Determinação dos custos médios e marginais de bobinas a frio

Abstract

In this study was created a supporting tool for analyzing transformation and marginal cold mill product costs resulting from two steelmaking plants. Fixed costs , variable costs, labour costs, raw material consumption and by-products generation of the Cold Strip Mill Line were available in internal reports from these steelmaking plants. The model was built using Excel© and it was analyzed two scenarios: the first one considering hot strip cost using internal plate; the second one considering hot strip cost using third parts plates. In both cases were used the following hot strip production levels: from 50 until 170 kt corresponding to Steelmaking Plant 1 and from 150 until 300 kt corresponding to Steelmaking Plant 2 with 10 kt jumps in both cases. At Steelmaking Plant 1, the results of medium and marginal costs calculated using the model with internal or external plates were so close. In addition there werent any marginal fixed costs for any production jumps tested in both scenarios. For 70, 100, 120, 140, 160 and 170 kt production levels there were an increase on labour costs showing the necessity to change the equipments modus operandi. At Steelmaking Plant 2, the results of medium and marginal costs calculated using internal plates were lower than using external plates. There were an increase at marginal fixed costs when the production levels were 200, 230 and 250 kt in both scenarios in order to satisfy the capacity needs. In both cases only at 160 kt level wasnt observed a labour marginal cost increase. The resources optimization like raw materials, equipment and labour could reduce medium and marginal costs of the final product. The supporting tool is been used to compare real costs with the model costs to minimize the final production expenses. Also the model provide more accurate analysis to support the strategic decisions of the company.