scholarly journals Microstructure Evolution of the Semi-Macro Segregation Induced Banded Structure in High Strength Oil Tubes During Quenching and Tempering Treatments

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3310 ◽  
Author(s):  
Bo Li ◽  
Ming Luo ◽  
Zhanbing Yang ◽  
Feifei Yang ◽  
Huasong Liu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Microstructure Evolution ◽  
High Strength ◽  
Oil Well ◽  
High Concentration ◽  
Corrosive Media ◽  
Obvious Effect ◽  
Tempering Temperature ◽  
Banded Structure ◽  
Quenching And Tempering

C110 oil well casing tubes should have high strength and corrosion resistance which is commonly used for deep wells operation containing corrosive media. In this paper, the microstructure evolution of a kind of semi-macro segregation originated banded structure in casing tubes is studied under different heat treatments. It is shown that the characteristics of the banded structure will change significantly in subsequent hot working and heat treatment processes. For the hot-rolled ones, the banded structure is composed of pearlite plus bainite. After quenching, it evolves into martensite band with high concentration solute elements. Finally, the banded structure will change into a carbide banding under the following tempering process. The temperature and cooling rate of the tempering practice show an obvious effect on the final band structure. To improve anti-SSC (sulfide stress corrosion cracking) performance, the favorable QT (quenching and tempering) practice for C110 steel should be a higher tempering temperature and a quicker cooling rate, from which the banded structure defects can be decreased together with an obvious improvement of the tube wall hardness uniformity.

Microstructure and Mechanical Properties of High Strength Alloyed Steel for Aerospace Application

2018 ◽  
Vol 284 ◽  
pp. 351-356 ◽  
Author(s):  
Mikhail V. Maisuradze ◽  
Maksim A. Ryzhkov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Strength ◽  
Single Stage ◽  
The Novel ◽  
Tempering Temperature ◽  
Quenching And Partitioning ◽  
Aerospace Application ◽  
Cooling Conditions ◽  
Quenching And Tempering

The high strength aerospace steel alloyed with Cr, Mn, Si, Ni, W and Mo was studied. The austenite transformations under continuous cooling conditions were investigated using the dilatometer analysis at the cooling rates 0.1...30 °C/s. The mechanical properties of the studied steel were determined after the conventional quenching and tempering heat treatment. The dependences of the mechanical properties on the tempering temperature were obtained. The novel quenching and partitioning heat treatment was applied to the steel under consideration. The microstructure and the mechanical properties were studied after three different modes of the quenching and partitioning (QP) treatment: single-stage QP, two-stage QP and single-stage QP with subsequent tempering (QPT).

Microstructure Evolution of Mg-10Gd-2Y-0.5Zn-0.3Zr Alloy during Isothermal Forging Process

2014 ◽  
Vol 783-786 ◽  
pp. 485-490
Author(s):  
De Bin Shan ◽  
X.Z. Han ◽  
Wen Chen Xu
Keyword(s):  
Microstructure Evolution ◽  
Ageing Time ◽  
High Strength ◽  
Aged Alloy ◽  
Secondary Phases ◽  
Obvious Effect ◽  
Isothermal Forging ◽  
Forging Process ◽  
The Matrix ◽  
Peak Aged

The isothermal forging process of a bracket and its microstructure evolution of Mg-10Gd-2Y-0.5Zn-0.3Zr alloy have been investigated in the present study. The results show that the bracket with thin-web and high-rib is well formed through modifying corners and adding an active damping block into male die. Amounts of lamellae and particles distribute uniformly on the matrix after the isothermal forging process and ageing process. The isothermal forging process has an obvious effect on the precipitation behaviour of secondary phases, while it did not change the grain size greatly. With the increase of ageing time, more secondary phases precipitate from α-Mg matrix until 60h. The optimal ultimate tensile strength and elongation of the peak-aged alloy are 382MPa and 4.03%, respectively. The combined effects of LPO and β′ phases contribute to the high strength of the peak-aged alloy.

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.

The development of a588 modified laterite steel using thermomechanical and low-temperature tempering process for weather resistant steel

Teknik ◽  
2021 ◽  
Vol 42 (2) ◽  
pp. 149-159
Author(s):  
Miftakhur Rohmah ◽  
Dedi Irawan ◽  
Dedi P. Utama ◽  
Toni B. Romijarso
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Cooling Rate ◽  
Nickel Content ◽  
High Strength ◽  
Water Medium ◽  
Tempered Martensite ◽  
Tempering Temperature ◽  
Thermomechanical Process ◽  
Tempering Process

Laterite Steel A-588 has the potential to be a high strength low alloy for Corten steel application. Laterite steel A-588 is developed through a thermomechanical process followed by a tempering process to obtain high strength and corrosion resistance. This study aims to determine the correlation between the addition of nickel content, the variation of the cooling rate during heat treatment to the mechanical properties, and the corrosion resistance of A-588 laterite steel. The Cu, Cr, Ni, P, and Si elements significantly impact microstructure transformation. Laterite Steel A-588 with nickel and thermo-mechanical process variation has been focused on in this research. Laterite steel with 0,42%, 1%, 2%, and 3% nickel varied was homogenized, hot rolled, and heat treated with three cooling variations by water, oil, and air. They are processed with 150 C tempering. Low tempering temperature caused fine carbide precipitation and phase transition of martensite to bainite. This resulted in bainite as the final microstructure, lath tempered martensite, carbide, and ferrite. 3% Ni with a fast cooling rate increased the tempered martensite and bainite phase formation. It allowed the strength and hardness to increase relatively, followed by decreased elongation and corrosion resistance caused by the galvanic reaction. Most optimal of mechanical properties determined at a sample with 2% nickel in a water medium (strength 1203 MPa, elongation 10%, hardness 404 BHN, corrosion rate 1,306 mpy).

