Investigation of the microstructure, mechanical properties and tensile behavior of a low carbon nickel-manganese dual-phase transformationinduced plasticity steel by heavy warm rolling

2020 ◽  
Vol 10 (4) ◽  
pp. 503-513
Author(s):  
Sohail Ahmad ◽  
Xiangyu Wang ◽  
Liming Fu ◽  
Javed Ahmad ◽  
Waseem Abbas ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Warm Rolling ◽  
Tensile Behavior ◽  
Dual Phase ◽  
Trip Effect ◽  
Low Carbon ◽  
Deformation Stage ◽  
Nickel Manganese

A dual phase (martensite–austenite) low carbon nickel-manganese transformation-induced plasticity (TRIP) steel was fabricated by heavily warm rolling (HWR), and the effect of annealing on the phase fraction, mechanical properties and tensile deformation behavior of the heavily warm rolled (HWRed) steel was investigated. The results showed that the reverse transformation of γ-austenite from α′-martensite occurs and that the γ-austenite volume fraction (VA) decreases from 91% to 55% as the annealing temperature increases from 400 °C to 800 °C, respectively. The HWRed steel annealed at 400 °C exhibits a high strength-high ductility combination with yield strength of 706 MPa, ultimate tensile strength (UTS) of 1573 MPa, total elongation (TEL) of 21.6%, and the product of the strength and elongation (PSE: UTS×TEL) is 34 GPa%. These excellent mechanical properties are principally attributed to the formation of a large volume fraction of austenite (γ) by the reverse transformation and subsequent TRIP effect during tensile deformation. It was found that the HWRed and annealed steels exhibit a special tensile behavior with a large yielding strain followed by pronounced strain hardening. The tensile curve can be readily divided into three obviously different stages. The strain-induced martensite (SIM) transformation (γ -α′) occurs in the early yielding deformation stage and in the intermediate rapidly hardening deformation stage, indicating that the TRIP effect dominates the process of these two stages. However, the retained γ-austenite remains very stable, and no TRIP effect is observed in the final hardening deformation stage. The load-unload reload (LUR) test was performed to evaluate the back stress (σb) hardening effect during tensile testing. It is believed that the pronounced strain hardening behavior after yielding is mainly associated with the σb enhancement induced by the strain partitioning between the soft retained γ-austenite and the hard α′-martensite due to the SIM transformation during tensile deformation.

scholarly journals Effect of Pre-Quenching Process on Microstructure and Mechanical Properties in a Nb-Microalloyed Low Carbon Q-P Steel

2015 ◽  
Vol 816 ◽  
pp. 729-735 ◽  
Author(s):  
Jun Zhang ◽  
Hua Ding ◽  
Jing Wei Zhao
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Room Temperature ◽  
Volume Fraction ◽  
Total Elongation ◽  
Trip Effect ◽  
Low Carbon ◽  
Quenching And Partitioning ◽  
The Stability ◽  
Critical Annealing

A refined microstructure consisting of martensite and retained austenite at room temperature has been produced in a Nb-microalloyed low carbon Si-Mn steel by a novel heat-treatment, pre-quenching prior to quenching and partitioning processes (Q&Q-P). The results showed that compared with the conventional quenching and partitioning steel the mechanical properties of steel obtained by the novel treatment have been significantly improved, with a good combination of ultimate tensile strength (1000MPa) and total elongation (above 30%). Meanwhile, the volume fraction of retained austenite has been increased. It was found that the improvement of mechanical properties was mainly attributed to the enhanced TRIP effect due to the relatively high fraction of metastable retained austenite at room temperature. The increased stability of austenite results from the C and Mn partitioning during inter-critical annealing, which increased the chemical stability of austenite. The formation of refined austenite at inter-critical annealing also had a positive effect on the stability of the austenite. As a consequence, the volume fraction of retained austenite at room temperature was significantly increased. Compared with the Q-P steel, the Q&Q-P steel exhibited higher work hardening exponents during the stage of TRIP effect and had the higher ductility.

scholarly journals Effect of Rolling Temperature on the Structural Refinement and Mechanical Properties of Dual-Phase Heterostructured Low-Carbon Steel

