Hydrogen Response of 304 SS and Ti Weld Realised by Explosion

2014 ◽  
Vol 782 ◽  
pp. 166-171 ◽  
Author(s):  
Eva Mazancová ◽  
Dmytro Ostroushko
Keyword(s):  
Intermetallic Phase ◽  
Threshold Level ◽  
Fatigue Tests ◽  
Commercial Purity ◽  
Thick Plates ◽  
Fracture Surfaces ◽  
Heat Treated ◽  
Hydrogen Induced Cracking ◽  
Hydrogen Response

Welds of thick plates (304 SS) cladded with Ti of commercial purity both in as received state and subsequently heat treated (HT, 600°C/1.5 h/air), charged by hydrogen, were investigated after fatigue tests (tension-pressure) with amplitude of 20 Hz. Simultaneously, samples of above mentioned welds were also exposed in H2S in accord with NACE Standard TM0284-2011 to find hydrogen induced cracking (HIC) response. Charged welds after the HT showed by 15 MPa higher threshold level than the welds without the HT. The HIC tests generally demonstrated favourable results both after as weld state and after subsequent HT. Short and thin cracks were observed, exclusively located in intermetallic phase areas, where approx. 16-20 wt. % of Ti was revealed. Fracture surfaces of fatigue bars showed maximal failure in areas with 42-97 wt. % of Ti.

scholarly journals Joint Hydrogen Susceptibility of 304 SS Welded with Titanium/ Podatność Połczenia Na Wodorowanie W Układzie Plateru Stal 304 Ss Zgrzewanym Wybuchowo Z Tytanem

2014 ◽  
Vol 59 (4) ◽  
pp. 1605-1610 ◽  
Author(s):  
E. Mazancová ◽  
D. Ostroushko ◽  
K. Saksl ◽  
A. Niesłony
Keyword(s):  
Heat Treatment ◽  
Intermetallic Phase ◽  
Threshold Level ◽  
Fatigue Tests ◽  
Subsequent Heat Treatment ◽  
Commercial Purity ◽  
Thick Plates ◽  
Hydrogen Charging ◽  
Hydrogen Induced Cracking ◽  
Monochromatic Synchrotron

Abstract Welds of thick plates (304 SS) clad with Ti of commercial purity in as-received state and also after subsequent heat treatment and/or after hydrogen charging were investigated. Fatigue tests were carried out at amplitude of 20 Hz and in case of bimetal without hydrogen charging also at amplitude of 40 Hz. After heat treatment, charged welds showed higher threshold level than the welds without heat treatment. Energy dispersed analyses (EDA) of fracture surfaces showed that failure predominantly occurred in joint. Hydrogen induced cracking (HIC) response of bimetal samples demonstrated favourable results both after welding and after subsequent heat treatment. Short and thin cracks were observed, exclusively located in mixed zone, where approx. 16-20 at. % of Ti using EDX (energy dispersed analyser) was revealed. By application of monochromatic synchrotron radiation Ti-α , Fe-fcc, Fe-bcc and intermetallic phase Fe2Ti were detected.

scholarly journals Low Cycle Fatigue Characteristics of Oxygen-Free Copper for Electric Power Equipment

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4237
Author(s):  
Takuma Tanaka ◽  
Togo Sugioka ◽  
Tatsuya Kobayashi ◽  
Ikuo Shohji ◽  
Yuya Shimada ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electric Power ◽  
Stress Amplitude ◽  
Low Cycle Fatigue ◽  
Ebsd Analysis ◽  
Fatigue Properties ◽  
Power Equipment ◽  
Cycle Fatigue ◽  
Fracture Surfaces ◽  
Heat Treated

The effect of heat treatment on tensile and low cycle fatigue properties of the oxygen-free copper for electric power equipment was investigated. The heat treatment at 850 °C for 20 min, which corresponds to the vacuum brazing process, caused the grain growth and relaxation of strain by recrystallization, and thus, the residual stress in the oxygen-free copper was reduced. The tensile strength and 0.2% proof stress were decreased, and elongation was increased by the heat treatment accompanying recrystallization. The plastic strain in the heat-treated specimen was increased compared with that in the untreated specimen under the same stress amplitude condition, and thus, the low cycle fatigue life of the oxygen-free copper was degraded by the heat treatment. Striation was observed in the crack initiation area of the fractured surface in the case of the stress amplitude less than 100 MPa regardless of the presence of the heat treatment. With an increase in the stress amplitude, the river pattern and the quasicleavage fracture were mainly observed in the fracture surfaces of the untreated specimens, and they were observed with striations in the fracture surfaces of the heat-treated ones. The result of the electron backscattered diffraction (EBSD) analysis showed that the grain reference orientation deviation (GROD) map was confirmed to be effective to investigate the fatigue damage degree in the grain by low cycle fatigue. In addition, the EBSD analysis revealed that the grains were deformed, and the GROD value reached approximately 28° in the fractured areas of heat-treated specimens after the low cycle fatigue test.

