Surface Crack and Organization of Hot Rolled S31803 Duplex Stainless Steel Bars

2014 ◽  
Vol 670-671 ◽  
pp. 41-45
Author(s):  
Ming Hua Wu ◽  
Zhan Ying Liu ◽  
Hui Yang

In bar rolling of S31803 duplex stainless steel, the surface crack is easy to appear. Through the observation on the microstructure, ferrite and austenite morphology and phase ratio were analyzed. The surface cracks of S31803 duplex stainless steel bar is mainly because of the dual phase microstructure softening mechanism of different in thermal processing, and the double phase stainless steel heat plasticity decrease. When the ferrite and austenite proportion close, and the heating temperature is too high, to reduce the binding force between the grains of billet surface, easy to cause the crack surface of a bar.

2018 ◽  
Vol 941 ◽  
pp. 118-123
Author(s):  
Dagoberto Brandão Santos ◽  
Raphael França Assumpção ◽  
Daniela Barçante Perasoli ◽  
Dalila Chaves Sicupira

The UNS S32205 duplex stainless steel was warm rolled at 600°C with 60 and 80% of thickness reduction. The microstructure was characterized by optical, scanning and transmission electron microscopy, X-ray diffractometry and EBSD. The corrosion resistance was evaluated by electrochemical behavior in the chlorine ion environment using potentiodynamic polarization measurements. The tensile strength reached 1185 MPa and 1328 MPa, after warm rolling with 60 and 80%, respectively. In steel as-supplied, hot rolled and annealed, the tensile strength was 774 MPa. Ferrite microtexture presented the α-fiber and the rotated cube component, while the austenite enhanced the brass, copper, and cube components to a lesser extent. The substructure was characterized by intense formation of tangles and forests of dislocations and discrete subgrains in the ferritic phase and by planar gliding of dislocations and formation of dense dislocations walls in the austenite. Despite the existence of a certain similarity among the values of pitting potentials obtained for all samples, the number of pits observed was higher in the as-received sample, followed by the samples with 60 and 80% reduction. These results draw attention to innovative routes in the industrial production of duplex stainless steel of this class, even considering ductility lost. Keywords: Warm rolling; Mechanical strength; Texture; Substructure; Corrosion resistance


2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Mehmet Emin Arıkan ◽  
Rafet Arıkan ◽  
Mustafa Doruk

In the present study as in our previous studies (Arikan and Doruk, 2008 and Arikan et al., 2012), similar specimens taken from a hot rolled cylindrical duplex stainless steel (DSS) bar with 22% Cr grade were solution annealed at 1050°C and then aged at 800∘C from 100 to 31622 min for sensitization treatment. Double loop electrochemical potentiodynamic reactivation and standard weight loss immersion acid tests were conducted. The solution annealed samples were found unsensitized. The samples aged for 100 min were less sensitized whereas samples aged for 316 min and more time were sensitized. The degree of sensitization (DOS) can be attributed to higher contribution of chromium and molybdenum depleted areas that result from intermetallic phases. However, especially the samples aged from 3162 to 31622 min have revealed chromium replenishment. Consequently, the degree of sensitization was lowered in comparison to the results obtained in previous studies.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Mehmet Emin Arıkan ◽  
Rafet Arıkan ◽  
Mustafa Doruk

Specimens taken from a hot-rolled cylindrical duplex stainless steel (DSS) bar with 22% Cr grade were solution annealed at1050∘C and then aged at725∘C from 100 to 31622 min for sensitization treatment. Double loop electrochemical potentiodynamic reactivation and standard weight loss immersion acid tests were conducted. The solution-annealed samples were found unsensitized. Those samples aged for 100 and 316 min were less sensitized whereas samples aged for 1000 min and especially those aged for 3162, 10000, and 31622 min were heavily sensitized. The degree of sensitization (DOS) can be attributed to higher contribution of chromium- and molybdenum-depleted areas resulting from intermetallic phases.


2013 ◽  
Vol 470 ◽  
pp. 15-18
Author(s):  
Hui Zhang ◽  
Yong Jun Zhang ◽  
Jing Tao Han ◽  
Yuan Dong ◽  
Jie Ren Hu

In hot rolling process of 2205 duplex stainless steel, it was found that bright line defects are mainly located at where is about distance of 200 mm from two sides of hot rolled plate. The forming reason of bright line defects is studied by means of metallographic microscope, scanning electron microscope (SEM) combined with energy dispersive spectrometer (EDS). It is concluded that the formation of bright line defects has associated with sticking and that the temperature reduction on the edge of hot rolling plate causes a high percentage of austenite phase which is network structure. In order to prevent or avoid the happening of the sticking phenomenon, it is necessary to uniformly distribute the oxide on the strip surface by controlled rolling process.


2007 ◽  
Vol 539-543 ◽  
pp. 4981-4986 ◽  
Author(s):  
Enrique Real ◽  
Cristina Rodríguez ◽  
A. Fernández Canteli ◽  
F.Javier Belzunce

The influence of shot peening on the fatigue properties of duplex stainless steel reinforcing bars manufactured using both hot and cold rolled processes was studied. From determination of the S-N curves, the experimental results show that shot peening improves the fatigue behaviour of the re-bars, but that the improvement is much greater for the hot rolled bars. A more severe peening action capable of promoting greater plastic deformation of the bar surface needs to be used to improve the fatigue resistance of cold rolled corrugated bars.


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