Piston rings and rider bands in compressors must withstand high loads and speeds between the piston and cylinder liner to prevent wear between the metal surfaces. Torlon 4540 is recommended as it has strength up to 530 degrees F, outstanding wear resistance, low friction, and dimensional stability for tight tolerances without abrasion of the mating surface. It has better properties than alternative materials like bronze, PTFE, PPS, PEEK, and Vespel due to its strength, wear resistance, temperature tolerance, and cost.

1. PISTON RING MATERIAL CHOICES
INDUSTRY: COMPRESSORS
PART FUNCTION: PISTON RINGS AND RIDER BANDS ARE UTILIZED AS
THE WEAR COMPONENTS BETWEEN A PISTON AND A
CYLINDER LINER. SINCE BOTH THE PISTON AND LINER
ARE TYPICALLY METAL, CONTACT BETWEEN THE TWO
CAN CAUSE SERIOUS PROBLEMS. THE RINGS MUST BE
STRONG ENOUGH TO HANDLE THE LOADS AND WEAR
WELL AT HIGH SPEEDS.
MATERIAL: TORLON 4540
ADVANTAGES: *STRENGTH AND RIGIDITY TO 530 DEGREES F
*OUTSTANDING WEAR RESISTANCE AT HIGH SPEEDS
AND PV RATES
*LOW COEFFICIENT OF FRICTION
*EXCELLENT DIMENSIONAL STABILITY PERMITS TIGHT
TOLERANCES
*COMPRESSION MOLDED TUBES ALLOW FOR SIZE
EFFICIENCIES
*NON ABRASIVE TO THE MATING SURFACE
*GOOD CHEMICAL RESISTANCE
MATERIAL
COMPARISON: *BRONZE -- POOR WEAR, ABRADED MATING SURFACE
*PTFE -- INSUFFICIENT STRENGTH AND STABILITY.
*PPS -- LIMITED WEAR RESISTANCE AND TOUGHNESS
*PEEK -- STABILITY AND WEAR RESISTNACE REDUCED
ABOVE 300 DEGREES F.
*VESPEL -- COSTLY