Recipe for improving the impact toughness of high-strength pearlitic steel by controlling the cleavage cracking mechanisms

2019 ◽  
Vol 764 ◽  
pp. 138256
Author(s):  
Swarnalata Behera ◽  
Rakesh Kumar Barik ◽  
Md Basiruddin Sk ◽  
Rahul Mitra ◽  
Debalay Chakrabarti
Keyword(s):  
Impact Toughness ◽  
High Strength ◽  
Pearlitic Steel ◽  
Cracking Mechanisms ◽  
Cleavage Cracking ◽  
The Impact

scholarly journals Tempforming as an Advanced Processing Method for Carbon Steels

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1566
Author(s):  
Anastasiya Dolzhenko ◽  
Rustam Kaibyshev ◽  
Andrey Belyakov
Keyword(s):  
Impact Toughness ◽  
Crack Propagation ◽  
Large Strain ◽  
High Strength ◽  
Close Relation ◽  
Carbon Steels ◽  
Processing Method ◽  
Propagation Mode ◽  
Displacement Curve ◽  
The Impact

The microstructural mechanisms providing delamination toughness in high-strength low-alloyed steels are briefly reviewed. Thermo-mechanical processing methods improving both the strength and impact toughness are described, with a close relation to the microstructures and textures developed. The effect of processing conditions on the microstructure evolution in steels with different carbon content is discussed. Particular attention is paid to tempforming treatment, which has been recently introduced as a promising processing method for high-strength low-alloyed steel semi-products with beneficial combination of strength and impact toughness. Tempforming consists of large strain warm rolling following tempering. In contrast to ausforming, the steels subjected to tempforming may exhibit an unusual increase in the impact toughness with a decrease in test temperature below room temperature. This phenomenon is attributed to the notch blunting owing to easy splitting (delamination) crosswise to the principle crack propagation. The relationships between the crack propagation mode, the delamination fracture, and the load-displacement curve are presented and discussed. Further perspectives of tempforming applications and promising research directions are outlined.

Physical Simulation of Weldability of Weldox 1300 Steel

2013 ◽  
Vol 762 ◽  
pp. 551-555 ◽  
Author(s):  
Marek Stanislaw Węglowski ◽  
Marian Zeman ◽  
Miroslaw Lomozik
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Physical Simulation ◽  
High Strength ◽  
Parent Material ◽  
Cooling Time ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Transformation Diagrams ◽  
The Impact

In the present study, the investigation of weldability of new ultra-high strength - Weldox 1300 steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on the microstructure and mechanical properties of the heat affected zone (HAZ). In the frame of these investigation the microstructure was studied by the light (LM) and transmission electron microscopies (TEM). It has been shown that the microstructure of the Weldox 1300 steel is composed of tempered martensite, and inside the laths the minor precipitations mainly V(CN) and molybdenum carbide Mo2C were observed. Mechanical properties of parent material were analysed by the tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 - 300 s. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The results show that the impact toughness and hardness decrease with the increase of t8/5 under the condition of a single thermal cycle in simulated HAZ. The continuous cooling transformation diagrams (CCT-W for welding conditions) of Weldox 1300 steel for welding purposes was also elaborated. The steel Weldox 1300 for cooling time in the range of 2,5 - 4 s showed martensite microstructure, for time from 4 s to 60 s mixture of martensite and bainite, and for longer cooling time mixture of ferrite, bainite and martensite. The results indicated that the weldability of Weldox 1300 steel is limited and to avoid the cold cracking the preheating procedure or medium net linear heat input should be used.

