For any bar, Olympic or powerlifting the material must be very strong but also ductile. High ductility is the crucial component that ensures a bar will maintain its straightness during repeated heavy lifting, and it should not be brittle which can lead to sudden failure or breaking. Many high-strength steels though strong are not suitable for lifting bars based on their lack of ductility. When you hear the term “tensile strength” this refers to the limit of force per square inch a bar can endure before breaking. “Yield strength” refers to the force a bar can endure before permanently bending or deviating from its original straightness. Whether using alloy or stainless steel these guidelines must be strictly followed.Understanding Tensile and Yield Strength
With any material, whether high strength or not, tensile and yield strengths fluctuate from manufacturing. Steel mills have targets of minimum tensile and yield strengths that must be met each time a heat or run is produced, meaning that the material must never fall below the stated numbers, but can and will be above after production. Any bar that is above 180,000 PSI tensile strength begins to loose elasticity and becomes very stiff. Olympic lifters prefer a bar with good elasticity (whip) during lifting, whereas a powerlifter prefers a much stiffer bar. Many companies quote strengths above 200,000 PSI tensile which is very stiff and therefore not desirable for Olympic lifts.Sleeves and Material
The ultimate finish is a sleeve with a heavy hard chrome overlay. With this you get a very hard outer shell for protection as bumper plate hubs can range in hardness and easily damage the sleeves from constant dropping. Decorative chrome is the least desirable choice again because of the danger from cracking and peeling.
Zinc: a plating process