Effects of heat treatment on the mechanical properties and microstructures of four different heats of a precipitation hardening HSLA steel

Hicho, G E; Brady, Clare; Smith, L. C.; Fields, Richard J.

doi:10.1007/bf02831616

Cited by 14 publications

(13 citation statements)

References 2 publications

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“…This fact indicates that both precipitating phases, the Cu-rich ε and Nb carbonitride, are precipitating at the same temperature range. This fact was previously reported in the literature [17].…”

Section: Resultssupporting

confidence: 75%

Austenite transformation and age hardening of HSLA-80 and ULCB steels

Gorni¹,

Mei

2004

Journal of Materials Processing Technology

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Alternative materials to HY-80, quenched and tempered structural alloy steel, like the microalloyed steels HSLA-80 and ULCB, allow the suppression of the quenching and tempering heat treatment and offer better weldability due to their extra-low C content. In the HSLA-80 steel copper precipitation is one of the main hardening mechanisms available, while in the ULCB steel the contribution of the bainitic transformation plus solid solution hardening is vital. The aim of this work was to determine the continuous cooling austenite transformation (CCT) diagrams of both steels and its performance during age hardening. It was verified that both alloys developed a bainitic microstructure with low C content, commonly designed by the literature as "granular" bainite. The hardenability of the ULCB steel was greater than the HSLA-80 due to the presence of Nb, B and Mo in the first alloy. The age hardening behavior of these alloys was slightly different between each other. The HSLA-80 steel developed maximum hardness during a 600 • C age hardening, while for the ULCB steel this occurred at a 500 or 600 • C age hardening and took less time. Both steels showed a significant hardness decrease during the 700 • C age hardening, that was probably due to overaging and tempering effects.

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Section: Resultssupporting

confidence: 75%

Austenite transformation and age hardening of HSLA-80 and ULCB steels

Gorni¹,

Mei

2004

Journal of Materials Processing Technology

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“…Studies of other Cu-precipitation-hardening tempering at 350 ЊC. This small dip in UTS and hardness steels, HSLA-80 and ASTM A 710 steel, by Wilson et al [3] at this early stage is commonly observed during the temperand Hicho et al, [8,9] respectively, have also indicated similar ing of quenched steel. Because of this particular trend of decreases in strength properties in this temperature range; lowering of UTS and hardness at the early stage, the heat this is attributed to the recovery of the lath matrix structure treatment of this steel after quenching can probably be better and the coarsening of the copper precipitates.…”

Section: Steel Tempered At 650 њCmentioning

confidence: 81%

“…In stage III, there was superimposed plots shown in Figure 11(e). Hicho et al [8] also found a continuous improvement of the RA percent in significant role in influencing the tempering behavior of the steel. The Nb(C, N) particles, which have been inherited in this temperature range for the ASTM A 710 grade of steel.…”

Section: Steel Tempered At 650 њCmentioning

confidence: 93%

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Influence of tempering on the microstructure and mechanical properties of HSLA-100 steel plates

Dhua¹,

Mukerjee²,

Sarma

2001

Metall Mater Trans A

103

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The influence of tempering on the microstructure and mechanical properties of HSLA-100 steel (with C-0.04, , and Nb-.038 pct) has been studied. The plate samples were tempered from 300 ЊC to 700 ЊC for 1 hour after austenitizing and water quenching. The transmission electron microscopy (TEM) studies of the as-quenched steel revealed a predominantly lath martensite structure along with fine precipitates of Cu and Nb(C, N). A very small amount of retained austenite could be seen in the lath boundaries in the quenched condition. Profuse precipitation of Cu could be noticed on tempering at 450 ЊC, which enhanced the strength of the steel significantly (yield strength (YS)-1168 MPa, and ultimate tensile strength (UTS)-1219 MPa), though at the cost of its notch toughness, which dropped to 37 and 14 J at 25 ЊC and Ϫ85 ЊC, respectively. The precipitates became considerably coarsened and elongated on tempering at 650 ЊC, resulting in a phenomenal rise in impact toughness (Charpy V-notch (CVN) of 196 and 149 J, respectively, at 25 ЊC and Ϫ85 ЊC) at the expense of YS and UTS. The best combination of strength and toughness has been obtained on tempering at 600 ЊC for 1 hour (YS-1015 MPa and UTS-1068 MPa, with 88 J at Ϫ85 ЊC).

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“…4) ASTM A710 grade steel (0.07 % C, 0.5 % Mn, 0.4 % Si, 0.75 % Cr, 0.9 % Ni, 0.2 % Mo, 1.15 % Cu and 0.0 2% Nb) was first to be developed in these low-carbon copper-bearing steels in late seventies for use in offshore structures. [5][6][7][8][9][10] Based on its chemistry, HSLA-80 steel was developed by United States Navy in early eighties as a substitute for HY-80 grade of steel. 1,[11][12][13][14] High strength (Minimum yield strength of 552 MPa), good low temperature impact toughness (81 J at Ϫ85°C) and good weldability of HSLA-80 steel made it a candidate for construction of naval ships and submarines.…”

Section: Introductionmentioning

confidence: 99%

Weldability and Microstructural Aspects of Shielded Metal Arc Welded HSLA-100 Steel Plates.

Dhua¹,

Mukerjee²,

Sarma

2002

ISIJ International

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HSLA-100 steel with 14 mm thickness in quenched and tempered condition was shielded metal arc welded (SMAW) with 2 kJ/mm heat input using basic flux coated filler rods without any pre or post welding heat treatments. The steel was found to be welded satisfactorily in this condition without developing any defect. Optical microscopy studies revealed typical cast dendritic structure in the weld metal and coarse bainite in grain-coarsened area of the heat-affected zone (HAZ). Transmission electron microscopy (TEM) study confirmed incidence of mixed structure of martensite laths and bainite in weld metal, while, it was mainly of bainite laths in HAZ with evidence of martensite-austenite (M-A) constituent and massive ferrite. The yield strength (YS), ultimate tensile strength (UTS) and Charpy V-notch (CVN) impact energy of the weld metal (YS-695 MPa, UTS-842 MPa and CVN-105 J at Ϫ50°C) and HAZ (YS-790 MPa, UTS-891 MPa and CVN-130 J at Ϫ50°C) were found satisfactory although HAZ properties were inferior to the base metal properties. The hardening of HAZ was not very significant in this steel under the present welding condition.

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Effects of heat treatment on the mechanical properties and microstructures of four different heats of a precipitation hardening HSLA steel

Cited by 14 publications

References 2 publications

Austenite transformation and age hardening of HSLA-80 and ULCB steels

Austenite transformation and age hardening of HSLA-80 and ULCB steels

Influence of tempering on the microstructure and mechanical properties of HSLA-100 steel plates

Weldability and Microstructural Aspects of Shielded Metal Arc Welded HSLA-100 Steel Plates.

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