The Effect of Nickel on the Mechanical Properties of High-Oxygen Underwater Wet Welds

1996 ◽  
Vol 118 (2) ◽  
pp. 165-168 ◽  
Author(s):  
A. M. Pope ◽  
J. C. G. Teixeira ◽  
V. R. dos Santos ◽  
M. T. P. Paes ◽  
S. Liu

The use of oxidizing electrodes for wet welding of offshore structural steels, in spite of their low susceptibility to hydrogen HAZ cracking, is limited, in part, by the poor mechanical properties of their weld deposits. Low levels of carbon, manganese, and other deoxidizers, together with high oxygen contents seems to be one of the reasons for this low performance. This work investigated the influence of nickel additions on the tensile strength and impact resistance of wet welds deposited at 1.1 m of water depth. It was found that welds with nickel contents between 2 and 3 weight percent exhibited maximum toughness and tensile strength. Nickel additions also had a strong effect in reducing the grain size of equiaxed ferrite in the reheated region of underwater wet welds, thereby improving their mechanical properties. The drop of mechanical properties for nickel contents higher than 3 weight percent was associated with weld metal solidification cracking.

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2359
Author(s):  
Harmaen Ahmad Saffian ◽  
Masayuki Yamaguchi ◽  
Hidayah Ariffin ◽  
Khalina Abdan ◽  
Nur Kartinee Kassim ◽  
...  

In this study, Kraft lignin was esterified with phthalic anhydride and was served as reinforcing filler for poly(butylene succinate) (PBS). Composites with different ratios of PBS, lignin (L), modified lignin (ML) and kenaf core fibers (KCF) were fabricated using a compounding method. The fabricated PBS composites and its counterparts were tested for thermal, physical and mechanical properties. Weight percent gain of 4.5% after lignin modification and the FTIR spectra has confirmed the occurrence of an esterification reaction. Better thermo-mechanical properties were observed in the PBS composites reinforced with modified lignin and KCF, as higher storage modulus and loss modulus were recorded using dynamic mechanical analysis. The density of the composites fabricated ranged from 1.26 to 1.43 g/cm3. Water absorption of the composites with the addition of modified lignin is higher than that of composites with unmodified lignin. Pure PBS exhibited the highest tensile strength of 18.62 MPa. Incorporation of lignin and KCF into PBS resulted in different extents of reduction in tensile strength (15.78 to 18.60 MPa). However, PBS composite reinforced with modified lignin exhibited better tensile and flexural strength compared to its unmodified lignin counterpart. PBS composite reinforced with 30 wt% ML and 20 wt% KCF had the highest Izod impact, as fibers could diverge the cracking propagation of the matrix. The thermal conductivity value of the composites ranged from 0.0903 to 0.0983 W/mK, showing great potential as a heat insulator.


2015 ◽  
Vol 799-800 ◽  
pp. 115-119 ◽  
Author(s):  
Anika Zafiah M. Rus ◽  
Nur Munirah Abdullah ◽  
M.F.L. Abdullah ◽  
M. Izzul Faiz Idris

Graphite reinforced bio-based epoxy composites with different particulate fractions of graphite were investigated for mechanical properties such as tensile strength, elastic modulus and elongation at break. The graphite content was varied from 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.% by weight percent in the composites. The results showed that the mechanical properties of the composites mainly depend on dispersion condition of the treated graphite filler, aggregate structure and strong interfacial bonding between treated graphite in the bio-based epoxy matrix. The composites showed improved tensile strength and elastic modulus with increase treated graphite weight loading. This also revealed the composites with increasing filler content was decreasing the elongation at break.


2021 ◽  
Vol 7 (8) ◽  
pp. 79528-79537
Author(s):  
Pedro Marcio Munhoz ◽  
Fernando Codelo Nascimento ◽  
Leonardo Gondim de Andrade e Silva ◽  
Julio Harada ◽  
Wilson Aparecido Parejo Calvo

The aim of this research was to evaluate the changes in the mechanical properties of poly(butylene adipate co-terephthalate)/poly(lactic acid) (PBAT/PLA) polymeric blend after the radiation process at different radiation doses. The irradiation was performed in an electron beam accelerator, with 1.5 MeV of energy and 25 mA electric current. The samples were irradiated with doses of 5, 10, 15, 25, 50, 65 and 80 kGy. Both irradiated and non-irradiated samples were characterized by Izod pendulum impact resistance and tensile strength at rupture. The results showed an increase of 44% in relation to Izod impact resistance at a dose of 65 kGy. However, the module of elasticity decreased 56% and tensile strength at rupture decreased 55% at the same radiation dose. In relation to elongation, significant alterations caused by electron beam irradiation was not observed. Therefore, it can be concluded that irradiated blends could be used to make environmentally friendly products, which could absorb impact energy. 


2015 ◽  
Vol 10 (4) ◽  
pp. 155892501501000
Author(s):  
Ramesh Kanagavel ◽  
K. Arunachalam

Mechanical properties of quaternary blending cement concrete reinforced with hybrid fibers are evaluated in this experimental study. The steel fibers were added at volume fractions of 0.5%, 1%, and 1.5 % and polypropylene fibers were added at 0.25% and 0.5% by weight of cementitious materials in the concrete mix individually and in hybrid form to determine the compressive strength, split tensile strength, flexural strength and impact resistance for all the mixes. The experimental results revealed that fiber addition improves the mechanical properties and also the ductility and energy absorption of the concrete. The results also demonstrate that the hybrid steel – polypropylene fiber reinforced concrete performs better in compressive strength, split tensile strength, flexural strength and impact resistance than mono steel and mono polypropylene fiber reinforced concrete.