Effect of Welding Processes with High Heat Input on the Microstructure and Toughness of Coarse-Grained Heat-Affected Zone of a High-Strength High-Toughness Steel

2018 ◽  
Vol 937 ◽  
pp. 61-67
Author(s):  
Yu Jie Li ◽  
Jin Wei Lei ◽  
Xuan Wei Lei ◽  
Oleksandr Hress ◽  
Kai Ming Wu
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Heat Input ◽  
High Strength ◽  
High Heat ◽  
Coarse Grained ◽  
Low Temperature Impact Toughness ◽  
The Impact ◽  
Welding Processes

Utilizing submerged arc welding under heat input 50 kJ/cm on 60 mm thick marine engineering structure plate F550, the effect of preheating and post welding heat treatment on the microstructure and impact toughness of coarse-grained heat-affected zone (CGHAZ) has been investigated. The original microstructure of the steel plate is tempered martensite. The yield and tensile strength is 610 and 660 MPa, respectively. The impact absorbed energy at low temperature (-60 °C) at transverse direction reaches about 230~270 J. Welding results show that the preheating at 100 °C did not have obvious influence on the microstructure and toughness; whereas the tempering at 600 °C for 2.5 h after welding could significantly reduce the amount of M-A components in the coarse-grained heat-affected zone and thus improved the low temperature impact toughness.

scholarly journals Evaluation of Microstructure and Impact Toughness of Shielded Metal Arc Dissimilar Weldments of High Strength Low Alloy Steel and Austenitic Stainless Steel

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Misbahu A Hayatu ◽  
Emmanuel T Dauda ◽  
Ola Aponbiede ◽  
Kamilu A Bello ◽  
Umma Abdullahi
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Impact Toughness ◽  
Impact Energy ◽  
High Strength ◽  
Impact Testing ◽  
Welding Parameters ◽  
Dissimilar Weld ◽  
Weld Joints ◽  
The Impact

There is a growing interest for novel materials of dissimilar metals due to higher requirements needed for some critical engineering applications. In this research, different dissimilar weld joints of high strength low alloy (HSLA) and 316 austenitic stainless steel grades were successfully produced using shielded metal arc welding (SMAW) process with 316L-16 and E7018 electrodes. Five variations of welding currents were employed within the specified range of each electrode. Other welding parameters such as heat inputs, welding speeds, weld sizes, arc voltages and time of welding were also varied. Specimens for different weld joint samples were subjected to microstructural studies using optical and scanning electron microscopes. The impact toughness test was also conducted on the samples using Izod impact testing machine. The analysis of the weld microstructures indicated the presence of type A and AF solidification patterns of austenitic stainless steels. The results further showed that the weld joints consolidated with E7018 electrode presented comparatively superior impact energy to the weldments fabricated by 316L-16 electrode. The optimum impact energy of E7018-weld joints (51J) was attained at higher welding heat inputs while that of 316L-16-weld joints (35J) was achieved at lower welding heat inputs, which are necessary requirements for the two electrodes used in the experiment. Hence, the dissimilar weld joints investigated could meet requirement for engineering application in offshore and other critical environments.Keywords—Dissimilar metal weld, heat input, impact toughness, microstructures

Metallurgical Design of High Strength/High Toughness Steels

2012 ◽  
Vol 706-709 ◽  
pp. 2084-2089
Author(s):  
Andrea di Schino ◽  
Mauro Guagnelli
Keyword(s):  
Impact Toughness ◽  
Yield Strength ◽  
High Strength Steels ◽  
High Strength ◽  
Carbon Steels ◽  
Main Concern ◽  
Microstructural Parameters ◽  
Fine Microstructure ◽  
The Impact ◽  
Strength And Toughness

The proper balance between yield strength, YS, and ductile to brittle transition temperature, DBTT, has been the main concern during development of high strength engineering steels and the effect of microstructure on impact toughness has attracted a great attention during the last decades. In this paper a review concerning the relationship between strength and toughness in steels will be presented and the effect of different microstructural parameters will be discussed, aiming toimprovesuch properties in designingnewhigh strength steels. Complex microstructures, obtained by quenching and tempering (Q&T) and thermo-mechanical (TM) processing are considered. The steels are low/medium carbon steels (C=0.04%-0.40%) with yield strength in the range YS=500-1000 MPa. Results show that the strength and the impact toughness behaviour are controlled by different microstructural parameters and not, as in the case of polygonal ferritic steels, by the same structural unit (the grain size) and that a “fine” microstructure is required in order to achieve high levels of both strength and toughness. The metallurgical design of high strength steels with toughness requirements is discussed using the same approach for both Q&T and TMCP processes.

