Metallurgical Studies on Explosive Welded Aluminium Alloy-Stainless Steel Bimetallic Plates

2012 ◽  
Vol 710 ◽  
pp. 644-649 ◽  
Author(s):  
Pravin Muneshwar ◽  
Satish Kumar Singh ◽  
K. Naresh Kumar ◽  
Bhanu Pant ◽  
K. Sreekumar
Keyword(s):  
Aluminium Alloy ◽  
Welded Joint ◽  
Austenitic Stainless Steels ◽  
Pressure Vessels ◽  
Metallographic Analysis ◽  
Pure Aluminium ◽  
Cryogenic Temperatures ◽  
Lap Shear ◽  
Indian Space Programme ◽  
Cryogenic Pressure Vessels

Aluminium alloys and austenitic stainless steels are often used for construction of cryogenic pressure vessels owing to their attractive properties at cryogenic temperatures. Indian space programme requires AA2219/ICSS1218-SS321 bimetallic components which are machined from explosive welded plates. Pure aluminium sheet is used as an interlayer between aluminium alloy and steel to achieve a satisfactory bond. Internal soundness of the joint is evaluated through ultrasonic testing (UT). The present paper discusses bonding trials carried out by varying the explosive parameters using facilities and expertise of Terminal Ballistic Research Laboratory (TBRL), Chandigarh and M/s Giridhari Explosives Private Limited (GEPL), Hyderabad. The welded joint is extensively characterised with respect to Lap Shear and Ultimate Tensile Strength at ambient temperature and for metallographic analysis.

Cold Stretching of Cryogenic Pressure Vessels From Austenitic Stainless Steels

2011 ◽  
Author(s):  
Jinyang Zheng ◽  
Abin Guo ◽  
Cunjian Miao ◽  
Ping Xu ◽  
Jian Yang ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Pressure Vessels ◽  
High Rate ◽  
Fatigue Properties ◽  
Numerical Studies ◽  
Deformation Hardening ◽  
Considerable Work ◽  
Cryogenic Pressure Vessels ◽  
Strength Improvement

Austenitic stainless steel (ASS) exhibits considerable work-hardening upon deformation while retaining the characteristics of the material. The high rate of austenite deformation hardening was utilized by cold stretching (CS) of cryogenic pressure vessels. A few percent deformation will give the vessel a considerable and homogeneous yield strength improvement, and the wall thickness may be greatly reduced. The authors have conducted extensive experimental and numerical studies on CS of cryogenic pressure vessels from ASS. A summary of our work as well as a brief introduction of the history, standards, safety, and advantages of CS are given in this paper. What should be further investigated, such as fatigue properties of cold stretched ASS especially under cryogenic temperature, design of cold stretched transportable cryogenic vessels based on life, are also presented.

Investigation on Influence Factors of Mechanical Properties of Austenitic Stainless Steels for Cold Stretched Pressure Vessels

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Jinyang Zheng ◽  
Cunjian Miao ◽  
Yaxian Li ◽  
Ping Xu ◽  
Li Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Stainless Steels ◽  
Welded Joint ◽  
Influence Factors ◽  
Austenitic Stainless Steels ◽  
Pressure Vessels ◽  
Welding Procedure ◽  
Preloading Method ◽  
Nickel Equivalent

