scholarly journals Pengaruh VariasiArus dan Posisi Pengelasan SMAW terhadap Sifat Mekanik Baja ST 37

2021 ◽  
Vol 14 (2) ◽  
pp. 134-139
Author(s):  
Iwan Nugraha Gusniar ◽  
Ahmad Juhri ◽  
Viktor Noubnome

The purpose of this study was to determine the difference in the value of tensile strength, impact and microstructure test results on ST 37 steel plates due to variations in current strength of 80 A, 85 A and 90 A and 1G, 2G and 3G welding positions. The results of this study show the value of Max.load, current strength of 80 A 3G welding position gets the highest value of 5650 kgf, value of Tinsile strength, current strength of 80 A 3G welding position gets the highest value of 44.78 (kgf/mm2), then the strain value, the current strength of 80 A for the 3G welding position gets the highest value of 0.9% and the value of the modulus of elasticity, the current strength of 80 A for the 3G welding position gets the highest value of 97.94 (GPa,KN/mm2), In the value of the impact test results, the current strength of 80 A is the 1G welding position that gets the highest value, which is 116 Joules. In the observation of microstructure testing, 3 points were carried out, Weld metal, HAZ and Base metal at each strong current

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Kohei Tateyama ◽  
Shino Naruke ◽  
Hisashi Sasaki ◽  
Shinichi Torigata ◽  
...  

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.


2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Hidekazu Takazawa ◽  
Kazuma Hirosaka ◽  
Katsumasa Miyazaki ◽  
Norihide Tohyama ◽  
Naomi Matsumoto

A new Japanese nuclear regulation involves estimating the possible damage to plant structures due to intentional aircraft impact. The effect of aircraft impact needs to be considered in the existing nuclear power plants. The structural damage and fuel dispersion behavior after aircraft impact into plant structures can be evaluated using finite element analysis (FEA). FEA needs validated experimental data to determine the reliability of the results. In this study, an analysis method was validated using a simple model such as a cylindrical tank. Numerical simulations were conducted to evaluate the impact and dispersion behavior of a water-filled cylindrical tank. The simulated results were compared with the test results of the VTT Technical Research Centre of Finland (VTT). The simulations were carried out using a multipurpose FEA code LS-DYNA®. The cylindrical tank was modeled using a shell element, and the tank water was modeled using smoothed particle hydrodynamics (SPH) elements. First, two analysis models were used to evaluate the effect of the number of SPH elements. One had about 300,000 SPH elements and the other had 37,000 SPH elements. The cylindrical tank ruptured in the longitudinal direction after crashing into a rigid wall, and the filled water dispersed. There were few differences in the simulated results when using different numbers of SPH elements. The VTT impact test was simulated with an arbitrary Lagrangian-Eulerian (ALE) element to consider the air drag. The analytical dispersion pattern and history of dispersion velocity ratio agreed well with the impact test results.


2018 ◽  
Vol 941 ◽  
pp. 224-229
Author(s):  
Takahiro Izumi ◽  
Tatsuya Kobayashi ◽  
Ikuo Shohji ◽  
Hiroaki Miyanaga

Microstructures and mechanical properties of lap fillet welded joints of several high and ultra-high tensile strength steel by arc welding were investigated. Steel plates having tensile strength of 400 (SPH400W), 590 (SPC590Y, SPC590R), 980 (SPC980Y) and 1500 MPa (SAC1500HP) class with 2 mm thickness were prepared. Four types of joints were formed by MAG welding; SPH400W/SPH400W, SPC590Y/SPC590Y, SPC980Y/SPC980Y and SAC1500HP/SPC590R. In joints with SPC590Y, SPC980Y and SAC1500HP steel which matrixes are martensitic microstructures, the HAZ softens due to transformation of martensite into ferrite with precipitating cementite. By using high and ultra-high tensile strength steel, the weld metal is strengthened due to dilution of the matrix into the weld metal and thus tensile shear strength of the welded joint increases. In the fatigue test, similar S-N diagrams were obtained in the all welded joints investigated. It seems that the effect of stress concentration due to the shape of the welded joint on fatigue properties is larger than that of the strength of the matrix.


