Understanding abrasion-corrosion to improve concrete mixer drum performance: A laboratory and field approach

Abstract

Two of Brazil's most important economic activities are mining and agribusiness, representing 17.3% of its GDP in 2017. It is crucial to note that water is vital for these prominent sectors and is the principal corrosive agent for carbon steel. The problems concerning wear resistance are closely linked to performance and, therefore, economic issues. Thus, increasingly efficient materials are being used, which are wear-resistant; however, in most cases, corrosion resistance and, more importantly, the combined effect of wear and corrosion are neglected, which accelerate equipment failure. This study specifically focussed on one sector that beneficiates mineral: the concrete industry; laboratory and field tests were performed that compared abrasion-corrosion of A36 common carbon steels, advanced high-strength steels (AHSSs), and ASTM 410 ferritic stainless steels. Initially, a piece of laboratory equipment, which approached actual service conditions, was built by adapting a manual concrete mixer. In the field, samples were placed in sand processing equipment and inside a concrete mixer drum in a truck. In the laboratory, rubber wheel and free-ball microabrasion tests were performed. Both the field and laboratory samples were collected and extensively analysed using SEM and hardness tests. Finally, a complete stainless-steel concrete mixer drum was built, adapted to a truck, and field-tested for five years (beginning in 2015). The useful life of the equipment increased up to three times compared to that made with A36 carbon steel, which is standard in this application. The ferritic stainless steel had better wear performance that AHSSs in a watery concrete environment, despite its lower hardness. In 2020, several companies began using ferritic stainless steel for the maintenance of concrete mixing drums. Manufacturers have also used it as an alternative when a longer service life, reduced downtime for repair, and weight reduction are required.