Cold stretched pressure vessels from austenitic stainless steels (ASS) have been widely used all over the world for storage and transportation of cryogenic liquefied gases. Cold stretching (CS) is performed by pressurizing the finished vessels to a specific pressure to produce the required stress which in turn gives an amount of plastic deformation to withstand the pressure load. Nickel equivalent (Nieq) and preloading, which is introduced in welding procedure qualification for cold stretched pressure vessels, are considered to be important factors to mechanical behavior of ASS. During the qualification, welded joint will be preloaded considering the effect of CS on pressure vessels. After unloading, the preloaded welded joint will go through tensile test according to standard requirements. There are two kinds of preloading method. One is to apply required tensile stress σk on specimen and maintain it for a long time (stress-controlled preloading). The other is to stretch specimen to a specific strain of 9% (strain-controlled preloading). Different preloading and preloading rates may lead to differences in mechanical behavior of preloaded welded joint. In order to understand the effects of nickel equivalent, preloading and preloading rate on the mechanical behavior of ASS for cold stretched pressure vessels, a series of tests were conducted on base metal, welded joint, and preloaded welded joint of ASS EN1.4301 (equivalent to S30408 and AISI 304). As regards to the preloaded welded joint, the ultimate tensile strength (UTS) decreased as the nickel equivalent increased, while the elongation to fracture increased. It was more difficult to meet the available mechanical requirements with strain-controlled preloading case than with stress-controlled preloading case. Rates of preloading had some effect on the mechanical properties of welded joint but nearly no effect on the mechanical properties of preloaded welded joint. These results are helpful for choosing appropriate material and determining a proper preloading method for welding procedure qualification.

Effects of Welding Wire Composition on Microstructure and Mechanical Properties of Welded Joint in Al-Mg-Si Alloy

2022 ◽  
Vol 905 ◽  
pp. 44-50
Author(s):  
Li Wang ◽  
Ya Ya Zheng ◽  
Shi Hu Hu
Keyword(s):  
Mechanical Properties ◽  
Fusion Zone ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Weld Zone ◽  
Xrd Analysis ◽  
Metallographic Analysis ◽  
Strengthening Effect ◽  
Welding Wire ◽  
Microstructure And Mechanical Properties

The effects of welding wire composition on microstructure and mechanical properties of welded joint in Al-Mg-Si alloy were studied by electrochemical test, X-ray diffraction (XRD) analysis and metallographic analysis. The results show that the weld zone is composed of coarse columnar dendrites and fine equated grains. Recrystallized grains are observed in the fusion zone, and the microstructure in the heat affected zone is coarsened by welding heat. The hardness curve of welded joint is like W-shaped, the highest hardness point appears near the fusion zone, and the lowest hardness point is in the heat affected zone. The main second phases of welded joints are: matrix α-Al, Mg2Si, AlMnSi, elemental Si and SiO2. The addition of rare earth in welding wire can refine the grain in weld zone obviously, produce fine grain strengthening effect, and improve the electrochemical performance of weld.

scholarly journals Corrosion of the Welded Aluminium Alloy in 0.5 M NaCl Solution. Part 2: Coating Protection

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2177 ◽  
Author(s):  
Andrey Gnedenkov ◽  
Sergey Sinebryukhov ◽  
Dmitry Mashtalyar ◽  
Igor Vyaliy ◽  
Vladimir Egorkin ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Welded Joint ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Weld Interface ◽  
Open Circuit ◽  
Al Alloy ◽  
Protective Properties ◽  
Coating Formation ◽  
Electrode Technique

The high electrochemical activity of the aircraft 1579 aluminium alloy with a welded joint and the necessity of the coating formation to protect this material against corrosion as well as to increase the stability of the weld interface in the corrosive medium has been previously established. In this work, two suggested methods of protective coating formation based on plasma electrolytic oxidation (PEO) in tartrate-fluoride electrolyte significantly increased the protective properties of the welded joint area of the 1579 Al alloy. The electrochemical properties of the formed surface layers have been investigated using SVET (scanning vibrating electrode technique) and SIET (scanning ion-selective electrode technique), EIS (electrochemical impedance spectroscopy), OCP (open circuit potential), and PDP (potentiodynamic polarization) in 0.5 M NaCl. The less expressed character of the local electrochemical processes on the welded 1579 Al alloy with the composite coating in comparison with the base PEO-layer has been established. Polymer-containing coatings obtained using superdispersed polytetrafluoroethylene (SPTFE) treatment are characterized by the best possible protective properties and prevent the material from corrosion destruction. Single SPTFE treatment enables one to increase PEO-layer protection by 5.5 times. The results of this study indicate that SVET and SIET are promising to characterize and to compare corrosion behaviour of coated and uncoated samples with a welded joint in chloride-containing media.