2014 ◽  
Vol 566 ◽  
pp. 232-237
Author(s):  
H. Ambarita ◽  
M. Daimaruya ◽  
H. Fujiki

The present study is concerned with the development of a fracture criterion for the impact fracture of jointed steel plates of a lap bolted joint used in the suspension parts of a car body. For the accurate prediction of crash characteristics of car bodies by computer-aided engineering (CAE), it is also necessary to examine the behaviour and fracture of the jointed steel plates subjected to impact loads. Although the actual impact fracture of jointed steel plates of a lap bolted joint in cars is complicated, for simplifying it is classified into the shear fracture and the extractive fracture of jointed steel plates. Three kinds of steel plates, i.e., common steel with the tensile strength of 270 MPa and two high tensile strength steels with the tensile strength of 440 and 590 MPa level used for vehicles, are examined. In the impact shear test, the specimens are made of two plates and jointed by a bolt, and in the impact extractive test the specimens are made of a plate and drilled in the centre for a bolt. The impact shear test of jointed steel plates of lap bolted joints is performed using a modified split Hopkinson bar apparatus, while the impact extractive one is performed using one-bar method. Numerical simulations by a FEM code LS-DYNA are also carried out in order to understand the mechanism of shearing and extractive fractures process of jointed steel plates. The obtained results suggest that a stress-based fracture criterion may be developed for the impact shearing and extractive fractures of jointed steel plates of lap bolted joints used in a car body.


Author(s):  
Philippe Thibaux ◽  
Filip Van den Abeele ◽  
Philippe Burlot

Each structure is designed with resistance versus the fracture, which requires the knowledge of the fracture resistance of the material. If no fracture mechanics data of the material is available, a KJC can be inferred from the master curve approach. The master curve approach relates a fracture toughness of 100 MPAm1/2 to the impact transition temperature T27J with a shift of 18°C. Although this relationship was successfully applied to a large number of experiments, some steels deviate significantly from the previous relationship, which can even lead to non-conservative design. In the present paper, instrumented impact tests (Charpy V-Notch CVN) and compact tensile (CT) tests were performed on two materials, one thermomechanically (TM-) rolled and one normalized steel. The difference between T0 and T27J was found to be different for these materials. Furthermore, the normalized steel exhibits a smooth transition from brittle to ductile behaviour, while the TM-rolled material shows a very steep transition. Extra information is gained by combining the instrumentation of the impact test and the finite element simulations of both the CT and impact tests. From the instrumented tests, it is also possible to determine the load at unstable crack propagation, the amount of energy dissipated at that moment, the load at crack arrest and the energy dissipated after crack arrest. From the finite element simulation, one learns about the constraints ahead of the crack tip for both configurations. The investigation teaches us that the smooth transition of the normalized material is related to a high energy dissipated after crack arrest, while the TM-rolled material has a much lower crack arrest load. The difference between T0 and T27J is then discussed by decomposing the total energy in the impact test between crack initiation, propagation and arrest. It is compared with KJC, which determines the toughness at unstable crack propagation, by reviewing the literature and local stress states computed from finite element.


2011 ◽  
Vol 250-253 ◽  
pp. 2089-2092
Author(s):  
Rong Jian Li ◽  
Xi An Li ◽  
Gao Feng Che ◽  
Wen Zheng ◽  
Wen Jun Chen

Stress path is one of the very important factors of soil strength. It is significant to study the strength and reveal the importance of the impact of sand in different stress path conditions. Firstly, an ameliorating approach on implementing for the reduced triaxial extension by the conventional triaxial apparatus was discussed. Then, In order to study shear behaviors of the eolian sand under different stress path, two monotonic shearing tests with the conventional triaxial compression and the reduced triaxial extension stress path were performed and analyzed. The test results not only indicate that the amelioration on conventional triaxial apparatus is simple, practicable and inexpensive, but also reveal the difference of strength’s parameter between the reduced triaxial extension and conventional triaxial compression stress path. In sum, the stress path has important effect on the strength of the eolian sand.


2020 ◽  
Vol 14 ◽  

The aim of the study was to research the behavior of the rubber-metal body mounting under various modeling options and to select the optimal, from the point of view of ensuring the accuracy of the results in the crash tests simulations. Body supports provide a link between the body and the car frame, and this has a critical effect on the impact test results of the car. The article discusses various options for modeling the body mounting by the degree of simplification from the simplest model with a rigid connection between the body and the frame to the model that takes into account the non-linearity of the stiffness characteristics of the supports, contact interaction between parts of the mounting and its surrounding parts, tension of the supports and failure. The results of virtual tests of a car with various options for modeling mountings were compared with the results of real tests. As a result of the study, a methodology for modeling the body supports was developed, which allows providing the necessary measurement error in virtual crash test modeling.