Effects of T5 and T6 Heat Treatments Applied to Rheocast A356 Parts for Automotive Applications

2008 ◽  
Vol 141-143 ◽  
pp. 237-242 ◽  
Author(s):  
Mario Rosso ◽  
Ildiko Peter ◽  
R. Villa
Keyword(s):  
Fatigue Behaviour ◽  
Cyclic Stress ◽  
Industrial Applications ◽  
Fatigue Tests ◽  
Controlled Cooling ◽  
Test Analysis ◽  
Heat Treated ◽  
Mechanical Performances ◽  
Semi Solid ◽  
Number Of Cycles

The correlation between the evaluation of the mechanical and of the fatigue behaviour of the rheocast, T5 and T6 heat treated SSM A356 aluminium alloy with respect to the microstructures of the component has been investigated. The study has been carried out on a suspension arm injected in a rheocasting 800 tons plant in Stampal S.p.A. The new rheocasting is a process that allows obtaining the alloys in a semisolid state directly from the liquid state, by controlled cooling of the molten alloys. The resulting microstructures are very fine, free from defects and homogeneous: these characteristics improve the mechanical properties of the alloys and specially the response to cyclic stress, an important issue for a suspension component. After a preliminary tensile test analysis, axial high frequency fatigue tests have been carried out at room temperature on specimen cut out from the suspension arm to determine the Wöhler curve and the number of cycles to failure. The results of this work allow a comparison of the effects of heat treatment process, T5 or T6, on Semi-Solid components for industrial applications in the automotive field. On the basis of these analysis the correlation between microstructure and mechanical performances can be established.

Fatigue tests of butt welds and plates edges of 80 mm thick plates

2011 ◽  
pp. 511-519
Author(s):  
H von Selle ◽  
O Doerk ◽  
J Kang ◽  
J Kim
Keyword(s):  
Fatigue Tests ◽  
Thick Plates ◽  
Butt Welds

Study of Fatigue Properties of AISI4130 Steel Joined by Upset Welding in Heat Treated Condition

2012 ◽  
Vol 567 ◽  
pp. 54-57
Author(s):  
H. Mollazadeh ◽  
R. Nouruzi
Keyword(s):  
Fracture Surface ◽  
Weld Interface ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Final Fracture ◽  
Treated Condition ◽  
Heat Treated ◽  
Proeutectoid Ferrite ◽  
Heat Treated Condition ◽  
Interface Study

Resistance upset welding (UW) is a widely used for joining metals parts. In this research, the fatigue properties of AISI4130 steel joined by upset welding in annealed and quenched-tempered heat treated condition are investigated. Microstructure of weld and base metals was studied using optical microscopy. Tensile, impact and fatigue tests were performed and the final fracture surface was studied by scanning electron microscopy (SEM). The fatigue resistance is better for tempered martensite base metal than for the ferrite-pearlite and upset welded specimens. Results shows during the welding, proeutectoid ferrite phase forms at the interface which reduce the fatigue strength of welded specimens. Fractography of fatigue and tension welded samples indicated that in all samples fracture occurred in the middle of weld interface. Study of fracture surface of fatigue samples shows that the final fracture mode for welded samples is cleavage.

Effect of Heat Treatment on the Creep Properties of Ti-22Al-27Nb/TiB Composite

2007 ◽  
Vol 345-346 ◽  
pp. 545-548
Author(s):  
Satoshi Emura ◽  
Masuo Hagiwara
Keyword(s):  
Heat Treatment ◽  
Intermetallic Phase ◽  
Powder Metallurgy Method ◽  
Ingot Metallurgy ◽  
Creep Properties ◽  
Matrix Microstructure ◽  
Heat Treated ◽  
The Matrix ◽  
Annealing Heat Treatment ◽  
Annealing Heat

A TiB particulate-reinforced Ti-22Al-27Nb (mol%) alloy, based on the orthorhombic intermetallic phase, was prepared using gas atomization powder metallurgy method. In the as-atomized condition, extremely fine TiB particulates of less than 1-μm diameter and 5-μm length were dispersed in the matrix. After annealing heat treatment (heat treated at 1423 K with subsequent furnace cooling), this composite exhibited a lamellar matrix microstructure and showed better creep properties than a composite produced using conventional ingot metallurgy method, with coarse TiB particulates of 5-μm diameter and 40-μm length. Coarsening of the matrix microstructure and growth of TiB particulates occurred after annealing heat treatment at higher temperature (ca. 1473 K). Creep-resistance improvement was also observed, which seemed to be mainly attribute to the effect of the matrix microstructure. From measurements of stress components and activation energy, all composites showed an identical creep mechanism: dislocation-controlled creep.

