scholarly journals Influence of thermomechanical processing parameters on critical temperatures to develop an Advanced High-Strength Steel microstructure

2021 ◽  
Vol 56 (33) ◽  
pp. 18710-18721
Author(s):  
L. F. Romano-Acosta ◽  
O. García-Rincon ◽  
J. P. Pedraza ◽  
E. J. Palmiere
Keyword(s):  
Mechanical Properties ◽  
Thermomechanical Processing ◽  
High Strength Steels ◽  
High Strength ◽  
Transformation Products ◽  
Processing Parameters ◽  
Deformation Bands ◽  
Critical Temperatures ◽  
Transformation Temperatures ◽  
Steel Microstructure

AbstractA good selection of the thermomechanical processing parameters will optimize the function of alloying elements to get the most of mechanical properties in Advanced High-Strength Steels for automotive components, where high resistance is required for passenger safety. As such, critical processing temperatures must be defined taking into account alloy composition, in order for effective thermomechanical processing schedules to be designed. These critical temperatures mainly include the recrystallization stop temperature (T5%) and the transformation temperatures (Ar1, Ar3, Bs, etc.). These critical processing temperatures were characterized using different thermomechanical conditions. T5% was determined through the softening evaluation on double hit tests and the observation of prior austenite grain boundaries on the microstructure. Phase transformation temperatures were measured by dilatometry experiments at different cooling rates. The results indicate that the strain per pass and the interpass time will influence the most on the determination of T5%. The range of temperatures between the recrystallized and non-recrystallized regions can be as narrow as 30 °C at a higher amount of strain. The proposed controlled thermomechanical processing schedule involves getting a severely deformed austenite with a high dislocation density and deformation bands to increase the nucleation sites to start the transformation products. This microstructure along with a proper cooling strategy will lead to an enhancement in the final mechanical properties of a particular steel composition.

Quenching and Partitioning of Ni-Added High Strength Steels

2007 ◽  
Vol 539-543 ◽  
pp. 4476-4481 ◽  
Author(s):  
F.C. Rizzo ◽  
A.R. Martins ◽  
John G. Speer ◽  
David K. Matlock ◽  
A. Clarke ◽  
...  
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Processing Parameters ◽  
Carbide Formation ◽  
X Ray Diffraction ◽  
Quenching And Partitioning ◽  
Steel Microstructure ◽  
Advanced High Strength Steels ◽  
Treatment Procedures

High strength steels containing significant fractions of retained austenite have been developed in recent years, and are the subject of growing commercial interest when associated with the TRIP phenomenon during deformation. A new process concept “quenching and partitioning” (Q&P) has been proposed by CSM/USA, and the results show the potential to create a new kind of steel microstructure with controlled amounts of retained austenite, enriched by carbon partitioning. Four steels containing C, Si, Mn, Ni, Cr and Mo, were designed with variation in the Ni and C content, aiming to decrease Bs temperature and to suppress carbide formation during the partitioning treatment. Several heat-treatment procedures were performed in specimens previously machined for tensile testing, while x-ray diffraction was used to determine the fraction of retained austenite. The tensile test results showed that except for the high C high Ni alloy, most of the processing conditions resulted in strengths superior to those of advanced high strength steels (AHSS), although it is importantly recognized that higher alloy additions were used in this study, in comparison with conventional AHSS grades.. A variety of strength and ductility combinations were observed, confirming the potential of the Q&P process and illustrating the strong influence of the final microstructure on the mechanical properties. Experimental results for samples partitioned at 400 °C indicate that higher ultimate tensile strength is associated with higher fraction of retained austenite for multiple heat treatments of each alloy investigated. The amount of retained austenite obtained was generally lower than that predicted by the model. Further studies are in progress to understand the influence of alloying and processing parameters (time/temperature) on the partitioning of carbon and precipitation of transition carbides.

Influence of Manufacturing Processes and Microstructures on the Performance and Manufacturability of Advanced High Strength Steels

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
K. S. Choi ◽  
W. N. Liu ◽  
X. Sun ◽  
M. A. Khaleel ◽  
J. R. Fekete
Keyword(s):  
Material Properties ◽  
Thermomechanical Processing ◽  
High Strength Steels ◽  
High Strength ◽  
Processing Parameters ◽  
Martensite Phase ◽  
Basic Material ◽  
Manufacturing Processes ◽  
Localized Deformation ◽  
Advanced High Strength Steels

Advanced high strength steels (AHSS) are performance-based steel grades and their global material properties can be achieved with various steel chemistries and manufacturing processes, leading to various microstructures. In this paper, we investigate the influence of the manufacturing process and the resulting microstructure difference on the overall mechanical properties, as well as the local formability behaviors of AHSS. For this purpose, we first examined the basic material properties and the transformation kinetics of three different commercial transformation induced plasticity (TRIP) 800 steels under different testing temperatures. The experimental results show that the mechanical and microstructural properties of the TRIP 800 steels significantly depend on the thermomechanical processing parameters employed in making these steels. Next, we examined the local formability of two commercial dual phase (DP) 980 steels which exhibit noticeably different formability during the stamping process. Microstructure-based finite element analyses are carried out to simulate the localized deformation process with the two DP 980 microstructures, and the results suggest that the possible reason for the difference in formability lies in the morphology of the hard martensite phase in the DP microstructure. The results of this study suggest that a set of updated material acceptance and screening criteria is needed to better quantify and ensure the manufacturability of AHSS.

