Effects of final rolling temperature and coiling temperature on precipitates and microstructure of high-strength low-alloy pipeline steel

2021 ◽  
Author(s):  
Ya-dong Wang ◽  
Zheng-hua Tang ◽  
Su-fen Xiao ◽  
Charles W. Siyasiya ◽  
Tao Wei
Keyword(s):  
Pipeline Steel ◽  
High Strength ◽  
Rolling Temperature ◽  
Coiling Temperature ◽  
Final Rolling Temperature ◽  
Final Rolling

Improvement of Mechanical Properties and Corrosion Resistance by Deformation Induced Precipitation in Al-Zn-Mg-Cu Alloy

2017 ◽  
Vol 898 ◽  
pp. 179-190 ◽  
Author(s):  
Jin Rong Zuo ◽  
Long Gang Hou ◽  
Jin Tao Shi ◽  
Hua Cui ◽  
Lin Zhong Zhuang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Thermomechanical Treatment ◽  
High Strength ◽  
Alloy Sheet ◽  
Rolling Temperature ◽  
Al Alloy ◽  
Deformation Degree ◽  
Dynamic Aging ◽  
Final Rolling Temperature ◽  
Final Rolling

A final thermomechanical treatment (FTMT) including peak aging and subsequent dynamic aging was proposed to prepare 7055 Al alloy sheets. The optimization was based on nine well-planned orthogonal experiments. Three main processing conditions in the thermomechanical treatment for obtaining the optimum synthetic properties of 7055 (i.e. preheating temperature, final rolling temperature and deformation degree) were investigated. It was shown that the final rolling temperature is the most important factor among the three parameters, and the optimum properties (yield strength: 651 MPa, ultimate tensile strength: 660 MPa) of 7055 Al alloy sheet can be gained with preheating at 140oC and 40% deformation at 170oC. With dynamic aging, grain boundary precipitates became discontinuous without much coarsening of matrix precipitates, while they were continuously distributed after T6 aging. The present optimal FTMT process can improve the intergranular / exfoliation corrosion resistance without sacrificing the strength compared to T6 tempering. The present FTMT process as a good alternative can produce high-strength Al alloy sheets with high strength and good corrosion resistance efficiently and economically.

Microstructure and Mechanical Properties of ER70-Ti Steel for Gas Shielded Welding Wire

2021 ◽  
Vol 1035 ◽  
pp. 377-387
Author(s):  
Xin Wei Wang ◽  
Ren Bo Song ◽  
Zhong Zheng Pei ◽  
Xing Han Chen
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Rolling Temperature ◽  
Test Material ◽  
Welding Wire ◽  
Microstructure And Mechanical Properties ◽  
Final Rolling Temperature ◽  
Bainite Structure ◽  
Wire Steel ◽  
Final Rolling

In this paper, ER70-Ti welding wire steel produced by an enterprise was used as the test material. The final rolling temperature was set at 960 °C, 930 °C and 900 °C, and the spinning temperature was set at 880 °C, 860 °C and 840 °C. The results showed that the microhardness of the steel decreased from 303HV to 248HV and from 317HV to 276HV as the spinning temperature decreased from 880 °C to 840 °C. The microstructure and mechanical properties of the wires with the diameters of 5.5mm, 4mm, 2.5mm, 1.4 mm and 1.2mm were examined. It was observed that the microstructure of each sample had bainite and ferrite dual phase structure. With the decrease of wire diameter, the strength gradually increased and the ductility decreased. The experimental results show that the existence of bainite structure in the welding wire is the main reason for the high strength of the welding wire and easy fracture in drawing. Based on this, the final rolling temperature of 900 °C and the spinning temperature of 840 °C should be adopted in the production of ER70-Ti welding wire steel.

