Chains. Grade 70, 80 or 100. what do you have and why??

Interesting: From the attachment that you provided I learned some things. For example, WLL of 7/16 grade 70 is 8750, and minimum breaking force is 35,000, for a difference of 26,250.

WLL of 3/8 grade 100 is 8,800, with a minimum breaking force of 35,200, for a difference of 26,400. 150 lbs. difference between the two - de minimus in my mind.

So, similarly rated chain has similar breaking points, with the biggest difference being how grade 70 stretches before it breaks.

Also, the publication states that grade 100 is suitable for tie down.

Thanks for the info RGN!

 

JD I respect you as well.
I believe that as the experienced ones that the newbies are looking to for advise on these subjects holds us to higher accountabilities.
This is a debate that shouldn't have any traction. People much smarter than all of us have analyzed this subject, created load securement grade alloys, and the FMCSA and their engineers have made rules based on these for us to follow.

You would be correct that I DO NOT have a degree in metallurgy. There is no specific metallurgy degree that I am aware of, it is a subject that is part of welding, machining, tool & die making, fabrication, engineering, etc.
I am NOT a machinist. I have a machine shop in my garage.
I am NOT a welder. I have several welders in my garage.
I am NOT an engineer.
I am NOT a mechanic.
I have designed & built several record holding dragsters. Every part of; chassis, transmissions, clutches...but I'm not a licensed mechanic.
I have a deep fundamental understanding of all of the above, so yes, what I say is anecdotal...to a point because I haven't actually performed the scientific experiments. But I am using the science that has been done to back up my statement.
I AM studying engineering in a "distance learning" capacity at this time, so I kinda know what I'm talking about.

Metallurgy is the study of the characteristics of the various types of metals and alloys. What properties are desired, and what properties are not wanted. To obtain the desired properties different alloys are added to the recipe.
ULTIMATE BREAKING POINT IS NOT THE ONLY THING TO LOOK AT!!! The intended purpose is not that simple.
How does it break?
Why does it break that way?
Is that acceptable or unacceptable for the application?
Is there a better alternative?

The people at your rigging supplier telling you that "as long as you don't exceed the WLL" have not been properly educated on the subject. I've talked to many that have told me the same thing, but simply put...they're wrong.
Don't believe me? Fine, go find a fully ticketed crane operator and tell him that your switching all his G100 lifting rigging for G70, just don't exceed the WLL.
Any of the operators I know, and that's quite a few as I'm sure it is for JD as well, will tell me to go F### myself! I don't know about south of the 49th, but in Canada it's not legal to lift with G70. Any crane op doing so would violate and probably void their insurance and most likely would never get any again.

G100 chain has much higher WLL ratings than G70, yes I said that! G100 has different alloys than G70, making the tensile strength much higher. That makes it great for lifting, because that's what is required for the application, lifting=direct tensile forces.
We don't lift, we hold down. We don't apply direct constant tensile forces. We shock load the crap out of our rigging. When we hit bumps in the road, our chains loosen and over tighten in high frequency cycles that require elasticity strength (that's why the WLL is RATED lower, because it DOES over tighten and needs an exceed factor). Yes, you can occasionally bend G70 chain links. Ever hear the saying "it will bend, but won't break?" That's what we want, bent chains keep the load from ejecting. G100 doesn't bend, it breaks, nothing to stop the load from coming off the trailer.
I know that NACM guide says G100 is used for tie down, but there is a difference between "tie down" and what we call tie down which is why it's listed as "Transport G70", and it's because of the shock loading.
You want a good comparison, look at your wheel studs and lug nuts. High carbon steel, exceptional clamping force...obviously fantastic for the application. They make great head bolts too. Oh, but take that same high carbon steel stud and pull sideways...SNAP!!! High carbon bolts have poor shear characteristics, that's where Grade 8 bolts come into play. Tell your mechanic to use Grade 8 bolts for your head next inframe...he'll get a kick out of that.

Based on that, we CAN NOT advise using anything other that G70 for load security. The alloy recipe is the correct material for our application.
Yeah you can probably use G100 for years and never have a problem, until you do.
Yeah you can probably cut corners and not hang as many chains as required, until you need them.
I have been in a head on collision. The shock load forces are frickin incredible!
I've had coworkers break trailers, at road speed. The destruction and devastation was unbelievable!
Chains bent.
Chains broke.
The loads stayed on the trailers.
That's not anecdotal, I was there.