The Effects of Thermomechanical Processing on the Microstructure and Mechanical Properties of Ultra-High Strength Dual Phase Steel

2013 ◽  
Vol 631-632 ◽  
pp. 666-669
Author(s):  
Zhuang Li ◽  
Di Wu ◽  
Wei Lv ◽  
Shao Pu Kang ◽  
Zhen Zheng
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
Thermomechanical Processing ◽  
High Strength ◽  
Transformation Products ◽  
Dual Phase ◽  
Laminar Cooling ◽  
Controlled Cooling ◽  
Hot Rolling Mill ◽  
Lower Temperature

In this paper, ultra-high strength dual phase steel was investigated. Thermomechanical processing was conducted by using a laboratory hot rolling mill. The results have shown that the main transformation products at three different kinds of thermomechanical processing were ferrite, bainite, and small amounts of martensite. Laminar cooling led to ferrite grain refinement. The mechanical properties of specimen 1 which was controlled cooling after a relative lower temperature rolling are much higher than that of specimen 2. The presence of martensite islands and precipitates contributed to the enhancement of strength of the present steel. And the presence of retained austenite resulted in higher toughness. As a result, these specimens exhibited satisfactory mechanical properties.

scholarly journals Development of Advanced High Strength Steels Using Hydrogen Quench Continuous Annealing Technology

2019 ◽  
Author(s):  
Francys Barrado ◽  
Tihe Zhou ◽  
Chad Cathcart ◽  
Peter Badgley ◽  
Sarah Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Strength Steels ◽  
High Strength ◽  
Product Yield ◽  
Processing Parameters ◽  
Continuous Annealing ◽  
Advanced High Strength Steels ◽  
Unique Customer ◽  
High Product Yield ◽  
Multi Phase

By using hydrogen quench continuous annealing technology, Stelco Inc. has developed a suite of Advanced High Strength Steel (AHSS) grades with tensile strength greater than 1000MPa to meet standard automotive specifications and for unique customer requirements. These grades were optimized by correlating chemical composition and processing parameters with microstructures and mechanical properties. Dual-Phase 980 (Stelco trademarked STELMAXTM 980DP), Multi-Phase 1180 (STELMAXTM 1180MP), Martensitic Steel 1300 (STELMAXTM 1300M) and 1500 (STELMAXTM 1500M) products met strength and formability requirements with excellent flatness and surface quality. Hydrogen quench continuous annealing technology not only ensures all developed AHSS grades have consistent mechanical properties across the entire strip length (from strip head to tail) and width (from edge to edge), but also produces high product yield compared with other continuous annealing processes.

X100 (Grade 690) Helical-Welded Linepipe

2008 ◽  
Author(s):  
Dengqi Bai ◽  
Laurie Collins ◽  
Fathi Hamad ◽  
Xiande Chen ◽  
Randy Klein ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Processing Parameters ◽  
Construction Costs ◽  
The Past ◽  
Controlled Processing ◽  
The World ◽  
Successful Production

During the past ten years, linepipe development activities around the world have been focused on high strength steels for Arctic gas transmission. The incentive for this work has been the potential for greater transportation efficiency and lower construction costs associated with the use of higher strength steels. The present paper describes the successful production of both 9.8 mm × 762 mm diameter and 12.7 mm × 1067 mm diameter Grade 690 linepipe. The alloying concept, thermomechanical controlled processing, and the resultant microstructures and mechanical properties will be presented. The key processing parameters which control the microstructure and mechanical behavior of the steels will also be discussed.

Modeling of steel hardening process at thermal and mechanical treatment

2019 ◽  
pp. 7-13
Author(s):  
A. S. Oryshchenko ◽  
V. A. Malyshevsky ◽  
E. A. Shumilov
Keyword(s):  
Mechanical Treatment ◽  
Thermomechanical Processing ◽  
High Strength Steels ◽  
High Strength ◽  
Accelerated Cooling ◽  
Rolling Mills ◽  
Hardening Process ◽  
Deformation Parameters ◽  
Research Complex ◽  
Steel Hardening

The article deals with modeling of thermomechanical processing of high-strength steels at the Gleeble 3800 research complex, simulating thermomechanical processing with various temperature and deformation parameters of rolling and with accelerated cooling to a predetermined temperature. The identity of steel hardening processes at the Gleeble 3800 complex and specialized rolling mills, as well as the possibility of obtaining steels of unified chemical composition, are shown.

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.

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.

Effects of Heat Treatment on Microstructure Parameters, Mechanical Properties and Cold Resistance of Sparingly Alloyed High-Strength Steel

2021 ◽  
Vol 410 ◽  
pp. 197-202
Author(s):  
Pavel P. Poleckov ◽  
Olga A. Nikitenko ◽  
Alla S. Kuznetsova
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cold Resistance ◽  
Heating Temperature ◽  
High Strength ◽  
Steel Microstructure ◽  
Treatment Conditions ◽  
Microstructure Parameters ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness

This study considers the influence of various heat treatment conditions on the change of steel microstructure parameters, mechanical properties and cold resistance at a temperature of-60 °C. The common behavior of these properties is considered depending on the heating temperature used for quenching and subsequent tempering. Based on the obtained results, heat treatment conditions are proposed that provide a combination of a guaranteed yield point σ0.2 ≥600 N/mm2 with a low-temperature impact toughness KCV-60 ≥50 J/cm2 and plasticity δ5 ≥17%. The obtained research results are intended for industrial use at the mill "5000" site of MMK PJSC.

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