scholarly journals MICRO-CRACK ANALYSIS IN THE STUDY OF FATIGUE FRACTURE IN THE HAZ IN THE HIGH YIELD STRENGTH MICRO-ALLOYED STEELS

10.6036/10139 ◽  
2022 ◽  
Vol 97 (1) ◽  
pp. 46-52
Author(s):  
MANUEL VISERAS ◽  
RAFAEL ERNESTO GONZALEZ PALMA ◽  
MARIA DEL CARMEN CARNERO MOYA ◽  
MANUEL TORNELL BARBOSA
Keyword(s):  
Fracture Toughness ◽  
Fatigue Fracture ◽  
Weld Line ◽  
High Strength ◽  
High Yield ◽  
Low Alloy Steels ◽  
Crack Tip Opening Displacement ◽  
Successful Operation ◽  
Opening Displacement ◽  
Summary Table

Various applications have been described in the literature for the High-Strength and Low-Alloy steels (HSLA) industry, analysing their use both in industrial and marine equipment and machines and in structures that require appropriate resilience values and toughness at low temperatures. For successful operation under conditions as large structures under extreme service conditions, it is essential to ensure the proper toughness both in base metal (USITEN 355 0.5 Ni Grade I steel) and in the heat-affected area of the weld. (ZAC). This research carries out Crack Tip Opening Displacement (CTOD) tests, showing, in this article, the first part of the test corresponding to fatigue pre-cracking and a summary table of the results of fracture toughness, to guarantee that, under the conditions which exist in welding, both the fatigue fracture values and the fracture toughness are acceptable by the applicable standards. Keywords: SMAW, weld line, CTOD, stress intensity factor, input heat energy, crack growth rate, fatigue fracture, fracture toughness

scholarly journals Investigation of Hydrogen Embrittlement Susceptibility and Fracture Toughness Drop after in situ Hydrogen Cathodic Charging for an X65 Pipeline Steel

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 430 ◽  
Author(s):  
Helen Kyriakopoulou ◽  
Panagiotis Karmiris-Obratański ◽  
Athanasios Tazedakis ◽  
Nikoalos Daniolos ◽  
Efthymios Dourdounis ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
High Strength ◽  
Electrolytic Cell ◽  
Low Alloy Steels ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Alloy Steels

The present research focuses on the investigation of an in situ hydrogen charging effect during Crack Tip Opening Displacement testing (CTOD) on the fracture toughness properties of X65 pipeline steel. This grade of steel belongs to the broader category of High Strength Low Alloy Steels (HSLA), and its microstructure consists of equiaxed ferritic and bainitic grains with a low volume fraction of degenerated pearlite islands. The studied X65 steel specimens were extracted from pipes with 19.15 mm wall thickness. The fracture toughness parameters were determined after imposing the fatigue pre-cracked specimens on air, on a specific electrolytic cell under a slow strain rate bending loading (according to ASTM G147-98, BS7448, and ISO12135 standards). Concerning the results of this study, in the first phase the hydrogen cations’ penetration depth, the diffusion coefficient of molecular and atomic hydrogen, and the surficial density of blisters were determined. Next, the characteristic parameters related to fracture toughness (such as J, KQ, CTODel, CTODpl) were calculated by the aid of the Force-Crack Mouth Open Displacement curves and the relevant analytical equations.

scholarly journals Guide for Recommended Practices to Perform Crack Tip Opening Displacement Tests in High Strength Low Alloy Steels

2016 ◽  
Vol 21 (3) ◽  
pp. 290-302 ◽  
Author(s):  
Julián A. Ávila ◽  
Vinicius Lima ◽  
Cassius O. F. T. Ruchert ◽  
Paulo Roberto Mei ◽  
Antonio J. Ramirez
Keyword(s):  
Crack Tip ◽  
High Strength ◽  
Low Alloy Steels ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Alloy Steels ◽  
Recommended Practices ◽  
Crack Tip Opening

scholarly journals Influence of the Welding Process on the Mechanical Characteristics and Fracture of the S700MC High Strength Steel under Various Types of Loading

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5249
Author(s):  
Tadeusz Szymczak ◽  
Katarzyna Makowska ◽  
Zbigniew L. Kowalewski
Keyword(s):  
Fracture Toughness ◽  
Welding Process ◽  
High Strength ◽  
Mechanical Tests ◽  
Parent Material ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Joint Stress ◽  
Characteristic Features ◽  
The Impact

This paper focuses on the mechanical properties analysis of the high strength S700MC steel applied in welding joints. The research comprised mechanical tests for checking what the changes of tensile characteristics, mechanical parameters, resistance to impact, and fracture toughness look like in selected regions of the welding joint. Stress-strain curves have shown significant differences in the tensile characteristic shape and the values of Young’s modulus, yield stress, ultimate tensile strength, and ductility due to the welding process applied. In the case of Charpy tests, the courses of the accumulated energy, force, deflection, and project velocity are presented, indicating the maximum value of absorbed energy, the same level of force during the first contact of the projectile with the specimens, and the significant variation of the velocity for the impact energy ranging from 50 J up to 300 J. On the basis of the fracture toughness tests, the distributions of the CTOD (Crack Tip Opening Displacement) values are presented for the parent material, HAZ (Heat Affected Zone) and weld. Moreover, the characteristic features of the fatigue pre-crack, transient and crack propagation zones are identified and discussed.

REPUBLIC 50

Alloy Digest ◽  
1967 ◽  
Vol 16 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Yield Strength ◽  
Physical Properties ◽  
Structural Steel ◽  
High Strength ◽  
Heat Treating ◽  
High Yield ◽  
Bend Strength ◽  
High Yield Strength

Abstract Republic 50 is a high-strength low-alloy structural steel recommended where high yield strength and toughness combined with good weldability and corrosion resistance are required. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and compressive, shear, and bend strength as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-205. Producer or source: Republic Steel Corporation.