Formation of Microstructure and Texture in Intercritically Rolled C-Mn Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4363-4368 ◽  
Author(s):  
Roumen H. Petrov ◽  
Leo Kestens ◽  
Yvan Houbaert
Keyword(s):  
Rolling Temperature ◽  
Accelerated Cooling ◽  
Orientation Relationships ◽  
Rolling Schedule ◽  
Rolling Pass ◽  
Final Rolling Temperature ◽  
Intercritical Region ◽  
Final Rolling ◽  
Mn Steel ◽  
Ferrite Grain Size

Series of trials were conducted on a laboratory rolling mill to evaluate the influence of intercritical rolling on the microstructure and texture of steel with 0.082%C, 1.54% Mn, 0.35% Si, 0.055%Nb and 0.078%V. Two parallel rolling schedules A and B were designed on the base of the experimentally deduced CCT diagram of the steel. In rolling schedule A the material was subjected to accelerated cooling and coiling simulation after final rolling in the intercritical region, whereas in rolling schedule B the last rolling pass in the intercritical region was replaced by a water quench at the same temperature of the intercritical rolling pass in schedule A. Microstructure and texture were characterized by means of light optical microscopy, scanning electron microscopy, EBSD and XRD. It was found that the average grain diameter and the texture depend significantly on the final rolling temperature in the intercritical region. The decrease of the intercritical rolling temperature leads to an increase of the {111}〈uvw〉 /{001}〈uvw〉 ratio, but at the same time the increase of the average ferrite grain size was also observed. A phenomenological model based on the K–S orientation relationships was used to predict the texture formation in the intercritical region.

Study on Microstructure and Mechanical Properties of Hot Rolled Steel Plate Strengthened Complexly by Titanium and Molybdenum

2011 ◽  
Vol 299-300 ◽  
pp. 197-201
Author(s):  
Hong Bin Wang ◽  
Sheng Li Li ◽  
Chun Tang Niu
Keyword(s):  
Mechanical Properties ◽  
Acicular Ferrite ◽  
Steel Plate ◽  
Polygonal Ferrite ◽  
Rolled Steel ◽  
Coiling Temperature ◽  
Final Rolling Temperature ◽  
Final Rolling ◽  
Hot Rolled ◽  
Hot Rolled Steel

Microstructure and mechanical properties of hot rolled steel plate strengthened complexly by titanium and molybdenum at different final rolling temperature and coiling temperature were studied by optical microscope (OM) and material testing machine. The precipitation behaviors of precipitates phase were obtained using transmission electron microscope (TEM) with EDS analysis. The results showed that at final temperature 850°C, microstructure of experimental steel were fine, uniform polygonal ferrite and acicular ferrite. With the coiling temperature decreasing from 620°C to 580 °C, the grain of polygonal ferrite became finer, and the amounts of acicular ferrite became more; precipitates phase mainly maintained both coarse TiN and small square round sheet (Ti,Mo)C. On the condition of the final rolling temperature (850°C) and coiling temperature (580°C), experimental steel acquired properties as follows: yield strength 608 MPa, tensile strength 720 MPa, elongation 24%. Ti-Mo composite strengthening effect had achieved, and significantly improved the strength of ferrite steel.

Effect of Lower Final Rolling Temperature on Mechanical Properties of V-N Microalloyed Mild Steel

2007 ◽  
Vol 561-565 ◽  
pp. 45-48
Author(s):  
Jian Qing Qing ◽  
Bao Qiao Wu ◽  
Jie Cai Wu ◽  
Yi He
Keyword(s):  
Mechanical Properties ◽  
Mild Steel ◽  
Optical Microscope ◽  
Rolling Temperature ◽  
Second Phase ◽  
Normal Deformation ◽  
Fine Grain ◽  
Final Rolling Temperature ◽  
Second Phase Particles ◽  
Final Rolling

The samples of V-N microalloyed mild steel were obtained in duo mill with the normal deformation rate and the normal rolling temperature except final rolling temperature, which is at 780°C, 730°C and 680°C respectively. The tensile test was carried out and the microstructure was observed with optical microscope. It was found that the mechanical properties improved dramatically compared with normal process, the final rolling temperature is more than 900°C. The main reason is the fine grain size and second phase particles. With the final rolling temperature decreasing, the mechanical property further improves until the final rolling temperature of 700°C.

