scholarly journals Effect of Annealing Process on Microstructure, Texture, and Mechanical Properties of a Fe-Si-Cr-Mo-C Deep Drawing Dual-Phase Steel

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 777
Author(s):  
Hongbo Pan ◽  
Xiaohui Shen ◽  
Dongyang Li ◽  
Yonggang Liu ◽  
Jinghua Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cooling Rate ◽  
Deep Drawing ◽  
Dual Phase Steel ◽  
Annealing Temperature ◽  
Recrystallization Process ◽  
Dual Phase ◽  
R Value ◽  
Thermal Dilation

Dual phase steel generally has poor deep drawing property with a low r value less than 1.0, making it difficult to be used for deep drawing automotive parts. In order to improve the mechanical properties of the steel through heat treatment, effect of heat treatments with different conditions on a Fe-Si-Cr-Mo-C deep drawing dual-phase steel was investigated with the aim of identifying effective heat treatment parameters for effective modification towards optimal properties. Relevant thermal dilation and heat treatment experiments were performed. Corresponding characters were investigated. The results show that island martensite can be obtained at low cooling rate. With the increase of cooling rate, the formation of pearlite and bainite is favored. During annealing at low temperatures, recrystallization of the steel is incomplete with the presence of the shear bands. With the increase of annealing temperature, the recrystallization process is gradually complete, and the number of high angle grain boundaries increases significantly. The ratio of gamma orientation components to alpha orientation components decreases first and then increases with the increase of annealing temperature. The strain hardening exponent and r value show an upward trend with respect to annealing temperature, and the r value is as high as 1.15.

Microstructures, Mechanical Properties and Textures of Deep Drawing Dual-Phase Steel

2012 ◽  
Vol 535-537 ◽  
pp. 670-673
Author(s):  
Jie Yun Ye ◽  
Zheng Zhi Zhao ◽  
Zhi Gang Wang ◽  
Ai Min Zhao ◽  
Jing Jing Chen
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Dual Phase Steel ◽  
Tensile Tests ◽  
Rolled Sheet ◽  
Dual Phase ◽  
Annealing Texture ◽  
Average Grain Size ◽  
R Value ◽  
Heterogeneous Deformation

C-Mn-Cr-Mo dual phase steel was piloted in laboratory. OM, SEM, tensile tests and XRD were used to characterize the microstructures, mechanical properties and to determine the texture. The results indicate that when annealed at 860 °C, the tensile strength of the tested steel is 440 MPa, elongation and r value exceed 35% and 1.4, respectively. With the temperature increases from 820°C to 860°C, the average grain size of ferrite increases and ferrite trends to be uniform gradually, therefore, the r value increase gradually. When the temperature is higher than 860°C, bainite forming results in reducing of r value. Al could weaken the tendency of heterogeneous deformation and modified the annealing texture by refining hot-rolling grain size. Mo-based carbides existed in hot-rolled sheet developed {111} texture in the stage of ferrite recrystallization, then re-dissolved in intercritial annealing stage so as to improve hardenability.

Research of the Continuous Annealing Process to Eliminate the "Band" Feature of Dual Phase Steels

2016 ◽  
Vol 867 ◽  
pp. 45-49
Author(s):  
Ji Lin Chen ◽  
Guo Hui Zhu ◽  
Jian Zhang ◽  
Yong Gang Liu ◽  
Hong Bo Pan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Dual Phase Steel ◽  
Annealing Temperature ◽  
Annealing Process ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Steel Sheets ◽  
Scanning Electron

A new continuous annealing process which can eliminate the "band" feature of dual phase steels has been designed. The sheets were annealed in MULTIPAS annealing simulator under variation of annealing temperature. The microstructure evolution of dual-phase steel sheets annealed at intercritical temperatures, were analyzed by optical microscopy and scanning electron microscopy. And the properties were compared with the sheets which annealed by the existing annealing process. The results show that: the "band" feature of dual-phase steel can be effectively eliminated by the optimizing continuous annealing process,and the mechanical properties are improved.

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