2019 ◽  
Vol 18 (3) ◽  
pp. 297-306
Author(s):  
Cecep Slamet Abadi ◽  
Rosidi Rosidi ◽  
Idrus Assagaf

Welding technology is used because besides being easy to use, it can also reduce costs so it is cheaper. Especially for welding repair. From the welding repair the extent to which the strength of GMAW welds can repair components from the molded plastic mold room made of AISI 420 stainless steel. Repair of the print room components using deposit welding is tested using tensile strength and hardness as realization of resistance when holding the rate of liquid plastic entering the print room by 25 to 40 MPa, depending on the plastic viscosity, the precision of the mold and the filling level of the print room. Deposition welding method as a welding repair can affect a procedure to be able to produce a component that is safe and capable of being used in accordance with the provisions. The welding process used is reverse polarity GMAW DC with 125 A current and ER 70 S welding wire diameter 1.2 mm. Test material AISI 420. Tests carried out were tensile test, impact test and hardness test in weld metal, HAZ and base metal. From the Charpy impact test and tensile test obtained the value of welding strength which is close to the strength of the complete object, which is equal to 65%. The energy absorbed by the impact test object with GMAW welding is 5.4 Joule while for the whole test object is 8.1 Joule. The welding tensile strength is 520 MPa compared to the tensile tensile strength of 820 MPa.


2021 ◽  
Vol 5 (1) ◽  
pp. 11-20
Author(s):  
Mardy Suhandani ◽  
Poppy Puspitasari ◽  
Jeefferie Abd Razak

The automotive and aviation fields require engineering materials that can save and optimise fuel consumption. Unique characteristics of lightweight, higher strength to weight ratio, good corrosion resistance, and good castability are indispensable for castable metal such as Silicon Aluminium (Al-Si). The mechanical properties of Al-Si could be further improved through the addition of Cobalt Oxide (CoO) nanoparticles during the casting process. The importance and purpose of this study were to determine the impact toughness, hardness and fracture morphology of Al-Si metal alloy filled with 0.015 wt.% CoO nanofiller at the various melting temperature of 750 °C, 800 °C and 850 °C. The stir casting method was utilised considering the most appropriate method for mixing nanoparticles powder into the Al-Si matrix. Three test specimens were prepared for each temperature variation. Impact testing using the Charpy method (ASTM E23-56 T) and hardness testing using Rockwell Superficial HR15T and fracture morphology obtained from impact testing fractures were performed accordingly. The impact test results showed that the Al-Si added with 0.015% CoO at 800 °C of melting temperature possessed the highest impact toughness value of 25.111 x 10-3 Joule mm-2 than the other variations. The hardness test results showed that Al-Si added 0.015% CoO with a melting temperature of 850 °C had the highest hardness value of 79.52 HR15T. The fracture morphology of the impact test in all specimens shows uniform brittle fracture characteristics. It is found that the melting temperature during the stir-casting process of Al-Si has played a significant role in influencing the resulted properties of Al-Si filled CoO nanoparticles metal matrix composites. The selection of an accurate melting temperature for the stir casting process will affect the resulted properties of produced metal composites.


2018 ◽  
Vol 4 (1) ◽  
pp. 58 ◽  
Author(s):  
Marish S. Madlangbayan ◽  
Nobuaki Otsuki ◽  
Takahiro Nishida ◽  
Tsuyoshi Saito

A method utilizing divided steel plates was used to investigate the corrosion of coated steel plates with impact defect while continuously submerged in 3% NaCl solution. The polarization behavior of circular divided steel plates was first compared to that of undivided ones. Half-cell potential and polarization resistance results show similar trend in divided and undivided form especially at the later stages of exposure. The method of using circular divided steel plates was then used to monitor the macrocell as well as microcell corrosion in coated steel plates induced with defect. The test results show that the defect causes macrocell corrosion to occur between the defect and sound portions. The impact defect also caused the reduction in the polarization resistance and consequently higher microcell corrosion at the neighbouring sound coated portions.


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