Effect of Hot Rolling Process Parameters on Microstructure Transformation and Microstructure of 45MnSiV Steel

2019 ◽  
Vol 944 ◽  
pp. 265-271
Author(s):  
Yun Long Wang ◽  
Yin Li Chen ◽  
He Wei ◽  
Yi Na Zhao ◽  
Ze Sheng Liu
Keyword(s):  
Phase Transition ◽  
Cooling Rate ◽  
Transformation Temperature ◽  
Martensite Phase ◽  
Rolling Temperature ◽  
Layer Spacing ◽  
Final Rolling Temperature ◽  
Test Steel ◽  
Temperature Ranges ◽  
Final Rolling

The effects of final rolling temperature, cooling rate and deformation on phase transition point, the duration of the phase transition and the pearlite laminar layer of non-quenched and tempered steel 45MnSiV were studied by simulating the process of rolling and post-rolling cooling on Gleeble-3500 thermal simulator and thermal expansion tester. The results show that: the ferrite and pearlite transformation temperature ranges from 510 °C to 700 °C, and the bainite transformation temperature ranges from 400 °C to 500 °C when the steel is continuously cooled at a final rolling temperature of 950 °C, and the martensite transforming temperature is 300 °C under high cooling rate (> 10 °C/s); The pearlite laminar spacing decreases with the decrease of final rolling temperature. It can be seen that the rolling deformation increases the temperature at which the test steel undergoes a phase change at each cooling rate by comparing the results of deformation and no-deformation test at 950 °C. The effect of time advance on the phase transition zone of ferrite and pearlite is particularly obvious, but the effect on the phase transition temperature and time of the bainite and martensite phase transition is not obvious. When the final rolling temperature remains constant, the Rockwell hardness value of the test steel gradually increases, and the pearlite layer spacing decreases with the decrease of ferrite transformation temperature gradually and the increase of the cooling rate.

Influence of Deformation and Coiling Temperature on Mechanical Properties of a High Strength Pipeline Steel

2005 ◽  
Vol 500-501 ◽  
pp. 597-604 ◽  
Author(s):  
A.M. Elwazri ◽  
D.Q. Bai ◽  
Fulvio Siciliano ◽  
Steve Yue
Keyword(s):  
Mechanical Properties ◽  
Low Voltage ◽  
Pipeline Steel ◽  
High Strength ◽  
Precipitation Strengthening ◽  
Air Cooling ◽  
Coiling Temperature ◽  
Voltage Imaging ◽  
Additional Control ◽  
Scanning Electron

One of the components required to successfully produce high strength pipeline steel is to optimize precipitation strengthening. Some high strength pipeline grades rely on increased levels of Nb; in these grades, it is important to ensure that all the Nb is effectively employed. It is generally accepted that choice of coiling temperature is critical in maximizing the Nb precipitation in ferrite. Additional control of this precipitation may be attained by deformation at these coiling temperatures, an approach termed ‘cool deformation’. In this work, steel specimens were heated to temperature of 1200°C and held at temperature for 20 minutes to ensure significant dissolution of Nb precipitates. Some specimens were aged at 400°C for times ranging from 10 minutes to 10 hours followed by air-cooling. Others were subjected to deformation at 400°C (‘cool deformation’) prior to aging. It was found that the cool deformation improves the mechanical properties by microstructure; both yield and tensile strengths are significantly higher than that of the aged only specimens. By using low voltage imaging on a field emission gun scanning electron microscopy (FE-SEM), precipitates were observed and identified. The effects of the thermal and cool deformation schedules on the precipitate characteristics are described in this paper.

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