scholarly journals Effect of Martensite Morphologies on Corrosion in 5% H2SO4 Solution of Borided X70 Dual Phase Steel

2021 ◽  
Vol 45 (1) ◽  
pp. 69-74
Author(s):  
Tassi Hocine ◽  
Zidelmel Sami ◽  
Allaoui Omar
Keyword(s):  
Corrosion Resistance ◽  
Dual Phase Steel ◽  
Annealing Temperature ◽  
Intercritical Annealing ◽  
Ferrite Matrix ◽  
Dual Phase ◽  
H2so4 Solution ◽  
Dp Steel ◽  
Direct Quenching ◽  
Step Quenching

In the present investigation, some electrochemical properties of dual phase X70 steels with different martensite morphologies which have undergone boriding were studied. To obtain a variety of martensite morphologies, Direct Quenching (DQ), Intermediate Quenching (IQ) and Step Quenching (SQ) heat treatments were applied at an intercritical annealing temperature (IAT) of 760℃. The treatment (DQ) allowed the formation of fine martensite evenly distributed in the ferrite matrix. (IQ) treatment showed the formation of martensite along the ferrite / ferrite grain boundaries. In contrast, treatment (SQ) induced the formation of a banded morphology of martensite and ferrite. The realization of borides on X70 (DP) steel was carried out in a powder mixture containing 5% of B4C as source of boron, 5% of NaBF4 as activator and 90% of SiC as diluent at 950℃ for a period of time from 4 h. The corrosion behavior of X70 (DP) steel has been explored by the Tafel extrapolation method in a 5 wt. % H2SO4 solution. The corrosion resistance of steel which has undergone boriding (BDP) is higher than that of steel which has not undergone it (DP).

Effect of Intercritical Annealing Temperature on Development of Cold Rolled Dual Phase Steel from Q345 Steel

2013 ◽  
Vol 313-314 ◽  
pp. 693-696
Author(s):  
Ji Yuan Liu ◽  
Fu Xian Zhu ◽  
Shi Cheng Ma
Keyword(s):  
Dual Phase Steel ◽  
Annealing Temperature ◽  
Simulation Experiment ◽  
Intercritical Annealing ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Automotive Applications ◽  
Treatment Procedure ◽  
Annealing Temperatures ◽  
Cold Rolled

Cold rolled dual phase steel was developed from Q345 steel by heat treatment procedure for automotive applications. The ultimate tensile strength was improved about 100MPa higher than the traditional cold-rolled Q345 steel in the continuous annealing simulation experiment. The microstructure presented varied characteristics in different intercritical annealing temperatures; mechanical properties were changed correspondingly as well. The chief discussions are focus on the recrystallization, hardenability of austenite and martensite transformation in the experiment.

scholarly journals Microstructure and Mechanical Properties of Dual-Phase Steel/ Mikrostruktura I Własności Mechaniczne Stali Dwufazowej

2014 ◽  
Vol 59 (4) ◽  
pp. 1257-1261
Author(s):  
K. Miernik ◽  
S. Pytel
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
High Strength ◽  
Phase Region ◽  
Dual Phase ◽  
Two Phase ◽  
Dp Steel ◽  
Direct Quenching ◽  
Microstructure And Mechanical Properties ◽  
Tempering Treatment

Abstract The paper presents results of microstructure and mechanical properties of the dual phase (DP) steel plate with 12 mm thickness produced by intercritical annealing at a two-phase region of ferrite and austenite (α + γ) and direct quenching in water. In addition the tempering treatment at temperature of 650°C was applied to investigate effect of martensite softening on mechanical properties of the tested steel. The parameters of heat treatment were designed to achieve the high strength while retaining optimum impact strength of the DP steel.

