Dissimilar weld metal joints such as aluminum alloys 5083 and 6061-T6 are mostly found in the application of aircraft, railroad structures, ships, bridges, and oil platforms and building structures. However, dissimilar welding metal is relatively more difficult due to metallurgical differences and the thermophysical properties of two different materials. The purpose of this study is to study the effect of shoulder rotation variations on the Friction Stir Welding (FSW) process through numerical simulations on the mechanical properties of dissimilar weld joints between two series of aluminum alloys, and there are 5083 and 6061-T6. The FSW welding simulation process is conducted by butt joints type on 300 x 100 x 3 mm of both aluminum plates with weld distance is 300 mm. Shoulder rotation variations are carried out for this process include 1,200, 1,400 and 1,600 rpm. Results show maximum temperature distributions are 467 oC for 1,200 rpm, 499 °C for 1,400 rpm and 527 °C for 1,600 rpm, respectively. Maximum temperatures appear close to the liquid temperature of Al-6061-T6 and Al 5083 base metals, which is about 600 °C. Physical and mechanical analysis at 1,200 rpm (the rotation parameter) can be seen as the coarse weld beads on the microstructure, and the weld joint is still weak. The physical properties observed that coarse weld beads on microstructures, the tensile strength obtained 138 MPa at 1,200 rpm (the rotation parameter). The maximum hardness test occurred 47.98 (Kg/mm2 in averages) at 1,400 rpm. The tensile strength of the dissimilar FSW process is 151 MPa occurred at 1,600 rpm of shoulder rotation speed. While the fracture position occurs in the nugget weld area for all parameters and corresponds with the result of hardness tests, it shows that low hardness value for the whole weld area for all parameters.

Dissimilar weld-metal joints in aluminum alloys 5083 and 6061-T6 are often found in aircraft, railroad structures, ships, bridges, oil platforms, and building structures. However, welding of dissimilar metals is relatively more difficult due to the different metallurgy and thermophysical properties of the two alloys. The purpose of this study is to evaluate the physical-mechanical properties of the Tungsten Arc Welding (GTAW) process through numerical simulations of different welded joints between the 5083 and 6061-T6 aluminum alloys. The GTAW welding simulation process is carried out by 300 x 100 x 3 mm plate butt joints along 300 mm. GTAW weld metal is prepared for tensile test samples and metal alloy composition, the test is observed in the base metal and welded area. The results of the chemical composition test of the weld metal obtained that the composition is close to Al 5083 base metal so that the mechanical properties of the weld metal tend to be identical with Al 5083 alloy. The results of numerical simulation on the mechanical properties of GTAW weld metal at temperature conditions of 25 to 700 °C obtained several things, including 1) the range of thermal conductivity decreased from 174.393 to 86.424 W/mK. 2) The density increased from 2,348 to 2,663 gr/cm3. 3), the young modulus appears to decrease from 68,667 to 0 GPa. 4) the shear modulus decreases from 25,724 to 0 GPa. 5) the type of heat increases from 0.904 to 17,306 J/gK, and 6) the Poisson ratio increased from 0.335 to 0.5.

Makalah ini difokuskan pada pengaruh kondisi parameter pengelasan MAG (<em>Metal Active Gas</em>) terhadap sifat kekerasan daerah HAZ, dan struktur mikro sambungan las baja tidak sejenis. Dalam industri Fabrikasi dan disain difokuskan pada kebutuhan untuk menggabungkan logam yang tidak sejenis, karena kebutuhan atau prasyarat Teknik baru disain yang kreatif dan sifat rancangan khusus.  Baja karbon rendah Hypoeutektoid (AISI 1015) dan baja tahan karat austentik (304L SS) dipilih dalam penelitian ini. Arus las digunakan dengan tiga variasi yang berbeda pada 120A, 130A dan 140A. Pengelasan MAG menggunakan kawat elektroda padat ER70S6, dengan diameter 1,2 mm. Identifikasi struktur makro di daerah terpengaruh panas (HAZ) dan kekerasan mikro <em>vickers</em> dan pengujian tarik dilakukan untuk setiap spesimen hasil las. Struktur makro sambungan las yang berbeda menunjukkan hasil pada variasi arus las 120A, kualitas sambungan las dan penetrasi lebih baik, jika dibandingkan dengan yang menggunakan arus las 130A dan 140A yang memiliki penetrasi berlebihan. Hasil kekerasan mikro <em>vickers </em>pada logam las lebih tinggi jika dibandingkan dengan logam induk dan baja hypoeutektoid (AISI 1015) dan baja tahan karat austenitik  AISI 304L, dan kekerasan <em>vickers</em> pada logam las juga lebih tinggi karena pengaruh elektroda kawat padat ER70S6 yang digunakan. Haisl pengujian kekuatan tarik dan kekuatan luluh sambungan las MAG  meningkat pada 120A dan 140A, dan patahan terjadi ada pada baja hipo euctektoid (AISI 1015) dibatas antara daerah yang terpengaruh panas dan logam induk. Dari penelitian ini didapatkan bahwa sambungan las MAG dengan arus las 120A lebih baik digunakan untuk penyambungan logam tidak sejenis antara baja karbon rendah (AISI 1015) dan baja tahan karat austenitik (AISI 304L).

The CCQM-K128 key comparison was organized by the Inorganic Analysis Working Group (IAWG) of CCQM to test the abilities of national metrology institutes in measuring the heavy metals and organo-tin in leather matrix material or other similar organics content materials, and a pilot study CCQM-P163 was conducted in parallel with this key comparison. The National Institute of Metrology (NIM), P. R. China, acted as the coordinating laboratory. This comparison includes two parts: part A is for heavy metals (eight elements include As, Cd, Pb, Co, Cu, Hg, Ni, Sb) in leather powder with concentrations levels (30 ~ 100) mg/kg, and part B is for organo-tin (tributyltin) in leather powder with the concentration range (150~600) nmol/g. There were 10 laboratories registered and 9 laboratories returned the results, and different measurement methods (ID-ICPMS, ICP-MS, ICP-OES) with the microwave digestion were used in Part A; There were 3 laboratories registered and returned the results, and ID-LC-ICPMS, ID-GC-ICPMS and LC-ICPMS were used in Part B. After several rounds results and technical discussion at CCQM IAWG meeting, the KCRV and which associated uncertainty for each component had been confirmed. The comparison is to ensure the comparable and traceable measurement results for heavy metals and organo-tin in leather products among the NMIs and other designated measurement bodies worldwide. The consequence is relatively successful overall, although some problem of mercury and antimony determination had been discussed and summarized in this report. All participants have shown their capabilities and gained experience through this comparison. The results of CCQM-K128 are expected to cover the measurement capability and support the relative CMC claiming in the leather materials and similar high organics content matrix industrial products. KEY WORDS FOR SEARCH Leather, metal, Organo-Tin Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).