scholarly journals Effect of enhanced weld cooling on the mechanical properties of a structural steel with a yield strength of 700 MPa

2020 ◽  
Vol 2 (11) ◽  
Author(s):  
Juhani Laitila ◽  
Lassi Keränen ◽  
Jari Larkiola
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Fatigue Strength ◽  
Impact Toughness ◽  
Yield Strength ◽  
Uniform Elongation ◽  
High Strength ◽  
Low Alloy Steel ◽  
External Cooling ◽  
Welding Processes

AbstractIn this study, we present the effect of enhanced cooling on the mechanical properties of a high-strength low-alloy steel (having a yield strength of 700 MPa) following a single-pass weld process. The properties evaluated in this study include uniform elongation, impact toughness, yield, tensile and fatigue strengths alongside the cooling time of the weld. With the steel used in this study, the enhanced cooling resulted in a weld joint characterized with excellent cross-weld uniform elongation, yield and fatigue strength. The intensified cooling reduced the time it takes for the weld to reach 100 °C by around 190 s. Not only the fusion line of the weld was less pronounced, but also the grain size of the CGHAZ was greatly refined as a result of the enhanced cooling. The results indicate that combining external cooling to the welding processes can be beneficial for the studied high-strength steel.

Paradox of Strength and Ductility in Metals Processed Bysevere Plastic Deformation

2002 ◽  
Vol 17 (1) ◽  
pp. 5-8 ◽  
Author(s):  
R. Z. Valiev ◽  
I. V. Alexandrov ◽  
Y. T. Zhu ◽  
T. C. Lowe
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
High Strength ◽  
High Ductility ◽  
Elongation To Failure ◽  
Failure Ductility ◽  
Strength And Ductility

It is well known that plastic deformation induced by conventional forming methodssuch as rolling, drawing or extrusion can significantly increase the strength of metalsHowever, this increase is usually accompanied by a loss of ductility. For example, Fig.1 shows that with increasing plastic deformation, the yield strength of Cu and Almonotonically increases while their elongation to failure (ductility) decreases. Thesame trend is also true for other metals and alloys. Here we report an extraordinarycombination of high strength and high ductility produced in metals subject to severeplastic deformation (SPD). We believe that this unusual mechanical behavior is causedby the unique nanostructures generated by SPD processing. The combination ofultrafine grain size and high-density dislocations appears to enable deformation by newmechanisms. This work demonstrates the possibility of tailoring the microstructures ofmetals and alloys by SPD to obtain both high strength and high ductility. Materialswith such desirable mechanical properties are very attractive for advanced structuralapplications.

scholarly journals Effect of Heat Treatment on Mechanical Properties and Microstructure Morphology of Low-Alloy High-Strength Steel

2016 ◽  
Vol 61 (2) ◽  
pp. 475-480
Author(s):  
K. Bolanowski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
Strengthening Phase ◽  
Average Grain Size

Abstract The paper analyzes the influence of different heat treatment processes on the mechanical properties of low-alloy high-strength steel denoted by Polish Standard (PN) as 10MnVNb6. One of the findings is that, after aging, the mechanical properties of rolled steel are high: the yield strength may reach > 600 MPa, and the ultimate tensile strength is > 700 MPa. These properties are largely dependent on the grain size and dispersion of the strengthening phase in the ferrite matrix. Aging applied after hot rolling contributes to a considerable rise in the yield strength and ultimate tensile strength. The process of normalization causes a decrease in the average grain size and coalescence (reduction of dispersion) of the strengthening phase. When 10MnVNb6 steel was aged after normalization, there was not a complete recovery in its strength properties.

