Effect of Hot Rolling and Thermal Treatment on the Microstructure Evolution of Microalloyed Bainitic Steels for Pipeline

2017 ◽  
Vol 746 ◽  
pp. 176-183 ◽  
Author(s):  
Alexander Kabanov ◽  
Grzegorz Korpala ◽  
Rudolf Kawalla ◽  
Sergey Ionov
Keyword(s):  
Heat Treatment ◽  
Microstructure Evolution ◽  
High Strength ◽  
Accelerated Cooling ◽  
Experimental Modelling ◽  
Heavy Plate ◽  
Bainitic Steels ◽  
Bainitic Microstructure ◽  
Effect Of Hot Rolling

Heavy plate for pipelines, which are used in earthquake-prone areas, must have among other a good ductility. The ductility is needed to prevent cracking in the case of local plastic deformation. The bainitic steels with retained austenite or martensite meet these requirements. The aim of this investigation is the determination of the thermo-mechanical treatment parameters with which such microstructures can be generated during the heavy plate production or an additional heat treatment. Experimental modelling of the production process for heavy plate was realized on a Gleeble HDS-V40 thermo-mechanical simulator. Moreover, the microstructure evolution processes during cooling on the round out table were investigated by dilatometry. The investigations on the formation of the microstructure during following accelerated cooling and heat treatment combination were carried out. All investigations were realized with two high-strength micro-alloyed steels, one of which was additionally alloyed with molybdenum. Results revealed that the decreasing of the temperature and duration of the heat treatment as well as addition of molybdenum reduce the size of grains and promotes the nucleation of the bainitic microstructure.

Development of NbTiB Microalloyed HSLA Steels for High-Strength Heavy Plate

2005 ◽  
Vol 500-501 ◽  
pp. 565-572 ◽  
Author(s):  
H. Meuser ◽  
F. Grimpe ◽  
S. Meimeth ◽  
C.J. Heckmann ◽  
C. Träger
Keyword(s):  
High Strength ◽  
Optimum Process ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Alloying Element ◽  
Heavy Plate ◽  
Hsla Steels ◽  
Bainitic Microstructure ◽  
Bainitic Structure ◽  
Low Temperature Toughness

This paper deals with the development of low carbon NbTiB micro-alloyed high strength low alloy steel for heavy plates with high wall thickness. In the production of heavy plate it is remarkably difficult to achieve a combination of high strength and good low-temperature toughness. Bainitic microstructures have shown the capability to attain such requirements. To achieve a bainitic microstructure even for heavy wall products the formation of bainite can be promoted and supported by the use of small amounts of boron as a micro-alloying element. This industrial research project is based on the addition of small amounts of boron to promote the desired bainitic structure. Mill rolling trials were carried out to determine the optimum process parameters. The results of experimental mill rolling trials on 35 mm plates will be presented in this paper.

Metallographic Analysis of ECAP Processed Selected Magnesium Alloys

2014 ◽  
Vol 782 ◽  
pp. 404-407 ◽  
Author(s):  
Stanislav Rusz ◽  
Michal Salajka ◽  
Lubomír Čížek ◽  
Stanislav Tylšar ◽  
Jan Kedroň
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloys ◽  
Weight Ratio ◽  
High Strength ◽  
Metallographic Analysis ◽  
Low Density ◽  
Ecap Processing ◽  
Experimental Part ◽  
Composition Study

Magnesium alloys has been used for a wide variety of applications, namely from the reason of their low density and high strength–to–weight ratio. The properties of magnesium alloys are connected with microstructure that is influenced by metallurgical and technological aspects. Scope of utilisation of foundry magnesium alloys is continuously being extended, so if we want to operate as competitive producers, it is necessary to investigate very actively properties of individual alloys, optimise their chemical composition, study issues of their metallurgical preparation, verify experimentally their casting properties and conditions of successful casting of castings by individual methods, including heat treatment. Recently, however, increases also utilisation of formed magnesium alloys namely application of SPD methods. The experimental part deals with hardness and structure determination of selected magnesium alloys after ECAP processing.

