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.

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.

Mechanical Properties and Aging Behavior of Ultrafine Grained Al-Ag Alloy Fabricated by Accumulative Roll-Bonding

2014 ◽  
Vol 794-796 ◽  
pp. 851-856
Author(s):  
Tadashiege Nagae ◽  
Nobuhiro Tsuji ◽  
Daisuke Terada
Keyword(s):  
Mechanical Properties ◽  
Grain Refinement ◽  
Accumulative Roll Bonding ◽  
Precipitation Hardening ◽  
Tensile Elongation ◽  
Solution Treatment ◽  
High Strength ◽  
Subsequent Aging ◽  
Roll Bonding ◽  
Ultrafine Grained

Accumulative roll-bonding (ARB) process is one of the severe plastic deformation processes for fabricating ultrafine grained materials that exhibit high strength. In aluminum alloys, aging heat treatment has been an important process for hardening materials. In order to achieve good mechanical properties through the combination of grain refinement hardening and precipitation hardening, an Al-4.2wt%Ag binary alloy was used in the present study. After a solution treatment at 550°C for 1.5hr, the alloy was severely deformed by the ARB process at room temperature (RT) up to 6 cycles (equivalent strain of 4.8). The specimens ARB-processed by various cycles (various strains) were subsequently aged at 100, 150, 200, 250°C, and RT. The hardness of the solution treated (ST) specimen increased by aging. On the other hand, hardness of the ARB processed specimen decreased after aging at high temperatures such as 250°C. This was probably due to coarsening of precipitates or/and matrix grains. The specimen aged at lower temperature showed higher hardness. The maximum harnesses achieved by aging for the ST specimen, the specimens ARB processed by 2 cycles, 4 cycles and 6 cycles were 55HV, 71HV, 69HV and 65HV, respectively. By tensile tests it was shown that the strength increased by the ARB process though the elongation decreased significantly. However, it was found that the tensile elongation of the ARB processed specimens was improved by aging without sacrificing the strength. The results suggest that the Al-Ag alloy having large elongation as well as high strength can be realized by the combination of the ARB process for grain refinement and the subsequent aging for precipitation hardening.

scholarly journals Mechanical properties, deformation and fracture mechanisms of bimodal Cu under tensile test

2021 ◽  
Vol 60 (1) ◽  
pp. 15-24
Author(s):  
Silu Liu ◽  
Yonghao Zhao
Keyword(s):  
Yield Strength ◽  
Grain Refinement ◽  
Volume Fraction ◽  
Shear Fracture ◽  
High Strength ◽  
Tensile Specimen ◽  
Deformation Mechanisms ◽  
Fracture Mechanisms ◽  
Fracture Angle ◽  
Area Reduction

Abstract Metals with a bimodal grain size distribution have been found to have both high strength and good ductility. However, the coordinated deformation mechanisms underneath the ultrafine-grains (UFGs) and coarse grains (CGs) still remain undiscovered yet. In present work, a bimodal Cu with 80% volume fraction of recrystallized micro-grains was prepared by the annealing of equal-channel angular pressing (ECAP) processed ultrafine grained Cu at 473 K for 40 min. The bimodal Cu has an optimal strength-ductility combination (yield strength of 220 MPa and ductility of 34%), a larger shear fracture angle of 83∘ and a larger area reduction of 78% compared with the as-ECAPed UFG Cu (yield strength of 410 MPa, ductility of 16%, shear fracture angle of 70∘, area reduction of 69%). Grain refinement of recrystallized micro-grains and detwinning of annealing growth twins were observed in the fractured bimodal Cu tensile specimen. The underlying deformation mechanisms for grain refinement and detwinning were analyzed and discussed.

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.

MHZ 420

Alloy Digest ◽  
2018 ◽  
Vol 67 (12) ◽  
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Tensile Properties ◽  
Yield Point ◽  
Precipitation Hardening ◽  
High Strength ◽  
Strength Properties ◽  
Cold Forming ◽  
Fine Grained

Abstract MHZ 420 (mininum yield strength of 420 MPa) is one of a series of microalloyed cold forming steels. The high-strength properties result from precipitation hardening thanks to finely-dispersed carbonitrides and a fine-grained microstructure. Even very small amounts of the elements titanium and/or niobium in the region of 0.01% result in a significant increase in the yield point and tensile strength. This datasheet provides information on composition and tensile properties as well as fatigue. It also includes information on forming and joining. Filing Code: SA-831. Producer or source: ThyssenKrupp Steel Europe AG.

