scholarly journals Effect of pre−corrosion on Electrochemical Corrosion and Fatigue Behavior of S135 High−Strength Drill Pipe Steel in Marine Environment

2019 ◽  
pp. 2589-2605
Author(s):  
Sheji Luo ◽  
Keyword(s):  
Marine Environment ◽  
Pipe Steel ◽  
Fatigue Behavior ◽  
Drill Pipe ◽  
Electrochemical Corrosion ◽  
High Strength

The Development and Experimental Study on High Strength and Toughness Drill Pipe Steel

2011 ◽  
Vol 287-290 ◽  
pp. 1024-1032
Author(s):  
Feng Hu ◽  
Li Hong Han ◽  
Hang Wang ◽  
Yao Rong Feng ◽  
He Lin Li
Keyword(s):  
Electron Microscopy ◽  
Yield Strength ◽  
Pipe Steel ◽  
Drill Pipe ◽  
Control Process ◽  
High Strength ◽  
Alloy Element ◽  
Deep Wells ◽  
Alloy Carbon ◽  
The Impact

With the development of oil industry, the high strength-toughness drill pipe suited to the task of sour environment and ultra deep wells would be considered more and more important. A new drill pipe steel, which was designed with the proper decrease of C content and increase of Cr, Ni, Mo, Nb and V alloy element, was developed and studied in this study. Large deformation hot rolling technology was used to obtain ultrafine grains microstructure. The results showed that the yield strength of this new drill pipe steel had reached 150ksi with the impact toughness more than 150J, which can perfectly meet the “leak-before-break” crack principle. The new low-alloy carbon steel drill pipe in the controlled yield strength grade 150ksi showing excellent sulfide stress cracking resistance and strength-toughness have been developed. Based on the observation of scanning electron microscopy and transmission electron microscopy, several kinds of carbide particles including (Nb, Mo, V)C with nanometer scale, were distributed in tempered sorbite matrix. The objective of this work was to study the relationship between carbide precipitation and strength-toughness by optimizing element design, thermo mechanical control process and heat treatment of drill pipe steel.

Precipitation Behavior and its Effect on Strengthening of High Strength and Toughness Drill Pipe Steel

2011 ◽  
Vol 335-336 ◽  
pp. 587-594
Author(s):  
Feng Hu ◽  
Li Hong Han ◽  
Hang Wang ◽  
Yao Rong Feng ◽  
He Lin Li
Keyword(s):  
Pipe Steel ◽  
Rapid Development ◽  
Drill Pipe ◽  
High Strength ◽  
Alloy Element ◽  
Deep Wells ◽  
Transmission Electron ◽  
Alloy Carbide ◽  
The Impact ◽  
Leak Before Break

With the rapid development of oil industry, the high strength-toughness drill pipe suited to the task of sour environment and ultra deep wells would be considered more and more important. A new drill pipe steel, which was designed with the proper decrease of C content and increase of Cr, Ni, Mo, Nb and V alloy element, was developed and studied in this study. The results showed that the yield strength of this new drill pipe steel had reached 150ksi with the impact toughness more than 150J, which can perfectly meet the “leak-before-break” crack principle. Based on the observation of optical microscopy and transmission electron microscopy, several kinds of carbide particles including (Nb, Mo, V)C with nanometer scale, were distributed in tempered sorbite matrix. The objective of this work was to study the relationship between multiple alloy-carbide precipitation and mechanical property of this drill pipe steel.

scholarly journals Fatigue Life Improvement of Cracked Aluminum 6061-T6 Plates Repaired by Composite Patches

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1421
Author(s):  
Armin Yousefi ◽  
Saman Jolaiy ◽  
Reza Hedayati ◽  
Ahmad Serjouei ◽  
Mahdi Bodaghi
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Weight Ratio ◽  
High Strength ◽  
Plastic Strain Amplitude ◽  
Composite Patch ◽  
Life Improvement ◽  
Cracked Structures ◽  
Aluminum Plates ◽  
High Flexibility

Bonded patches are widely used in several industry sectors for repairing damaged plates, cracks in metallic structures, and reinforcement of damaged structures. Composite patches have optimal properties such as high strength-to-weight ratio, easiness in being applied, and high flexibility. Due to recent rapid growth in the aerospace industry, analyses of adhesively bonded patches applicable to repairing cracked structures have become of great significance. In the present study, the fatigue behavior of the aluminum alloy, repaired by a double-sided glass/epoxy composite patch, is studied numerically. More specifically, the effect of applying a double-sided composite patch on the fatigue life improvement of a damaged aluminum 6061-T6 is analyzed. 3D finite element numerical modeling is performed to analyze the fatigue performance of both repaired and unrepaired aluminum plates using the Abaqus package. To determine the fatigue life of the aluminum 6061-T6 plate, first, the hysteresis loop is determined, and afterward, the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted and validated against the available experimental data from the literature. Results reveal that composite patches increase the fatigue life of cracked structures significantly, ranging from 55% to 100% for different applied stresses.

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