Lifting chain is designed to elongate before fracturing as much as which percentage range?

• A. 5% to 10%
• B. 25% to 35%
• C. 15% to 30%
• D. 30% to 50%

Answer: (C)

Ductility is the capability of a material to deform under load before it breaks, and lifting chains are designed to show a measurable amount of elongation as they approach failure. This elongation provides a warning that the chain has been overloaded and helps prevent sudden, unexpected breaks. For lifting chains, the typical elongation before fracture falls in the mid-range, about 15% to 30%. That range balances having enough stretch to indicate overload while not being so ductile that a moderate overload causes excessive permanent deformation or loss of strength. The other ranges are either too small to give a clear warning (5%–10%) or too large, suggesting unusually high ductility (30%–50% and beyond).