scholarly journals The Influence of Rehabilitation Techniques on Static and Variabile Loads in Case of a HSLA Steel Samples

2018 ◽  
Author(s):  
Claudiu Babis ◽  
Gheorghe Solomon ◽  
Gabriel Iacobescu ◽  
Oana Roxana Chivu ◽  
Anca Alexandra Purcarea
Keyword(s):  
Hsla Steel ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Filler Materials ◽  
Variable Load ◽  
Low Alloy Steels ◽  
Static Loads ◽  
Welded Structures ◽  
Weld Toe ◽  
Alloy Steels

There are many welded structures in the world such as bridges and viaducts that are subject to fatigue. These structures, generally made of non-alloy or low-alloy steels, have been put into operation some of them with many years ago and have accumulated a large number of variable load cycles over the time. For this reason the occurrence of fatigue phenomenon is inevitable and consists in the occurrence of failures at stresses applied to the structure, below the yield limit of the material. These stresses under the static loads would not cause the failures to appear..This paper will investigate whether two reconditioning techniques “weld toe grinding” and “WIG remelting weld toe”, influences favorably the behavior of welded structures made from HSLA steel, in static and variable loads and therefore if the application of these techniques is justified in both cases. In the paper will be presented the chemical composition and mechanical properties of the base and filler materials, micro and macrostructures, graphics with the variation of microhardness, static and fatigue tensile tests will be performed, and it will be rised durability curve in case of fatigue tests.

scholarly journals The Environmental Impact of Ecological Rehabilitation Techniques Applied to Statically and Variably Stressed Welded Structures

2018 ◽  
Vol 10 (12) ◽  
pp. 4782
Author(s):  
Oana Roxana Chivu ◽  
Claudiu Babis ◽  
Augustin Semenescu ◽  
Olivia Doina Negoita ◽  
Gabriel Iacobescu ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Hsla Steel ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Filler Materials ◽  
Variable Load ◽  
Low Alloy Steels ◽  
Welded Structures ◽  
Ecological Rehabilitation ◽  
Weld Toe

There are many welded structures in the world such as bridges and viaducts that are subject to fatigue. Some of these structures, generally made of non-alloy or low-alloy steels, have been put into operation many years ago and have accumulated a large number of variable load cycles over time. For this reason, the occurrence of the fatigue phenomenon is inevitable and consists in the occurrence of failures at stresses applied to the structure, below the yield limit of the material. These stresses under the static loads would not cause the failures to appear. This paper will investigate if the ecological reconditioning techniques “weld toe grinding” and “WIG re-melting weld toe,” influence favourably the behaviour of the welded structures made from HSLA steel, in static and variable loads, if the application of these techniques is justified in both cases and finally which is the environmental impact of applying these techniques. In the paper we will present the chemical composition and mechanical properties of the base and filler materials, micro and macrostructures, graphics with the variation of the micro-hardness, we will perform static and fatigue tensile tests and we will rise the durability curve in the case of the fatigue tests. We will also present a mathematical computational algorithm, which highlights the extent to which these ecological rehabilitation techniques pollute the environment. It is more efficient both for technological and ecological reasons to recondition a product than to manufacture it from the very beginning.

scholarly journals Experimental and numerical investigation of the overload effect on fatigue behaviour of spot-welded steel sheets

2018 ◽  
Vol 106 (3) ◽  
pp. 309 ◽  
Author(s):  
Fabienne Pennec ◽  
Bianzeubé Tikri ◽  
Sébastien Bergamo ◽  
Michel Duchet ◽  
Bastien Weber ◽  
...  
Keyword(s):  
Failure Modes ◽  
Hsla Steel ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Favourable Effect ◽  
Low Alloy Steels ◽  
Element Analysis ◽  
Alloy Steels ◽  
Spot Welded

Spot-weld joints are commonly used to fasten together metal sheets in automotive industry. The car frame used in Renault vehicles is a representative example of the usefulness of this method. Most of the spot-welds experience fatigue damaging occurrence due to rough roads or driving conditions which apply periodical overloads to the vehicle. Understanding their fatigue behaviour is crucial from the viewpoint of failure prevention in design. In this study, a series of experiments was conducted to study the fatigue failure of spot-welded tensile-shear specimens made of a deep-drawing steel (XES) and High strength low alloy steels (HE360D and XE360D). Two different types of fatigue tests were performed, the first one with a constant-amplitude sinusoidal loading (loading ratio equal to 0.1) and the second one with one incidental overload cycle introduced per 100 cycles. The experimental results show a favourable effect of overloads for HSLA steel specimens, whereas the effect is the opposite for XES steel specimens. A finite element analysis was carried out using the open-source Salome-Meca platform to determine the stress states within the specimens around the weld spot and explains both failure modes observed on the specimens at high and low loads.

