Materials Science Forum Vol. 1101

Abstract: The purpose of this research is to investigate cold work effect on corrosion behavior of stainless steels of type AISI 304, AISI 316L and AISI 2101. The specimen were processed through cold work simulated by the tensile test at various percentages elongation and then tempered at 600°C for different time intervals. Two electrochemical techniques and hardness test were utilized in this investigation. The first technique was the double loop electrochemical potentiokinetic reactivation (DL-EPR) that yields the values of degrees of sensitization (DOS). The second one was the cyclic potentiodynamic polarization (CPP) to study the ability of the metals to build or repair the damaged films under localized corrosion. The DOS values from the DL-EPR tests of the samples under the same heating conditions suggested that specimens drawn at higher percentage elongation tend to have more chromium depleted areas. Also, the test specimens with more exposure time to heat were more prone to chromium deficiencies. As for the ability of the metal to create or repair damaged film after corrosion has occurred, it was found that AISI 316L had hihger corrosion resistance than AISI 304. However, AISI 2101 stainless steel had highest corrosion resistance. In this study, it was also found that AISI 2101 did not exhibit pitting corrosion, but the crevice corrosion. This could be due the fact that AISI 2101 which is a duplex stainless steel has high corrosion resistance and could trigger the crevice corrosion take place before the pitting initiation.

Abstract: To investigate the behaviour of oxidation and chromium volatilisation, AISI 430 stainless steel was oxidised in O₂-H₂O and Ar-CO₂-H₂O atmospheres for 96 h at 800°C with varying water vapour content. In the O₂-H₂O environment, the volatilisation rate of Cr and Mn increased as the water vapour content increased from 5% to 20%. In the case of Ar-CO₂-H₂O conditions, the presence of water vapour in the Ar-20%CO₂ environment reduced the oxidation rates of the steel. However, increasing the H₂O content in Ar-20%CO₂ had an insignificant effect on the oxidation rate. Water vapour was found to accelerate the volatilisation rate of Cr and Mn. Breakaway oxidation occurred in Ar-20%CO₂-40%H₂O, resulting in the highest volatilisation rates of Cr and Mn.

Abstract: The addition of hydrogen in shielding gas has been found to contribute to increasing the productivity of gas tungsten arc (GTA) welding compared to the processes using argon-nitrogen shielding gas. In this report, the GTA welding joints of AISI 304 stainless steel with Ar-N₂ and Ar-N₂-H₂ addition were fabricated. The microstructure and pitting corrosion resistance were studied in this work. The corrosion characterisation of welds metal was investigated by a potentiodynamic method in NaCl solution. It was found that H₂ addition also had effects on delta-ferrite microstructures and corrosion behaviour. Increasing hydrogen in argon-nitrogen shielding gas increased the delta-ferrite content and improved pitting corrosion resistance.

Abstract: This paper investigates residual stresses of the laser welded abrasion resistant steel butt joints. X-ray diffraction (XRD) was used to measure the residual stresses of the laser welded joints. The geometry and mechanical properties of the joints were also investigated. The weld metal hardness of the weld made with the lowest welding energy corresponded to the hardness of the base material. The welding energy had a significant effect on the hardness profiles of the welds. With the lowest welding energy, the tensile strength reached a strength corresponding to the yield strength of the base material. The residual stress results perpendicular to the weld corresponded well to the hardness profiles of the joints. The residual stresses were mainly tensile stress. The measured maximum residual stresses were 480 MPa.

Abstract: In this article, we aim to investigate the effect of pipe thickness on the deformation of welded joints in tubular structures. To this end, pipes with a diameter of 60 mm and a length of 215 mm will be utilized in both simulation and experimental processes. The Tungsten Inert Gas (TIG) welding method, known for its high-quality welds, will be employed to join the two steel pipes. The study will be conducted with four different pipe thicknesses: 2.5 mm, 3.2 mm, 4.0 mm, and 5.2 mm, to cover a wide range of thicknesses commonly used in industrial applications. In addition, to validate the accuracy of the simulation method, experimental tests will be carried out for selected simulated cases. The results of the study indicate that structures with thinner pipe walls exhibit higher residual temperatures and stresses, which leads to more deformation. Therefore, it is crucial to consider the pipe thickness when designing and welding tubular structures. After comparing the deformation results obtained from both simulation and experimental tests, we conclude that the simulation method is an effective tool for predicting the deformation of welded joints in tubular structures. By utilizing simulation methods, engineers can optimize the welding parameters and select the appropriate pipe thickness to minimize deformation and ensure the structural integrity of tubular structures.

