Grade 70 Steel Chains and Chain Tensioner
Tie down chains and chain binders are tough tie down devices , both chains and binders are made of carbon steel, compare to tie down straps, the chains and binders have higher working load limit , let’s look at 5/16” transport chain(WLL 4700lbs) vs. WLL 3333lbs 2” ratchet tie down straps , 6600lbs 3/8” transport chains vs. 5400lbs 4” tie down straps , you will see that compare to tie down straps, binder chains are much stronger, and chain binders are even stronger than same size chains, for instance, 5/16”-3/8” binder has WLL 5400lbs which is stronger than 4700lbs WLL of 5/16” grade 70 chain . If we examine the design factor of chains and tie down straps, we will see that chains and binders have 4:1 design factor while tie down straps have design factor 3:1, that’s another reason we consider chains and binders are heavy duty tie downs .
The National Association of Chain Manufacturer recommends that the steel which can be used to make grade 70 binder chains must have less than 0.35% Carbon, 0.040% Phosphorous and 0.050% Sulfur. As long as the choice made by chain manufacturers meets the recommended criteria and the final products meet or exceeds DOT requirements(or CHP, California Highway Patrol, or some other mandated requirements), we can use these products for transportation purpose and don’t have to worry about inspections.
These chains and binders are mostly used to haul big, heavy equipment, such as backhoe, bulldozer, these things are hard on straps, only carbon steel chains can sustain that kind of abuse , when we talk about backhoe, forklift, we need at least 3/8” grade 70 chains and binders to secure them, for something which has less weight we consider 5/16” chains are good fit, of course we still have 1/2” and up chains and binders, these chains will most likely be used to tie down something out of ordinary, such as battle tanks, or some other applications require super heavy duty chains.
As we stated above, transport chains, or say binder chains are used on a lot things except for overhead lifting. There are people who use these chains to tear trees, to tow mobile loading docks, a lot of forestry services use large quantity of these grade 70 chains.