scholarly journals Investigations on arc brazing for galvanized heavy steel plates in steel and shipbuilding

2021 ◽  
Author(s):  
Philipp Andreazza ◽  
Andreas Gericke ◽  
Knuth-Michael Henkel
Keyword(s):  
Low Cost ◽  
Thin Sheet ◽  
Steel Structures ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Steel Plates ◽  
Galvanized Steel ◽  
Filler Materials ◽  
Static Tensile ◽  
Brazed Joints

AbstractArc brazing with low-melting copper-based filler materials, which has long been established and standardized in the thin sheet sector, offers numerous advantages in the processing of predominantly electrolytically galvanized steel structures. In steel and shipbuilding, on the other hand, equipment parts made of thick steel sheets are hot-dip galvanized at low cost and with good corrosion-inhibiting properties. Quality welding of such constructions is not possible without special precautions such as removing the zinc layer and subsequent recoating. With regard to greater plate thicknesses, arc brazing was analyzed in these investigations as an alternative joining method with regard to its suitability for practical use. Within the scope of the investigations, CuSi3Mn, CuMn12Ni2, and four different aluminum bronzes were examined on different sheet surface conditions with regard to the geometrical and production parameters. This was carried out by build-up and connection brazing, executed as butt and cross joints. Quasi-static tensile tests and fatigue tests were used to assess the strength behavior. In addition, metallographic analyses are carried out as well as hardness tests. The suitability for multi-layer brazing and the tendency to distortion were also investigated, as well as the behavior of arc brazed joints under corrosive conditions.

Effect of Different Welded Structures on Mechanical Properties of TA2 Tube-to-Tubesheet Joints

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Xinlong Wei ◽  
Yang Qian ◽  
Junhui Wang ◽  
Jianxin Zhou ◽  
Xiang Ling
Keyword(s):  
Applied Load ◽  
Low Cycle Fatigue ◽  
Weld Zone ◽  
Steel Tube ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Welded Structures ◽  
Pull Out ◽  
Weld Toe ◽  
Welded Tube

Four types of TA2 welded tube-to-tubesheet joints prepared by manual tungsten arc argon-shielded welding technique are studied in this paper. The pull-out tests and low cycle fatigue tests were performed to optimize welded structures of tube and tubesheet. The results show that fractures of welded TA2 tube and tubesheet samples occur at weld zone of TA2 steel tube for the pull-out tests and low cycle fatigue tests. The extension-tubesheet welded joints have the maximum pull-out forces and the best fatigue resistance, and the internal-bore welded joint with 45 deg bevel occupies second place. Fractures are both initiated from weld toe of the outside of tube for the pull-out tests and low cycle fatigue tests. Crack propagates along the direction of 45 deg for the pull-out test. However, crack propagates perpendicularly to the direction of the applied load for low cycle fatigue test, and then fractures immediately parallel to the direction of the applied load. Fatigue striations with a spacing of about 10 μm can be observed on the fatigue crack propagation zone. However, hemispheroidal dimples exist on instant rupture zone.

Fatigue Properties of 3D Welded Thin Structures

2020 ◽  
Author(s):  
Seyed M. Allameh ◽  
Avery Lenihan ◽  
Roger Miller ◽  
Hadi Allameh
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Fatigue Testing ◽  
Interfacial Area ◽  
Tensile Tests ◽  
Orientation Dependence ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Mig Welding ◽  
Welded Structures