scholarly journals FINE GRAINED DUAL PHASE STEEL BY THERMO MECHANICAL PROCESSING

2013 ◽  
pp. 237-240
Author(s):  
NEERAJAGARWAL NEERAJAGARWAL ◽  
G.P. CHAUDHARI ◽  
S.K. NATH
Keyword(s):  
Dual Phase Steel ◽  
Intercritical Annealing ◽  
Hsla Steel ◽  
Coarse Grained ◽  
Dual Phase ◽  
Mechanical Processing ◽  
Dp Steel ◽  
Fine Grained ◽  
Ultrafine Grained ◽  
Open Die Forging

The effect of thermo mechanical processing (TMP) on the mechanical properties of HSLA steel was investigated. TMP was conducted using a laboratory open die forging machine.Multiaxial forging (MAF) and intercritical annealing methods were used. TMP is designed to obtain ultrafine grained (UFG) steels. MAF is performed on prismatic shaped samples up to nine strain forging steps to produce ultra-fine grained (UFG) ferrite-pearlite steel with higher strength as compare to as received steel.Fine grained (FG) ferrite-martensite dual phases (DP) steel was fabricated by using combined effect of warm MAF and intercritical annealing. The tensile strength of FG-DP steels was much higher than that of the coarse-grained (CG) counterpart, and the uniform elongations were significantly enhanced. This steel exhibited the superior combination of higher strength and more rapid strain hardening compared to those of CG-DP steel was explained in terms of their specific microstructural features.

Microstructure and Property Control of Hot Rolled DP600 Steel

2011 ◽  
Vol 415-417 ◽  
pp. 938-942
Author(s):  
Le Yu Zhou ◽  
Ya Zheng Liu ◽  
Lian Hong Yang ◽  
Dan Zhang
Keyword(s):  
Dual Phase Steel ◽  
Volume Fraction ◽  
Ferrite Matrix ◽  
Accelerated Cooling ◽  
Dual Phase ◽  
Dp Steel ◽  
Fine Grain ◽  
Mechanical Experiment ◽  
Property Control ◽  
Hot Rolled

Thermal mechanical experiment of step-cooling of 600MPa hot-rolled DP steel after compressed was carried out on Gleeble-1500 thermal mechanical simulator, using design of butterfly-shaped sample. Microstructure evolution during step-cooling and its effect on mechanical property of tested steel were analyzed. It is shown that, dual phase microstructure which martensite islands disperses in fine grain ferrite matrix is obtained by holding for 8~10s at 670°C followed accelerated cooling to 200°C. With increasing of holding time, grain size of ferrite coarsens, and volume fraction of ferrite has few changes. Meanwhile, tensile strengths of tested steel are all near 600MPa. That is to say, ferrite transformation is adequate during holding for 8~10s at 670°C and tensile strength of dual phase steel is stable accordingly.

Effect of Niobium on Zn-Coated Dual Phase Steel Sheet

2007 ◽  
Vol 539-543 ◽  
pp. 4411-4416 ◽  
Author(s):  
Shunichi Hashimoto
Keyword(s):  
Chemical Composition ◽  
Steel Sheet ◽  
Dual Phase Steel ◽  
Ferrite Matrix ◽  
Dual Phase ◽  
Dp Steel ◽  
Steel Sheets ◽  
Structural Parts ◽  
Bake Hardenability ◽  
Grade Steel

Dual Phase (DP) steel sheets, mainly 590 MPa TS grade steel, have been applied to structural parts of automobile because of their good formability, large bake hardenability and high crash worthiness. Although the concept of DP steel was established as early as the mid-1970th, the literature contains little discussion of Zn-coated DP steel, which has been the main application in recent years. In manufacturing Zn-coated DP steel, chemical composition which secures adequate Zn coatability and appropriate heat cycles, including galvannealing, must be considered. In this paper, the effect of Nb on the tensile properties, stretch flange formability and bake hardenability of 590 MPa TS grade DP steel is discussed. The base chemical composition was 0.05%C-2%Mn-0.5%Cr steel. The effect of Nb on the above-mentioned properties was studied using 0.05%Nb added steel and found that the addition of 0.05%Nb results in improved elongation, stretch flangeability and bake hardenability with higher tensile strength under both simulated GA and GI heat cycles. These improved properties by the addition of Nb are brought about by the grain refinement of ferrite matrix and finer dispersion of martensite.

