Chain Marking I.D.

[oldballs]

After "google" search about chain manufacturers and chain markings, I'd like to be sure what the marks on my chain mean.

I've got 50 feet of silver colored 5/16" chain that has these marking every six links........"PM" and "M3" alternating every six links.

This must be grade 43 chain made by Peerless with a WLL of 5,400 lbs...I guess. After 164 pages of their catalog, I couldn't find the key to their identification.

Just for the sake of accuracy , what is the WLL etc. of this chain?

Cheers,
Mike

 

[kevinj]

After "google" search about chain manufacturers and chain markings, I'd like to be sure what the marks on my chain mean.

I've got 50 feet of silver colored 5/16" chain that has these marking every six links........"PM" and "M3" alternating every six links.

This must be grade 43 chain made by Peerless with a WLL of 5,400 lbs...I guess. After 164 pages of their catalog, I couldn't find the key to their identification.

Cheers,
Mike

About Chain Grading

Chain strength is identified throughout our website by

Working Load Limits* (WLL) - the higher the WLL, the stronger the chain.

Chain Strength Chart
(Working Load Limit WLL Comparison Chart)

Gr 30

Proof Coil


A general purpose chain of standard commercial quality. Made from low carbon steel, this chain is frequently used for fabricating tow chains, logging chains and, when appropriate, tie down or binding chains. Hallmarked every 3 feet or less on sizes over 5/16" with manufacturer's symbol and grade marking: 3, 30 or 300. Not for overhead lifting.

More info: Order Here Specifications Here

BBB Anchor Chain


A compact (short) link chain of standard commercial quality. Made from low carbon steel, this chain is used primarily for boat windlasses when hot galvanized. Hallmarked every link with "3B". Not for overhead lifting.

More info: Order Here and Specifications

Gr 40

High Test


Strength levels are the same as Gr 43 but the dimensions of the chain links are smaller using ISO standards. Primarily used for boat windlasses, this grade has become a standard for that industry. The Grade 40 designation was exclusively used by ACCO Chain until 2005 to designate their High Test grade chain. They now use "43" in keeping with the rest of the industry. The chain is hallmarked "G4" on every link. Not for overhead lifting.

More info: Order Here and Specifications



Gr 43

High Test




This is a higher strength chain used for years in the trucking industry for tie downs that meet DOT specifications. Made from a higher carbon steel, its strength surpasses proof coil working load limits, size for size, by a factor of 2 to 1. Hallmarked every 1 to 3 feet with manufacturer's symbol and grade marking: 4, 40, 43 or 400. Not for overhead lifting.

More info: Order Bulk Here Order Assemblies Here Specifications Here

Gr 70

Transport


As its name implies Transport Chain is used primarily to tie down loads on over-the-road equipment. The yellow chromate (gold) plating makes it easily recognizable even from a distance. Made from heat-treated carbon steel it has about 25% more strength than high test chains. Hallmarked every 1 to 3 feet with manufacturer's symbol and grade marking: 7, 70 or 700. Not for overhead lifting.

More info: Order Bulk Here Order Assemblies Here Specifications Here

Gr 80

Alloy


The first chain specifically designed for safety and approved by OSHA and other agencies for overhead lifting. Its alloy, heat-treated steel makes it ideal for making lifting slings and heavy duty tow chains. Hallmarked no more than 3 feet apart with manufacturer's symbol and grade marking: 8, 80 or 800.Suitable for overhead lifting.

More info: Order Bulk Here Order Assemblies Here Order Slings Here Specifications Here

Gr 100

Alloy


This new innovation in alloy chain metallurgy provides about 25% higher working load limits over Gr 80 chain with some limitations reported in lower ambient temperatures. Hallmarked no more than 3 feet apart with manufacturer's symbol and grade marking: 10 or 100. Listed as suitable for overhead lifting.

More info: Order Here Order Slings Here Specifications Here


*WLL is sometimes called Safe Working Load (SWL)



THE MEANING OF CHAIN GRADE NUMBERS


The chain grade numbers which manufacturers use are actually one tenth of the actual grades. Therefore, our grade 80 is 800, grade 70 is 700, and so on.
Just for the sake of accuracy , what is the WLL etc. of this chain?

