Originally Posted by thekauz
What about the bolt heads on the drum shield that are exposed? They always corroded badly.
If ultimate strength isn't a requirement, stainless steel is an option. Most stainless strength is a bit under US grade 5 (120,000 PSI), or it's metric equivalent, class 8.8, but above common steel, US grade 2 . Stainless tends to gall, so be sure to use anti-seize (or something) with stainless.
One metric hardware site that I found, mmsacc-stainless.com Metric Products
, advertises its stainless at "85,000-90,000 P.S.I. Average Tensile Strength". Most common, low-strength metric stainless, A2-70 or A4-70, is around 100,000 psi.
ARP makes a good range of high-strength (metric class 10.9 = US grade 8) metric stainless (arp-bolts.com) and totallystainless.com carries most of them, plus some low strength SS (A2-70) as well. Be alert NOT to use common low-strength stainless where a medium or high-strength bolt is required.