp://www.unified-eng.com/scitech/hardness/hardness.htmlI also found a table for bronze hardness:
Bronze, hardness (HV):
% tin _ as cast ___ work-hardened by 50% reduction
0.0 _____ 40 ______ 120
2.0 _____ 50 ______ 140
4.0 _____ 60 ______ 165
6.0 _____ 70 ______ 185
8.0 _____ 84 ______ 210
10.0 ___ 100 ______ 230
15.0 ___ 140 ______ 300
This is from "The prehistory of metallurgy in the British Isles" by R.F. Tylecote. I don't actually own it, it's a quote of a quote.
So, 10& tin bronze out of mold has tensile fracture of 333000 KPa. Seems to match roughly the latest MatWeb bronze, though that was softer (more comparable to the 8% tin bronze on the table).
When hardened by hammering it down to 50% of the original thickness, the edge goes up to 730000.
Some highlight from the iron swords and other objcets from the links in my previous post. All values in KPa, the same as game.
Iron age sword from Waltham Abbey, UK, Core: 550000 Edge: 827000.
Can I stop at this point to say WOW? I was not expecting that kind of figures from 2000 year old non quenched rod of iron. Not to mention I picked that because it seemed to have rather average properities for late iron age and low to non-existant carbon content. There was a harder iron age sword there... I now truly understand what they mean when they say that stainless steel sucks for swords.
Roman Spatha: 400000-510000.
Ulfberht sword, Donnybrook, Dublin, Ireland, early medieval period, quench-hardened. Edge is 1669000.
Pattern-welded sword of Palace of Westminster, UK, 9nd century AD. Core: 620000 Edge: 462000. Possibly a result of overtempering?
Merovingian spearheads: ~300000-814000.
Late Roman period spearhead: 400000.
Iron age high carbon quenched sword: 2400000. Actually broke the 50% margin with adamantite. Oh dear.
Merovingian mail link: 634000.
The axes at the merovingian metalworking seem to follow similar figures to the swords posted here, though none get nearly as high as the latest sword example (which is also from that link).
Again, all those values were tensile fracture values, which are used for shear fracture in game. I often took averages between the two conversion sites and between conversion methods, in case you are wondering.
In general, it seems that my request for iron to have great variance in properities was well placed. It is notable though that the line between wrough iron and steel becomes quite blurry here, especially the two very hard swords should be taken as being "steel". Also, by now it is pretty clear that the only period where bronze could have suprassed iron was when ironworking was in it's very infancy. This would no longer have been the case by late iron age, and bronze was mostly obsolete by then. Iron items that had worse properities than bronze were still manufactured thoughout iron and middle ages, however.
Nice to hear that this stuff is of interest.
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Topic: Pure iron (100% iron) nor cast iron shouldn't be dominant metal for arms (Read 25086 times)