SOLVING HIGH-TEMP GUIDE ROLL BEARING FAILURES

These assemblies are designed to keep hot metal bars centred on the conveyor line. When bars glance off the guide rolls, the rolls need to rotate freely, and that's where the problem began.

Originally, the mill used greaselubricated roller bearings, but with operating temperatures ranging from 170–180°C, the grease was consistently baking out, leading to seized bearings and frequent maintenance interruptions. In certain applications, minimal grease use was required, which only worsened the issue.

The mill's plant engineer consulted with Graphite Metallizing Corporation's engineering team to explore a more durable, high-temperature solution. Together, they selected a GRAPHALLOY bronze grade bushing, housed in stainless steel. Unlike conventional bearings, GRAPHALLOY bushings are self-lubricating and perform reliably in extreme temperatures, up to 400°C, with no need for grease.

Four of these bushings were installed in the guide roll assembly and after six months in service, the plant manager reported that the Graphalloy bushings were performing very well."

Based on this success, the team has decided to replace all roller bearings in these assemblies with GRAPHALLOY components. The upgrade has already reduced maintenance time and costs, and promises even greater savings moving forward.

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This article appeared in Renew magazine. To read more or request your personal digital or print edition of Renew, click here.