Effects of Heat Treatment on Microstructure of High-Strength Manganese-Silicon Steels

2017 ◽  
Vol 270 ◽  
pp. 239-245
Author(s):  
Dagmar Bublíková ◽  
Štěpán Jeníček ◽  
Kateřina Opatová ◽  
Bohuslav Mašek
Keyword(s):  
Heat Treatment ◽  
Cooling Rate ◽  
Microstructure Evolution ◽  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength ◽  
Quenching And Partitioning ◽  
Alloying Additions ◽  
New Procedures ◽  
Strength And Ductility

Today’s advanced steels are required to possess high strength and ductility. This can be accomplished by producing appropriate microstructures with a certain volume fraction of retained austenite. The resulting microstructure depends on material’s heat treatment and alloying. High ultimate strengths and sufficient elongation levels can be obtained by various methods, including quenching and partitioning (Q&P process). The present paper introduces new procedures aimed at simplifying this process with the use of material-technological modelling. Three experimental steels have been made and cast for this investigation, whose main alloying additions were manganese, silicon, chromium, molybdenum and nickel. The purpose of manganese addition was to depress the Ms and Mf temperatures. The Q&P process was carried out in a thermomechanical simulator for better and easier control. The heat treatment parameters were varied between the sequences and their effect on microstructure evolution was evaluated. They included the cooling rate, partitioning temperature and time at partitioning temperature. Microstructures including martensite with strength levels of more than 2000 MPa and elongation of 10–15 % were obtained.

scholarly journals Experimental determination of continuous cooling transformation diagram for high strength steel X153CrMoV12

2021 ◽  
Vol 16 (1) ◽  
pp. 19-24
Author(s):  
Michal Krbaťa ◽  
◽  
Róbert Cíger ◽  
Keyword(s):  
Experimental Data ◽  
Heat Treatment ◽  
High Strength Steel ◽  
Microstructural Analysis ◽  
High Strength ◽  
Cooling Curves ◽  
Treatment Mode ◽  
Heat Treatment Mode ◽  
Continuous Cooling Transformation Diagram

The article is a continuation of the article ,DILATOMETRIC ANALYSIS OF COOLING CURVES FOR HIGH STRENGTH STEEL X153CrMoV12”, which deals with the phase transformations of tool steel X153CrMoV12. The experimental data obtained was used to evaluate the resulting CCT diagram, which consists of seven dilation curves. All experimental samples from dilatometric analyses were then subjected to microstructural analysis and hardness measurements to characterize the microstructure and hardness for each heat treatment mode tested. AFM microscopy was also used to study the carbides present in steels and their size and shape for all selected cooling modes.

A Method for Simulation of Microstructure Evolution in 980MPa-ULCB Steels during On-Line Heating Treatment

2011 ◽  
Vol 214 ◽  
pp. 472-476
Author(s):  
Jian Xin Zhang ◽  
Ai Hua Gao
Keyword(s):  
Microstructure Evolution ◽  
Treatment Process ◽  
Steel Plate ◽  
Volume Fraction ◽  
High Strength ◽  
Accelerated Cooling ◽  
Line Heating ◽  
Treatment Parameter ◽  
Heating Treatment ◽  
On Line

Influence of the off line heating treatment parameter on the microstructure of a high strength steel plate was studied system previously. However, the information about the effect of on-line heating treatment process on ultra-high steel plate, especially on the plate with a tensile strength 980MPa or above, is limited due to the lack of effective method to simulation for the on-line heating treatment process. A method, which is preformed with a thermo-mechanical simulator, simulation the parameter of on-line heating treatment on the microstructure evolution a high strength ULCB steel plate after the accelerated cooling. By means of observation the original microstructure and microstructure morphologies varied with the parameter of the on-line heating treatment process, the present results demonstrate the microstructure characterizations before and after heating treatment process, while also the distribution of M(C, N) particles on lath boundaries or lath interior and the volume fraction and the average size of M/A island.

scholarly journals The study of influence of heat treatment procedures on structure and properties of the new high-strength steel with increased cold resistance

2020 ◽  
pp. 50-54
Author(s):  
P. P. Poletskov ◽  
A. S. Kuznetsova ◽  
O. A. Nikitenko ◽  
D. Yu. Alekseev
Keyword(s):  
Heat Treatment ◽  
Impact Strength ◽  
Heating Temperature ◽  
Structural Phase ◽  
High Strength ◽  
Residual Austenite ◽  
Ministry Of Education ◽  
Iron And Steel ◽  
Heavy Plate ◽  
Treatment Procedures

