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Hearth roll

Hearth roll is one of the most important parts of the continuous annealing furnace. Its working condition is the decisive factor if annealing furnace can be normal production.

Work and structural features of a hearth roll

Structures and materials of hearth roll

Working at over 800 ℃ in the furnace and rotation under load, meantime mechanical damage by charge, the hearth roll material must have high-temperature strength and oxidation resistance. The structure shown that the centrifugal casting roll is a hollow cylinder, two alloy roll end welded. Furthermore two end shaft welded in the roll end. The thin-walled rollers to give axial thermal resistance. The insulation materials inserted from the roll barrel to roll the end to reduce the temperature of the bearings.

Furnace hearth roll materials are ZG35Ni20Si or ZGCr25Ni35Nb, due to the high Ni alloy is expensive, domestic production of furnace hearth rollers using cheap ZG3Cr24Ni7SiNRe, this material has high-temperature strength, endurance strength higher than ZGCr25Ni20Si2, after long-term use aging embrittlement tendency is small. Due to the addition of rare earth the oxidation resistance of the steel improved.

The hearth roll body

The diameter of the furnace hearth roll if possible use of smaller size at high-temperature strength permitting to reduce the weight of the weight and save precious metal.

The furnace hearth roll commonly use spiral roller bearings or spherical bearings. The bearing temperature is high so high-temperature grease lubrication is needed. The diameter of the haft journal is usually smaller than the 0.1-0.25mm of bearing because of radial expansion.

The roller can be applied in not only metallurgy industry but other appliance.

Application:

The various rolls/rollers are of good heat, corrosion, wear resistant properties, working at high temperature environment on average: 800 to 1, 200° C, which are used in the steel mills, like continuous annealing line, continuous galvanizing line.

Process: 

Centrifugal casting for barrel/tube, forging for journal/shaft, static /investment or sand casting for cone/trunions, welding and machining and grinding.

Material:

High nickel and high chrome heat resistant alloys, cobalt base alloys, like HU, HT, HK, HP, HW, 24/24NbTiZr, 50Cr/50Ni (2.4813), 1.4865, 1.4849, 1.4848, 1.4410, 1.4059, 1.4841, 1.4845, 1.4852, 2.4879 or as per customer's requirements.

The roller can be forged in perfect quality and also manufactured by centrifugal cast. The ceramic molds centrifugal castings offer many advantages as to flexibility of diameter and length. The production is dense, sound castings and has almost the same mechanical properties as forging production. The production can be machined to different roller, hydraulic cylinder, pipe model, etc. Our production has grand application area in industry and has international standards of quality that help us assuring our customers of our credibility.

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