 

[oldballs]

So, on my chain, what does "PM" "M3" mean?.........or did I miss something in your reply....?
Thanks,
Mike

 

[kevinj]

the 3 is no doubt grade 30. Silver chain is seldom high quality.
Most gr43 is black, grade 70 yellow etc

 

[bdog]

Grade 70 5/16" chain doesn't even have a WLL of 5,400lb. On the 5/16 grade 43 is 3,900 lb and grade 30 is 1,900lb.

The 3 on the chain designates it as grade 30. Here is a chart of WLL and you can click on the about link for info on the markings.

https://www.1st-chainsupply.com/WLLchart.htm

 

[oldballs]

Thanks folks.........It never hurts to know the limits of one's tools. Today I broke the head off of a self tapping screw by using a wrench that was too big trying to force it into a hole too small. Just a minor irritant compared to knowing and abiding to the limits of a chain's WLL limit.

 

[ModMech]

I wouldn't want to be caught with anything not marked Gr7 or higher! Doing so *might* be legal, but not very safe.

 

[sdef]

I wouldn't want to be caught with anything not marked Gr7 or higher! Doing so *might* be legal, but not very safe.

+1. For tractor tie downs, all of mine are 3/8" G70 with G70 and G80 hooks. The 6600 # WLL matches the tie down d-rings on the trailer. And the ratchets are WLL 7100#. For general use, on tractor chain, I prefer 5/16" G70 but have some 3/8" G43 also. The only damage ever to any of the transport rated chain is wearing off of the gold coating due to being drug through the woods, etc., many, many times.

 

[1bush2hog]

Are the markings the same for chain from China? Is there any actual testing performed here in the US to make sure a grade 70 Chinese mfg chain meets standards? I purchased some chain from etrailer and didn't think about the CoO and they didn't divulge this either, so I'm a little concerned about using it to tie my machines down.

 

[sdef]

Are the markings the same for chain from China? Is there any actual testing performed here in the US to make sure a grade 70 Chinese mfg chain meets standards? I purchased some chain from etrailer and didn't think about the CoO and they didn't divulge this either, so I'm a little concerned about using it to tie my machines down.

All of my offshore manufactured chains are marked the same as the typical U.S. standards. I assume they are not tested here as testing standards for most normal things are left up to the manufacturers. I feel similar to you. But with my previous years of experience with HFT chains, I feel pretty confident that real use testing in my hands have proven them to be strong enough. The G70 3/8" chains I have are untested at this point and came from eBay. Same with the 7100# WL ratchets.

 

[LD1]

I wouldn't want to be caught with anything not marked Gr7 or higher! Doing so *might* be legal, but not very safe.

WHY?

What is unsafe about using Gr43 or even lesser grade chain if you stay within the WLL?

Exceeding the WLL of Gr70 or higher is JUST as unsafe as exceeding it with a lower grade.

How is using 3/8" Gr43 (which you say is unsafe) compared to using 5/16" Gr70?

 

[sdef]

WHY?

What is unsafe about using Gr43 or even lesser grade chain if you stay within the WLL?

Exceeding the WLL of Gr70 or higher is JUST as unsafe as exceeding it with a lower grade.

How is using 3/8" Gr43 (which you say is unsafe) compared to using 5/16" Gr70?

Point taken and I agree with you in principle for brand new chain, rope, tie-downs, ladders, whatever. And this blanket statement is too broad and should have been more specific. When I added my +1, I was thinking of my situation and should have been more specific also. In general, as long as the WLL is maintained and the device manufactured properly, all should be well.

However, in use, tie down equipment of any type do get marginally damaged with nicks and abrasions which will decrease the WLL an unknown amount. I keep a few 5/16" G70 chains on my tractor and a 3/8" G43 chain and use them periodically. Since I use my tractor to its maximum capabilities often, sometimes things gets damaged in some minor manner, including the chains. Now, I am not saying these 5/16" G70 chains are EVER going to be broken by my tractor. However, I would not consider using them to tie down my 7400# tractor load with two chains on each end. Same thing if they were 3/8" G70, as I have no way to quantify what minimally apparent "wear" from being drug across countless large, sharp rocks has done to the WLL.