Fatigue Performance of Laser Brazes in Advanced High Strength Steels

2010 ◽  
Vol 638-642 ◽  
pp. 3254-3259 ◽  
Author(s):  
M.H.E. Janssen ◽  
M.J.M. Hermans ◽  
M. Janssen ◽  
I.M. Richardson
Keyword(s):  
Mechanical Properties ◽  
Trip Steel ◽  
Uniform Elongation ◽  
High Strength Steels ◽  
High Strength ◽  
Process Conditions ◽  
Trip Steels ◽  
Advanced High Strength Steels ◽  
Brazed Joints ◽  
Welding Processes

Advance high strength steels (AHSS), like dual phase (DP) and transformation induced plasticity (TRIP) steels, offer high strength and toughness combined with excellent uniform elongation. However, the higher alloying content of these steels limit their weldability and the thermal cycle of welding processes destroys the carefully designed microstructure. This will result in inferior mechanical properties of the joint. Therefore, joining processes with a low heat input, like brazing, are recommendable. Data regarding mechanical properties of joints in DP and TRIP steel is limited, especially for brazed joints. Results with respect to the fatigue lifetime of laser brazed butt joints are presented. In DP and TRIP steel, crack initiation takes place at the braze toe. In DP steel the crack propagates through the base metal. In TRIP steel, however, the crack may either follow the interface or may continue through the steel depending on the maximum stress level. The different failure mechanisms are explained on the basis of process conditions, the microstructure and the stress state.

Improvement on Impact Toughness of Cold Formed S420 Steel by Direct Quenching

2021 ◽  
Vol 1016 ◽  
pp. 648-653
Author(s):  
Antti Kaijalainen ◽  
Juho Mourujärvi ◽  
Juha Tulonen ◽  
Petteri Steen ◽  
Jukka I. Kömi
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Yield Strength ◽  
Uniform Elongation ◽  
Cold Deformation ◽  
Strength Level ◽  
Cold Forming ◽  
Direct Quenching ◽  
The Impact

The aim of this work is to study the effect cold forming rate (CFR) on the mechanical properties and microstructure of a conventional TMCP and a direct-quenched steel in 420 MPa strength level. The microstructure was characterized using FESEM-EBSD. Tensile properties and Charpy-V impact toughness were determined. As the CFR increased, the yield and tensile strength raised quite linearly with both steels. Yield strength values increased from 450 MPa (as-rolled material) to 700 MPa (25 % CFR). However, tensile strength increased less compared to yield strength. Uniform elongation decreased linearly till about 10 % CFR and total elongation till about 15 – 20 % CFR. The impact values decreased quite linearly in -40 °C and -60 °C test temperature when the cold forming rate increased. In longitudinal direction (L-T) the impact values were at high level at -40 °C and -60 °C with both steels with all CFR. In transverse direction (T-L) the impact results were lower. Impact energies were enhanced by direct quenching compared to conventional steel in every CFR stage. EBSD results showed no major difference between steels in the grain sizes in generally. However, cold forming decreased the grain size and increased low-angle grain boundaries in correlation with increasing CFR. Small size of the coarsest grains (d90%) usually indicate better toughness, however in this case the impact values were decreased even with smaller grain size as cold deformation occurs. On the other hand, the strength level increased with forming rate. Therefore, a brief discussion of the microstructural features controlling the impact toughness is given.

Mechanical Properties and Microstructure of Mg-Zn-Y Alloys Processed by ECAE

2006 ◽  
Vol 503-504 ◽  
pp. 769-774 ◽  
Author(s):  
Shintaro Yoshimoto ◽  
Yuichi Miyahara ◽  
Z. Horita ◽  
Yoshihito Kawamura
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
High Strength ◽  
Mg Alloys ◽  
Tensile Yield Strength ◽  
Ordered Structure ◽  
Lpso Phase ◽  
Microstructure Refinement

Development of high strength I/M Mg alloys has been tried by ECAE processing. The mechanical properties and microstructure of ECAE-processed Mg97Zn1Y2 alloy with LPSO (long-periodic stacking ordered) structure were investigated. The tensile yield strength and elongation of as-cast Mg97Zn1Y2 were improved substantially by ECAE process. ECAE-processed with yield strength of 290 MPa and elongation of 22 % was obtained. The microstructure of ECAE-processed Mg97Zn1Y2 alloy consisted of refined α-Mg with the grain size around 6.5 μm and finely dispersed LPSO phase. Furthermore, the some texture was formed by ECAE process. The improved mechanical properties seem to be originated by the microstructure refinement and texture.

