Aluminum alloys are widely used in engineering structures and components due to their light weight and excellent mechanical properties. However, the alloying elements which contribute to the good mechanical properties also make the alloy prone to localized corrosion. One of the most common and economic approaches to protect Al alloys from corrosion is to apply coatings as protective layers. For example, powder coatings and magnesium-rich primers (MgRP) are both widely used for the corrosion protection of Al alloys.
Aluminum, after iron is the second -most widespread metal used on earth. Unpainted aluminum forms a protective aluminum oxide layer over the pure aluminum metal alloy and, in most atmospheric environments, is resistant to corrosion deterioration. However, pure aluminum is virtually always alloyed with other metallic elements to enhance its properties, primarily to increase its strength, but also to improve its formability, weldability, machineability, electrical conductivity, and corrosion resistance.
Material requirements for resistance to sulfide stress cracking (SSC) in sour refinery process environments (i.e., environments that contain wet hydrogen sulfide [H2S]). AKA "wet H2S cracking".
CORRECTION OF PUBLICATION:
In January 2016, NACE published an incorrect version of ANSI/NACE MR0103/ISO 17945:2015 (Petroleum, petrochemical and natural gas industries — Metallic materials resistant to sulfide stress cracking in corrosive petroleum refining environments). That document was incorrectly titled ANSI/NACE MR0103/ISO 17495:2016. The erroneous standard was retracted at the time and the NACE Store has the corrected version. NOTE: The contents of both versions of the standard are identical. The only discrepancies are in the title.
NACE MR0175/ISO 15156 gives requirements and recommendations for the selection and qualification of carbon and low-alloy steels, corrosion-resistant alloys, and other alloys for service in equipment used in oil and natural gas production and natural gas treatment plants in H2S-containing environments, whose failure could pose a risk to the health and safety of the public and personnel or to the equipment itself.
HISTORICAL DOCUMENT. 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.
In the recent years, the reduction of the environmental footprint of industrial processes is gaining momentum, targeting the carbon neutrality. This also involves Aluminum industry, in which the use of secondary (e.g. recycled) alloys is a possible solution in order to decrease the greenhouse gases (GHG) emissions. Indeed, raw materials produced starting from secondary Aluminum show GHG emission values up to one order of magnitude lower with respect to their primary equivalents.
Measuring the severity of corrosion on a specific alloy is often accomplished via mass loss using ASTM G-1. These processes work well and provide high fidelity data for many materials, especially steels. However, recent internal findings and disclosures from other research groups have highlighted a potential issue with using mass loss techniques to measure the damage on some aluminum alloy surfaces.
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.