Development of Hot Rolled Ship Plate with High Strength and High Toughness

2013 ◽  
Vol 690-693 ◽  
pp. 106-109 ◽  
Author(s):  
Xiang Dong Huo ◽  
Lin Guo ◽  
Jin Song Feng ◽  
Chao Luo ◽  
Jun Qu
Keyword(s):  
Acicular Ferrite ◽  
Precipitation Hardening ◽  
High Strength ◽  
Experimental Methods ◽  
Polygonal Ferrite ◽  
High Toughness ◽  
Microstructural Constituent ◽  
Lath Width ◽  
Nanometer Particles ◽  
Hot Rolled

A new hot-rolled ship plate with high strength and high toughness is successfully developed through chemical composition design and TMCP process. Experimental methods, such as OM, TEM and X-EDS, were used to study the microstructure and precipitates of steel. The primary microstructural constituent is acicular ferrite, quasi-polygonal ferrite with second constituents along grain boundaries. Lath width of acicular ferrite is about 1μm. Cubic particles about several hundreds nanometers and nanometer particles exist in experimental steel. It can be concluded that acicular ferrite is the main reason for high strength and super toughness. precipitation hardening due to dispersed precipitations of carbonitrides can not be overlooked.

Precipitation Hardening of Titanium Carbides in Ti Micro-Alloyed Ultra-High Strength Steel

2011 ◽  
Vol 284-286 ◽  
pp. 1275-1278
Author(s):  
Xiang Dong Huo ◽  
Sheng Xia Lv ◽  
Xin Ping Mao ◽  
Qi Lin Chen
Keyword(s):  
Precipitation Hardening ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Methods ◽  
Chemical Phase ◽  
Ultra High Strength Steel ◽  
Average Grain Size ◽  
Chemical Phase Analysis ◽  
Ultra High Strength Steels ◽  
Hot Rolled

New 700MPa hot rolled ultra-high strength steels were successfully developed by using Ti micro-alloying technology in CSP line. Experimental methods, such as OM, TEM and chemical phase analysis, were used to study the experimental steel. The microstructure is composed of quasi-polygonal ferrite grains, whose average grain size is about 4μm. Large number of nanometer TiC particles distribute along dislocations. The mass fraction of MX phase is 0.0793wt%, in which the particles smaller than 10nm account for 33.7%. The contribution of precipitation hardening resulting from nanometer particles is calculated as approximate 158MPa.

Study on Microstructure and Properties of X80 Pipeline Steel

2014 ◽  
Vol 941-944 ◽  
pp. 138-141 ◽  
Author(s):  
Xiang Dong Huo ◽  
Feng Dong ◽  
Lie Jun Li
Keyword(s):  
Grain Refinement ◽  
Impact Energy ◽  
Acicular Ferrite ◽  
Precipitation Hardening ◽  
Pipeline Steel ◽  
High Strength ◽  
Experimental Methods ◽  
Microstructural Characteristics ◽  
X80 Pipeline Steel ◽  
Toughness Improvement

Experimental methods, such as OM, SEM and X-EDS, were used to study the microstructure of X80 pipeline steel. It mainly consists of fine acicular ferrite (AF). X80 pipeline steel possesses high strength and impact energy at-30°C approaches to 400J. Grain refinement and precipitation hardening are the main reasons for high strength, and toughness improvement can be attributed to grain refinement and particular microstructural characteristics of AF.

API 5L X80 ERW Pipes: TenarisConfab and Usiminas Development

2006 ◽  
Author(s):  
Juliana E. Roza ◽  
Marcelo C. Fritz ◽  
Marco A. Tivelli ◽  
Ronaldo C. Silva ◽  
Lu´cio S. Miranda ◽  
...  
Keyword(s):  
Pipe Wall ◽  
High Strength Steels ◽  
High Strength ◽  
Mechanical Resistance ◽  
Electric Resistance ◽  
Pipe Wall Thickness ◽  
High Toughness ◽  
Operation Costs ◽  
Electric Resistance Welding ◽  
Hot Rolled

The utilization of high strength steels can decrease, both, installation and operation costs of a new pipeline, since the increase of mechanical resistance can reduce the pipe wall thickness and, consequently, the weight of the pipe. For this purpose, the manufacture of electric resistance welding (ERW) pipes is recent, and it comes as an opportunity for gas pipelines, mainly onshore projects. As a function of their larger productivity, ERW pipes are more economically attractive than those produced by seamless and SAW processes. TenarisConfab and Usiminas, through studies and investments in manufacturing processes, have been working to increase their skills, in order to supply API 5L X80 ERW pipes. The steel elaborated by Usiminas is low C, high Mn, Nb, V and Ti microalloyed, and with additions of Cr and Mo, aiming to produce hot rolled coils with acicular microstructure, achieved as a combination between its chemical composition and higher cooling rates after hot rolling. The results in φ18” (457 mm) × 0,469” (11,91 mm) pipes are presented in this article. High toughness values reached at very low temperatures suggest that X80 ERW pipes developed by TenarisConfab and Usiminas may be an excellent option of choice for onshore projects that request pipes in diameters up to 20” (508 mm) and thickness up to 0.500” (12.7 mm).

