Comparison of the Annealing Behavior of Three Cold Rolled (Ti-bearing, Nb-bearing and V-bearing) HSLA Steels

2014 ◽  
Vol 1611 ◽  
pp. 123-132
Author(s):  
R. Ordonez ◽  
A.J. DeArdo ◽  
C. Isaac Garcia
Keyword(s):  
Energy Distribution ◽  
High Strength Steels ◽  
High Strength ◽  
Grain Boundary Character Distribution ◽  
Stored Energy ◽  
Annealing Behavior ◽  
Distribution Maps ◽  
Hsla Steels ◽  
Cold Rolled ◽  
Microstructural Condition

ABSTRACTThe annealing behavior of three HSLA steels is studied using the combined techniques of EBSD-KAM and Sub-grain Method. These techniques have been successfully used to assess the annealing behavior of AK, IF and other high strength steels. Stored energy maps in the hot band, cold rolled and after annealing are constructed and analyzed. The combined usage of the Sub-grain Method and EBSD-KAM techniques are employed to calculate and compare the evolution of the stored energy and recrystallization behaviour during the annealing of Ti-bearing, Nb-bearing, and V-bearing HSLA steels. Orientation dependent stored energy distribution maps at different annealing stages are constructed and analysed. The results show that the stored energy distribution through the thickness of the samples is not uniform and is independent of the steel composition. Similarly the recrystallization behaviour is strongly related to the initial microstructural condition and particularly to the grain boundary character distribution of the steels.

Assessment of the Stored Energy Evolution during Batch Annealing Process of Cold Rolled HSLA Steels

2012 ◽  
Vol 715-716 ◽  
pp. 557-562
Author(s):  
Chao Fang ◽  
C. Isaac Garcia ◽  
Shi Hoon Choi ◽  
Anthony J. DeArdo
Keyword(s):  
Energy Distribution ◽  
Driving Force ◽  
Steel Sample ◽  
Annealing Process ◽  
Grain Structure ◽  
Structural Factors ◽  
Stored Energy ◽  
Hsla Steels ◽  
Batch Annealing ◽  
Cold Rolled

Stored energy in deformed metals plays an important role during the annealing process by providing the initial driving force for recovery and recrystallization. Many direct or indirect measurement and calculation methods have been used to evaluate the amount and distribution of the stored energy in the past decades. The advent of relatively new analytical techniques such as Electron Back-Scattered Diffraction (EBSD) has permitted the development of mathematical models such as Sub-grain Method, Image Quality (IQ) Method and Taylor Factor Method etc., these new techniques have permitted a much better understanding of the annealing behavior of cold rolled steels. The sub-grain method based on the level of sub-grain structure is used in our study to quantify the stored energy distribution prior to and its evolution during the batch annealing process of cold rolled HSLA steels. Orientation dependent stored energy distribution maps at different annealing stages have been constructed and analyzed. The results of this study show that the stored energy increases with cold rolling reduction ratio and its distribution through the thickness of the steel sample is not uniform due to the inherit inhomogeneous deformation process. The stored energy was continuously consumed during annealing. The amount of γ-fiber was relatively lower than the α-fiber in the specific steel sample, which can have a strong effect on the available driving force for recovery and recrystallization. Hence other structural factors such as precipitation and/or solute drag might become more important in controlling the kinetic behavior of the steel during annealing.

YOUNGSTOWN YS-T50 to YS-T140 STEELS

Alloy Digest ◽  
1977 ◽  
Vol 26 (4) ◽  
Keyword(s):  
Physical Properties ◽  
High Strength Steels ◽  
High Strength ◽  
Heat Treating ◽  
Steel Alloy ◽  
Bend Strength ◽  
Weight Saving ◽  
Cold Rolled ◽  
Hot Rolled ◽  
Minimum Yield

Abstract YS-T 50 to YS-T 140 Steels comprise a series of high-strength, cold-rolled steels designed to meet performance and weight-saving objectives. They are an extension of Youngstown's series of hot-rolled high-strength steels (see Youngstown YS-T Steel, Alloy Digest SA-261, March 1971). The YS-T 50 to YS-T 140 steels have minimum yield strengths ranging from 50,000 psi to 140,000 psi. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength. It also includes information on heat treating, machining, and joining. Filing Code: SA-331. Producer or source: Youngstown Sheet and Tube Company.

