‎‏FINDING PERCENTAGE OF BREAKDOWN STIMULATION OF ALUMINUM WIRES THAT OPERATES IN A CORROSIVE MEDIUM

The study of the duration of mechanical resistance to static tensile stress (withstand time) for an aluminum wire that being suffers from the corrosion effect stimulated by stray currents at different temperatures. Test device was designed and produced locally "in advance" in accordance with the specification (ASTM G103 - 97) to create static tensile stress of (1 N) on an aluminum wire of type ASTM (B231/B231M) with particular dimensions and utilized in the transmission of electrical energy, and when the wire is surrounded by a corrosive environment (NaCl solution) (3.5 % NaCl) at three different temperatures (25, 50, and 75 ° C) without any external electrical current causing corrosion; this symbolizes stray currents. Then compare the findings of that example to the results of the same wire's withstand time in the presence of an external electrical current generated by corrosion of type (D.C) by (5V & 3A). Following that, the resulting diagrams were analyzed, and it was discovered that the wire resistivity time (without the existence of stray currents and at a temperature of 25 ° C) completed (17 days), which is the longest duration of endure, and the lowest time of resistivity or resistance period (in the existence of an external electric current) is (18 hr.).Impact of (stray currents) at (75 ° C), and this is an indicator of the stray currents with corrosive environment temperatures on the resistance period (withstand duration) in the existence of static stress. The total stimulation increase is 1.9% between corrosion at 75°C and 25°C.

Gaps in Material Qualification Requirement and Acceptance for Severe to Extreme Sour-Sweet Corrosive HPHT Environments Impacting Completion Design

Severe to extreme sour-corrosive environment assisted cracking (EAC) phenomenon are complex. Mandatory test qualification requirements and acceptance criteria is non-existent, in relevant API and NACE standards for fracture toughness of the CRA's. This paper, perhaps an industry first, attempts to highlight some of these gaps and how it translates into material strength uncertainties thereby impacting tubing design and risk assessment. The materials in this context are high strength group 1 to 4 corrosion resistant alloys of API 5CRA. Fracture toughness or critical stress intensity factor is a measure of resistance to failure due to crack propagation - a key parameter for HPHT tubing material selection and design. This material aspect of fracture toughness can be influenced by several factors like Microstructure, Strength, Hardness, Heat treatment, Anisotropy etc. Low temperature is generally considered as worst case, nevertheless at higher temperatures, well environment driven embrittlement can have a serious impact on the fracture toughness value. Therefore, with several factors influencing, its characterization is important to define the burst envelope of the tubing when exposed to severe to extreme sour-sweet corrosive environment typical of HPHT wells. A unique approach is followed to determine the brittle burst tri-axial envelope of selected tubing based on minimum fracture toughness value of the CRA material, referred to as KIMAT for SSC (or EAC) as prescribed by the mill. Proportional radial scaling is proposed to generate scaled down von-mises brittle-burst envelope. The tubing loads and the safety factors are analyzed to the shrunken envelope to visualize the risks of tubular failure under sour-sweet corrosive environment. The analysis includes varying crack depths of 5% and 3%. In addition, a minimum KIMAT for SSC (or EAC) value required to achieve full scale VME is investigated to determine specific material property requirements. TM0177 NACE D covers methods to measure fracture toughness KIMAT for sour service at ambient temperature only and does not address the context of EAC exposure at ambient or elevated conditions i.e., KIMAT for EAC.This implies that a methodology for evaluation of EAC risk is not available as yet. Guidance on the potential for corrosion to cause cracking of CRAs is given in Table B.1 of ISO 15156-3 with primary and secondary failure mechanisms. However, a quantitative test to cover the risk of cracking of materials by specifying minimum required KIMAT for EAC for each group type in 5CRA is non-existent. Even KIMAT for sour service minimum requirements with SSC as primary failure mechanism, e.g., group 1 CRA, does not currently exist. Consequently, KIMAT for EAC minimum requirements are considered as far-fetched. Additionally, mills prescribed KIMAT for SSC lacks basis due to gaps in the minimum fracture toughness requirement stipulations for group 1 to 4 CRA materials listed at API 5CRA. Therefore, this paper provides risk insights and potential of tubing failure that can lead to serious integrity issues on a HPHT well. A joint industry program or joint API/NACE task group is proposed as a logical next step.

Degradation of the Layer Applied by Cold Kinetic Deposition

During the described experiment, a sample with a copper coating was formed on an aluminum substrate by cold spray. Subsequently, this sample was split for corrosion tests, where the split samples were exposed to a corrosive environment for different exposure times. The extent of corrosion degradation of the samples was evaluated by acoustic emission and metallographic analysis for corrosion-loaded samples for 100, 200 and 300 hours.

Environment-assisted fatigue of steel bridges: A conceptual framework for life assessment

This paper presents a framework based on a recently proposed fatigue strength curve of corroded steel to assess the life of an existing steel bridge exposed to environment-assisted fatigue. Environment-assisted cracking (EAC) and how it affects the structural integrity of steel bridges are introduced by the framework. Determination of both corroded and uncorroded details in a corrosive environment are also included in this framework. To conform the applicability and significance, a fatigue life of a railway bridge was assessed by methods given in the framework. The obtained fatigue lives were compared. The difference of the estimated fatigue lives emphasizes the importance of having this framework to consider the interaction of corrosion and fatigue mechanisms.

ANALISIS KEBOCORAN & KEBAKARAN TANGKI BLENDING BAHAN BAKAR MIGAS

Explosions and fires that occurred in the blending/mixing tanks of fuel with naphtha to produce pertalite type fuel were initiated by a leak in the tank wall. Based on the results of observations, inspections and tests that have been carried out, the leak of the tank which is the cause of the explosion and fire is the result of the reaction of the tank wall in the weld joint area with base metal (HAZ) which is susceptible to corrosion with acidic tank fluid contents (pH- 5) so as to form an acidic and corrosive environment in the tank with the formation of H2S as a corrosion initiator, reinforced by the discovery of corrosion products in the form of MnS, FeS2, and FeS compounds, elements (S), and the appearance of fractography in the form of white dots indicating uniform corrosion if it occurs for a long time can erode the tank wall and form a leak hole.