Effect of Corrosion on Crack Development and Fatigue Life

1998 ◽  
Vol 1624 (1) ◽  
pp. 110-117 ◽  
Author(s):  
John W. Fisher ◽  
Eric J. Kaufmann ◽  
Alan W. Pense
Keyword(s):  
Fatigue Life ◽  
Weld Metal ◽  
Fatigue Cracking ◽  
High Strength ◽  
Time Dependent ◽  
Structural Behavior ◽  
The Past ◽  
Fatigue And Fracture ◽  
Bridge Structures

Fatigue and fracture as well as loss of section caused by corrosion are time-dependent performance characteristics that have the potential to jeopardize the integrity of bridge structures. During the past 25 years these conditions have developed in a number of bridges, resulting in loss of service, costly repairs, and concern about the safety of these structures. A review of the experience with such time-dependent damage since 1970 is presented. The experience is grouped into three categories: fatigue cracking resulting from changes in structural behavior as a result of corrosion, fatigue cracking resulting from development of corrosion notches in members, and stress corrosion of high-strength steel and weld metal. The examples cited illustrate the role of corrosion phenomena in bridge service and the need to control the corrosion conditions on bridge structures.

scholarly journals Hydrogen-assisted cracking in GMA welding of high-strength structural steels using the modified spray arc process

2020 ◽  
Vol 64 (12) ◽  
pp. 1997-2009
Author(s):  
Thomas Schaupp ◽  
Michael Rhode ◽  
Hamza Yahyaoui ◽  
Thomas Kannengiesser
Keyword(s):  
Weld Metal ◽  
Gma Welding ◽  
High Strength ◽  
Economic Benefits ◽  
Structural Steels ◽  
Test Series ◽  
Deposition Rates ◽  
The Past ◽  
Hydrogen Assisted Cracking ◽  
Implant Test

Abstract High-strength structural steels are used in machine, steel, and crane construction with yield strength up to 960 MPa. However, welding of these steels requires profound knowledge of three factors in terms of avoidance of hydrogen-assisted cracking (HAC): the interaction of microstructure, local stress/strain, and local hydrogen concentration. In addition to the three main factors, the used arc process is also important for the performance of the welded joint. In the past, the conventional transitional arc process (Conv. A) was mainly used for welding of high-strength steel grades. In the past decade, the so-called modified spray arc process (Mod. SA) has been increasingly used for welding production. This modified process enables reduced seam opening angles with increased deposition rates compared with the Conv. A. Economic benefits of using this arc type are a reduction of necessary weld beads and required filler material. In the present study, the susceptibility to HAC in the heat-affected zone (HAZ) of the high-strength structural steel S960QL was investigated with the externally loaded implant test. For that purpose, both Conv. A and Mod. SA were used with same heat input at different deposition rates. Both conducted test series showed same embrittlement index “EI” of 0.21 at diffusible hydrogen concentrations of 1.3 to 1.6 ml/100 g of arc weld metal. The fracture occurred in the HAZ or in the weld metal (WM). However, the test series with Mod. SA showed a significant extension of the time to failure of several hours compared with tests carried out with Conv. A.

Fatigue Life of Welded Joints of High-Strength Structural Steel S960QL

2016 ◽  
Vol 250 ◽  
pp. 169-174 ◽  
Author(s):  
Tomasz Slezak ◽  
Lucjan Sniezek
Keyword(s):  
Fatigue Life ◽  
Structural Steel ◽  
Welded Joints ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Fatigue Cracking ◽  
High Strength ◽  
Propagation Rate ◽  
Total Strain Amplitude ◽  
Fatigue Life Analysis

The article presents the results of research on low cycle fatigue strength of welded joints of structural steel S960QL. Two types of butt welds were analysed: I-joints and V-joints. The tests were performed under load controlled using the total strain amplitude εac. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue parameters. High concordance was found of the adopted description model with experimental results. Studies have shown differences in the fatigue life of the various joints analysed, wherein I-joints showed about 20-50% higher fatigue life. Fractographic tests of fatigue fractures in joints revealed the details of fatigue cracking and differences in the propagation rate of fatigue cracks.

Some Notes on the Influence of Manufacturing on the Fatigue Life of Welded Aluminum Marine Structures

2004 ◽  
Vol 20 (03) ◽  
pp. 164-175
Author(s):  
J. Kecsmar ◽  
R. A. Shenoi
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Fatigue Cracking ◽  
High Strength ◽  
Stress Concentrations ◽  
Alloy Matrix ◽  
Workshop Practice ◽  
Weld Porosity ◽  
The Cost ◽  
Fatigue Life Reduction

Designers are constantly looking for ways to reduce the structure weight to lower the overall displacement and hence the cost of fast ferries and other high-speed vessels. The easiest option for the designer is to choose a lightweight material. Aluminum has become the adopted choice of material for high-speed vessels owing to its high strength to weight characteristics. Unlike steel, aluminum is more prone to fatigue cracking and has no fatigue limit. In order to minimize weight, the designer will make use of finite element methods to optimize the scantlings and perform fatigue checks against established codes. This can lead to a structure that has the empirical margins of safety reduced owing to the accuracy of mathematical modeling. However, what is often overlooked is the effect the manufacturing process has on the fatigue life of the fabricated structure. This aspect is excluded from the designer's fatigue calculations, which assist in reducing the scantlings. Currently, there is no guidance for fatigue life reduction for the designer that establishes good and bad workshop practice, other than experience, or the implications of basic shipyard fabrication. It is shown that whereas strain-hardened alloys improve mechanical strength, they reduce ductility. This has consequences when forming the hull plate by potentially introducing crack like flaws into the alloy matrix if the plater overrolls the plate. If there is misalignment or there is too much gap between the plates, the weld will create localized stress concentrations. If the welder has poor joint preparation or gas shielding, porosity can be introduced into the weld. Porosity has a significant effect on the fatigue life of the weldment. This paper brings together a collection of data on such issues that the designer needs to be aware of to prevent an unwanted fatigue failure in the fabrication process.