Development of Low Carbon Microalloyed Ultra High Strength Steels

2005 ◽  
Vol 500-501 ◽  
pp. 551-558 ◽  
Author(s):  
A. Ghosh ◽  
Brajendra Mishra ◽  
Subrata Chatterjee
Keyword(s):  
Room Temperature ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Hsla Steels ◽  
Finish Rolling ◽  
Ultra High Strength Steels ◽  
Rolling Temperatures ◽  
Carbon Microalloyed ◽  
Carbon Concentrations

In the present study HSLA steels of varying carbon concentrations, alloyed with Mn, Ni, Cr, Mo, Cu and micro-alloyed with Nb and Ti were subjected to different finish rolling temperatures from 850oC to 750oC in steps of 50oC. The microstructure of the steel predominantly shows martensite. Fine twins, strain induced precipitates in the martensite lath along with e-Cu precipitates are observed in the microstructure. With an increase in carbon content the strength value increases from 1200MPa UTS to 1700MPa UTS with a negligible reduction in elongation. Impact toughness values of 20-26 joules at room temperature and −40oC were obtained in sub-size samples.

Microstructural Condition Features of High-Strength Steels for Large Diameter Pipes

Metallurgist ◽  
2017 ◽  
Vol 61 (1-2) ◽  
pp. 32-39
Author(s):  
K. Yu. Mentyukov ◽  
A. N. Bortsov ◽  
S. Yu. Makushev ◽  
I. P. Shabalov ◽  
Yu. I. Lipunov ◽  
...  
Keyword(s):  
Large Diameter ◽  
High Strength Steels ◽  
High Strength ◽  
Microstructural Condition ◽  
Large Diameter Pipes

The Role of Niobium in Lightweight Vehicle Construction

2007 ◽  
Vol 537-538 ◽  
pp. 679-686 ◽  
Author(s):  
Hardy Mohrbacher ◽  
Christian Klinkenberg
Keyword(s):  
Grain Refinement ◽  
High Strength Steel ◽  
Mechanical Performance ◽  
High Strength Steels ◽  
High Strength ◽  
Interstitial Free ◽  
Niobium Microalloying ◽  
Hsla Steels ◽  
Steel Grades ◽  
Different Characteristics

Modern vehicle bodies make intensive use of high strength steel grades to improve the weight and the mechanical performance simultaneously. A broad range of medium and extra high strength steel grades is available. These steel grades have different characteristics concerning strength, formability and weldability. For many steel grades microalloying by niobium is the key to achieve their characteristic property profile. In HSLA steels niobium enhances the strength primarily by grain refinement. In interstitial free high strength steels niobium serves as a stabilizing element and also assists in obtaining the bake hardening effect. Some modern multiphase steels rely on niobium to achieve additional strength via grain refinement and precipitation hardening. Microstructural control provides a way to further optimize properties relevant to automotive processing such as cutting, forming and welding. The relevance of niobium microalloying in that respect will be outlined.

scholarly journals Hydrogen Embrittlement and Diffusion in High Strength Low Alloyed Steels with Different Microstructures

2018 ◽  
Author(s):  
Marina Cabrini ◽  
Sergio Lorenzi ◽  
Diego Pesenti Bucella ◽  
Tommaso Pastore
Keyword(s):  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Tempered Martensite ◽  
Hsla Steels ◽  
And Diffusion ◽  
Embrittlement Resistance ◽  
Hydrogen Embrittlement Resistance

<span lang="EN-US">The paper deals with the effect of microstructure on the hydrogen diffusion in traditional ferritic-pearlitic HSLA steels and new high strength steels, with tempered martensite microstructures or banded ferritic-bainitic-martensitic microstructures. Diffusivity was correlated to the hydrogen embrittlement resistance of steels, evaluated by means of slow strain rate tests.</span>

