"The Hoist Rings Changed Color"
Recently a customer called concerned about some lifting hooks they recently purchased had changed to an “odd color”. The customer attached the once bright pink lifting points to a crane for a lift. They started to notice that the pink color was starting to change to a beige color. Concerned, they called in to describe the odd color change. So what happened that would make the lifting points turn color?
RUD lifting points are coated in a pink power coating, which will actually change colors when it is subjected to high temperatures. The color change that occurred on the hooks that were attached to the crane indicates that the load ring was exposed temperatures where hot enough to affect the power coating, and the integrity of the steel. Metal becomes weaker and more ductile when exposed to high temperatures, thus diminishing the initial working load limit of the load ring. The operator will now need to determine if the lifting hooks that are attached to the crane can still lift the weight of the load by determining how much the WLL has been diminished.
The color change also indicated the temperature that the lifting point had been subjected to. The specially heat treated lifting hook is coated with a heat indicating powder coating that permanently shows the temperature to which the lifting point has been exposed; if the lifting point reaches temperatures of 482°F (250°C) or above, the pink powder coating permanently changes color. When the color of the chain turns from pink to brown, it indicates that the strength of the chain has diminished and the original working load limit has decreased. RUD VIP chains and lifting points can be used up to 572°F (+300°C) at a WLL of 90%. The item cannot be used above 760°F (380°C), because at this point the color will change to black with small bubbles. The color change to black indicates that the lifting point has been subjected to enough heat to compromise the integrity and strength of the metal; at this point the lifting point is unsafe to use and must be taken out of service.
The good news is that if the crane operator had used hooks that were not coated in heat indicating powder coating, the operator would not be aware that the lifting points they are using to lift with have been compromised and the working load limit has been diminished.
Please contact RUD Chain Inc. for additional information about powder coated lifting points.
sales@rudchain.com
