This NACE Standard establishes material requirements for resistance to sulfide stress cracking (SSC) in sour refinery process environments, i.e., environments that contain wet hydrogen sulfide (H2S). It is intended to be used by refineries, equipment manufacturers, engineering contractors, and construction contractors.
The 6XXX aluminum alloys are magnesium and silicon alloys that are widely used in several applications for their attractive mechanical properties. However, there are some problems associated with the welding of aluminum alloys. Aluminum alloys are difficult to weld due to their high thermal conductivity and high thermal expansion. The weldability of aluminum alloys varies significantly, depending on its chemical composition. In this paper, an experimental investigation studies the effect of heat treatment on mechanical properties of 6063 aluminum alloy for a single pass of Activated Tungsten Inert Gas (ATIG) welding. A thin layer of flux was applied to the welding area. Using ATIG, using the edge preparation, time and power consumption, shielding gas amount and wire quantity can be considerably reduced. Moreover, the number of joints per shift can be increased. No degradation in the microstructure and mechanical properties of the ATIG welds have been observed compared to those produced by conventional TIG welding. The optimal ageing parameters (temperature-time) have been determined to improve the mechanical properties. Taguchi method used to optimize the ageing parameters to improve the mechanical properties.
Aluminum alloys have high strength to weight ratio, and during the years they have been used successfully in the maritime industry, due to their good corrosion resistance when correctly applied (e.g., properly selected). In the subsea environment, the oil and gas industry currently uses aluminum alloys for Remotely Operated Vehicle (ROV), but due to its limited information regarding long-term application in seawater, these alloys are not generally selected for subsea structural purposes. The aim of the current paper is to compare the performance of three different aluminum alloys through electrochemical tests in artificial seawater and under accelerated intergranular corrosion (IGC) tests. Samples were tested through potentiodynamic polarization (ASTM(1) G61), under aerated and de-aerated environments, and in order to compare their IGC resistance, they were tested following ISO(2) 11846 (method B). The polarization curves revealed that the open circuit potential (OCP) increased when the solution moved from de-aerated to aerated. Additionally, no improved performance was seen from any alloy tested concerning pitting and repassivation potential, even when subjected to different aeration conditions. Finally, the IGC testing was satisfactory to distinguish the alloys’ IGC resistance.