scholarly journals Assessment of the Hardening Behavior and Tensile Properties of a Cold-Rolled Bainitic–Ferritic Steel

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6662
Author(s):  
Emilio Bassini ◽  
Antonio Sivo ◽  
Daniele Ugues
Keyword(s):  
Strain Hardening ◽  
High Strength ◽  
Dual Phase ◽  
Low Carbon ◽  
Soft Phase ◽  
Bending Tests ◽  
Ductile Materials ◽  
Hardening Behavior ◽  
Material State ◽  
Cold Rolled

The automotive field is continuously researching safer, high-strength, ductile materials. Nowadays, dual-phase (DP) steels are gaining importance, since they meet all these requirements. Dual-phase steel made of ferrite and bainite is the object of a complete microstructural and mechanical characterization, which includes tensile and bending tests. This specific steel contains ferrite and bainite in equal parts; ferrite is the soft phase while bainite acts as a dispersed reinforcing system. This peculiar microstructure, together with fine dispersed carbides, an extremely low carbon content (0.09 wt %), and a minimal degree of strain hardening (less than 10%) allow this steel to compete with traditional medium-carbon single-phase steels. In this work, a full pearlitic C67 steel containing 0.67% carbon was used as a benchmark to build a comparative study between the DP and SP steels. Moreover, the Crussard–Jaoul (C-J) and Voce analysis were adopted to describe the hardening behavior of the two materials. Using the C-J analysis, it is possible to separately analyze the ferrite and bainite strain hardening and understand which alterations occur to DP steel after being cold rolled. On the other hand, the Voce equation was used to evaluate the dislocation density evolution as a function of the material state.

Work-Hardening Behavior of Cold Rolled Interstitial-Free Steel Sheet and Dual Phase High Strength Steel Sheets Subjected to Two-Stage, Coaxial and Non-Coaxial Tension/Compression

2015 ◽  
Vol 651-653 ◽  
pp. 83-88 ◽  
Author(s):  
Satoshi Shirakami ◽  
Shigeru Yonemura ◽  
Tohru Yoshida ◽  
Noriyuki Suzuki ◽  
Toshihiko Kuwabara
Keyword(s):  
Work Hardening ◽  
Steel Sheet ◽  
High Strength ◽  
Dual Phase ◽  
Interstitial Free ◽  
If Steel ◽  
Two Stage ◽  
Work Hardening Behavior ◽  
Hardening Behavior ◽  
Cold Rolled

In-plane tension/compression tests of a cold rolled interstitial-free (IF) steel and sheet a 980MPa dual phase high strength steel sheet (980DP) were carried out to investigate the work-hardening behavior under two-stage loading paths. The two-stage loading paths consist of the uniaxial tension/compression for the rolling direction (RD) followed by unloading and subsequent uniaxial tension/compression in the 0°, 45° and 90° directions from the first loading direction (0°-, 45°- and 90°-loading). The work hardening behavior in the second loading was different between the 980DP and the IF steel. It was found that the work hardening behaviors were significantly affected by the inner product of the strain rate mode tensors for the first and second loading and that the effect of the deformation mode (tension/compression) was small.

Microstructure, Properties and Work Hardening Behavior of High Strength Cold Rolled Dual-Phase Steel

2011 ◽  
Vol 399-401 ◽  
pp. 1682-1686 ◽  
Author(s):  
Zheng Zhi Zhao ◽  
Zhi Gang Wang ◽  
Ai Min Zhao ◽  
Jie Yun Ye
Keyword(s):  
Work Hardening ◽  
Dual Phase Steel ◽  
High Strength ◽  
Distribution Patterns ◽  
Phase Region ◽  
Dual Phase ◽  
Two Phase ◽  
Soft Phase ◽  
Cold Rolled ◽  
Si Content

Two kinds of high strength cold rolled dual-phase steel with different Si content were trial-produced in the laboratory. Tensile strength and elongation of the two steels exceed 1000MPa and 15%, respectively. The phase transformation behaviors of both steels were compared and investigated in continuous cooling process by thermal dilatometer. The effects of Si on the mechanical properties and microstructures of dual-phase steel were studied by tensile testing, OM and SEM observation. The results show that the two phase region (α+γ) is enlarged, the precipitation and growth of pro-eutectoid ferrite is promoted, and the morphology and distribution patterns of martensite are improved for high Si steel. Both steels show two-stage strain hardening characteristics. StageⅠ (ε<0.05), the solution of Si hinder the movement of dislocations, make the work hardening exponent of high Si steel is higher than that low Si steel. At stage Ⅱ (ε>0.05), the compatibility and delivery between hard phase and soft phase eliminate the differences between the two steels.

