Effect of cooling rate on the as-quenched microstructure and mechanical properties of HSLA-100 steel plates

Abstract

The effect of cooling rate on the as-quenched microstructure and mechanical properties of a 14-mm-thick HSLA-100 steel using various cooling media such as brine, water, oil, air, and furnace has been studied. While quenching in brine, water, and oil resulted in lath martensite structures, the granular bainite and martensite-austenite (M-A) constituents were found in air-or furnace-cooled specimens. The average lath spacing increased slightly on decreasing the cooling rate (300 nm in brine-quenched specimen to 400 nm in oil-quenched specimen). The precipitates of Cu and Nb(C, N) were observed in all the quenching conditions except in the brine-quenched specimen. The as-quenched strength and toughness of the brine-, water-, and oil-quenched specimens were higher (yield strength: 894 to 997 MPa, ultimate tensile strength: 1119 to 1153 MPa, and Charpy V-notch energies: 65 to 70 J at Ϫ85 °C) than those of air-and furnace-cooled specimens (yield strength: 640 to 670 MPa, ultimate tensile strength: 944 to 1001 MPa, and Charpy V-notch energies: 10 to 20 J at Ϫ85 °C). For industrial production of HSLA-100 steel plates, oil or water quenching is recommended in lower thickness plates (Ͻ25 mm). For production of thicker plates, however, water quenching is more suitable.

Effect of Solidification Cooling Rate on Mechanical Properties and Microstructure of Al-Si-Mn-Mg Alloy

“…The cooling rate with water quenching was at 9000 K/min. The results support a previous study where cooling rates of water quenching and air cooling were >1 K/s (>60 K/min) and >130 K/s (>7800 K/min), respectively 13) .…”

Influence of cooling rate on the precipitation behavior in Ti–Nb–Mo microalloyed steels during continuous cooling and relationship to strength

“…Continuous cooling of pancake-shaped austenite from finish rolling temperature at different cooling rates results in various types of microstructures with different strengths and hardnesses. The effects of cooling rates on structure and properties of HSLA steels have also been studied by the previous researchers [13][14][15]. However, in most of the cases the steels were processed in rolling route, either in continuous cooling process or in rolled-quenched conditions.…”

Formation of Microphases and Constituents from Remaining Austenite Decomposition in API X80 Steel Under Different Processing Conditions

“…All this promotes the carbon enrichment of the remaining austenite during dual phase finishing rolling and significantly influences the final microstructure of as-received material. The cooling rate affects the product from the remaining austenite transformation and its volumetric fraction [7][8][9][10][11] . However, the stability of austenite phase stems from significant differences in grain volume and carbon content from grain to grain 12 .…”