Study of Contact Strength of Working Rolls in Continuous Rolling of Wide Hot-Rolled Steel Strips

The ability of working rolls of rolling mills to withstand loads and wear during operation in quarto stands is affected by contact stresses in the deformation zone and at the contact surface of the working and support rolls. However, there is no assessment of the combined effect of contact stresses on the durability of working rolls in hot strip rolling, taking into account the number of cycles and loading frequency in the stands of a continuous mill. The analysis of actual rolling modes of hot-rolled strips is performed, the values of the parameters of the cyclic load of the working rolls in the inter-roll contact are determined, the contact strength of the working rolls during a rolling campaign in an operating continuous industrial hot rolling mill is investigated. It is shown that a low loading frequency in the inter-roll contact of heat-resistant rolls in the first stands of the finishing group allows for the implementation of the greatest partial reductions, ensuring a decrease in contact stresses in the last stands of the finishing group to 5% with an increase in their operational resistance to abrasive action both in the inter-roll contact and in the deformation zone. Based on the research results, recommendations are proposed to increase the durability of working rolls when rolling thin low-alloy products.