Figure 6-22. - Stress on slings at various vertical angles.
Table 6-1. - Safe Working Load of Chains and stopped.
The impact load is several times the weight of the load.
When hoisting heavy metal objects using chain for slings, you should insert padding around the sharp comers of the load to protect the chain links from being cut.
Store chains in a clean, dry place where they will not be exposed to the weather. Before storage, apply a light coat of lubricant to prevent rust.
Do NOT perform makeshift repairs, such as fastening links of a chain together with bolts or wire. When links become worn or damaged, cut them out of the chain, then fasten the two nearby links together with a connecting link. After the connecting link is closed, welding makes it as strong as the other links. For cutting small-sized chain links, use bolt cutters. To cut large-sized links, use a hacksaw.
Inspect the chain to ensure it is maintained in a safe, operating condition. A chain used continuously for heavy loading should be inspected frequently. Chain is less reliable than manila or wire rope slings because the links may crystallize and snap without warning.
Examine the chain closely link by link and look for stretch, wear, distortion, cracks, nicks, and gouges. Wear is usually found at the ends of the links where joining links rub together. If you find wear, lift each link and measure its cross section.
NOTE: Remove chains from service when any link shows wear more than 25 percent of the thickness of the metal.Continue Reading