MHZ 380

Alloy Digest ◽  
2018 ◽  
Vol 67 (11) ◽  
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Tensile Properties ◽  
Yield Point ◽  
Precipitation Hardening ◽  
High Strength ◽  
Strength Properties ◽  
Cold Forming ◽  
Fine Grained

Abstract MHZ 380 (mininum yield strength of 380 MPa) is one of a series of microalloyed cold forming steels. The high-strength properties result from precipitation hardening thanks to finely-dispersed carbonitrides and a fine-grained microstructure. Even very small amounts of the elements titanium and/or niobium in the region of 0.01% result in a significant increase in the yield point and tensile strength. This datasheet provides information on composition and tensile properties as well as fatigue. It also includes information on forming and joining. Filing Code: SA-828. Producer or source: ThyssenKrupp Steel Europe AG.

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.

scholarly journals Regulating Precipitates by Simple Cold Deformations to Strengthen Mg Alloys: A Review

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2507 ◽  
Author(s):  
Bo Song ◽  
Jia She ◽  
Ning Guo ◽  
Risheng Qiu ◽  
Hucheng Pan ◽  
...  
Keyword(s):  
Precipitation Hardening ◽  
Low Cost ◽  
Cold Deformation ◽  
High Strength ◽  
Mg Alloys ◽  
Strengthening Mechanisms ◽  
Precipitation Behavior ◽  
Research Directions ◽  
Hardening Effect ◽  
Peak Aged

Regulating precipitates is still an important issue in the development of high-strength Mg alloys, due to it determining the precipitation hardening effect. Cold deformation, as a simple and low-cost method, can remarkably influence the precipitate features. It is found that pre-cold deformation before aging can be utilized to enhance the precipitation hardening effect of Mg alloys. Moreover, post-deformation after aging could be an effective method to regulate precipitation orientation. In this review, recent research on the regulation of precipitation behavior by cold deformation in Mg-Al, Mg-Zn, and Mg-RE (RE: rare-earth elements) alloy systems was critically reviewed. The changes in precipitate features and mechanical properties of peak-aged Mg alloys via cold deformation were summarized. The corresponding strengthening mechanisms were also discussed. Finally, further research directions in this field were proposed.

MHZ 460

Alloy Digest ◽  
2019 ◽  
Vol 68 (1) ◽  
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Tensile Properties ◽  
Yield Point ◽  
Precipitation Hardening ◽  
High Strength ◽  
Strength Properties ◽  
Cold Forming ◽  
Fine Grained

Abstract MHZ 460 (mininum yield strength of 460 MPa) is one of a series of microalloyed cold forming steels. The high-strength properties result from precipitation hardening thanks to finely-dispersed carbonitrides and a fine-grained microstructure. Even very small amounts of the elements titanium and/or niobium in the region of 0.01% result in a significant increase in the yield point and tensile strength. This datasheet provides information on composition and tensile properties as well as fatigue. It also includes information on forming and joining. Filing Code: SA-835. Producer or source: ThyssenKrupp Steel Europe AG.

Effects of Cooling Rate on Microstructure and Properties of Nb-Ti Micro-Alloyed Steel

2013 ◽  
Vol 341-342 ◽  
pp. 208-212
Author(s):  
Xin Li ◽  
Jie Zhao ◽  
Xun Yang ◽  
Jun Cheng Bao ◽  
Bao Qun Ning
Keyword(s):  
Mechanical Property ◽  
Cooling Rate ◽  
Grain Refinement ◽  
Hot Rolling ◽  
High Strength Steel ◽  
High Strength ◽  
Alloyed Steel ◽  
Continuous Cooling Transformation ◽  
Micro Alloyed Steel ◽  
P Colonies

Continuous cooling transformation (CCT) curves of deformed austenite (A) of Nb-Ti microalloying high strength steel were measured using Gleeble-3800 thermo-mechanical simulator, and corresponding transformation and structure were analyzed, and the effects of cooling rate on the tested steels mechanical property were studied. The resultes showed that the Ar3transformation point decreased with increasing cooling rate after hot-rolling. The morphology of ferrite (F) grains changed from polygonal to lath, and the pearlite (P) colonies became more fine with increasing cooling rate. The quantity of ferrite and pearlite decreased, and the quantity of bainite (B) and martensite (M) increased. Then the hardness of Nb-Ti micro-alloyed steel is increased along with the increasing cooling rate, which may owing to the reasons that the hardness of ferrite and pearlite is far smaller than that of bainite and martensite, and the grain refinement causes the hardness increasing.

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