Influence of Microalloying Elements Ti and Nb on Recrystallization during Annealing of Advanced High-Strength Steels

2016 ◽  
Vol 879 ◽  
pp. 217-223 ◽  
Author(s):  
Marion Bellavoine ◽  
Myriam Dumont ◽  
Josée Drillet ◽  
Philippe Maugis ◽  
Véronique Hebert
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Solute Drag ◽  
Dual Phase ◽  
Comparative Efficiency ◽  
Advanced High Strength Steels ◽  
Steel Grades ◽  
Cold Rolled ◽  
Microalloying Elements ◽  
Predominant Effect

Microalloying elements Ti and Nb are commonly added to high-strength Dual Phase steels as they can provide efficient means for additional strengthening due to grain refinement and precipitation strengthening mechanisms. In the form of solute elements or as fine carbonitride precipitates, Ti and Nb are also expected to have a significant effect on the microstructural changes during annealing and especially on recrystallization kinetics. The present work investigates the influence of microalloying elements Ti and Nb on recrystallization in various cold-rolled Dual Phase steel grades with the same initial microstructure but different microalloying contents. Using complementary experimental and modeling approaches makes it possible to give some clarifications regarding both the nature of this effect and the comparative efficiency of Ti and Nb on delaying recrystallization. It is shown that niobium is the most efficient micro-alloying element to impede recrystallization and that the predominant effect is solute drag.

The Research of Hardox400 HSLA Steels Weldability

2014 ◽  
Vol 881-883 ◽  
pp. 1257-1262
Author(s):  
Jing Zhang
Keyword(s):  
Impact Toughness ◽  
High Strength Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Optical Microscope ◽  
Weld Strength ◽  
Temperature Influence ◽  
Hot Temperature ◽  
Hsla Steels ◽  
Weld Fusion Zone

This paper deals with contact to carry on tension, bend, impact toughnesss stretch and the inclined Y type ascent experiments of the Hardox400 high strength steels welding. It research weld, fusion zone and heat affected zones micro organization of Hardox400 high strength steel in making use of the optical microscope, and prepare hot temperature, weld hot importation and empress hot temperature influence weld strength, bend and impact toughness, and the weld craft parameter can be assured under physically produces condition.

Springback Behavior of Advanced High Strength Steel (AHSS) CP800

2013 ◽  
Vol 820 ◽  
pp. 45-49 ◽  
Author(s):  
Mei Zhang ◽  
Jun Zhang ◽  
Yu Xiang Ning ◽  
Tao Wang ◽  
Zi Wan
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Test Results ◽  
Complex Phase ◽  
Advanced High Strength Steels ◽  
Test Conditions ◽  
Hsla Steels ◽  
Blank Holding Force ◽  
Microalloying Elements ◽  
Springback Behavior

800MPa grade Advanced High Strength Steels (AHSS), Complex Phase steel CP800, containing microalloying elements, are chosen to test the stamping properties in different test conditions and compared with traditional high strength low alloy (HSLA) steels HSLA S700MC. Tensile test, and HAT shape stamping test are taken to investigate the properties of the materials. Test results indicate that the studied 800MPa grade AHSS shows a better strength ductility balance compared with the reference HSLA steels. Under the same HAT shape springback stamping condition, HSLA steels S700MC always show the largest springback deformation among the investigated steels. While springback angles of all the AHSS studied are markedly smaller than that of steel S700MC. Among the 3 kinds of AHSS researched, CP800T always show the largest springback deformation. Domestic steel CP800 and imported CP800S show much smaller springback deformation respectively. In BHF of 100KN condition, springback deformation of 3 kinds of AHSS reaches the top value among all the BHF conditions. However, steel CP800 indicates an outstanding springback restrain trend in blank holding force (BHF) further increasing attempt. Thus, springback behavior can be restricted obviously by using a larger blank holding force (BHF) in steel CP800 stamping cases.

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