Producing HP Pump Barrels Utilizing Powder Metallurgy and Hot Isostatic Pressing

2009 ◽  
Author(s):  
Martin Bjurstro¨m ◽  
Carl-Gustaf Hjorth
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Hot Isostatic Pressing ◽  
Austenitic Stainless Steels ◽  
Pressure Vessels ◽  
Uniform Structure ◽  
Isostatic Pressing ◽  
Near Net Shape ◽  
Hip Process

The fabrication of near net shape powder metal (PM) components by hot isostatic pressing (HIP) has been an important manufacturing technology for steel and stainless steel alloys since about 1985. The manufacturing process involves inert gas atomization of powder, 3D CAD capsule design, sheet metal capsule fabrication and densification by HIP in very large pressure vessels. Since 1985, several thousand tonnes of parts have been produced. The major applications are found in the oil and gas industry especially in offshore applications, the industrial power generation industry, and traditional engineering industries. Typically, the components replace castings, forgings and fabricated parts and are produced in high alloy grades such as martensitic steels, austenitic stainless steels, duplex (ferritic/austenitic) stainless steels and nickel based superalloys. The application of PM/HIP near net shapes to pump barrels for medium to high pressure use has a number of advantages compared to the traditional forging and welding approach. First, the need for machining of the components is reduced to a minimum and welding during final assembly is reduced substantially. Mechanical properties of the PM/HIP parts are isotropic and equal to the best forged properties in the flow direction. This derives from the fine microstructure using powder powder and the uniform structure from the HIP process. Furthermore, when using the PM HIP process the parts are produced near net shape with supports, nozzles and flanges integrated. This significantly reduces manufacturing lead-time and gives greater design flexibility which improves cost for the final component. The PM HIP near net shape route has received approval from ASTM, NACE and API for specific steel, stainless steel and nickel base alloys. This paper reviews the manufacturing sequence for PM near net shapes and discusses the details of several successful applications. The application of the PM/HIP process to high pressure pump barrels is highlighted.

Mechanical and Corrosion Behavior of Pure Aluminium Added Friction Stir Weld Joint of Aluminium Alloy

2019 ◽  
Vol 821 ◽  
pp. 327-333
Author(s):  
Sunil Sinhmar ◽  
Dheerendra Kumar Dwivedi
Keyword(s):  
Friction Stir Welding ◽  
Aluminium Alloy ◽  
Corrosion Behavior ◽  
Weld Joint ◽  
Second Phase ◽  
Pure Aluminium ◽  
Nugget Zone ◽  
Friction Stir ◽  
Aluminium Addition ◽  
Aluminium Strip

Friction stir welding (FSW) of AA2014 aluminium alloy was performed by sandwiching pure aluminium (Al) in the form of strip between the abutting surfaces. Mechanical and corrosion behavior of weld joint with and without pure aluminium addition was compared. Friction stir welding was carried out at rotational speed of 931 rpm and traverse speed of 41 mm/min. Pure aluminium strip of 1 mm thickness was used for incorporating Al in weld nugget zone. Microstructure analysis was carried out using optical microscope and FESEM with energy dispersive spectroscopy (EDS). Microhardness and tensile testing were performed on the weld joints. Corrosion behavior was investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (Tafel) test. FESEM analysis was performed before and after corrosion test. Traces of pure aluminium strip were observed in the microstructure. The incorporated strip was found not to be uniformly distributed in the nugget zone. Pure aluminium addition reduced the extent of formation of the second phase particle in the nugget zone as compared to the normal FSW joint i.e. without Al addition. This metallurgical homogeneity resulted in better corrosion resistance of the Al added weld joint than the normal FSW joint.

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