Fatigue Life Analysis and Tensile Overload Effects with High Strength Steel Notched Specimens

1983 ◽  
Vol 22 ◽  
Author(s):  
J. H. Underwood
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Fatigue Cracking ◽  
High Strength ◽  
Pressure Vessels ◽  
Life Testing ◽  
Stress Concentrations ◽  
Notched Specimens ◽  
Life Analysis ◽  
Fatigue Life Analysis

Pressure vessels often have notches or other stress concentrations present. Considering further that pressure vessels are nearly always subjected to some cyclic loading, fatigue cracking at notches is an important problem. The objective here is to describe some fatigue life testing and analysis which was performed with notched specimens in order to determine the effects of notch overload on fatigue life of pressure vessels.

scholarly journals Laboratory research on functioning of bridge structures reinforced with induction brazing

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
Sergey Bokarev ◽  
Andrei Usoltsev
Keyword(s):  
Fatigue Cracks ◽  
Fatigue Cracking ◽  
High Strength ◽  
Laboratory Research ◽  
Induction Brazing ◽  
Research Institution ◽  
Bridge Span ◽  
Metal Plates ◽  
Bridge Structures ◽  
Bridge Spans

Welded metal bridge spans are one of the most wide-spread types of bridge spans, several thousand of them being in operation along motorways and in city areas in Russia. Similar to other welded structures they are prone to fatigue cracking which is usually repaired using metal plates fixed with high-strength bolts. The Siberian Research Institution of Bridges located in Siberian Transport University has developed the structure and technology of welded bridge span reinforcement using round metal plates fixed by induction brazing. To prove the efficiency of the technology a laboratory research and testing of girders reinforced with round metal plates fixed by induction brazing has been conducted. The research shows that after the induction brazing enforcement the bridge structures that have fatigue cracks obtain strength parameters 25 per cent higher compared to those of completely new unreinforced samples without fatigue cracks. The article is part of the dissertation research Usoltseva A.M.

scholarly journals Role of welding flux in formation of weld metal during arc welding of high-strength low-alloy steels

2014 ◽  
Vol 2014 (6) ◽  
pp. 62-65 ◽  
Author(s):  
V.V. Golovko ◽  
◽  
S.N. Stepanyuk ◽  
D.Yu. Ermolenko ◽  
◽  
...  
Keyword(s):  
Weld Metal ◽  
Arc Welding ◽  
High Strength ◽  
Low Alloy Steels ◽  
Welding Flux ◽  
Alloy Steels

scholarly journals Fatigue Life Evaluation Considering Fatigue Reliability and Fatigue Crack for FV520B-I in VHCF Regime Based on Fracture Mechanics

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 371 ◽  
Author(s):  
Jinlong Wang ◽  
Yuxing Yang ◽  
Jing Yu ◽  
Jingsi Wang ◽  
Fengming Du ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fracture Mechanics ◽  
Evaluation Method ◽  
Evaluation Model ◽  
Fatigue Cracking ◽  
High Strength ◽  
Fatigue Reliability ◽  
Life Evaluation ◽  
Fatigue Life Evaluation ◽  
Very High

This paper focuses on the fatigue reliability analysis and the development of a new life model of reliability and crack growth mechanisms in FV520B-I (high strength martensitic-type stainless steels) in the very-high cycle fatigue (VHCF) regime, which haven’t been studied well. First, the fatigue test was carried out to clarify the fatigue failure mechanism in the very-high cycle regime. Based on the test results and fatigue reliability theory, the fatigue life distribution and P-S-N curves were modeled. A new fatigue life evaluation model for FV520B-I is proposed according to the fracture mechanics and classic life evaluation method. With the comprehensive application of P-S-N curves and a new proposed fatigue life evaluation model, a new assumption of a P-Sc-N curve is developed and verified, to quantitatively express the relationship between fatigue life, reliability and fatigue cracking. This is novel and valuable for further fatigue study of FV520B-I.

scholarly journals Influence of technology temperature on the fatigue cracking resistance of asphalt mixtures used for bridge pavement

2014 ◽  
Vol 13 (4) ◽  
pp. 225-235
Author(s):  
Piotr Radziszewski ◽  
Andrzej Plewa ◽  
Karol Kowalski ◽  
Jan Król ◽  
Michał Sarnowski ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Cracking ◽  
Asphalt Mixtures ◽  
Regression Equations ◽  
Bridge Structure ◽  
Cracking Resistance ◽  
Stiffness Modulus ◽  
Bridge Structures ◽  
Asphalt Mix ◽  
Different Levels

Bridges are an integral part of road infrastructure. In times of the roadnetwork expansion in Poland a lot of bridges were constructed. Due to the nature of work, a bridge structure should comply with specific features and requirements. This article presents the results of the fatigue life of selected asphalt mixtures used in bridge structures. Mixtures for various pavement layers were investigated. The effect of high temperature on stiffness modulus and fatigue cracking resistance with different levels of strain were analyzed. These relationships were presented in the regression equations form. The crucial influence of increased technology temperature on asphalt mix fatigue life was proved.

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