High Strength Offshore Steel with Excellent Weldability

2012 ◽  
Vol 482-484 ◽  
pp. 1650-1653
Author(s):  
Yan Tang Chen ◽  
Kai Guang Zhang
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Yield Strength ◽  
Thermal Cycle ◽  
Hsla Steel ◽  
High Strength ◽  
High Impact ◽  
Weld Thermal Cycle ◽  
Offshore Engineering ◽  
Base Steel

A new high strength low alloy (HSLA) steel in 370MPa yield strength grade with low susceptivity to weld cold cracking has been developed for offshore engineering. The microstructure feature of base steel and weld heat affected zone (HAZ) has been investigated. The systematic studies showed that the developed steel exhibited high strength(yield strength≥370MPa)、high impact toughness and excellent weldability. The complex inclusions containing fine oxides in HAZ promoted the acicular ferrite formation in weld thermal cycle and resulted in desired mechanical properties of HAZ.

scholarly journals Building strategy effect on mechanical properties of high strength low alloy steel in wire + arc additive manufacturing

2020 ◽  
Vol 65 (3) ◽  
pp. 125-136
Author(s):  
Yildiz Suat ◽  
Baris Koc ◽  
Oguzhan Yilmaz
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Yield Strength ◽  
High Strength ◽  
Inert Gas ◽  
High Deposition Rate ◽  
Thin Wall ◽  
Cold Metal Transfer ◽  
Welding Processes ◽  
Wire Arc Additive Manufacturing

Wire arc additive manufacturing (WAAM) which is literally based on continuously fed material deposition type of welding processes such as metal inert gas (MIG), tungsten inert gas (TIG) and plasma welding, is a variant of additive manufacturing technologies. WAAM steps forward with its high deposition rate and low equipment cost as compared to the powder feed and laser/electron beam heated processes among various additive manufacturing processes. In this work, sample parts made of low allow high strength steel (ER120S-G) was additively manufactured via WAAM method using robotic cold metal transfer technology (CMT). The process parameters and building strategies were investigated and correlated with the geometrical, metallurgical and mechanical properties on the produced wall geometries. The results obtained from the thin wall sample parts have showed that with increasing heat input, mechanical properties decreases, since higher heat accumulation and lower cooling rate increases the grain size. The tensile tests results have showed that casting steel (G24Mn6+QT2) mechanical properties which requires 500 MPa yield strength can be compared to with as build WAAM process having 640 MPa yield strength. Tensile strength were fulfilled for S690Q and yield strength is very close to the reference value.

MAXI-FORM 80

Alloy Digest ◽  
1975 ◽  
Vol 24 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Impact Toughness ◽  
Yield Strength ◽  
High Strength ◽  
Heat Treating ◽  
Low Alloy Steel ◽  
Temperature Performance ◽  
Complex Parts

Abstract MAXI-FORM 80 is a high-strength low-alloy steel that provides superior ductility, good fatigue resistance, good weldability and outstanding impact toughness even at temperatures down to -40 F and below. It has a yield strength of 80,000 psi along with the high formability that complex parts require. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on low temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-312. Producer or source: Republic Steel Corporation.

Effect of the Strain Rate on Mechanical Properties and Microstructure of High Strength Low Alloy Steel HC340LA

2012 ◽  
Vol 217-219 ◽  
pp. 467-470
Author(s):  
Xiao Hang Liu ◽  
Wen Jing Yuan ◽  
Hao Bin Tian ◽  
Fa Xi Diao
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Strain Rate ◽  
Alloy Steel ◽  
High Speed ◽  
Hsla Steel ◽  
High Strength ◽  
Static Tension ◽  
Low Alloy Steel

The mechanical properties and microstructure of the high strength low alloy HC340LA were obtained with different strain rate. The research shows that the better plasticity, higher tensile strength and yield ratio can be found in high speed tensile state than in quasi-static tension. The plasticity and tensile strength decrease with the increasing of the strain rate during the high speed tension. With the increasing of the strain rate, the grain size of the ferrite decreases and its distribution is uneven, and the grain boundaries increases. The HSLA steel HC340LA submit to obvious Ductile Frecture mechanism. The size of the dimples is more uniform, bigger and deeper with the strain rate 50 s-1 than with the strain rate 200 s-1. Therefore, the higher strain rate with over strain rate 50 s-1 has less Superscript textcontribution to the improvement of plasticity of the HSLA steel HC340LA.

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