Effect of Ferrite Volume Fraction on Mechanical Properties of X80 Pipeline Steel

2014 ◽  
Vol 989-994 ◽  
pp. 212-215
Author(s):  
J. Liu ◽  
G. Zhu ◽  
W. Mao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Work Hardening ◽  
Single Phase ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
X80 Pipeline Steel ◽  
Hardening Behavior ◽  
Two Phases ◽  
Better Than

The effect of volume fraction of ferrite on the mechanical properties including strength, plasticity and wok hardening was systematically investigated in X80 pipeline steel in order to improve the plasticity. The microstructures with different volume fraction of ferrite and bainite were obtained by heat-treatment processing and the mechanical properties were tested. The work hardening behavior was analyzed by C-J method. The results show that the small amount of ferrite could effectively improve the plasticity. The work hardening ability and the ratio of yield/tensile strength with two phases of ferrite/bainite would be obviously better than that with single phase of bainite. The improvement of plasticity could be attributed to the ferrite in which more plastic deformation was afforded.

scholarly journals Investigation of intercritical heat treatment temperature effect on microstructure and mechanical properties of dual phase (DP) steel

10.30544/293 ◽  
2017 ◽  
Vol 23 (2) ◽  
pp. 143-152
Author(s):  
Mohammad Davari ◽  
Mehdi Mansouri Hasan Abadi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Work Hardening ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Dual Phase ◽  
Work Hardening Behavior ◽  
Hardening Behavior ◽  
Heat Treated ◽  
Intercritical Heat Treatment

In the present study, the effect of intercritical heat treatment temperature on the tensile properties and work hardening behavior of ferritic-martensitic dual-phase steel have been investigated utilizing tensile test, microhardness measurement and microscopic observation. Plain carbon steel sheet with a thickness of 2 mm was heat treated at 760, 780, 800, 820 and 840 °C intercritical temperatures. The results showed that martensite volume fraction (Vm) increases from 32 to 81%with increasing temperature from 760 to 840 °C. The mechanical properties of samples were examined by tensile and microhardness tests. The results revealed that yield strength was increased linearly with the increase in Vm, but the ultimate strength was increased up to 55% Vm and then decreased afterward. Analyzing the work hardening behavior in term of Hollomon equation showed that in samples with less than 55% Vm, the work hardening took place in one stage and the work hardening exponent increased with increasing Vm. More than one stage was observed in the work hardening behavior when Vm was increased. The results of microhardness test showed that microhardness of the martensite is decreased by increase in heat treatment temperature while the ferrite microhardness is nearly constant for all heat-treated samples.

scholarly journals Effect of heat treatment on the microstructure and mechanical properties of a low-carbon X80 pipeline steel

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
B.C. Acosta-Cinciri ◽  
N.M. López-Granados ◽  
J.A. Ramos-Banderas ◽  
C.A. Hernández-Bocanegra ◽  
P. Garnica-González ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Pipeline Steel ◽  
American Petroleum Institute ◽  
The Other ◽  
Low Carbon ◽  
Electron Backscattered Diffraction ◽  
X80 Pipeline Steel ◽  
Microstructure And Mechanical Properties ◽  
Treatment Conditions

Abstract In this work, the effect of heat treatment conditions on the microstructure and mechanical properties of an American Petroleum Institute (API) X80 steel with a low carbon content of ~0.02% wt., destined for the manufacture of pipelines and pipeline transmission systems by welding, was investigated. Samples were heat treated under different conditions and then were characterized by scanning electron microscopy (SEM), orientation image microscopy (OIM), and electron backscattered diffraction (EBSD). The results showed that when the steel is fastly cooled from the austenitic field (990°C), the mechanical properties increase significantly [ultimate tensile strength (UTS) >1,100 MPa, yield strength (YS) 900 MPa, and elongation 27%] due to the high percentage of martensite (M) present in the microstructure (95%). In contrast, when the cooling rate decreases and the treatment conditions remain at/or above the bainitic/martensitic transformation (from 990°C to 600°C and 450°C), the mechanical properties are decreased by almost 50% because of the decrease in the percentage of martensite (18%). However, the percentage of elongation increases significantly (38%) due to the presence of other micro-constituents resulting from the phase transformation. On the other hand, the best combination of mechanical properties (UTS above 800 MPa and YS between 610 MPa and 720 MPa) was obtained when the steel acquired a dual-phase microstructure [(martensite/austenite)-(ferrite/martensite)] since the amount of martensite is conserved between 45% and 82%, in combination with the other micro-constituent present in the steel that allows us to achieve elongation percentages close to 30%.