Abstract Additive manufacturing technology has matured enough to produce real industrial components. A newer method of 3D printing is the deposition of molten metal beads using a MIG weld torch. This involves a 3D printer equipped with a MIG torch layering the metals in desired shapes. It allows the fabrication of components made of MIG weld wires, currently available from various elements including Cu, Al, steel and alloys. Some of these structures made by 3D welding will have applications in critical load bearing conditions. The reliability of such components will be vital in applications where human lives are at stake. Tensile tests are conducted to verify the required strength of the fabricated parts which will undergo monotonic loading; however, fatigue tests are required for cases where cyclic loading will take place. Conventional tensile and fatigue testing requires macro-scale samples. With MIG welding, it is possible to make thin-walled structures. Fatigue testing on samples extracted from thin walls is made possible by microtesting. This study is focused on the mechanical properties of 3D welded structures made from MIG welding wires. Our earlier results showed orientation dependence of mechanical properties in 3D welded structures. They also showed the effect of substrates in expression of the orientation dependence. Welding on metal substrate produces weld beads that are harder at the substrate interfacial area. However, for structures welded on ceramics, the opposite is true. They exhibit a softer substrate interfacial area and a relatively harder top. Our newer results show fatigue properties of structures made by 3D welding. Microsamples measuring 0.2 mm × 0.2 mm × 1.0 mm were extracted from metal beads using a CNC mill along with an EDM. The contours of the samples were machined by milling and the back side was cut by electro discharge machining. Specimens were then polished to the desired size and mounted in the grippers of an E1000 Instron load frame. WaveMatrix® application software from Instron was used to control the machine and to obtain testing data. Fatigue tests were performed, and life cycles were determined for various stress levels up to over 5 million cycles. The preliminary results of tensile tests of these samples show strength levels that are comparable to those of parent metal, in the range of 600–950MPa. Results of fatigue tests show high fatigue lives associated with relatively high stresses. The preliminary results will be presented and the implications of the use of 3D welded rebar in 3D printing of reinforced concrete structures will be discussed.

High Strength Low Alloy Steels in Naval Construction

1986 ◽  
Vol 2 (03) ◽  
pp. 145-162 ◽  
Author(s):  
T. W. Montemarano ◽  
B. P. Sack ◽  
J. P. Gudas ◽  
M. G. Vassilaros ◽  
H. H. Vanderveldt
Keyword(s):  
Hsla Steel ◽  
Development Program ◽  
Cost Savings ◽  
High Strength ◽  
Development Effort ◽  
Low Alloy Steels ◽  
Commercial Development ◽  
Ongoing Research ◽  
The Status ◽  
Alloy Steels

The Naval Sea Systems Command has recently certified a lower-cost alternative steel to the HY-80 steel presently used in construction of naval surface ships. This alternative steel is based on the commercial development of high strength low alloy (HSLA) steels originally directed to the offshore oil exploration platform and gas line transmission industries. The certification is a result of an ongoing research and development program begun in 1980. This paper addresses several aspects of the HSLA steel development effort, including a discussion of the properties and metallurgy of this steel, and the cost savings which are achievable. Finally, the status of the current and planned Navy HSLA usage and the R&D program is described.

Development of New Design Fatigue Curves in Japan: Proposal of a New Fatigue Evaluation Method

2018 ◽  
Author(s):  
Seiji Asada ◽  
Akihiko Hirano ◽  
Toshiyuki Saito ◽  
Yasukazu Takada ◽  
Hideo Kobayashi
Keyword(s):  
Stainless Steels ◽  
Evaluation Method ◽  
Austenitic Stainless Steels ◽  
Fatigue Tests ◽  
Carbon Steels ◽  
Low Alloy Steels ◽  
Stress Effect ◽  
Fatigue Data ◽  
Alloy Steels ◽  
Fatigue Evaluation

In order to develop new design fatigue curves for carbon steels & low-alloy steels and austenitic stainless steels and a new design fatigue evaluation method that are rational and have clear design basis, Design Fatigue Curve (DFC) Phase 1 subcommittee and Phase 2 subcommittee were established in the Atomic Energy Research Committee in the Japan Welding Engineering Society (JWES). The study on design fatigue curves was actively performed in the subcommittees. In the subcommittees, domestic and foreign fatigue data of small test specimens in air were collected and a comprehensive fatigue database (≈6000 data) was constructed and the accurate best-fit curves of carbon steels & low-alloy steels and austenitic stainless steels were developed. Design factors were investigated. Also, a Japanese utility collaborative project performed large scale fatigue tests using austenitic stainless steel piping and low-alloy steel flat plates as well as fatigue tests using small specimens to obtain not only basic data but also fatigue data of mean stress effect, surface finish effect and size effect. Those test results were provided to the subcommittee and utilized the above studies. Based on the above studies, a new fatigue evaluation method has been developed.