Real example using different medium: Early this summer while finishing clearing major trees from my property for a new home to be built, I had a 12k# winch attached to the tractor's 3PH and the wife was using the remote. I was at the base of the ~75', large diameter oak tree that was heavy 120 degrees to the right of where it needed to go. Left on its own path, it would have fallen 1/2 way down and stopped at an angle- supported by the rest of the forest. This was the last thing I wanted to happen, as to say this would be dangerous would be an understatement. Very long story short, the tree ended up exactly where I did not want it and the high dollar synthetic rope on the winch had been smashed in several spots between layers on the winches drum. I have no idea what the smashing of the ropes fibers at several points have done to the WLL, but my guess is it decreased it significantly and needs to be replaced. I had no idea this could even happen, but appearances are the rope's fibers are compressed so tightly together they appear to have been manufactured that way.

I am very **** retentive. And where most things are concerned, I up size one level rather than what would be the minimum requirement due to any factor out of my control, including offshore manufacturing. I do not care if it is a chain or a fire extinguisher. But there has to be a limit and I have chosen to stop with two each, 3/8" G70 chains on each end of my maximum 7400# tractor load when tying it down. Lose one chain on either end due to whatever unseen forces and I am exceeding the WLL of the chain still holding the load. Most times the WLL of a single chain will cover the WLL of the tractor at its loaded weight. And this still leaves the rest of the chains actually breaking strength, which is several times the WLL.

 

[LD1]

Dont matter if its grade 43 or grade 70, damage is damage. And I wouldnt say one is easier to damage than the other.

Benefit of using grade 70 is the ability to use a lighter chain to reach whatever WLL you need. But at a greater cost.

Grade 43 is just as safe. Even grade 30 is safe when used within WLL. I personally like grade 70 3/8" as well for tying down my equipment and for skidding logs. My tractor with attachments is ~5500#. I have broke too many 5/16 chains to feel confident doing hard skidding with them. So I needed to upsize. No weight difference between 3/8 gr43 or 3/8 gr 70, so I spent the little extra money and got gr70. Glad I did cause with the backhoe now, I have on ocassion broke some of those. gr43 would be worse. So I am carefull how I use them, and try to double up until I get some 1/2" chains for it.

 

[ModMech]

WLL is not static in an accident, when you factor in inertia, enough chain for the "load" is way too little for the inertia of an accident.

 

[DuckSlayer1017]

+1. Check out this link to see some of the possible G's in an accident. Car Crash Example The no seat belt example closely applies to a tractor tied on a trailer with chains. I'm too tired right now to redo the math with weight of a tractor but assume chains stretch very little so we can approximate the impact as the tractor hitting an solid object (chain). In their example a 160 lb man sees 150G or 12 tons with a 30 mph crash. A 5k tractor would be see a lot more force. To tie a tractor down to withstand crashes and not have anything fail would require a tremendous amount of WLL. Now I'm sure the physics in this example are very simple compared to what actually happens in real life but it does put things into perspective. I'm not saying that we need to use 2" chain to tie tractors down, obviously DOT has done the appropriate testing and research to develop their standards. I just wanted to elaborate on what ModMech was getting at.

 

[sdef]

+1. Check out this link to see some of the possible G's in an accident. Car Crash Example The no seat belt example closely applies to a tractor tied on a trailer with chains. I'm too tired right now to redo the math with weight of a tractor but assume chains stretch very little so we can approximate the impact as the tractor hitting an solid object (chain). In their example a 160 lb man sees 150G or 12 tons with a 30 mph crash. A 5k tractor would be see a lot more force. To tie a tractor down to withstand crashes and not have anything fail would require a tremendous amount of WLL. Now I'm sure the physics in this example are very simple compared to what actually happens in real life but it does put things into perspective. I'm not saying that we need to use 2" chain to tie tractors down, obviously DOT has done the appropriate testing and research to develop their standards. I just wanted to elaborate on what ModMech was getting at.

Agreed Such is with most things mechanical or electrical and the reason for standards and common sense. Stay within the ratings and operate as designed. Most folks can't cover all possibilities.