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 115
Author(s):  
Tao Xu ◽  
Zhiyi Pan ◽  
Bo Gao ◽  
Jiaxi Huang ◽  
Xuefei Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Steel ◽  
Deformation Temperature ◽  
Lamellar Structure ◽  
Room Temperature ◽  
Low Carbon Steel ◽  
Warm Rolling ◽  
Dual Phase ◽  
Low Carbon ◽  
Structural Refinement

Warm rolling at temperatures ranging from 25 °C to 500 °C was conducted on the dual-phase heterostructured low-carbon steel to investigate the effect of deformation temperature on the structural refinement and mechanical properties. Defying our intuition, the grain size and strength of the rolled steels do not deteriorate with the increase in deformation temperature. Warm rolling at 300 °C produces a much finer lamellar structure and higher strength than steels rolled at both room temperature and elevated temperature. It is supposed that the enhanced interactions between carbon atoms and defects (interfaces and dislocations) at 300 °C promote dislocation accumulation and stabilize the nanostructure, thus helping with producing an extremely finer structure and higher strength than other temperatures.

Effect of Microstructure on Mechanical Properties and Abrasive Wear Behavior of Low Carbon Dual-Phase Steels

2014 ◽  
Author(s):  
Mehmet Çağrı Tüzemen ◽  
Elmas Salamci
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Steel Specimen ◽  
Total Elongation ◽  
Dry Sliding Wear ◽  
Dual Phase ◽  
Low Carbon ◽  
Wear Properties ◽  
Dp Steels

The mechanical properties and wear behavior of Dual Phase (DP) steels have been investigated and compared with those observed in normalized (N) steel that has the same chemical composition. The DP steels having different content and morphology of martensite were produced by varying intercritical annealing temperature and initial microstructures. Mechanical properties of four different DP steels and N steel have been investigated by carrying out tensile and macrohardness tests. Dry sliding wear tests have been conducted on four different the DP steels and the N steel using pin-on-plate to investigate their wear characteristics. It has been found that the yield and tensile strengths and macrohardness increase with increasing martensite content and decreasing martensite size. The yield and tensile strengths and macrohardness of the N steel were significantly lower than the DP steels whereas percentage of total elongation was higher. Wear properties are improved by increasing martensite volume fraction and size in the DP steels. The N steel specimen showed the highest wear rate.

Microstructural and Tribological Characterization of API X52 Dual-Phase Steel

2021 ◽  
Author(s):  
Gamri Hamza ◽  
Allaoui Omar ◽  
Zidelmel Sami
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Normal Load ◽  
Great Influence ◽  
Dual Phase ◽  
Martensite Volume Fraction ◽  
Direct Quenching ◽  
Disc Configuration

Abstract The effect of the morphology and the martensite volume fraction on the microhardness, the tensile, the friction and the wear behavior of API X52 dual phase (DP) steel has been investigated. Three different heat treatments were used to develop dual phase steel with different morphologies and with different amounts of martensite: Intermediate Quenching Treatment/Water (IQ); Step Quenching Treatment (SQ) and direct quenching (DQ). Tribological tests are conducted on DP steels using a ball-on-disc configuration under normal load of 5 N and at a sliding speed of 4 cm/s were used to study the friction and wear behavior of treated samples. Results show that the ferrite–martensite morphology has a great influence on the mechanical properties of dual phase steel. The steel subjected to (IQ) treatment attain superior mechanical properties compared to the SQ and the DQ treatments. On the other hand, it is also found that the friction coefficient and the wear rate (volume loss) decrease when the hardness and the martensite volume fraction increase. The steel with fine fibrous martensite provide good wear resistance.

Effect of Tailoring Martensite Shape and Spatial Distribution on Tensile Deformation Characteristics of Dual Phase Steels

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
B. Ravi Kumar ◽  
Vishal Singh ◽  
Tarun Nanda ◽  
Manashi Adhikary ◽  
Nimai Halder ◽  
...  
Keyword(s):  
Grain Size ◽  
Spatial Distribution ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Void Formation ◽  
Martensite Phase ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Deformation Characteristics ◽  
Dp Steels

The authors simulated the industrially used continuous annealing conditions to process dual phase (DP) steels by using a custom designed annealing simulator. Sixty-seven percentage of cold rolled steel sheets was subjected to different processing routes, including the conventional continuous annealing line (CAL), intercritical annealing (ICA), and thermal cycling (TC), to investigate the effect of change in volume fraction, shape, and spatial distribution of martensite on tensile deformation characteristics of DP steels. Annealing parameters were derived using commercial software, including thermo-calc, jmat-pro, and dictra. Through selection of appropriate process parameters, the authors found out possibilities of significantly altering the volume fraction, morphology, and grain size distribution of martensite phase. These constituent variations showed a strong influence on tensile properties of DP steels. It was observed that TC route modified the martensite morphology from the typical lath type to in-grain globular/oblong type and significantly reduced the martensite grain size. This route improved the strength–ductility combination from 590 MPa–33% (obtained through CAL route) to 660 MPa–30%. Finally, the underlying mechanisms of crack initiation/void formation, etc., in different DP microstructures were discussed.