scholarly journals Usage of Ti-surface-modified filler material to increase the joint strength of High-Strength Low Alloyed (HSLA) steels under different load types

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Kai Treutler ◽  
Volker Wesling
Keyword(s):  
Dynamic Load ◽  
Base Material ◽  
High Strength ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Structural Steels ◽  
Titanium Coating ◽  
Fine Grained ◽  
Weld Toe ◽  
Load Types

AbstractWelding-related loss of strength, especially in the case of fatigue, significantly reduces the range of applications for high-strength fine-grained structural steels. In order to counteract this situation, the aim of the work is to increase the strength of welded joints made of high-strength fine-grained structural steels by using coated welding consumables. This is described using the example of a titanium coating for quasi-static and abrupt dynamic load and fatigue. The thermomechanical rolled fine-grained structural steel S700MC is used as the base material, using a welding filler of the same type. MAG welding was used to produce the fillet welds on a T-joint. In addition to tensile tests at four different load speeds up to 2 m/s, the results of fatigue tests are presented. In addition, the microstructure of the weld seams is examined by metallographic methods and the scanning electron microscope. A comparison with two joints from an unmodified variant and another steel grade with comparable properties (S690QL) serves to classify the results. It is shown that the use of modified filler metals has a significant influence on the overall strength of the welded joint due to the rounding of the weld toe. Thus, the fatigue strength can be increased by around 50%. In addition, the strength under sudden dynamic load can be increased by 10%.

Investigation of Dynamic Strain Ageing Effects of Low Alloy Steels 15Kh2MFA and 15Kh2NMFA

2005 ◽  
Vol 482 ◽  
pp. 367-370
Author(s):  
Miroslava Ernestová
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Low Alloy Steels ◽  
Strain Rates ◽  
Dynamic Strain Ageing ◽  
Strain Ageing ◽  
Lower Strain ◽  
Wide Range ◽  
Alloy Steels

The paper summarizes results of tensile tests in low alloy steel (LAS) specimens (steels 15Kh2MFA and 15Kh2NMFA). Slow Strain Rate Tensile tests (SSRT) were performed in air at temperatures from 22 to 325°C over a wide range of strain rates from 2.5×10-6 to 1.67×10-3 s-1. The possible effect of strain rate and temperature to mechanical properties of tested LAS is searched for. The dynamic strain ageing (DSA) was observed within certain temperature ranges at lower strain rates tested and its hardening effect in terms of the maximum strengthening stress decreased linearly with the increase of log strain rate. It has been found that the occurrence of susceptibility to environmentally assisted cracking (EAC) of tested steels in high temperature water (HTW) is corelated to the DSA behavior. The result suggest that DSA reduces ductility of reactor pressure vessel (RPV) steel and its role in enhancing the EAC of RPV steels should not be neglected, in view of the coincidence with susceptibility zones for DSA and EAC in terms of strain rate and temperature. A reasonable coincidence was observed between the susceptibility to DSA exhibited by SSRT in air and with the EAC behavior observed in laboratory experiments.

Relationship between the Microstructure of the Welded Steel Plates and the Efficiency of Vibration Stress Relief

2014 ◽  
Vol 941-944 ◽  
pp. 2062-2065
Author(s):  
Shu Qi Li ◽  
Hong Yuan Fang ◽  
Xue Song Liu ◽  
Wei Cui
Keyword(s):  
Residual Stress ◽  
Stress Relief ◽  
Steel Plates ◽  
Low Alloy Steels ◽  
Welded Steel ◽  
Welded Structures ◽  
Vibration Stress ◽  
Alloy Steels ◽  
The Difference ◽  
Main Factor

Welded components of low alloy steels are widely used in various applications. Stress reliving is very important to these welded structures. Vibration stress relief (VSR) is an relatively new method for this purpose. In this study, Q235 and Q345 steel plates were welded. Then they were treated by VSR. The microstructure of the welded lines were investigated and the residual stresses in two directions in these welded structures were measured. The difference of the efficiency of VSR on the two materials were investigate. It is found that, the decreasing amplitude of the residual stress in the Q235 welded structures significantly exceeded that in the Q345 welded structures. The grain size in the area near the weld lines is the main factor that affects the efficiency of the VSR treatment.

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