Resumo APPLICATION OF HIGH STRENGTH NIOBIUM MICROALLOYED STEELS IN THE CONTAINERS OF GRAIN TRASPORT TRUCKS AbstractTo reduce weight and increase payload, CBMM applied high strength niobium microalloyed steels in the containers of grain transport trucks in the Triângulo Mineiro and Alto Paranaíba regions of the state of Minas Gerais, Brazil. The new design reduced container weight by 10% and increased volume from 27 m 3 to 29 m 3 . Return on investment was achieved in only eight days for rice transportation. Gains were also made in corn and soybean transport, attaining return on investment in 21 and 56 days, respectively. The paper describes the steels used and the key design modifications in the containers.

ResumoA CBMM aplicou aços micro ligados ao nióbio em dois tipos de caçambas de carregadeiras de rodas que operam na usina de Araxá, Brasil. O objetivo foi avaliar os benefícios destes aços relacionados com redução dos custos, aumento da produtividade e vida útil dos componentes. Uma das máquinas analisadas coleta peças quentes de ferro nióbio para carregamento dos silos do britador. O uso de um aço ferramenta de alta resistência e resistente ao desgaste solucionou os problemas de deformação, desgaste e rachaduras durante o serviço, aumentando a vida útil da caçamba em cerca de 190%. A outra máquina avaliada foi uma carregadeira de rodas que opera na mina de minério de nióbio. O novo desenho com aços de alta resistência mecânica e resistente ao desgaste reduziu o peso em 14%, correspondendo ao incremento na capacidade de carga. A carga extra possibilitou um aumento na produtividade dos caminhões de 42 toneladas. Com os novos materiais, as trincas anteriormente encontradas na caçamba da pá carregadeira foram eliminadas, enquanto foi mantida a resistência ao desgaste antes oferecida pelo aço revestido com carbeto de cromo reduzindo também os custos de investimento em 7%. Palavras-chave: Carregadeiras de rodas; Caçambas; Aço; Resistência ao desgaste; Nióbio. REDUCING COST AND INCREASING LIFE CYCLE IN LOADER BUCKETS USING HIGH STRENGTH STEEL AND WEAR RESISTANT STEEL MICROALLOYED NIOBIUM AbstractCBMM applied niobium microalloyed steels in two types of buckets of wheel loaders operating at its facility in Araxá, Brazil. The objective was to evaluate the benefits of these steels related to cost reduction, productivity and component life cycle. One of the analyzed machines collects hot pieces of ferroniobium after ingot stripping and loads them into crusher silos. The use of wear resistant steel and tool steel solved the problems of deformation, wear and cracks during service, increasing bucket life by about 190%. The other evaluated machine was a wheel loader operating at the niobium ore mine. The new design with wear resistant and high strength steels reduced bucket weight by 14%, with a corresponding increase in load capacity. The extra capacity made loading the 42-tonne mine trucks more productive. With the new materials, the cracks that previously occurred in the buckets wheel loaders were eliminated, while the same wear resistance of the original chromium carbide clad steel was retained. Furthermore, investment costs were reduced by 7%.