Microstructure, mechanical properties, and corrosion resistance of supermartensitic steel UNS S41426: comparison between forged and hot-rolled seamless pipe

Supermartensitic stainless steels are a sub-family of stainless steels designed to meet the demands of harsh environments and high mechanical stresses. The performance of these materials comes from balanced chemical composition and correct thermal treatment of quenching and tempering. These stainless steels have a severe reduction in C content, Ni, and Mo additions, besides microadditions of Ti, Nb, V, and/or N. The oil and gas industries used the supermartensitic stainless to mandrels for gas and chemical product injection. These mandrels are manufactured using forged parts and seamless pipes joined by welding. Due to recent failures in this equipment, an investigation of the performance and properties of those materials is necessary. This work investigated the different manufacturing processes used in UNS S41426, a supermartensitic stainless steel with Ti and V microadditions. The microstructural characteristics, mechanical properties, and corrosion resistance of seamless tubes and forged parts were analyzed and compared.