Two high-strength low-alloy (HSLA) families, acicular-ferrite steels and pearlite-reduced steels, contain microalloying additions of vanadium and niobium. Vanadium, niobium, and titanium combine preferentially with carbon and/or nitrogen to form a fine dispersion of precipitated particles in the steel matrix. This article summarizes the metallurgical effects of vanadium, niobium, molybdenum, and titanium. The metallurgical fundamentals were first applied to forgings in the early 1970s. The ultimate strength of first- and second-generation microalloy steels is adequate for many engineering applications, but these steels do not achieve the toughness of conventional quenched and tempered alloys under normal hot-forging conditions. Third-generation microalloy steels differ from their predecessors in that they are direct quenched from the forging temperature to produce microstructures of lath martensite with uniformly distributed temper carbides. Without subsequent heat treatment, these materials achieve properties, including toughness, similar to those of standard quenched and tempered steels.
Peter H. Wright, High-Strength Low-Alloy Steel Forgings, Properties and Selection: Irons, Steels, and High-Performance Alloys, Vol 1, ASM Handbook, By ASM Handbook Committee, ASM International, 1990, p 358–362, https://doi.org/10.31399/asm.hb.v01.a0001022
Download citation file:
FALL / WINTER 2020 CATALOG
View the new, upcoming, and best-selling resources in ASM Handbooks, technical books, and databases in the Fall / Winter 2020 Catalog.