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.

Microstructural Features of a Ultra Low Carbon High Strength Acicular Ferrite Steel Thick Plate

2007 ◽  
Vol 561-565 ◽  
pp. 57-60 ◽  
Author(s):  
Zhi Qiang Cao ◽  
Ai Bing Zhang ◽  
Deng Luo ◽  
Zheng Hai Xia ◽  
Yong Dong Zhang ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Acicular Ferrite ◽  
Retained Austenite ◽  
Thick Plate ◽  
Steel Plate ◽  
High Strength ◽  
Polygonal Ferrite ◽  
Low Carbon ◽  
Heavy Plate ◽  
Ferrite Steel

A ultra low carbon high strength steel heavy plate (60∼80mm thick) was produced with TMCP at Xiangtan Steel. The steel has a good combination of high strength (σb∼600MPa) and impact toughness (∼300J). The microstructural features were analyzed by optical microscopy and scanning electron microscopy (SEM). Results showed that microstructures consisted of a large amount of acicular ferrite and a small amount of polygonal ferrite. A very few amount of retained austenite was also observed in the microstructures. The formation of fine acicular ferrite resulted in the high strength of the steel plate. The good impact toughness of the steel plate is mainly attributed to the formation of acicular ferrite and a very few amount of retained austenite.

Microstructure and Mechanical Properties of ULCB Steels Affected by Advanced TMCP Technology

2011 ◽  
Vol 689 ◽  
pp. 289-295
Author(s):  
Zi Yong Hou ◽  
Yun Bo Xu ◽  
Di Wu ◽  
Wei Hua Sun ◽  
She E Hu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Strength Steel ◽  
Critical Factor ◽  
High Strength ◽  
Steel Plates ◽  
Granular Bainite ◽  
Finish Rolling ◽  
Ultra High Strength Steel ◽  
Lath Width ◽  
Hot Rolled

Good combination of high strength and high toughness has been considered as a critical factor of ultra-high strength steel plates. In this paper, a novel high strength steel plate of HSLA type containing Cu with 910MPa yield strength and 1163MPa tensile strength has been developed using an advanced TMCP (thermo-mechanical control processing) technology. The steel plates provide excellent combination of high strength, toughness and deformability. Microstructural evolution and mechanical properties of this steel during hot-working have been investigated. It is demonstrated that, at the relatively higher finish rolling temperature and cooling rate, the microstructure consists of acicular and granular bainite structures and a small amount of low bainite /martensite whose lath width is approximately 200~300nm. For the as-rolled conditions, despite the high strength and so low yield ratio, impact energy about 154J and fully ductility fracture at -90°C can still be obtained as documented for as-hot rolled plates.

Strengthening Mechanisms of Vanadium Micro-Alloyed Reinforcing Steel Bar

2011 ◽  
Vol 130-134 ◽  
pp. 942-945
Author(s):  
Lie Jun Li ◽  
Xiang Dong Huo ◽  
Lin Guo
Keyword(s):  
Yield Strength ◽  
Grain Refinement ◽  
Precipitation Hardening ◽  
High Strength ◽  
Experimental Methods ◽  
Strengthening Mechanisms ◽  
Large Numbers ◽  
Steel Bar ◽  
Micro Alloyed Steel ◽  
Grain Refinement Strengthening

High strength vanadium micro-alloyed steel with yield strength of 600MPa has been developed based on commercial 20MnSi steel bar. Experimental methods, such as OM, SEM and TEM, were used to study the experimental steels. Compared with 20MnSi, steel 20MnSiV boasts much finer microstructure, and large numbers of nanometer precipitates exist in the specimens of 20MnSiV. Analysis shows that strength of 20MnSiV dramatically increases through grain refinement strengthening and precipitation hardening of nanometer VCN particles.

scholarly journals The hot rolled duplex laminated steel presenting both high strength and high toughness

2018 ◽  
Vol 461 ◽  
pp. 012011
Author(s):  
S L Chen ◽  
Z X Cao ◽  
M D Zhang ◽  
H F Xu ◽  
J Dzugan ◽  
...  
Keyword(s):  
High Strength ◽  
High Toughness ◽  
Hot Rolled

Precipitation in Al-Li-Zr alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 186-187
Author(s):  
D.M. Vanderwalker
Keyword(s):  
Fracture Toughness ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Transmission Electron ◽  
Water Quench ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys ◽  
Zr Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

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