Hearth roller structure optimization and cost control(1)

INTRODUCTION

Hearth roller is a typical centrifugal casting pipe fittings, is one of the important components in support of metallurgical equipment and transport slabs, widely used in Continuous casting- rolling production line, in the rolling processfirst, the need to heat the steel slab to 1050 ~ 1150 rolling temperature in the furnace continuously and stablyStable support of the slab through the hearth roller, to ensure a smooth and uniform delivery. Since intermediate section of  the Hearth roller mounted on the billet calcining furnace directly , the furnace temperature is about 1150 during the process of productionHearth roller usually was manufactured with ZG45Cr28Ni48W5Si2 and other high-temperature alloys. Meanwhilesince the intermediate section of the hearth roller mounted in furnace directlyThe tapered section and the bearing support section are mounted inside the calcining furnace and outside the furnace respectively. The temperature gradient of hearth rolls is very large at different partsSo hearth roller  welded  together by  the sleeve and cone and shaft generallyIn order to reduce the burning of the inner surface of the cone, the inside of the cone have insulation board to ensure the smooth delivery of high-temperature slab.

Hearth roller
Hearth roller

Requirements hearth roller shaft not deformed, external roller ring heat-resistant, wear-resistant. Research shows that the hearth roller is use of large in the metallurgical industry, high manufacturing costs, long-term high temperature overload working conditionsprone to failure damage

Several major forms of roller hearth failure:

1 Weld fracture.

2 Shaft neck fracture.

3 Connect the fracture.

Which mainly reason include: welding performance of high temperature nickel-base alloy is poor, prone to weld cracking and other defects; welds to withstand pull – push alternating stress loads, prone to fatigue fracture; weld is cold-hot junctional zone, exists of large temperature gradient cause thermal stress, thermal stress will accelerate fracture Despite attempts to improve hearth roller on material and welding workmanship , but The life of a hearth roller has not achieved significant results. So by structural optimization to improve the performance of a hearth roller and increase their use life, may improve the quality of the product, an effective way to enhance the market competitiveness has important research value. Therefore, to improve the performance of  hearth roller and improve its life by structural optimization, it may improve the quality of the product, effective way to enhance the competitiveness of products.

to be continue

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