Effect of Different Heat Treatment Conditions on the Microstructure and Mechanical Properties of Inconel 718 Nickel Based Super Alloy Used in Petroleum Production

Abstract

The development of the oil and gas industry in Brazil in the last decades has led to petroleum extraction in deeper water and extremely corrosive environments, associated to the presence of H2S, CO2 and chlorides, as well as mechanical loads caused by the wave's movement and sea streams. In these adverse conditions the search for new materials with adequate properties for this kind of application is intense.In the present work a study is carried out on the microstructure and mechanical properties of the super alloy Inconel 718 subjected to different temperatures and times of solution and aging heat treatments. This material, usually used in the fabrication of aircraft motor and energy generation turbines, in the present case is proposed for the fabrication of bolts used in the fixation of submarine pipes for oil extraction.The use of techniques like optical microscopy, automatic image analysis, scanning electron microscopy (SEM) and hardness and tensile tests, allowed the identification of the ideal conditions for heat treating this material for this kind of application.

Effect of Aging Treatment on Pitting Corrosion and Corrosion Fatigue Crack Propagation Behavior of Oil-Grade Alloy 718

“…The effect of heat treatment in terms of microstructure and mechanical properties on FCP rates in alloy 718 has been extensively studied [13][14][15][16][17][18][19][20][21]. Tsay et al [22] have investigated the FCP behavior o f IN 718 plate and laser annealed specimens in air.…”

Corrosion Fatigue Crack Propagation of Oil-Grade Alloy 718 in NaCl Solution

“…It was first used in the oil and gas industry for fasteners, valve stems, shafts, and drill tools (applications that only involve brief exposure to corrosive conditions). By the 1980s, alloy 718 began to be used in critical well completion equipment such as hangers, packers, and subsurface safety valves [7][8][9][10]. Recently, the largest use of alloy 718 is for downhole tools such as subsurface safety valves, packers, flow control devices, and other tools [5,8,11,12].…”