Yazar "Tumer, Mustafa" seçeneğine göre listele
Listeleniyor 1 - 4 / 4
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe The effect of heat input in multi-pass GMAW of S960QL UHSS based on weaving and stringer bead procedure on microstructure and mechanical properties of HAZ(Iop Publishing Ltd, 2023) Mert, Tolga; Gurol, Ugur; Tumer, MustafaQuenched and tempered S960QL (yield strength & GE; 960 MPa) ultra-high strength steel (UHSS) thick plates were joined by multi-pass robotic gas metal arc welding (GMAW) using weaving and stringer bead techniques. The effects of microstructural changes in heat-affected zone (HAZ) of the joint on toughness and hardness were examined. Weaving and stringer bead techniques applied for the multi-pass welding procedure altered average peak temperatures and exposure time to those temperatures. Mechanical properties of HAZs were evaluated by utilizing notch impact and hardness tests, and these results were correlated with microstructural characterizations using optical (OM) and scanning electron microscopes (SEM). Prior austenite grain (PAG) coarsening occurred because of increased exposure time to peak temperature in coarse-grained HAZ (CGHAZ) of the W-5 (weaving pass) joint. CGHAZs at the face pass, which have not been subjected to a second thermal cycle, have the highest hardness in both joints. Hardness of SCHAZ and CGHAZ of S-12 joint was 7% and 1% higher compared with W-5 joint, respectively. Weld metal hardness of W-5 joint was 15% lower than that of S-12 joint. Both joints not only fulfilled the requirements of minimum 50 J per EN ISO 10025-6 at -20 & DEG;C but exceeded this limit by 50% (W-5) and 200% (S-12). Lateral expansions for impact toughness specimens were around 17.5% for S-12 joint, whereas it was 4% for W-5 joint. Since HAZ in the S-12 (stringer bead) joint is narrow compared with the one in the W-5 joint, impact toughness values were higher with the S-12 joint due to the locations of the notches of the impact specimens.Öğe Experimental Investigation of Wire Arc Additively Manufactured Inconel 625 Superalloy(Springer India, 2023) Gurol, Ugur; Tumer, Mustafa; Dilibal, SavasThe aim of the present study was to reveal how the microstructure and mechanical properties of Inconel 625 superalloy produced via wire arc additive manufacturing (WAAM) changed in relation to deposition direction. Results showed that the microstructure mainly consists of columnar dendrites including some intermetallic and carbides constituents, which are Laves and NbC phases. The hardness values showed heterogeneous distribution from bottom to top and mainly change between 275 +/- 15 to 298 +/- 16 HV5 except for the initial area reaching 318 +/- 14 HV5. The tensile test results revealed that the stress-strain responses of the samples change depending on the extracted direction. The lowest elongation was obtained at the transverse top and bottom regions with 33.5 +/- 1.5% and 35 +/- 6% while the highest elongation was obtained at the angular top and bottom with 48.5 +/- 6.7% and 55.5 +/- 2%. The results confirmed the more pronounced difference with sample direction, indicating anisotropy in ductility.Öğe Microstructural studies and impact toughness of dissimilar weldments between AISI 316 L and AH36 steels by FCAW(Springer London Ltd, 2013) Yilmaz, Ramazan; Tumer, MustafaIn this study, AISI 316 L austenitic stainless steel and AH36 low-alloy ship building steel pair were joined with flux-cored arc welding method by using E309LT1-1/4 filler metal under four different shielding gas compositions containing CO2 at different ratios. Microstructure, impact toughness of welded materials, and their microhardness distribution throughout joining were determined. In macro- and microstructure examinations, stereo optical microscope, scanning electron microscope (SEM), SEM/energy dispersive spectroscopy, and SEM/mapping analysis techniques were used. After notched impact toughness, fracture surfaces were examined using the scanning electron microscope. This study investigated effects of shielding gas composition on microstructure, impact toughness, and microhardness distribution of transition zone between AH36 steel and weld metal of joined material. It is observed that based on an increase in amount of CO2 in shielding gas, impact toughness values of the weldment decreased. Microhardness values change throughout weld metal depended on shielding gas composition. Moreover, an increase in amount of CO2 within shielding gas decreased delta-ferrite amount in weld metal. The increase in amount of CO2 within shielding gas leads to expanded transition zone in interface between AH36 and weld metal and also affects notched impact toughness values negatively due to the inclusion amounts occurring in weld metal and hence caused it to decrease.Öğe Strengthening of AISI 2205 duplex stainless steel by strain ageing(Elsevier Sci Ltd, 2014) Karahan, Tuba; Emre, Hayriye Ertek; Tumer, Mustafa; Kacar, RamazanIn this study, static strain ageing behavior of commercially available and solution heat treated duplex stainless steel was investigated and the effect of static strain ageing on the mechanical properties was also determined in detail. Some of as-received duplex stainless steel test specimens were pre-strained in tension by 5% and then aged at 100 degrees C, 200 degrees C, 300 degrees C, 400 degrees C, 500 degrees C and 600 degrees C for 30 min in furnace. Some of duplex stainless steel test specimens were solution heat treated at 1050 degrees C for 30 min, water quenched and then pre-strained for 5% in tension shortly after the solution heat treatment. In order to identify the effect of static strain ageing on the mechanical properties, the tensile strength, the change in the strength due to ageing (Delta Y), elongation fracture and hardness were determined. The test results showed that the mechanical properties were affected by static strain ageing mechanism which was applied at different temperatures for same time interval. (C) 2013 Elsevier Ltd. All rights reserved.