scholarly journals Control of Mechanical Properties of High Strength Steels Through Optimized Welding Processes

2016 ◽  
Author(s):  
M. Fiedler ◽  
A. Plozner ◽  
B. Rutzinger ◽  
W. Scherleitner
Keyword(s):  
Mechanical Properties ◽  
High Strength Steels ◽  
High Strength ◽  
Welding Processes

scholarly journals Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa

2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Joint Strength ◽  
Solid Phase ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Friction Stir ◽  
Welding Processes

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.

scholarly journals The Assessment of Selected Properties of Welded Joints in High-Strength Steels

2020 ◽  
pp. 73-79
Author(s):  
Lechosław Tuz
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Welded Joints ◽  
Heat Input ◽  
Structural Changes ◽  
High Strength Steels ◽  
High Strength ◽  
High Quality ◽  
Treatment Processes ◽  
Welding Processes

The use of technologically advanced structural materials entails the necessity of adjusting typical welding processes to special requirements resulting from the limited weldability of certain material groups. Difficulties obtaining high-quality joints may be the consequence of deteriorated mechanical properties and structural changes in materials (beyond requirements of related standards). One of the aforementioned materials is steel characterised by a guaranteed yield point of 1300 MPa, where high strength is obtained through the addition of slight amounts of carbide-forming elements and the application of complex heat treatment processes. A heat input during welding may worsen the aforesaid properties not only in the weld but also in the adjacent material. The tests discussed in the article revealed that the crucial area was that heated below a temperature of 600°C, where the hardness of the material decreased from approximately 520 HV to 330 HV.

scholarly journals Control of mechanical properties of high-strength steels through optimized welding processes

2016 ◽  
Vol 2016 (7) ◽  
pp. 32-36
Author(s):  
M. Fiedler ◽  
◽  
A. Plozner ◽  
B. Rutzinger ◽  
W. Scherleitner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Strength Steels ◽  
High Strength ◽  
Welding Processes

Cooling Curve Based Estimation of Mechanical Properties in High Strength Steel Welds

2016 ◽  
Vol 879 ◽  
pp. 1760-1765 ◽  
Author(s):  
Rahul Sharma ◽  
Uwe Reisgen
Keyword(s):  
Mechanical Properties ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Structural Steels ◽  
Cooling Time ◽  
Cooling Curve ◽  
Welding Parameters ◽  
Steel Welds ◽  
Welding Processes

The application of high strength steels in welded structures relies on easy to use quality assurance concepts for the welding process. For ferritic steels, one of the most common methods for estimating the mechanical properties of welded joints is the cooling time concept t8/5. Even without experimental determination, the calculation of cooling time with previously introduced formulas based on the welding parameters leads to good results. Because high strength structural steels and weld metals with a yield strength of 960 MPa contain higher quantities of alloying elements, the transformation start temperature Ar3 is found to be outside of the range of 800 °C to 500 °C. This leads to inadequate estimation results, as the thermal arrest caused by the microstructural transformation in this case is not considered. In this work the usage of the well-proven cooling time concept t8/5 is analyzed using high strength fine grained structural steels and suitable welding filler wires during gas metal arc and submerged arc welding processes. The results are discussed taking into account the microstructure and the transformation behavior. Based on the experimental work, an improved concept is presented.

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.

scholarly journals Control of mechanical properties of high-strength steels through optimized welding processes

2016 ◽  
Vol 2016 (7) ◽  
pp. 35-40
Author(s):  
M. Fiedler ◽  
◽  
A. Plozner ◽  
B. Rutzinger ◽  
W. Scherleitner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Strength Steels ◽  
High Strength ◽  
Welding Processes

Investigations on the Mechanical Properties and Formability of Friction Stir Welded Tailored Blanks

2007 ◽  
Vol 344 ◽  
pp. 143-150 ◽  
Author(s):  
Gianluca Buffa ◽  
Livan Fratini ◽  
Marion Merklein ◽  
Detlev Staud
Keyword(s):  
Mechanical Properties ◽  
Stress Condition ◽  
Research Effort ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Sheet Stamping ◽  
Wide Range

Tight competition characterizing automotive industries in the last decades has determined a strong research effort aimed to improve utilized processes and materials in sheet stamping. As far as the latter are regarded light weight alloys, high strength steels and tailored blanks have been increasingly utilized with the aim to reduce parts weight and fuel consumptions. In the paper the mechanical properties and formability of tailored welded blanks made of a precipitation hardenable aluminum alloy but with different sheet thicknesses, have been investigated: both laser welding and friction stir welding have been developed to obtain the tailored blanks. For both welding operations a wide range of the thickness ratios has been considered. The formability of the obtained blanks has been characterized through tensile tests and cup deep drawing tests, in order to show the formability in dependency of the stress condition; what is more mechanical and metallurgical investigations have been made on the welded joints.

Application of Quenching-Partitioning-Tempering Process in Hot Rolled Plate Fabrication

2010 ◽  
Vol 654-656 ◽  
pp. 82-85 ◽  
Author(s):  
Shu Zhou ◽  
Ying Wang ◽  
Nai Lu Chen ◽  
Yong Hua Rong ◽  
Jian Feng Gu
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Significant Fraction ◽  
Rolled Plate ◽  
Quenching And Partitioning ◽  
Good Ductility ◽  
Hot Rolled ◽  
Rolled Plates

The quenching-partitioning-tempering (Q-P-T) process, based on the quenching and partitioning (Q&P) treatment, has been proposed for producing high strength steels containing significant fraction of film-like retained austenite and controlled amount of fine martensite laths. In this study, a set of Q-P-T processes for C-Mn-Si-Ni-Nb hot rolled plates are designed and realized. The steels with Q-P-T processes present a combination of high strength and relatively good ductility. The origin of such mechanical properties is revealed by microstructure characterization.

The Role of Inclusions on Mechanical Properties in High Strength Steels

1972 ◽  
Vol 9 (6) ◽  
pp. 1339-1339 ◽  
Author(s):  
J. J. Hauser ◽  
M. G. H. Wells ◽  
I. Perlmutter
Keyword(s):  
Mechanical Properties ◽  
High Strength Steels ◽  
High Strength
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