scholarly journals Case Study of the Tensile Fracture Investigation of Additive Manufactured Austenitic Stainless Steels Treated at Cryogenic Conditions

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3328
Author(s):  
Róbert Bidulský ◽  
Jana Bidulská ◽  
Federico Simone Gobber ◽  
Tibor Kvačkaj ◽  
Patrik Petroušek ◽  
...  

Additive manufacturing is a key enabling technology in the manufacture of highly complex shapes, having very few geometric limitations compared to traditional manufacturing processes. The present paper aims at investigating mechanical properties at cryogenic temperatures for a 316L austenitic stainless steel, due to the wide possible cryogenic applications such as liquid gas confinement or superconductors. The starting powders have been processed by laser powder bed fusion (LPBF) and tested in the as-built conditions and after stress relieving treatments. Mechanical properties at 298, 77 and 4.2 K from tensile testing are presented together with fracture surfaces investigated by field emission scanning electron microscopy. The results show that high tensile strength at cryogenic temperature is characteristic for all samples, with ultimate tensile strength as high as 1246 MPa at 4.2 K and 55% maximum total elongation at 77 K. This study can constitute a solid basis for investigating 316L components by LPBF for specific applications in cryogenic conditions.

2014 ◽  
Vol 529 ◽  
pp. 237-241
Author(s):  
Juan Jia ◽  
Shuang Xin Liu ◽  
Dierk Rabbe

The mechanical properties of the rolled isotactic polypropylene and the morphology of fracture surfaces were measured and observed by tensile tests and the scanning electron microscopy. And then the tensile fracture behaviors along the rolling and transvers directions of the rolled samples were analyzed. After rolling, strong anisotropy mechanical properties occurred along the rolling and transverse directions: high tensile strength with low total elongation along the rolling direction and low tensile strength with high total elongation along the transverse direction. After tensile test, three characteristic structures were found on the fracture surfaces. The tensile fracture behavior of the rolled samples is: stress concentration happens on the edge of tensile sample and then fracture develops to the center part of the tensile sample. When the fracture is big enough, the tensile sample will be failed very quickly.


2013 ◽  
Vol 699 ◽  
pp. 795-801 ◽  
Author(s):  
Subha Kumpaty ◽  
Sheku Kamara ◽  
Brandon Tomlin ◽  
Jisun Yoo ◽  
Hephzibah Kumpaty ◽  
...  

Greatbatch Medical, specializing in orthopedic implants and instruments, is currently utilizing direct metal laser sintering (DMLS) technology to develop concept prototypes. Greatbatch uses EOS GP1 Stainless Steel which adheres to the American standard for 17-4 Precipitation Hardened SS. Following DMLS, Greatbatch heat treats its parts to obtain desirable mechanical properties. In this study, three different heat treatment methods were examined: heat treatment and stress relief (HT+SR), stress relief (SR), and solution aging and annealing (SAA). The Vickers Hardness Test and the Tensile Strength Test were used to assess the mechanical properties of each sample. The research also included grain structure analysis using a Scanning Electron Microscope and surface roughness studies via profilometer measurements. For example, the HT+SR sample yielded 456 HV (hardness), an ultimate tensile strength of 1319 MPa, an yield strength of 1120 MPa, and 6.36% elongation. It was found that compared to the untreated sample, HT+SR decreased the total elongation by 73% and SAA decreased total elongation by 17% and additionally decreased hardness by 17%. It was learnt that stress relieving the part after DMLS was the superior method of choice based on its resulting mechanical properties. It was found that the grain structure of the non-treated sample resembled a solution treated sample and the stress-relieved sample actually matched an age-hardened sample. The sample that was precipitation hardened was actually over-aged. Thus it was found that the DMLS process seemed to be acting as an aging process while simultaneously building the part. Further studies in examining specific effects of DMLS and how it impacts what order heat treatments should follow would be appropriate.


2013 ◽  
Vol 849 ◽  
pp. 50-57 ◽  
Author(s):  
N.V. Amudarasan ◽  
K. Palanikumar ◽  
K. Shanmugam

In this study, AISI 316 L types of austenitic stainless steels are welded by GTAW (gas tungsten arc welding) using 430L and 2209 filler metals, respectively. Mechanical properties of 316L austenitic stainless steel weldments, such as tensile properties, hardness and impact properties are determined. GTA weld microstructures are presented by optical microscopy with 1000X magnifications of weld metal region. The values obtained for ultimate tensile strength, yield strength and percentage of elongation for the welded joints are compared to the data obtained. From this investigation, the result shows that the yield, tensile strength and impact energy values of 316L stainless steels welded by GTAW using 2209 filler metal is superior compared to 430L filler metal.


2014 ◽  
Vol 915-916 ◽  
pp. 576-582 ◽  
Author(s):  
H. C. Wu ◽  
B. Yang ◽  
Ming Xian Zhang ◽  
Sheng Long Wang ◽  
Y. Z. Shi

The effect of forging and solution temperature on the microstructure and mechanical properties of 316LN stainless steel has been investigated by optical microscope, tensile testing machine and scanning electron microscope (SEM). The results show that the average grain size of the steel was refined from 150μm to 70μm after forging and solution treatment. With increasing solution temperature, the tensile strength and yield strength decreased. On the contrary, the elongation of the steel increased with increasing solution temperature except at 1200°C. The tensile strength of the samples forged at 1100°C is better than those of the samples forged at 1000 and 1200°Cafter solution treatment. Tensile fracture morphologies observation showed that all the specimens have ductile fracture morphologies. With increasing solution temperature, the toughness of the steel becomes better and better except at 1200°C. Both the microstructure and mechanical properties of the 316LN stainless steel have been improved after forging at 1100°C and following by solution treatment at 1150°C.