Mechanical Properties of a Mild-Alloy Steel for Aerospace Engineering

2021 ◽  
Vol 410 ◽  
pp. 221-226
Author(s):  
Mikhail V. Maisuradze ◽  
Maxim A. Ryzhkov ◽  
Dmitriy I. Lebedev
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Strength ◽  
Aerospace Engineering ◽  
Isothermal Heat Treatment ◽  
Tempering Temperature ◽  
Optimal Heat Treatment ◽  
Treatment Conditions ◽  
Quenching And Tempering ◽  
Conventional Oil

The features of microstructure and mechanical properties of the aerospace high strength steel were studied after the implementation of various heat treatment modes: conventional oil quenching and tempering, quenching-partitioning, austempering. The dependence of the mechanical properties on the tempering temperature was determined. The basic patterns of the formation of mechanical properties during the implementation of isothermal heat treatment were considered. The optimal heat treatment conditions for the studied steel were established.

Study on CCT Curve and Microstructure Evolution of HRB500E

2013 ◽  
Vol 470 ◽  
pp. 699-702
Author(s):  
Peng Tian ◽  
Zhi Yong Zhong ◽  
Rui Guo Bai ◽  
Xing Li Zhang ◽  
Quan Li Wang ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Microstructure Evolution ◽  
Theoretical Basis ◽  
High Strength ◽  
Micro Hardness ◽  
Cooling Process ◽  
Controlled Cooling ◽  
Steel Rebar ◽  
Cct Curve ◽  
Hardness Change

The microstructure evolution and hardness change were studied for vanadium containing high strength seismic rebar HRB500E at different cooling rates. The experimental results showed that bainite and martensite gradual emerged with the increasing cooling rate and resulted in an increasing micro-hardness. The cooling rate should be controlled at 0.5°C/s to 7°C/s to ensure good performances of steel rebar. The CCT curve of HRB500E measured with the inflation method and metallographic-Hardness method could provide the theoretical basis for controlled cooling process.

In situ observation on microstructure evolution of 22MnB5 in hot stamping process

2019 ◽  
Vol 116 (2) ◽  
pp. 209
Author(s):  
Ling Kong ◽  
Yan Peng
Keyword(s):  
Martensitic Transformation ◽  
Grain Boundary ◽  
Cooling Rate ◽  
Microstructure Evolution ◽  
Hot Stamping ◽  
High Strength ◽  
Continuous Cooling ◽  
Austenite Grain ◽  
Austenite Grains ◽  
Austenite Grain Boundary

High temperature confocal laser scanning microscopy (CLSM) was used to investigate the microstructure evolution of high-strength boron steel 22MnB5 during hot stamping. The experimental results show that it is complete austenitized at temperatures about 810 °C during the heating process. Most of the initial austenite grain size is small and locally coarse. At 920 °C to 1000 °C, the phenomenon of B remelted and solidified was observed which played a very good pinning role at the austenite grain boundary, preventing coarsening of austenite grains. The segregation of B and the addition of Mn result in a significant reduction in both the minimum boron reverse melt content and the final solidification temperature. In the continuous cooling stage, martensitic transformation occurs at the cooling rate of 60 °C/s, and the martensite start point is 400 °C and martensite finish point is 280 °C. A large number of bursts are concentrated from 380 °C to 330 °C. There are two main forms of martensitic transformation: first, martensite begins to appear at the coarse austenite grain boundary, and grows transgranularly. Second, the new martensite laths starts from the previously formed laths and grows at a certain angle into the austenite grains. The main factor in the increase of martensite in continuous cooling is the formation of variable temperature martensite rather than the growth of martensite laths. At the cooling rate of 20 °C/s, the bainite and ferrite transformation appeared and the conversion temperature of bainite was about 600 °C. The cooling speed has a great influence on the performance of the 22MnB5 hot stamping component. The room temperature microhardness at cooling rates of 5 °C/s, 20 °C/s, and 60 °C/s was 194 HV, 243 HV, and 430 HV, respectively. Therefore, ensuring sufficient cooling rate is a key condition for obtaining ultra-high strength hot stamping components.

Study of the Mechanical Behaviors of Fabric Made of Polyester Fibers in the Corrosive Ozone Gas Environment

2012 ◽  
Vol 166-169 ◽  
pp. 3206-3209
Author(s):  
Guo Ning Liu ◽  
Hua Dong Zhao ◽  
Wei Yang ◽  
Shuang Cheng Wang ◽  
Ming Hao Zhao
Keyword(s):  
Mechanical Properties ◽  
Uv Light ◽  
High Strength ◽  
Extreme Environment ◽  
Polyester Fabric ◽  
Failure Behavior ◽  
High Concentration ◽  
Corrosive Media ◽  
Polyester Fibers ◽  
Corrosive Environments

Polyester textile is widely adopted in ordinary engineering applications where mechanical properties like high strength and relatively good plasticity are demanded at the same time. Though there has been some research on the change to its mechanical behavior in corrosive environments to study the effects of corrosion, for example, the ultraviolet (UV) light, the influence of corrosive media like ozone gas (O3) on its mechanical properties is rarely explored up to now. Here fabric made of polyester fibers is chosen to study the possible influence of ozone gas with extremely high concentration in the tensile strength as well as the failure behavior of this material. The aim of this research is at extending or expanding the application of polyester fabric to wider engineering areas through the study of the influence of extreme environment conditions in the mechanical properties of polyester fabric and the failure mechanism as well.

Sign in / Sign up

Export Citation Format

Share Document