If your new or not sure what rigging you should buy...I agree, most DOT officers are a pain in the butt...but the engineers that researched, came up with, and wrote the rules for load security, they're engineers, and they're pretty frickin smart people.

FWIW, Paying attention to smart people has made me smarter, ymmv.

I know the IDIOT statement pissed some people off, it was supposed to. Remember, a kick in the ### is still a step forward!

 

L

Ok this is a lot to take in if I miss something let me know. First I believe all of your examples are true and honesty told, my question would be how do you know in any of those situations that grade 80 or 100 wouldn't have held? You/we don't without a side beside comparison. I do fully understand rigging and lifting principles, for the record I'm a CCO certified operator I would be more than happy to PM you a copy of my CCO license just for good faith. Our union offers a really good course put on by Crosby the leader in lifting and rigging on the principles of ductility of steel and it behavior in different environments (it's amazing how much cold affects it by the way) and I to have been made smarter by listening to others. My dad always said if you want to learn find an old guy and shut up, the same applies to people that are knowledgable in their respective fields. I come off here as a know it all sometimes and I know it but I'm a voracious consumer of information, I read magazines, Internet articles, literature you name it I'm a nerd and I'm aware of it. But I have worked around a lot of smart people and have had these conversations and have been assured that it's is safe. A grade 100 chain is required to stretch more than grade 70 and it will indeed stretch and distort before it breaks I have seen it with my own eyes. Even with shock it still has to momentarily exceed its ultimate breaking strength which will usually result in failure of what ever its hooked to before the chain itself. I said before I've yet to break a grade 8 or 10 chain and that's a true statement and to be honest I can count on one hand the number of chains I've broken on one hand. I have however yanked a couple of D-rings off. I use 15,000# rated binders, they are Lebus brand made by Crosby, the ring that connects the screw to the hook had a 1/2" cross section so it's essentially a half inch chain link and since it has a 15,000# WLL I have to assume it's a grade 10 link. Why would Crosby produce for and market this the transport industry if they think it won't be safe to use? We may have to agree to disagree on this one and leave it as friends, I have zero desire to sour a friendship even if it is just online over something we both have our minds made up about. Take care brother.

 

I don't need to see your certification JD, just reading your posts makes me aware that you are an intelligent individual that reads and pays attention. That's a big part of the mutual respect thing.
You're right, unless we did side by side tests, We don't truly know which would or would not hold up in a given set of circumstances.
I have only broke 3 G70 chains in my career. 1 in the head on collision, 1 over tightened and shock loaded. 1 manufacturing defect, you could see the bubble inside the center of the weld when it broke.
I broke a bunch when I was young, stupid, and broke, so I bought the cheapest crap I could get my hands on, but none of it was G70.
I have been to Crosby-Lebus' Longview, TX. manufacturing facility many times when I still pulled a step deck. The bizarre thing I can assure you of...because they started cutting up pieces that they took off my trailer before they finished unloading me, and put them in the furnace...is that they use an absolute #### grade of recycled steel to forge the snap binders. Never did see them make ratchets while I was there.
Crosby-Lebus, and I'm sure most others, get the strength by using the forging process. Yup, that 3/8's snap binder was a 3" diameter chunk of pig iron before it was heated to the point of transparency, then steam hammered twice, flipped into the next steam hammer, hit twice more and less than 10% of the original 3"dia chunk becomes scrap! It blew my mind the first time I saw that. After the steel comes out of the furnace, it takes 15 seconds to become a snap binder!
That facility also makes the massive hooks used for ship cranes, and I got to watch them make one once. It takes 3 days to heat the steel billet, and then 4 days to a week depending on size before the center is cool after its done!
That's why binders are as heavy as they are considering the volume of steel. They actually compress much thicker steel into that smaller package making the material more dense, thus stronger.

 

I do not see anywhere in the FMCSA regulations where it is stipulated that grade 100 should not be used for load securement. The attachment contains the various WLL limits of chain.

I'm not trying to prolong the argument, but rather attempting to find where these "pretty frickin smart people" say that Grade 100 should not be used for load securement.

 

Cause some times size matters ....

 

Looks like the tools of a serial killer.

 

The right tool for the right job ....,

 

I said before, I say it again. Yer a special kinda tool RON LOL! Have a good holiday I'm heading home before I start another job over east.

 

Enjoy the home time!

Hope we cross paths soon!

I am hanging out here in Phoenix, hoping something good comes up for next week.