Effect of Tempering Temperature on Mechanical Properties of High Strength Wear Resistant Cast Steel

2013 ◽  
Vol 791-793 ◽  
pp. 440-443
Author(s):  
Hong Bo Li ◽  
Jing Wang ◽  
Han Chi Cheng ◽  
Chun Jie Li ◽  
Xing Jun Su
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Cast Steel ◽  
High Strength ◽  
Fracture Morphology ◽  
Temperature Quenching ◽  
Tempering Temperature ◽  
Wear Resistant ◽  
Dimple Fracture ◽  
The Impact

This paper mainly studied the high temperature quenching oil quenching, tempering temperature on the influence of high strength steel mechanical properties of wear resistant. The results show that high strength and toughness wear-resistant cast steel with 880°C× 30min after oil quenching, the hardness of 38.6HRC steel, the impact toughness value reaches 40.18J/cm2. After 200°C, 400°C and 600°C tempering, with the increase of the tempering temperature, the hardness decreased linearly, as by 600°C tempering, the hardness has been reduced to 22.3HRC. Impact toughness with the tempering temperature, the overall upward trend, the impact toughness of some reduced at 400°C, the highest impact toughness value reaches 113.34J/cm2. From the fracture morphology can be seen, with the increase of tempering temperature, ductile fracture increased, by 600°C tempering is dimple fracture, obviously can not see the traces of brittle fracture.

EFFECT OF BORON ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HOT-ROLLED Nb-ADDED HSLA H-SECTION STEEL

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1885-1890 ◽  
Author(s):  
ZUOCHENG WANG ◽  
GUOTAO CUI ◽  
TAO SUN ◽  
WEIMIN GUO ◽  
XIULING ZHAO ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Charpy Impact ◽  
High Strength ◽  
Charpy Impact Test ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Boron Addition ◽  
Low Temperature Impact Toughness ◽  
The Impact

In our research, boron was added into the Nb -added high strength low alloy (HSLA) H -section steels. The contents of boron added were 4ppm, 8ppm and 11ppm, respectively. The mechanical properties of H -section steels with/without boron were examined by using uniaxial tensile test and Charpy impact test ( V -notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results indicate that boron gives a significant increase in impact toughness, especially in low temperature impact toughness, though it leads to an unremarkable increase in strength and plasticity. For instance, the absorbed energy at -40°C reaches up to 126J from 15J by 8ppm boron addition, and the ductile-brittle transition temperature declines by 20°C. It is shown that boron has a beneficial effect on grain refinement. The fracture mechanism is transited from cleavage fracture to dimple fracture due to boron addition.

scholarly journals Analysis of Selected Properties of Welded Joints of the HSLA Steels

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1301 ◽  
Author(s):  
Ivan Miletić ◽  
Andreja Ilić ◽  
Ružica R. Nikolić ◽  
Robert Ulewicz ◽  
Lozica Ivanović ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Welded Joints ◽  
Welded Joint ◽  
High Strength ◽  
Hardness Distribution ◽  
Micro Hardness ◽  
Hsla Steels ◽  
Applied Technology ◽  
Welding Procedure ◽  
The Impact

This paper presents research of the impact toughness and hardness distribution in specific zones of a ‘single V’butt multiple-pass welded joints of the high-strength low-alloyed steels. Obtained values of the impact toughness are analyzed in correlation with a microstructure in specific zones of the welded joint, together with the micro hardness distribution found in the related zones. Based on the carried out analysis and results obtained in experiments, the applied technology of welding was evaluated. The original conclusions on influence of the selected welding procedure manual metal arc (MMA) for the root passes and metal active gas (MAG) for the filling and covering passes) on impact toughness of the high-strength low-alloyed steels are drawn. The paper also presents discussion on the valid standards and recommendations related to welding of those steels, from the aspect of applications in design of steel welded constructions.

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