Low carbon manganese steels microalloyed with vanadium and nitrogen

Abstract

With the objective of studying the effect of vanadium and nitrogen microalloying on microstructure and strength of low carbon steels with different manganese contents, three series of low carbon steels (0.1% C) with manganese content (between 0.8 and 3.5%), vanadium content (up to 0.17%) and nitrogen content (up to 0.025%) have been designed and investigated in the hot forging condition using a preheating and finish forging temperatures of 1200 and 950°C, respectively. Steels with a manganese content up to 2.3% revealed ferrite‐pearlite structures, whereas higher manganese contents from 2.7 to 3.5% resulted in the formation of bainitic structures. A pronounced effect of manganese on the mechanical properties of steels was detected at lower manganese contents < 1.5%, due to solid solution and grain refining effects, and higher manganese contents > 2.3, due to bainite formation. Manganese content in the range of 1.5‐2.3% had less pronounced effect due to solely solid solution hardening. Vanadium microalloying effectively increased the strength of steels through solely precipitation strengthening or both precipitation strengthening and grain refining effect. The effectiveness of vanadium was greatly enhanced by increasing the nitrogen content. The grain refinement of vanadium‐nitrogen microalloying seems to be due to inhibition of austenite grain growth as a result of precipitation of vanadium nitride in austenite during forging. Precipitation strengthening of these steels is achieved by precipitation of vanadium carbide and nitride in ferrite or bainite. Nitrogen enhanced the precipitation strengthening of vanadium microalloyed steels which could be attributed to the finer vanadium nitride dispersion precipitates compared with vanadium carbide. Up to 70% of the total nitrogen content of steel precipitates as vanadium nitride which could be achieved with V/N ratio of about 6‐7. Microalloying of low carbon‐manganese steels (0.1% C and 1.8% Mn) with 0.15% vanadium and 0.025% nitrogen was found to be effective in attaining high levels of yield and ultimate tensile strengths of 835 and 940 N/mm2, respectively in the forging condition.

Vanadium: A U.S. Perspective on an Understudied Metal

“…The forms of use of vanadium are quite diverse and cross several industrial sectors. The uses of most significant magnitude are iron alloys, which, for vanadium-related purposes, can be divided into four groups. Carbon steel: the traditional iron alloy is customarily strengthened by the addition of ∼0.01% V High-strength low-alloy (HSLA) steels: , typically containing ∼0.05% V …”

“…• Carbon steel: the traditional iron alloy is customarily strengthened by the addition of ∼0.01% V. 25 • High-strength low-alloy (HSLA) steels: 4,26 typically containing ∼0.05% V. 27 • Alloy steel: a diverse group that incorporates small amounts of several alloying elements together with enhanced processing to achieve high tensile strength and substantial elongation. 28−31 Vanadium is typically included at ∼ 0.01% or less (alloy steels are also termed special steels or full-alloy steels).…”

Recent Trends in Producing Ultrafine Grained Steels

“…Steel Technology Department, CMRDI staff makes a great effort for studying the strengthening of steel through different methods such as microalloying [241]- [248], strengthening by solid solution elements [249] [250] for example N, C and Mn, interrupted accelerated cooling [251], cold drawing [252] [253], well design rolling schedule [254], reheating and finishing temperature [255] [256], and heat treatment [257].…”

Production and Properties of FeCuSnNi Sinter as a Matrix of a Metal-Diamond Composite

“…The obtained results indicate that the produced sinters are characterized by a sufficiently high hardness and appropriate mechanical parameters. The matrix material had mechanical properties that would allow to replace cobalt-based sinters [18][19][20][21][22][23][24].…”