Optimization of Strength and Ductility in Ultra-Fine 304 Stainless Steel after Equal-Channel Angular Processing

2010 ◽  
Vol 667-669 ◽  
pp. 937-942 ◽  
Author(s):  
Z.J. Zheng ◽  
Yan Gao ◽  
Y. Gui ◽  
M. Zhu

The microstructure and mechanical properties of 304 stainless steel were investigated which was subjected to equal channel angular pressing (ECAP). Tensile strength, elongation, Vickers hardness of as-ECAPed and annealed ECAPed 304 stainless steel were systematically measured and compared and microstructure evolution during ECAP and ECAP+annealing was observed by OM and TEM. It was found that with the increasing of ECAP passes, the grain size of stainless steel was effectively refined to nanoscale, such as about 50 nm after 8 ECAP-passes. In addition, the dislocation density in ECAPed samplel increased greatly, consequently, the tensile strength and hardness of ECAPed 304 stainless steel increased and elongation decreased remarkably. After annealing at 600°C for 10 min,the ductility of ECAPed stainless steel was improved greatly while grains did not have obvious growth, and strength did not change much. The above results showed that the optimization of strength and ductility in ultra-fined 304 stainless steel can be achieved by appropriate ECAP plus annealing processes.

2019 ◽  
Vol 26 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Yun ZOU ◽  
Zhenkuan SANG ◽  
Qilong WANG ◽  
Tingchao LI ◽  
Dalei LI ◽  
...  

Abstract: In this study, waterjet peening (WJP) treatments under different water pressures were utilized to improve the mechanical properties of 304 stainless steel. The surface morphologies, microstructures, phases, and mechanical properties under different pressures in the WJP process were systematically investigated. The results show that WJP treatments successfully introduced a hardening layer and residual compressive stress. The optimal hardening layer, hardness, residual compressive stress, tensile strength, and ductility were all recorded at the pressure of 200 MPa. The improved hardness, tensile strength, and ductility of 304 stainless steel treated with WJP treatments at the pressure of 200 MPa can be attributed to the hardening layer with much apparent grain refinement effect, phase transformation, smaller surface roughness, and a specific residual compressive stress, as compared with the WJP treatments under other water pressures.


2012 ◽  
Vol 268-270 ◽  
pp. 291-296
Author(s):  
Li Min Wang ◽  
Zhi Hua Gong ◽  
Gang Yang ◽  
Zheng Dong Liu ◽  
Han Sheng Bao

Ultrafine-grain or even nano-grain microstructure can be made by equal channel angular pressing (ECAP), mainly resulting from shear strain. The authors experimentally investigated 00Cr18Ni12 austenitic stainless steel and its mechanical properties during and after ECAP. The results showed that because of larger shear stress, many slipping bands occured inside grains, with the increase of pressing pass, the slipping bands may interact with each other to separate slipping bands into sub-grains, finally, the sub-grains transformed into new grains with large angular boundaries. The grain size was about 200nm after the 7th pass. After the 1st and 2nd pass, the tensile strength was higher 93% and 144% than that without ECAP, the yield strength was 5.3 and 6.6 times of that without ECAP respectively.


2011 ◽  
Vol 682 ◽  
pp. 49-54
Author(s):  
Bin Chen ◽  
Chen Lu ◽  
Dong Liang Lin ◽  
Xiao Qin Zeng

The Mg96Y3Zn1 alloy processed by equal channel angular pressing has been investigated. It was found that the Mg96Y3Zn1 alloy processed by ECAP obtained ultrafine grains and exhibits excellent mechanical properties. After ECAP, the average grain size of Mg96Y3Zn1 alloy refined to about 400 nm. The highest strengths with yield strength of 381.45MPa and ultimate tensile strength of 438.33MPa were obtained after 2 passes at 623K. It was found that cracks were preferentially initiated and propagated in the interior of X-phase during the tensile test. As a result, the elongation of alloy is decreased with pass number increasing.


2013 ◽  
Vol 829 ◽  
pp. 86-90 ◽  
Author(s):  
Mohsen Toofaninejad ◽  
Mahmoud Nili Ahmadabadi

The present paper describes the effect of severe plastic deformation on the microstructure and mechanical properties of AISI type 304 stainless steel by equal channel angular pressing (ECAP) at room temperature. The strain-induced martensitic transformation occurred in the specimens, and martensite phase increased with increasing strain up to 42% for three passes of ECAP. X ray diffraction was used to identify the strain-induced martensite phase and its volume fraction. The martensite phase, mechanical twins and micro hardness have increased with increasing passes of ECAP. Microstructures of specimens show that with increasing strain, subgrains less than microns are susceptible to be created by fragmentation of twins.