Fatigue Properties of a Ck45 Steel Coated with a Post-Heat Treated Ni-Cu-P Electroless Deposit

2006 ◽  
Vol 514-516 ◽  
pp. 574-578
Author(s):  
Sasan Yazdani ◽  
N. Parvini-Ahmadi ◽  
Tohid Saeid
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Crack Nucleation ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Interfacial Cracks ◽  
Heat Treated ◽  
Base Steel ◽  
Surface Notch

The Fatigue tests under rotating bending conditions have been conducted on samples of a quenched and tempered Ck45 steel in two different conditions: (a) uncoated, (b) coated with an electroless Ni-Cu-P deposit, followed by a post-heat treatment (PHT) at 673 K for 1 h. Such a deposit had a thickness of approximately 10µm, with Cu and P contents of 6wt.% and 13.7wt.% respectively. The results indicate that plating the base steel with this kind of deposit leads to a reduction of the fatigue life of the material. The reduction in fatigue life has been quantified in terms of the Basquin parameters of the materials tested under different conditions. The microscopic observation of the fracture surfaces of the samples indicates that the reduction in fatigue life is associated with the nucleation of fatigue cracks on the coating-substrate interface and the deposit remains well adhered to substrate during fatigue testing since interfacial cracks have been very rarely observed. It is therefore concluded that, in the present case, the interface acts as a surface crack source or surface notch, which decreases the fatigue life of the coated material by reducing the crack nucleation stage.

scholarly journals Microstructural, Surface Topology and Nanomechanical Characterization of Electrodeposited Ni-P/SiC Nanocomposite Coatings

2019 ◽  
Vol 9 (14) ◽  
pp. 2901 ◽  
Author(s):  
Konstantinos Tsongas ◽  
Dimitrios Tzetzis ◽  
Alexander Karantzalis ◽  
George Banias ◽  
Dimitrios Exarchos ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Computational Models ◽  
Intermetallic Phase ◽  
Three Dimensional ◽  
Surface Topology ◽  
Nanocomposite Coatings ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior ◽  
Heat Treated

In the present study, nickel phosphorous alloys (Ni-P) and Ni-P/ silicon carbide (SiC) nanocomposite coatings were deposited by electrodeposition on steel substrates in order for their microstructural properties to be assessed while using SEM, XRD, and three-dimensional (3D) profilometry as well as nanoindentation. The amorphisation of the as-plated coatings was observed in all cases, whereas subsequent heat treatment induced crystallization and Ni3P intermetallic phase precipitation. Examination of the surface topology revealed that the surface roughness follows the deposition characteristics and heat treatment induced microstructural changes. Additionally, substantial improvements in mechanical properties, including hardness, yield stress, and elasticity modulus, were obtained for the Ni-P, Ni-P/SiC nanocomposites when heat treated as seen from the nanoindentation results. A Finite Element Analysis (FEA) was developed to simulate the nanoindentation tests that enable the precise extraction of the Ni-P and Ni-P/SiC nanocomposite coatings’ stress-strain behavior. It is shown that the correlation between the nanoindentation tests and the computational models was satisfactory, while the stress-strain curves revealed higher yield points for the heat-treated samples.

scholarly journals Cr Segregation and Impact Fracture in a Martensitic Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 843 ◽  
Author(s):  
Eleonora Bolli ◽  
Alessandra Fava ◽  
Paolo Ferro ◽  
Saulius Kaciulis ◽  
Alessio Mezzi ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Photoelectron Spectroscopy ◽  
Martensitic Stainless Steel ◽  
Steel Matrix ◽  
X Ray ◽  
Fracture Surfaces ◽  
Heat Treated ◽  
Brittle Fractures ◽  
Cr Concentration ◽  
Inner Parts

The fracture surfaces of a 10.5 wt.% Cr martensitic stainless steel broken in Charpy tests have been investigated through X-ray photoelectron spectroscopy (XPS). The specimens have been examined in two different conditions: as-quenched and heat treated for 10 h at 700 °C. The trends of Fe/Cr ratio vs. test temperature are similar to the sigmoidal curves of absorbed energy and, after both ductile and quasi-cleavage brittle fractures, such ratio is always significantly lower than the nominal value of the steel chemical composition. Cr segregation does not occur on a macroscopic scale but takes place in microscopic zones which represent weaker spots in the steel matrix and a preferred path for moving cracks. Small area (diameter 300 µm) XPS measurements evidenced a higher density of such microscopic zones in the inner part of probes; this is explained by the different diffusion length of Cr atoms in the external and inner parts during quenching from austenitic field which has been calculated through FEM simulations. No significant differences of Cr concentration were observed in fracture surfaces of probes with and without heat treatment. The results highlight how Cr segregation plays a role not only in the intergranular mode of fracture but also in the quasi-cleavage and ductile ones.

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