TRI-MARK TM-115

Alloy Digest ◽  
1983 ◽  
Vol 32 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Arc Welding ◽  
High Strength ◽  
Heat Treating ◽  
Low Alloy Steels ◽  
Mining Equipment ◽  
Alloy Steels ◽  
Temperature Impact ◽  
Welding Electrode

Abstract TRI-MARK TM-115 is a gas-shielded flux-cored welding electrode for continuous high deposition are welding. It is designed specifically for semiautomatic and automatic arc welding of high-strength low-alloy steels and quenched-and-tempered steels. This gas-sheilded tubular wire can be used for single and multiple-pass welding. It has outstanding low-temperature impact properties. Its applications including mining equipment, large vehicles and similar items. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SA-392. Producer or source: Tri-Mark Inc..

Experimental Study on Fracture Toughness of Q460C the High-Strength Construction Steel at Low Temperature

2011 ◽  
Vol 71-78 ◽  
pp. 890-897 ◽  
Author(s):  
Yuan Qing Wang ◽  
Yun Lin ◽  
Yan Nian Zhang ◽  
Yong Jiu Shi
Keyword(s):  
Low Temperature ◽  
High Strength ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Three Point Bending ◽  
Function Fitting ◽  
Ductile Brittle Transition Temperature ◽  
Boltzmann Function ◽  
Fracture Appearance ◽  
Crack Tip Opening

Three point bending tests were carried out on 14mm-thick Q460C the high-strength structural steel at low temperature, and scanning electronic microscope of the fracture appearance was analyzed. The results showed that the obvious feature of brittle mechanism was shown on the three point bending specimen fracture whose testing took place at -40°C. And the crack tip opening displacement value of Q460C steel, which was less than that of Q235 steel, Q345 steel and Q390 steel at low temperature, tended to decrease with respect to the temperature reduction. Moreover, a Boltzmann function fitting analysis was applied to the experimental data, and the ductile-brittle transition temperature and the changing regularity were obtained.

Applying Gurson Type of Damage Models to Low Constraint Tests of High Strength Steels and Welds

2006 ◽  
Author(s):  
Ming Liu ◽  
Yong-Yi Wang
Keyword(s):  
Damage Mechanics ◽  
Ductile Failure ◽  
High Strength Steels ◽  
High Strength ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Critical Crack ◽  
Gtn Model ◽  
Strain Capacity ◽  
Low Constraint

Pipelines experiencing displacement-controlled loading need to have adequate strain capacity. Large tensile strain capacity can only be achieved when the failure processes are ductile. In ductile failure analyses, the strain capacity may be determined by two approaches. The first approach uses the conventional fracture mechanics criteria, such as the attainment of the critical crack tip opening displacement, to assess the onset of the crack propagation. The other approach uses damage mechanics models in which the onset and propagation of cracks are controlled by the nucleation, growth, and coalescence of voids in the material. The damage mechanics models can provide some insights of the ductile failure processes as they have more physical mechanisms built in the constitutive model. In this paper, the Gurson-Tvergaard-Needleman (GTN) model is applied to two types of low-constraint tests: curved wide plates and back-bend specimens. The wide plate test is considered more representatives of full-scale pipes than the conventional laboratory-sized specimens, but requires large-capacity machines. The back-bend test is a newly developed low-constraint laboratory-sized test specimen. A relatively simple approach to determine the damage parameters of the GTN model is discussed and the transferability of damage parameters between those two test types is also analyzed.

Impact of Metallic Foam’s Microstructure to its Mechanical Property

2013 ◽  
Vol 634-638 ◽  
pp. 2808-2812
Author(s):  
Zhu Feng Sun ◽  
Ling Yun Xie
Keyword(s):  
Fracture Toughness ◽  
Cell Structure ◽  
Crack Tip ◽  
Metallic Foam ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Metal Material ◽  
Loading Mode ◽  
Foam Metal ◽  
Material Fracture

Explored the influence of pore structure of foam metal material on mechanical behavior of fracture. Discuss fracture toughness of several different micro geometric structure of foam metal material with finite element method. The author's calculations showed, microstructure and loading mode has an important effect on the fracture toughness of the foam metal material. due to ignoring the effects of cell structure on the mechanical properties of materials, the classic fracture toughness criterion -crack tip opening displacement (COD) is incomplete, it would be more efficient to take opening displacement change rate of the crack-tip as the parameter to characteristic the metallic foam material fracture toughness.

Analysis on Critical CTOD of Long-Term Used Penstock

2017 ◽  
Vol 741 ◽  
pp. 57-62
Author(s):  
Fumito Kawamura ◽  
Masazumi Miura ◽  
Ryuichiro Ebara ◽  
Keiji Yanase
Keyword(s):  
Fracture Toughness ◽  
Structural Integrity ◽  
Steel Structures ◽  
Chemical Compositions ◽  
Structural Components ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Critical Crack ◽  
Crack Tip Opening

Many studies have been conducted to characterize the fracture toughness of structural steels and their welded joints. However, most studies focus on newly developed steels, and the number of studies on the fracture toughness of long-term used steels in structural components is rather limited. Furthermore, a lack of data on the fracture toughness causes difficulties in evaluating the structural integrity of existing steel structures. In this study, CTOD tests were performed to characterize the fracture toughness of penstock that has been in service for 50 years. By measuring the critical crack tip opening displacement in conjunction with analysis for chemical compositions, the characteristics of fracture toughness were investigated.

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