Microstructure and Compressive Properties of Fe-Modified L12-TYPE Al3Ti

1990 ◽  
Vol 186 ◽  
Author(s):  
H.R. Pak ◽  
C.M. Wayman ◽  
L.H. Favrow ◽  
C.V. Cooper ◽  
J.S.L. Pak
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Yield Stress ◽  
Single Phase ◽  
Small Volume ◽  
Volume Fraction ◽  
Small Region ◽  
Compressive Properties ◽  
Small Volume Fraction

AbstractThe microstructures and mechanical properties of an Fe-modified L12 alloy containing 7.5 at.% Fe have been investigated. This alloy has been determined to be essentially single phase following a homogenization heat treatment (HHT) at 1100°C for 100h, with a very small volume fraction of precipitates having been observed to form along dislocations. Conversely, in the case of the as-cast (AC) condition, the alloy has been determined to contain band-like precipitates, which have also formed along dislocations. In addition, a high density of very thin plate-like precipitates have formed parallel to {001} planes of the L12 matrix. Although these plate-like precipitates appear to exhibit lattice tetragonality, their crystal structure cannot be explained by assuming D022 and D023 structures. Five different <110>-type dislocations havfe been activated within a small region of a matrix grain during deformation at 1100°C, some of which cross slipped from {111} to {001} planes. Specimens in both AC and HHT conditions were deformed in compression to approximately 0.5% without fracture at both 22 and 1 100°C, the yield stress for the HIT condition having been determined to be 192 MPa at 22°C and 98 MPa at 1100°C.

Topological Analysis of Martensite Morphology in Dual-Phase Steels

2011 ◽  
Vol 409 ◽  
pp. 725-729 ◽  
Author(s):  
Naoko Sato ◽  
Mayumi Ojima ◽  
Satoshi Morooka ◽  
Yo Tomota ◽  
Yoshitaka Adachi
Keyword(s):  
Mechanical Properties ◽  
Work Hardening ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Intercritical Annealing ◽  
Topological Analysis ◽  
Three Dimensional ◽  
Dual Phase ◽  
Hardening Behavior ◽  
Dp Steels

Martensite morphology such as connectivity or dispersivity in ferrite (F)/martensite (M) dual-phase (DP) steels was investigated from topological viewpoint to reveal the effect of the martensite morphology on the mechanical properties. Topological analysis permits evaluation of the microstructural connectivity and dispersivity by measuring the number of handles, independent bodies and genus, etc. The topological analysis was performed on three-dimensional (3D) reconstructed images of the microstructure with different connectivity, dispersivity, volume fraction and hardness of martensite in DP steels that were prepared by changing the intercritical annealing temperature. The connectivity and the volume fraction of martensite increased while the dispersivity and hardness of it decreased with increasing annealing temperature. The effect of connectivity and dispersivity as well as volume fraction and hardness, in particular, on work hardening behavior was individually evaluated at a given strain.