Microstructure Characterization of Deep-Drawn DP780-Grade Dual Phase Steel

2013 ◽  
Vol 752 ◽  
pp. 75-84
Author(s):  
Adám Filep ◽  
Valéria Mertinger
Keyword(s):  
Dual Phase Steel ◽  
Annealing Temperature ◽  
Crack Formation ◽  
Intercritical Annealing ◽  
High Strength ◽  
Rolled Sheet ◽  
Dual Phase ◽  
Hsla Steels ◽  
Dp Steels

Dual phase (DP) steels belong to the group of high-strength low-alloy (HSLA) steels. Our study focuses on the causes of crack formation of sheets, which are designed for deep drawing, of DP780-grade dual phase steel. Also, a series of heat treatment experiments were performed regarding the effect of intercritical annealing temperature on the structure and mechanical properties of the finished product (in this case a rolled sheet).

scholarly journals Effects of DP steel microstructure on the disappearance of discontinuous yielding

2018 ◽  
Vol 204 ◽  
pp. 07013 ◽  
Author(s):  
Prita Dewi Basoeki
Keyword(s):  
Dual Phase Steel ◽  
Intercritical Annealing ◽  
High Strength ◽  
Heating Time ◽  
Annealing Process ◽  
Dual Phase ◽  
Dp Steel ◽  
Steel Microstructure ◽  
Discontinuous Yielding ◽  
Automotive Steel

Although in terms of quality is not as high as TRIP steel, DP steel has been developed as an option to meet the minimum standard industrial requirement for automotive. Steel development for automotive material leads to posses high strength without suffering its ductility and weld ability, in addition there is no appearance of discontinuous yielding that cause stretcher strain marking. The change of micro structure as a result of the intercritical annealing process not only increases the strength of Dual Phase Steel, but also eliminates the discontinuous yielding. The phenomenon of discontinuous yielding is no longer appear in Dual Phase Steel which heating time on intercritical annealing process more than 1 minute, the minimum time is equal to the disappearance of discontinuous yielding. The phenomenon of upper yield point and discontinuous yielding on carbon steel is strongly influenced by the magnitude of the stress acting on the Ferrite phase to move the dislocation of the pinned state by the interstitial atom. From the recent works gives the result that the disappearance of discontinuous yielding in Dual Phase Steel resulting from the intercritical annealing process makes Dual Phase Steel very suitable as an automotive material.

Precipitation Characterization and Mechanical Behavior in Novel DP Steels

2018 ◽  
Vol 939 ◽  
pp. 9-15
Author(s):  
Chih Yuan Chen ◽  
Cheng Han Li ◽  
Pei Herng Liu ◽  
Shao Pu Tsai ◽  
Chien Chon Chen ◽  
...  
Keyword(s):  
Dual Phase Steel ◽  
Decomposition Reaction ◽  
Ferrite Matrix ◽  
Dual Phase ◽  
Austenite Decomposition ◽  
Hardness Testing ◽  
Dp Steel ◽  
Copper Particles ◽  
Transmission Electron ◽  
Dp Steels

Dual precipitates of carbide and copper particles formed within Cu-Ti microalloyed DP (Dual Phase) steel in the present study. The precipitation behaviors of tiny precipitates, especially in the ferrite matrix, were checked precisely by several methods, such as optical microscopy, high resolution transmission electron microscopy, and hardness testing. It was found that copper particles nucleated only on the interphase precipitated TiC and were not dispersed randomly within the ferrite matrix. Therefore, the formation of dual precipitates within the ferrite grains should be considered as separated phase transformation; initially, only titanium carbides form during the austenite decomposition reaction, after which copper particles heterogeneously nucleate on these carbides. Furthermore, as compared to Cu microalloyed DP steel, the tempering behavior of martensite in the Cu-Ti microalloyed DP steel showed a tempering hardening characteristic.

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