Effect of intermediate heat treatment on the properties of profiles used in the manufacture of slotted screens

Slotted screens are a group of products with demanding service requirements, in which durability, geometric accuracy, and the stability of performance characteristics depend largely on the quality of the working and support profiles. During manufacturing, profile rolling leads to strain hardening and microstructural changes that may impede further forming and affect the final properties of the product. This study investigates the effect of intermediate heat treatment carried out in a plasma furnace on the mechanical properties, microhardness, and microstructure of the 42Sbb working profile made of 1.4482 duplex steel and the Q55 support profile made of 1.4016 ferritic steel, both intended for the manufacture of slotted screens. The investigations were performed for three heat treatment temperature variants applied between profile rolling and sizing rolling. The process was evaluated using static tensile testing, microhardness measurements, optical and scanning electron microscopy, and X-ray diffraction residual-stress measurements. The results enabled the most favorable heat-treatment conditions within the investigated parameter range to be identified with respect to the material condition prior to sizing rolling and resistance welding.