Ginormous
Gold Member
Ok, I'll put a #2 bolt in. But......won't a hardened bolt shear quicker, due to being more brittle? Any metallurgists out there that can answer this?![]()
Storm... that's a good question. My wife is a metallurgist, and I'm a materials engineer. The harder steel may fracture more quickly in an impact situation, but only if the toughness is low enough, i.e., only if it is very brittle, which would probably be from being heat treated wrong. I looked up the specs for grades 2, 5 and 8 bolts. Tensile strength is 74 ksi, ~100 ksi and 150 ksi. They mention toughness but don't give the values. The steel for 2 & 5 are normal carbon steel, but the grade 8 bolts are a different alloy. The grade 8 bolts have both high strength and high toughness. I would expect that the grade 5 bolt still has relatively high toughness and is not likely to brittle fracture, therefore, you would have the overcome the higher shear strength. From a materials perspective, I agree with the chorus... use a grade 2 bolt. :thumbsup: