TPT July 2008

H eat & S urface T reatments

A n annealing furnace in which tube and

pipe is strengthened and hardened is the very model of a crucible, in every one of its definitions: a vessel, itself heatproof, for melting materials at high temperatures; a severe test; a place of confluence of powerful forces. It is also a remarkably flexible industrial apparatus,

adapting without difficulty to roller hearth or mesh belt designs; electric or gas-fired operation; ferrous or nonferrous applications; full anneal, clean anneal, spherodize anneal, or stress relieving heating cycles. Using this equipment, it is also possible to apply coatings and undertake galvanizing operations. A modern roller hearth continuous furnace must heat quickly and uniformly, regardless of the size of the tubing being processed or the length of the run. It must accept wall thickness from several thousandths of an inch, on up – and adjust readily to a variety of production rates. Operation will be by means of a total system for monitoring, controlling, recording, and storing such parameters as temperature, tube wall gauge, conveyor speed, loading, and atmospheric conditions, and a great deal more. The unit will feature PC/ PLC integration, and instant recall and downloading of data to a centralized computer system. All of this will be immediately responsive to fingertip control by the operator. Does this sound like over-engineering, for a furnace? No one has ever said so. It takes a tough piece of equipment to impart the heat treatment necessary if a length of tube or pipe is to stand up to the rigours of a long and trouble-free life in service, perhaps in severe conditions. What it takes, in fact, is a crucible.

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J uly 2008

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