Isothermal Transformation, Microstructure and Mechanical Properties of Ausformed Low-Carbon Carbide-Free Bainitic Steel

2018 ◽  
Vol 941 ◽  
pp. 329-333 ◽  
Author(s):  
Jiang Ying Meng ◽  
Lei Jie Zhao ◽  
Fan Huang ◽  
Fu Cheng Zhang ◽  
Li He Qian
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Bainitic Ferrite ◽  
Isothermal Transformation ◽  
Bainitic Transformation ◽  
Isothermal Treatment ◽  
Bainitic Steel ◽  
Low Carbon ◽  
Microstructure And Mechanical Properties

In the present study, the effects of ausforming on the bainitic transformation, microstructure and mechanical properties of a low-carbon rich-silicon carbide-free bainitic steel have been investigated. Results show that prior ausforming shortens both the incubation period and finishing time of bainitic transformation during isothermal treatment at a temperature slightly above the Mspoint. The thicknesses of bainitic ferrite laths are reduced appreciably by ausforming; however, ausforming increases the amount of large blocks of retained austenite/martenisite and decreases the volume fraction of retained austenite. And accordingly, ausforming gives rise to significant increases in both yield and tensile strengths, but causes noticeable decreases in ductility and impact toughness.

Influence of Volume Fraction of Bainite on Mechanical Properties of X80 Pipeline Steel with Excellent Deformability

2011 ◽  
Vol 695 ◽  
pp. 271-274
Author(s):  
Xiao Yong Zhang ◽  
Hui Lin Gao ◽  
Xue Qin Zhang ◽  
Yan Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
Dual Phase ◽  
Absorption Energy ◽  
Impact Absorption Energy ◽  
Impact Absorption ◽  
Work Hardening Exponent

The pipeline steel with excellent deformability with ferrite and bainite dual-phase microstructure are obtained by inter-critically accelerating cooling method, aiming to get good deformation capability of avoiding failure from the geological disasters such as landslides and earthquake. The influence of volume fraction of bainite on the mechanical properties of dual-phase pipeline steels was investigated by means of microscopic analysis method and mechanical properties testing. The results indicated that both yield strength and ultimate tensile strength of the steels increase almost linearly with the increasing volume fraction of bainite, while ductility, work hardening exponent and impact absorption energy decrease. When the volume fraction of bainite is about 50%, the yield strength, the yield strength/tensile strength ratio (Y/T), work hardening exponent, uniform elongation and impact absorption energy of X80 pipeline steels with excellent deformability is 665MPa, 0.8, 0.12, 8% and 245J respectively.

scholarly journals Impact of Cold-Rolling and Heat Treatment on Mechanical Properties of Dual-Phase Treated Low Carbon Steel

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Le Van Long ◽  
Dinh Van Hien ◽  
Nguyen Truong Thanh ◽  
Nguyen Chi Tho ◽  
Van Thom Do
Keyword(s):  
Mechanical Properties ◽  
Carbon Steel ◽  
Low Carbon Steel ◽  
High Strength ◽  
Processing Parameters ◽  
Dual Phase ◽  
Low Carbon ◽  
Forming Process ◽  
Good Ductility ◽  
Rolling Deformation

The low carbon steel has good ductility that is favorable for forming process, but its low strength leads to limiting their application for forced structures. This paper studied improving strength of low-carbon steel via rolling deformation and dual-phase treatment. The results showed that the dual-phase treated steel had a combination of high strength and good ductility; its tensile ultimate strength reached 740 MPa with elongation at fracture of over 15%, while that of the cold-rolled steel only reached 700 MPa with elongation at fracture of under 3%. Based on the obtained results, relationships between mechanical properties and dual-phase processing parameters were established to help users choose suitable-processing parameters according to requirements of products.

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