Moly nuts eliminate galling in steel tubing systems

A new line of stainless steel compression fitting nuts from the Instrumentation Products Division of Parker Hannifin Corporation may virtually eliminate the problems of inconsistent remakes or product galling during the assembly of stainless steel tubing systems.

The inside of each new Moly Inside!™ Nut features a bonded coating of molybdenum disulfide that serves as a barrier between the threads of both the nut and the fitting body in a stainless steel tubing system to help prevent galling, said M. Pikul, Manager of Marketing for Parker IPD.

"Galling can occur when the combined forces of high torque and friction break down the protective oxide on the stainless steel threads of the compression fitting nut and body into microscopic fragments, causing the threads of the entire fitting assembly to lock together almost as if the parts had been welded," Pikul noted.

The 'moly' coating also functions as a lubricant, which means the fitting can be installed with less torque in most applications, compared to fittings without this feature. "This makes the installation process simple and quick, resulting in a beneficial effect on maintenance costs," said Pikul.

"Also," said Pikul, "with this new nut, assembly remakes can be consistent and easy over the life of the fitting. This can minimize the troublesome and costly problems that engineers and maintenance supervisors face when fitting assemblies have been remade many times, resulting in leaks or other problems," said Pikul.

"More remakes per fitting can mean fewer fittings have to be purchased," Pikul observed.

The Moly Inside!™ Nuts can be used on either the A-LOK® or CPI™ brands of Parker compression fittings. The standard nut on A-LOK® fittings are silver plated , stainless steel. The standard nut on CPI™ fittings are coated overall with 'moly', while the Moly Inside!™ Nut has a 'moly' coating only on the inside. "All three nuts are highly engineered, manufactured according to high standards, and offer outstanding value to our customer," Pikul noted. "People simply have to decide which product benefits they prefer when specifying the nuts, either as replacement items or as a part of an entire fitting assembly."