AP Posted January 30, 2002 Share Posted January 30, 2002 does anyone know whether grade 2 bolts are hot or cold rolled? i was at the hardware store today and asked, they called the company that they buy them from and they didn't even know... perhaps bolts aren't rolled at all- sorry if this is a (duh) for some of you.. if so, how does a 1/4" thick by 6" long bolt compare to the same size cold rolled... at the store they had both hot and cold rolled rods and i flexed them (i couldn't just bend them and leave them there) to see how strong they were. anyway the cold rolled seemed about as strong as the bolts. Quote Link to comment Share on other sites More sharing options...
Guest baldy Posted January 30, 2002 Share Posted January 30, 2002 AP, I don't know the answer about the bolts. The harder ones are tempered, so hot / colled rolled is irrelevant in that case. At the factory I work at I deal with both hot and cold rolled steel, but once it has been heat treated it is a whole new ballgame. I can ding up a hot or colled rolled piece by scratching it, banging on it with a hammer, whatever. Once it is heat treated they are hard to mark. As for grade 2 bolts, that is the only kind I have successfully bent. Your ending question would depend a lot on what kind of bolt (lag bolt or carriage bolt). A 1/4" * 6" carriage bolt threaded its entire length is way easier than most 60d nails. The ones I have bent didn't offer much of a challenge, though it looks good to someone who doesn't bend. I have bent fairly thick grade 2 carriage bolts and I am not a good bender. A lag bolt is tougher, but rumor has it they vary in difficulty worse than nails. Bolts are very deceptive, you cannot go by look. That grade 5 that Tom Black bent doesn't look like much next to a 3/8" * 8" bolt carriage bolt, but try both and you feel a huge difference. Here is a question to all the benders out there: How much of a difference can you feel between hot and cold rolled small steel (nail sized)? I have never attempted either, only long bars (2 - 3 feet). When bending hot rolled long bars once you start a bend the steel has already weakened considerably at the bend site (color changes from carbon looking to almost gray / white). Not so with cold rolled, it keeps bending and bending. Much more durable. There are many different grades of both hot and cold rolled steel, too. Quote Link to comment Share on other sites More sharing options...
terminator Posted January 30, 2002 Share Posted January 30, 2002 Grade 2 bolts are pretty soft, low carbon steel, slightly more than half the tensile strength of grade 5. Also take into account the thread depth when figuring the size of a bend. For a 1/4" bolt (carriage for example) the size of the stock before thread cutting is 0.25. Approximately .05 of material is removed cutting the threads making the effective size of the bolt quite a bit less than 1/4". This would make a 1/4" threaded carriage bolt effectively smaller than the IM white nail. Probably softer material as well. Nowhere near a 60D IMHO. I have personally noticed a great deal of difference in bending strength between hot rolled and cold rolled steel of identical diameters and materials. I don't have numbers to attach to it but it is not trivial. Quote Link to comment Share on other sites More sharing options...
Tom Black Posted January 30, 2002 Share Posted January 30, 2002 According to nutty.com grade 2 bolts are "Low Carbon Steel (60,000 PSI)." If the PSI rating has any relation to the bending, which it probably does, that would make them only half of the grade 5, which I've tested at 365-pounds to bend. Thus, they would be about 182 pounds to bend, which is what I would describe as "weak." I've tested 6"x1/4" hot rolled steel at 190-pounds to bend (I used to bend 8"x3/8" carriage bolts bare handed, so you can see their not much either). I would recommend the hot rolled steel over the bolts because it would be cheaper. The grade 5 bolt has characteristics unavailable in the cold rolled steel (i.e., you can't find steel that hard with that dimension) and it's worth the extra cost if you can reach that level of strength. Quote Link to comment Share on other sites More sharing options...
AP Posted January 30, 2002 Author Share Posted January 30, 2002 i have bent steel, bolts, carriage bolts, and steel rods before. i did not know whether the steel rods i have bent in the past were hot or cold rolled becouse they were unmarked. today at the hardware store, the rods were labeled hot and cold. after flexing both of them, i felt the cold rolled was about the same difficulty as the rods i have bent before- which is also about the same difficulty as the bolts i have bent in the same size. these are bolts with no threading, carriage bolts are way easier. now, i know i could bend at least the hot at 1/4 thick 5in long, ive done it before. am i mistaken? is there no way that the previous rods i've bent are cold rolled?- hot rolled felt really easy ... ps Baldy-i've never seen any discoloration in the steel rods that i've bent Quote Link to comment Share on other sites More sharing options...
Guest baldy Posted January 31, 2002 Share Posted January 31, 2002 AP, the discoloration I have seen has been on long bars (22" or greater) of hot rolled steel 1/2" or greater diameter. I bought one 1/2" hot rolled bar @ Home Depot, it was very cheap steel with visible carbon on the outside diameter. Once bent it turned gray / white in the middle. At work I have found some scraps of 14.4 mm hot rolled bar that fed a slug forming press, and it did not have the carbon look to it. It looked gray / silver like a lot of our raw material steel. However, once bent it turned white at the joint of the bend. We use only cold rolled bars in the dept I work in, and they show no discoloration when bent (that I have noticed, but I have not bent many of the cold rolled bars because almost all are too thick to bend for me). Terminator, thanks for the reply. No numbers needed, your comment is sufficient. Quote Link to comment Share on other sites More sharing options...
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