2011 ◽  
Vol 117-119 ◽  
pp. 402-408
Author(s):  
Shazarel Shamsudin ◽  
Phoon Chee Yoon

Product with low cost, lightweight and enhanced mechanical properties were the main reasons welding dissimilar materials thrived by most of the industries. The laser welding technique which has high-energy density beam was found suitable of carrying this task. This paper attempts to investigate welding of AISI 304 stainless steel to AISI 1008 steel through Nd:YAG pulse laser method. The main objective of this study was to find out the weldability of these materials and investigate the mechanical properties of the welded butt joints. Peak power, pulse duration and weld speed combinations were carefully selected with the aims of producing weld with a good tensile strength, minimum heat affected zone (HAZ) and acceptable welding profile. Response surface methodology (RSM) approach was adopted as statistical design technique for tensile strength optimization. Statistical based mathematical model was developed to describe effects of each process parameters on the weld tensile strength and for response prediction within the parameter ranges. The microstructure of the weld and heat affected zones were observed via optical microscope. The results indicate the developed model can predict the response within ±9% of error from the actual values.


2021 ◽  
Vol 2117 (1) ◽  
pp. 012018
Author(s):  
Suheni ◽  
A A Rosidah ◽  
D P Ramadhan ◽  
T Agustino ◽  
F F Wiranata

Abstract AISI 1045 and 304 stainless steel are widely used in automotive and industrial fields However, both of these steels have their own advantages and disadvantages. AISI 1045 is not resistant to corrosion but has good wear resistance and low price. Meanwhile, the 304 stainless steel provides good corrosion resistance and mechanical properties but is costly. Their combination is able to provide a good property and reduce the costs. Thus, in order to combine these two metals, shield metal arc welding is carried out using welding groove and electrode variation. The groove variations used were double bevel, V, and double V-groove, additionally, the electrode variations used were E6013 and E7016. Then, the welding results were characterized using the tensile strength and macrostructure analysis. The results revealed that the specimen using E7016 electrode for the double V-groove resulted in the highest tensile test results the value of 270.48 MPa yield strength, 411.49 MPa tensile strength, and 19.81% elongation. The macrostructure analysis showed that the specimens using E7016 electrode gave a narrow HAZ that led to higher mechanical properties.


2017 ◽  
Vol 17 (2) ◽  
pp. 124-129
Author(s):  
K. Sülleiová ◽  
B. Ballóková ◽  
M. Besterci ◽  
T. Kvačkaj

Abstract The development of the nanostructure in commercial pure copper and the strength and ductility after severe plastic deformation (SPD) with the technology of equal channel angular pressing (ECAP) are analysed. Experimental results and analyses showed that both strength and ductility can be increased simultaneously by SPD. The final grain size decreased from the initial 50μm by SPD to 100-300 nm after 10 passes. An increase of the ductility together with an increase of strength caused by SPD are explained by a strong grain refinement and by a dynamic equilibrium of weakening and strengthening, and it is visible on the final static tensile test stress-strain charts.


2020 ◽  
Vol 12 (5) ◽  
pp. 168781401985099 ◽  
Author(s):  
H Abdelrahim ◽  
HB Mohamed ◽  
Peiqing La ◽  
Wei Fuma ◽  
Fuling Ma ◽  
...  

304 stainless steels were prepared by aluminothermic reaction method; first steels are annealed at 1000°C and then rolled at 700°C for different deformation. The microstructures evolution and mechanical properties were distinguished in details. It was found that the steel contains nanocrystalline/submicrocrystalline/microcrystalline austenite and submicrocrystalline ferrite. After rolling to a thickness reduction of 30%, 50%, and 70%, the mechanical properties of the rolled steels were substantially increased, as the deformation increased from 30% to 50%, the tensile strength increased from 650 to 1110 MPa, the yield strength increased from 400 to 665 MPa, and the elongation increased from 8% to 8.5%.


2016 ◽  
Vol 1818 ◽  
Author(s):  
Jairo Alberto Muñoz ◽  
Oscar Fabián Higuera ◽  
José María Cabrera

ABSTRACTThe aim of this work was to study the deformation behavior of an Armco iron after severe plastic deformation by equal channel angular pressing (ECAP). Particular attention was paid to predict the dislocation density by different approaches like the model proposed by Bergström. Experimental measures of dislocation density by different techniques are used in the discussion. Cylindrical samples of ARMCO iron (8mm of diameter, 60mm of length) were subjected to ECAP deformation using a die with an intersecting channel of Φ=90° and outer arc of curvature of ψ= 37° die. Samples were deformed for up to 16 ECAP passes following route Bc. The mechanical properties of the material were measured after each pass by tensile tests. The original grain size of the annealed iron (70 μm) was drastically reduced after ECAP reaching grain sizes close to 300nm after 16 passes.


2012 ◽  
Vol 602-604 ◽  
pp. 602-607
Author(s):  
Ping Wang ◽  
Fu Yin Han ◽  
Yong Sheng Wang ◽  
Lu Geng ◽  
Shao Feng Meng ◽  
...  

The microstructure and mechanical properties of AZ61-4Si magnesium alloy before and after equal channel angular processing (ECAP) were studied. Results show that the matrix α-Mg and divorced eutectic β-Mg17Al12are refined and chinese script type Mg2Si phases are broken to dispersed particles after ECAP. The mechanical properties of the alloy after ECAP are significantly improved. After 4 passes of ECAP, the yield strength is increased from 50MPa to 109 MPa, tensile strength from 129MPa to 237MPa, elongation from 6% to 22%, and hardness from 61.2HBS to71.5HBS. The modification mechanism for microstructure and mechanical properties of the experimental alloy by ECAP was analyzed.


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