MITTAL DI-FORM T700, HF80Y100T

Alloy Digest ◽  
2007 ◽  
Vol 56 (2) ◽  
Keyword(s):  
Automotive Industry ◽  
High Strength ◽  
Martensite Phase ◽  
Carbon Steels ◽  
Ferrite Phase ◽  
Dual Phase ◽  
Low Carbon ◽  
Advanced High Strength Steel ◽  
Dp Steels ◽  
Soft Ferrite

Abstract MITTAL DI-FORM T700 and HF80Y100T are low-carbon steels with a manganese and silicon composition. Dual-phase (DP) steels are one of the important advanced high-strength steel (AHSS) products developed for the automotive industry. Their microstructure typically consists of a soft ferrite phase with dispersed islands of a hard martensite phase. The martensite phase is substantially stronger than the ferrite phase. The DI-FORM grades exhibit low yield-to-tensile strengths, and the numeric designation in the name corresponds to the tensile strength. This datasheet provides information on microstructure and tensile properties as well as deformation and fatigue. It also includes information on forming. Filing Code: SA-561. Producer or source: Mittal Steel USA Flat Products.

MITTAL DI-FORM T590, T600

Alloy Digest ◽  
2007 ◽  
Vol 56 (1) ◽  
Keyword(s):  
Tensile Strength ◽  
Automotive Industry ◽  
High Strength ◽  
Martensite Phase ◽  
Ferrite Phase ◽  
Dual Phase ◽  
Bend Strength ◽  
Low Carbon ◽  
Advanced High Strength Steel ◽  
Soft Ferrite

Abstract MITTAL DI-FORM T590 and T600 are low-carbon dual-phase steels containing manganese and silicon. Dual-phase (DP) steels are important advanced high-strength steel (AHSS) products developed for the automotive industry. Their microstructure typically consists of a soft ferrite phase with dispersed islands of a hard martensite phase. The martensite phase is substantially stronger than the ferrite phase. The DI-FORM grades exhibit low yield-to-tensile strength ratios. The numeric designation in the grade name corresponds to the tensile strength in MPa. This datasheet provides information on microstructure, tensile properties, and bend strength as well as fatigue. It also includes information on forming. Filing Code: SA-558. Producer or source: Mittal Steel USA Flat Products.

Strain Hardening Behavior Prediction Model For Automotive High Strength Multiphase Steels

2015 ◽  
Vol 86 (12) ◽  
pp. 1574-1582 ◽  
Author(s):  
Antonella Dimatteo ◽  
Valentina Colla ◽  
Gianfranco Lovicu ◽  
Renzo Valentini
Keyword(s):  
Prediction Model ◽  
Strain Hardening ◽  
High Strength ◽  
Behavior Prediction ◽  
Hardening Behavior ◽  
Strain Hardening Behavior ◽  
Multiphase Steels

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.

scholarly journals Effect of Grain Size on the Microstructure and Strain Hardening Behavior of Solution Heat-Treated Low-C High-Mn Steel

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1489 ◽  
Author(s):  
Marek Opiela ◽  
Gabriela Fojt-Dymara ◽  
Adam Grajcar ◽  
Wojciech Borek
Keyword(s):  
Grain Size ◽  
Strain Hardening ◽  
Strengthening Mechanism ◽  
Strength Properties ◽  
Low Carbon ◽  
Premature Failure ◽  
Hardening Behavior ◽  
Heat Treated ◽  
Strain Hardening Behavior ◽  
Grain Diameter

The low-carbon high-Mn austenitic steel microalloyed with titanium was investigated in this work. The steel was solution heat-treated at different temperatures in a range from 900 to 1200 °C. The aim was to receive a different grain size before the static tensile test performed at room temperature. The samples of different grain sizes showed the different strain hardening behavior and resulting mechanical properties. The size of grain diameter below 19 μm was stable up to 1000 °C. Above this temperature, the very enhanced grain growth took place with the grain diameter higher than 220 μm at 1200 °C. This huge grain size at the highest temperature resulted in the premature failure of the sample showing the lowest strength properties at the same time. Correlations between the grain size, the major strengthening mechanism, and fracture behavior were addressed. The relationships were assessed based on microstructural investigations and fractography tests performed for the deformed samples. The best combination of strength and ductility was found for the samples treated at 1000–1100 °C.

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