2012 ◽  
Vol 472-475 ◽  
pp. 707-711
Author(s):  
Guan Lu ◽  
Ya Qin Yang ◽  
Bao Cheng Li ◽  
Zhi Min Zhang

In this paper, the effects of hot extrusion and T5、T6 heat treatment on the microstructures and mechanical properties of ZK60 magnesium alloys are investigated by optical microscope, electronic scanning microscope and mechanical testers. The result shows that both the tensile strength and the elongation of the ZK60 alloy extruded at 380°Care much higher than that of the as-cast alloys, as there are much granular second phases precipitated during the extrusion. The tensile strength of the extruded and T5 treated alloy increases while the elongation decreases faster than that of the extruded alloy. The strengthening effect of the T6 treatment is inferior to that of the T5 treatment. The tensile fracture of the as-cast alloy is brittle fractured while that of the extruded and T5 treated alloy is ductile fractured with lots of deep and even dimples.


2013 ◽  
Vol 753 ◽  
pp. 473-476 ◽  
Author(s):  
Naoto Sakai ◽  
Kunio Funami ◽  
Masafumi Noda ◽  
Hisashi Mori ◽  
Kenji Fujino

In the present study, the grain refinement, grain growth behavior, and tensile properties of rolled and annealed AZX311 Mg alloys were investigated. The yield strength and ultimate tensile strength of the rolled material were 360 MPa and 370 MPa, respectively, and the total elongation was 5%. When annealing was performed at 423 K for 1hr, the yield strength and ultimate tensile strength were unchanged, but the elongation increased to 10%. Furthermore, the strength and elongation did not change for annealing temperatures of 473–673 K owing to Al2Ca precipitations.


2016 ◽  
Vol 879 ◽  
pp. 2528-2531
Author(s):  
Akira Yanagida ◽  
Ryo Aoki ◽  
Masataka Kobayashi

A Nb alloyed low carbon steel was processed by hot equal channel angular extrusion (ECAE) and following transformation. The workpieces were heated up to the 960°C in the furnace for 10 min within the container block. Before extrusion, the die was preheated to 400oC. The workpiece was cooled in the die after ECAE process. 1 pass and 2 pass via route C were conducted at a speed of 32mm/s, the inter-pass time is about 2 sec. The sample of average ferrite grain size of about 2μm, a tensile strength of 800MPa, a total elongation about 20% is produced after 2 pass ECAE processed and subsequent cooling.


2015 ◽  
Vol 808 ◽  
pp. 28-33 ◽  
Author(s):  
Constantin Dulucheanu ◽  
Nicolai Bancescu ◽  
Traian Severin

In this article, the authors have analysed the influence of quenching temperature (TQ) on the mechanical properties of a dual-phase steel with 0.094 % C and 0.53% Mn. In order to obtain a ferrite-martensite structure, specimens of this material have been the subjected to intercritical quenching that consisted of heating at 750, 770, 790, 810 and 830 °C, maintaining for 30 minutes and cooling in water. These specimens have then been subjected to metallographic analysis and tensile test in order to determine the volume fraction of martensite (VM) in the structure, ultimate tensile strength (Rm), the 0.2% offset yield strength (Rp0.2), the total elongation (A5) and the Rp0.2/Rm ratio.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2276
Author(s):  
Rozyanty Rahman ◽  
Syed Zhafer Firdaus Syed Putra ◽  
Shayfull Zamree Abd Rahim ◽  
Irwana Nainggolan ◽  
Bartłomiej Jeż ◽  
...  

The demand for natural fiber hybrid composites for various applications has increased, which is leading to more research being conducted on natural fiber hybrid composites due to their promising mechanical properties. However, the incompatibility of natural fiber with polymer matrix limits the performance of the natural fiber hybrid composite. In this research work, the mechanical properties and fiber-to-matrix interfacial adhesion were investigated. The efficiency of methyl methacrylate (MMA)-esterification treatments on composites’ final product performance was determined. The composite was prepared using the hand lay-up method with varying kenaf bast fiber (KBF) contents of 10, 15, 20, 25, 30, 35 (weight%) and hybridized with glass fiber (GF) at 5 and 10 (weight%). Unsaturated polyester (UPE) resin and methyl ethyl ketone peroxide (MEKP) were used as binders and catalysts, respectively. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to examine the effects of MMA-esterification treatment on tensile strength and morphology (tensile fracture and characterization of MMA-esterification treatment) of the composite fabricated. The tensile strength of MMA-treated reinforced UPE and hybrid composites are higher than that of untreated composites. As for MMA treatment, 90 min of treatment showed the highest weight percent gain (WPG) and tensile strength of KBF-reinforced UPE composites. It can be concluded that the esterification of MMA on the KBF can lead to better mechanical properties and adhesion between the KFB and the UPE matrix. This research provides a clear reference for developing hybrid natural fibers, thus contributing to the current field of knowledge related to GF composites, specifically in transportation diligences due to their properties of being lightweight, superior, and involving low production cost.


2010 ◽  
Vol 146-147 ◽  
pp. 678-681
Author(s):  
Zheng You Tang ◽  
Hua Ding

The effect of the partial substitution of Si by Al on the microstructures and the mechanical properties of cold rolled C-Mn-Si TRIP steel was investigated. The results show that the partial substitution of Si by Al could refine the microstructures, increase the volume fraction of ferrite and retained austenite. In addition, the excellent mechanical properties of the Al partial substituted TRIP steel could be obtained, the tensile strength, total elongation and strength-ductility of C-Mn-Si-Al TRIP steel are 739MPa, 38% and 28082MPa%, respectively.


Sign in / Sign up

Export Citation Format

Share Document