The study of influence of different heat treatment procedures on microstructure and mechanical properties of the new high-strength weldable cold-resistant steel 20G2SMRA (20Г2СМРА) is conducted. Morphology of martensite after steel quenching, as well after quenching and consequent tempering, is examined using optical metallography and electron microscopy. Regularities of varying of microstructure parameters, hardness values (HV1) and impact strength KCV were revealed in this work at the temperature –60 °С depending on heating temperature for quenching and consequent tempering. Amount of residual austenite after quenching starting from the temperatures 850, 950 and 1000 °C was determined using X-ray structural phase analysis. The rational procedure of heat treatment was established as a result of the study; it provides combination of guaranteed yield strength σ0,2 ≥ 600 N/mm2 together with low-temperature impact strength KCV–60 ≥ 50 J/sm2 and ductility δ5 ≥ 17%. The obtained results of investigation are aimed for commercial putting into practice in the conditions of heavy plate production at 5000 rolling mill of Magnitogorsk Iron and Steel Works (MMK). The work was done under financial support of the RF Ministry of Education and Science within the framework of execution of the grant of RF President (Agreement No. 075-15-2020-205 dated 17.03.2020 (int. No. MK-1979.2020.8)).

scholarly journals Effect of Cooling and Isothermal Holding on the Amount of Martensite/Austenite (M/A) Constituents, Microstructure and Mechanical Properties of Microalloyed Pipeline Steel

2018 ◽  
Vol 918 ◽  
pp. 152-158 ◽  
Author(s):  
Alexander Kabanov ◽  
Grzegorz Korpala ◽  
Rudolf Kawalla ◽  
Sergey Ionov
Keyword(s):  
Mechanical Properties ◽  
Pipeline Steel ◽  
Isothermal Holding ◽  
High Strength Steels ◽  
High Strength ◽  
Cold Climate ◽  
Throughput Capacity ◽  
Accelerated Cooling ◽  
Bainitic Steels ◽  
Strength And Plasticity

Constant increase of energy consumption in modern industry requires construction of heavily loaded pipelines with high throughput capacity. Therefore, high-strength steels should be used for the cost reasons. Additionally, the pipelines are also often used in the areas with cold climate and high seismicity. Therefore, strength and plasticity reduction is unacceptable. Bainitic steels with retained austenite (RA) or martensite/austenite (M/A) constituents meet these requirements. The purpose of this investigation is to determine thermo-mechanical treatment parameters with further accelerated cooling and additional isothermal holding for M/A-phase and mechanical properties formation. Experimental modeling of the production process was carried out using Gleeble HDS-V40 thermo-mechanical simulator. All investigations were realized with two high-strength micro-alloyed steels with different molybdenum and carbon content. Results showed that decrease of temperature and duration of isothermal holding as well as addition of molybdenum promote bainitic microstructure nucleation and reduce grain size and M/A-constituents. All these factors lead to a slight improvement in mechanical properties.

High Strength Heavy Plate Optimised for Application in Remote Areas and Low-Temperature Service

2010 ◽  
Author(s):  
Charles Stallybrass ◽  
Joachim Konrad ◽  
Heike Meuser ◽  
Fabian Grimpe
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
High Strength ◽  
Alternative Methods ◽  
Accelerated Cooling ◽  
Processing Conditions ◽  
Remote Areas ◽  
Heavy Plate ◽  
Low Temperature Toughness ◽  
Ebsd Method

The last decades have seen a steady increase in the demand for high-strength linepipe steels. These offer the most economical option to transport large gas volumes at high pressures from remote areas to the market. Since the beginning of the 1980’s, high strength heavy plates, pipes and pipe bends were developed and produced at Salzgitter Mannesmann Grobblech GmbH and EUROPIPE. Since these days, these products were steadily improved for example in terms of toughness and weldability. As gas resources in increasingly hostile environments are developed, the requirements with regard to deformability and low-temperature toughness have gained growing significance. This is a strong focus of materials development around the world. Modern high-strength heavy plates used in the production of UOE pipes are generally produced by thermomechanical rolling followed by accelerated cooling (TMCP). If accelerated cooling starts above the ferrite-austenite transformation temperature, this processing route results in a microstructure that consists predominantly of bainite. The combination of high strength and high toughness of these steels are a result of the microstructure realised by TMCP and are strongly influenced by the rolling and cooling conditions. Classical light-optical characterisation of the microstructure of these steels is at its limits because the size of the observed features is too small to allow reliable quantitative results. Therefore alternative methods have to be used to obtain a better understanding of the influence of processing conditions on the microstructure. The mechanical properties of high strength plates produced at Salzgitter Mannesmann Grobblech (MGB) and of material rolled using a laboratory rolling mill at the Salzgitter Mannesmann Forschung (SZMF) was characterised with special emphasis on low-temperature toughness. The microstructure was investigated using the electron backscatter diffraction (EBSD) method. With this method, it is possible to gain quantitative information related to features of the microstructure and relate these to the mechanical properties of the plate material. It was found that a variation of the processing conditions has a direct influence on parameters that are accessible through the EBSD method and correlates with mechanical properties. These results can be used as valuable input for the definition of the processing window for heavy plate production depending on the required plate properties.