2018 ◽  
Vol 930 ◽  
pp. 241-247
Author(s):  
J. Fiori Júnior ◽  
Raquel Piletti ◽  
J. Ilha ◽  
M. Pierini ◽  
Humberto Gracher Riella ◽  
...  

This study evaluated the effects of temperature and speed screw rotation of rigid recycled PVC pipe extrusion process on mechanical properties and dimensional variation. In developing the experiments were used the factorial design method type 2k. Were studied the influence of process variables on the properties of impact resistance, dimensional change and tensile strength of PVC pipe. From this study, it was possible to define the best extrusion process conditions with a point of view on the best properties of PVC pipes. The results indicated that the screw rotation has a significant influence on the impact property. For the dimensional variation, the extrusion temperature had a significant influence. There is no significant statistical values for the tensile strength in the studied variables.


2021 ◽  
Vol 903 ◽  
pp. 134-139
Author(s):  
Jānis Zicans ◽  
Remo Merijs Meri ◽  
Tatjana Ivanova ◽  
Andrejs Kovalovs ◽  
Piotr Franciszczak

Investigation presents an experimental study of mechanical properties of hybrid bio-composites made from man-made cellulose fibres and soft wood microfiller embedded into polypropylene homopolymer matrix at different weight contents. Mechanical properties such as elastic modulus, tensile strength, and impact resistance of the reinforced composites determined for various total weight contents of both biobased fillers were used as the design parameters. The problem was solved by planning the experiments and response surfaces method. The results demonstrate that using the both filler types enhance the mechanical properties. The tensile modulus increases by ~115%. The bio-composite with the highest weight content of man-made cellulose fibres and the lowest content of soft wood microfibers possesses maximum tensile strength (more 66 MPa). Addition of man-made cellulose fibres demonstrate a significant influence on the impact resistance of the investigated composites.


2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Kumaraswamy Jayappa ◽  
Vijaya Kumar ◽  
Gange Gowda Purushotham

Hybrid Metal Matrix Composites (HMMCs) have gained wide applications in aerospace, marine, and domestic areas because of its significant properties relative to external forces and enabling environment. In present research work, Ni-alloy selected as a matrix and Al2O3 of 40–80 μm and TiO2 of 1–5 μm were selected as reinforcements. The composites were prepared by keeping 9 wt. % of TiO2 as unvarying and Al2O3 is varied from 3 weight % to 12 weight % in steps of 3 weight %. Induction furnace is used for the casting of composites and mixing is done by using mechanical stirring at 160 rpm for a time period of 5 min. The prepared composites are then tested for their tensile and hardness as per the ASTM standards. The Scanning Electron Microscopy was used for microstructural study. From experimentation, it was observed that increment in the weight percentage of Al2O3 with constant TiO2 increases the mechanical properties of hybrid composites and proper stirring improves homogeneity in the composite material. The test results show that the addition of Al2O3 up to 9 weight percent increases in tensile strength compared to Ni alloy and tensile strength slowly decreases with the addition of Al2O3 and that the hardness values are directly proportional to the weight percent of the addition of Al2O3 / TiO2.


2012 ◽  
Vol 557-559 ◽  
pp. 201-204 ◽  
Author(s):  
Wen Yong Liu ◽  
Yi Chen ◽  
Xi Tu ◽  
Yue Jun Liu ◽  
Xi Hai Hao

The thermoplastic processing and mechanical properties of starch and polyvinyl alcohol (PVA) composites were studied. Glycerol was chosen as the plasticizer and nano-silica (nano-SiO2) as the reinforcing agent of the starch/PVA composites. The results showed that the mechanical properties of the obtained starch/PVA blend were best when the glycerol content was 30% of starch and 20% of PVA, and the weight ratio of PVA and starch was 0.8 (wPVA/ wstarch= 0.8/1). After the addition of nano-SiO2, the mechanical properties of the starch/PVA blends were improved. When the weight percent of nano-SiO2was 2%, the mechanical properties of the SiO2/starch/PVA composite were most excellent. It was shown that the tensile strength was increased by 16% and the elongation increased by 72%. Moreover, it was confirmed by rheological measurements that nano-SiO2could interact with the composite materials, which results in the improvement of the mechanical strength of the starch/PVA composites.


2012 ◽  
Vol 496 ◽  
pp. 134-137 ◽  
Author(s):  
Wen Yong Liu ◽  
Yi Chen ◽  
Long Ouyang ◽  
Yue Jun Liu ◽  
Xi Hai Hao

The thermoplastic processing and mechanical properties of starch and polycaprolactone (PCL) composites reinforced by nano-silica (nano-SiO2) were studied. The results showed that the mechanical properties of the starch/PCL blends improved significantly with the increase of PCL. After the addition of nano-SiO2, the mechanical properties of the starch/PCL blends further improved. When the weight percent of nano-SiO2 was 1.8%, the mechanical properties of the SiO2/TPS/PCL composite were most excellent. By comparison with the starch/PCL (50/50) blends, the tensile strength of the SiO2/TPS/PCL composite with 1.8% SiO2 was increased by 20% and the elongation increased by 33%. Moreover, it was confirmed by rheological measurements that nano-SiO2 could interact with the composite materials, which results in the improvement of the mechanical strength of the TPS/PCL composites.


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