Abstract: Roads play an important role in realizing the development and distribution of development results in certain areas. Pavement performance shows a decreased durability over time-related to how long the pavement construction can carry out its functions without experiencing fatal damage. This study aims to identify the effect of using steel slag as a substitute for filler with steel slag content of 0%, 1%, 2%, and 3% on concrete compressive and flexural strength values. This study used an experimental method by conducting experiments for testing the compressive and flexural strength of concrete specimens. The results showed that the use of steel slag as a substitute for filler obtained the average compressive strength value of MPa, 21.87 MPa, 22.17 MPa, and 28.47 MPa in concrete aged 28 days with steel slag content of 0%, 1%, 2% and 3% 25.07 respectively. The average flexural strength of concrete aged 28 days with steel slag content of 0%, 1%, 2% and 3% were 3.84 MPa, 2.83 MPa, 3.41 MPa, and 4.09 MPa respectively. The composition of 3% steel slag was the optimal composition as a filler replacement material. The pozzolanic properties of steel slag could increase the durability and density of the concrete specimen, but it required a long curing time and the increase in the initial strength of concrete slows down.

Abstract: Limited land with good soil quality results in infrastructure being built in areas with unfavorable soil characteristics. development. Soil with unfavorable characteristics one of which is swamp land. Swamp soil needs to be stabilized if we want to build buildings on that land, the stabilizing material used can be silica waste or other binding materials. In this test, steel slag, fly ash, and glass bottle powder were used as the main stabilizers, with a fixed percentage of 20% steel slag and 20% fly ash, and glass bottle powder as an independent variable with a percentage of 0%. 5%, 10%, and 15%, and with the aging time of 0, 3, and 7 days. Testing the characteristics of Situ Rawa Arum, Jl. Kp. Tegal Wangi No. 62, Kec. Gerogol City of Cilegon Banten has poor soil carrying capacity with a CBR value of 1%. After stabilization using steel slag, fly ash, and glass bottle powder there was a significant change. The most optimum change in soil carrying capacity occurred in a mixture of 5% glass bottle powder + 20% steel slag + 20% fly ash with a CBR value of 31%.

Abstract: Concrete is a crucial building material used for various structural components in buildings. It consists of cement, water, fine aggregate (sand), and coarse aggregate (gravel). This research focuses on the development of steel slag concrete as a replacement material for coarse aggregate, aiming to appropriately utilize steel slag waste, which poses environmental and health concerns. The study investigates the effect of substituting steel slag for coarse aggregate on the compressive strength of concrete and determines the optimal steel slag to normal concrete ratio. Concrete samples aged for three, seven, and 28 days were prepared using SNI 7656:2012, incorporating different proportions of steel slag as a substitute for coarse aggregate. Results indicate that variations of 20%, 40%, and 60% show improvements in comparison to normal concrete after three and seven days of curing. However, the variations of 80% and 100% are less commonly used than standard concrete. The increase in compressive strength of steel slag concrete aged 28 days, compared to normal concrete, for variations of 20%, 40%, and 60% is 1.54%, 3.00%, and 6.57%, respectively, while the reduction for variations of 80% and 100% is 7.93% and 18.80%. Based on the results, steel slag concrete with a 60% substitution of coarse aggregate exhibits the optimal compressive strength ratio in the mixture.

Abstract: Soil is a material that has an essential role in construction. Soils that have low bearing capacity require soil improvement. One method of soil improvement is soil stabilization using composite portland cement. Based on the results of the Dynamic Cone Penetrometer (DCP) test, the location in this study, namely Cibingbin village, Pandeglang Regency, has a bearing capacity of 2.67%, meaning that the soil at this location needs to be repaired. This study aimed to determine the effect of portland cement on physical properties and unsoaked CBR values. Variations of portland cement used were 0%, 4%, 6%, and 8%, with curing times of 0 days and seven days. The results showed that based on the unified soil classification system (USCS), the soil classification was in the CH category (inorganic clay with high plasticity, fat clay) and the maximum CBR value was obtained at 8% Portland cement variety at seven days curing time, namely 13.23%.