Effect of Cooling Rate on Microstructures and Mechanical Properties of X80 Pipeline Steel

2012 ◽  
Vol 535-537 ◽  
pp. 525-528 ◽  
Author(s):  
Qing Bo Yu
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
Controlled Rolling ◽  
Granular Bainite ◽  
Controlled Cooling ◽  
X80 Pipeline Steel ◽  
Microstructures And Mechanical Properties ◽  
Ferrite Grain Size

The thermal simulation experiments of X80 pipeline steel were performed using Gleeble 1500 thermomechanical simulator. The controlled rolling and controlled cooling experiments were used to investigate the effect of cooling rate on the microstructures and mechanical properties of X80 pipeline steel. The results show that the cooling rate plays an important role in the ferrite grain size and the volume fraction of granular bainite. In order to obtain good comprehensive mechanical properties, it is necessary that the cooling rate should be 12~20°C/s.

scholarly journals Heat Treatment Evaluation for the Camshafts Production of ADI Low Alloyed with Vanadium

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1036
Author(s):  
Eduardo Colin García ◽  
Alejandro Cruz Ramírez ◽  
Guillermo Reyes Castellanos ◽  
José Federico Chávez Alcalá ◽  
Jaime Téllez Ramírez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Ductile Iron ◽  
Volume Fraction ◽  
Energy Impact ◽  
Treatment Conditions ◽  
Mold Casting ◽  
Grade 3 ◽  
Good Agreement

Ductile iron camshafts low alloyed with 0.2 and 0.3 wt % vanadium were produced by one of the largest manufacturers of the ductile iron camshafts in México “ARBOMEX S.A de C.V” by a phenolic urethane no-bake sand mold casting method. During functioning, camshafts are subject to bending and torsional stresses, and the lobe surfaces are highly loaded. Thus, high toughness and wear resistance are essential for this component. In this work, two austempering ductile iron heat treatments were evaluated to increase the mechanical properties of tensile strength, hardness, and toughness of the ductile iron camshaft low alloyed with vanadium. The austempering process was held at 265 and 305 °C and austempering times of 30, 60, 90, and 120 min. The volume fraction of high-carbon austenite was determined for the heat treatment conditions by XRD measurements. The ausferritic matrix was determined in 90 min for both austempering temperatures, having a good agreement with the microstructural and hardness evolution as the austempering time increased. The mechanical properties of tensile strength, hardness, and toughness were evaluated from samples obtained from the camshaft and the standard Keel block. The highest mechanical properties were obtained for the austempering heat treatment of 265 °C for 90 min for the ADI containing 0.3 wt % V. The tensile and yield strength were 1200 and 1051 MPa, respectively, while the hardness and the energy impact values were of 47 HRC and 26 J; these values are in the range expected for an ADI grade 3.

scholarly journals The Effect of Quenching and Partitioning (Q&P) Heat Treatment on the Microstructure and Mechanical Properties of High Boron Steel

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1556
Author(s):  
Zhao Li ◽  
Run Wu ◽  
Mingwei Li ◽  
Song-Sheng Zeng ◽  
Yu Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Volume Fraction ◽  
Martensitic Steel ◽  
Boron Steel ◽  
Quenching And Partitioning ◽  
Effect Mechanism ◽  
Microstructure And Mechanical Properties ◽  
High Boron ◽  
Cast Condition

High boron steel is prone to brittle failure due to the boride distributed in it with net-like or fishbone morphology, which limit its applications. The Quenching and Partitioning (Q&P) heat treatment is a promising process to produce martensitic steel with excellent mechanical properties, especially high toughness by increasing the volume fraction of retained austensite (RA) in the martensitic matrix. In this work, the Q&P heat treatment is used to improve the inherent defect of insufficient toughness of high boron steel, and the effect mechanism of this process on microstructure transformation and the change of mechanical properties of the steel has also been investigated. The high boron steel as-casted is composed of martensite, retained austensite (RA) and eutectic borides. A proper quenching and partitioning heat treatment leads to a significant change of the microstructure and mechanical properties of the steel. The net-like and fishbone-like boride is partially broken and spheroidized. The volume fraction of RA increases from 10% in the as-cast condition to 19%, and its morphology also changes from blocky to film-like. Although the macro-hardness has slightly reduced, the toughness is significantly increased up to 7.5 J·cm−2, and the wear resistance is also improved.

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