Friction and wear of a polyurethane elastomer used in dewatering for bi-directional pipeline inspection gages

Abstract

As a drying method for new construction pipeline, basic bi-directional pipeline inspection gages are employed to dewater the pipeline. Their sealing discs, made of cast grade polyether-based urethanes, are worn out quickly due to the rubbing against steel surfaces under water-lubricated condition. The severe wear out in the polyurethane sealing disc would cause a sealing leakage in dewatering operation. In this research, the frictional behavior and wear mechanisms of the polyurethane sealing disc are investigated. Experimental study was carried out on polyurethane samples against rough steel pipe materials in the water-lubricated condition using a pin-on-disc tribometer. The morphologies and wear modes were studied using an optical microscope. Results showed the completing mechanisms of abrasion, oxidation, and surface fatigue. The inter-correlation between these modes and test conditions are discussed here. The understanding obtained in this research can be used to prolong the working life of the sealing discs.