Development of Process Technology for Vanadium Containing, High-Strength, Low-Carbon, Heavy Plate and Its Trial Manufacture

2005 ◽  
Vol 500-501 ◽  
pp. 589-596
Author(s):  
Boris Z. Belenky ◽  
Leonid A. Smirnov ◽  
Iosif M. Srogovich ◽  
Peter S. Mitchell
Keyword(s):  
Yield Strength ◽  
Yield Stress ◽  
High Strength ◽  
Accelerated Cooling ◽  
Air Cooling ◽  
Low Carbon ◽  
Process Technology ◽  
Industrial Trial ◽  
Heavy Plate ◽  
Finish Rolling

The effects of adding vanadium (up to 0.1%) and niobium (0.02%) to a steel containing 0.07%C – 1.5%Mn – 0.29%Si – 0.035%Al – 0.01%N have been studied in the laboratory. It was determined that a steel containing 0.05%V had a yield stress, after accelerated cooling, greater than 480 MPa and toughness, as measured by U-notch and Vee-notch impact specimens, improving as the finish rolling temperature was lowered from 950oC to 750oC. Consequently, a semi-industrial trial, involving the manufacture of a steel containing 0.07%V, rolled to 22 mm and 32 mm thick, narrow plates, was carried out. This demonstrated that after finish rolling at 750oC, followed by air cooling, the steel had a yield strength in excess of 470 MPa accompanied by excellent toughness. The work demonstrates the potential for achievement of high levels of strength and toughness in heavy plate steels, micro-alloyed with vanadium.

Recent Developments of Oil and Gas Transmission Pipeline Steels: Microstructure, Mechanical Properties and Sour Gas Resistance

2008 ◽  
Author(s):  
Navid Pourkia ◽  
Morteza Abedini
Keyword(s):  
Mechanical Properties ◽  
Acicular Ferrite ◽  
Oil And Gas ◽  
High Strength ◽  
Accelerated Cooling ◽  
Low Carbon ◽  
Pipeline Steels ◽  
Bainitic Microstructure ◽  
Transmission Pipeline ◽  
Sour Gas

In modern oil and gas transmission pipeline steels technology, a suitable microstructure is an important factor for improvement of strength, toughness and sour gas resistance. Therefore, thermo-mechanically controlled rolling processes have been developed and their microstructures have been changed from ferrite-pearlite to acicular ferrite. Moreover in the recent years extensive attempts have been made to improve pipeline steels properties, which include: i) Ultra fine-grained steels, which are produced by optimized usage of dynamic recrystallization and strain-induced transformation with about 1μm equiaxed ferrite grain size. ii) Ultra low carbon steels with less than 0.025 wt% carbon and significant amount of Mo and Nb microalloying elements. iii) Ultra fine acicular ferrite steels, which are produced by application of more accurate controlled thermo mechanical processes and accelerated cooling. iv) Ultra high strength X100 and X120 grade steels, which are produced by thermo-mechanically controlled processes and heavy accelerated cooling. The former is without special technological changes and mainly consist of low carbon upper bainitic microstructure while the latter needs more technological developments with very little amount of boron and mainly consists of lower bainitic microstructure. This paper gives an overview of these new pipeline steels in viewpoint of microstructure, mechanical properties and sour gas resistance. The studies show that ultra fine acicular ferrite is the best alternative microstructure for nowadays ordinary pipeline steels, but because of numerous advantages of ultra high strength pipelines steels which finally reduce the cost of pipeline projects, the trend of the investigations is focused on further development of these steels. Moreover, acicular ferrite microstructure which is generally accepted by pipeline engineers and it is just in doubt because of its differences with acicular ferrite microstructure of weld metal and numerous offered definitions, is completely described.

Sign in / Sign up

Export Citation Format

Share Document