One major concern of a steel plant owner is the product quality of bars from hot rolling mills. The quality of the stock is measured mainly by means of its shape, roughness and dimensional tolerances, all of them depending strongly on the shape profile and surface quality of the work roll. The productivity of the rolling mill is directly related to the length of campaigns which can be derived from these rolls, the essential aim being to maintain over time the surface roughness and shape profile as close as possible to the initial ones. Moreover, saving costs with minimum roll grinding is also important, since rolls are responsible for 5 to 15% of overall production costs.
In most cases, work rolls for the finishing stands of hot rolling mills are cast composite components made of an outer shell of wear-resistant material and a core of ductile iron or steel. Regarding the work rolls for the early finishing stands, the development of materials for the outer shell has enjoyed rapid advances beginning in the early 1980s, culminating in the application of cast alloy of the Fe-C-CR-W-Mo-V system, which gradually replaces high chromium cast iron and Ni-hard cast iron with better performance.
The idea of using these alloys for manufacturing work rolls for Rolling mills resulted from an insight into the requirements involved in this type of application, fundamentally, the capacity to retain a high level of hardness even when submitted to high temperatures, and wear resistance. Both are fulfilled by the classical high speed steels for tools, leading the alloy design of the high speed steel rolls (HSS Rolls) to be based on the composition of the M2 steel. Thus, although the roll makers have developed alloys specifically designed to the operational conditions of each hot-strip mill plant, their chemical compositions often fall into the following range: 1.5-2.5%C; up to 6% W; up to 6% Mo; 3-8% Cr and 4-10% V.
CASE HSS Rolls are specifically designed and manufactured for bar mills, structure mills, and strip mills. High Speed Steel (HSS) Rolls are known worldwide for their extended roll life, quality of end product, efficient and effective roll pass. Because of this, the roll cost per tonne is much less and mill downtown on account of pass/roll change is drastically reduced which further enhances production and makes the best use of applied resources. Many rolling mills are now understanding this and slowly and steadily shifting to HSS Rolls.
About CASE Group:
CASE is a 30 years old engineering company with a well-established set up in India. CASE deals in FRP Rectangular Cooling Towers, FRP Multicell Cooling Towers, FRP Intelligent Cooling Towers which came in variable color options, Hot Gas Coal Gasifier, Pyrolysis Clean Gas Coal Gasifiers, Circulating Fluidized Bed Coal Gasifiers, Pulse jet Air Pollution Control Equipment Bag House, Scale-Ban (Non Chemical Online Scale Preventor), HSS Rolls (High Speed Steel Rolls), Block Mills and Coal Briquetting machines etc. and many more.