Study on Precipitation Behavior of High Strength Steel Plate Strengthened Complexly by Titanium and Molybdenum

2011 ◽  
Vol 217-218 ◽  
pp. 812-818
Author(s):  
Hong Bin Wang ◽  
Sheng Li Li ◽  
Li Li ◽  
Peng Cheng Ma
Keyword(s):  
Electron Microscope ◽  
Steel Plate ◽  
High Strength ◽  
Optical Microscope ◽  
Steel Plates ◽  
Transmission Electron ◽  
Cold Rolled ◽  
Hot Rolled ◽  
Hot Rolled Steel ◽  
Energy Disperse Spectroscopy

The precipitation behaviors of hot rolling and cold rolled annealing steel plates strengthened complexly by titanium and molybdenum were studied in the paper. The microstructures and precipitate phases were analyzed using optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) with energy disperse spectroscopy (EDS). The results showed that the coarsening square TiN phase and the fine roundness (Ti,Mo)C phase were precipitated mostly in the hot rolled steel plate. As the finishing temperature decreased and coiling holding time increased, the quantity of fine precipitates increased. And also the fine round precipitates increased, dispersion expanded and shape of the phase being uniformed as the annealing temperature increased. Therefore, the strengthen effects can be improved effectively by a reasonable control toward titanium and molybdenum precipitation behaviors.

scholarly journals A Study of the Optimum Quenching Temperature of Steels with Various Hot Rolling Microstructures after Cold Rolling, Quenching and Partitioning Treatment

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 579 ◽  
Author(s):  
Bin Chen ◽  
Juhua Liang ◽  
Tao Kang ◽  
Ronghua Cao ◽  
Cheng Li ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
High Strength ◽  
Quenching Temperature ◽  
Austenite Grain Size ◽  
Quenching And Partitioning ◽  
Transmission Electron ◽  
Cold Rolled ◽  
Lower Temperature ◽  
Means Of Transmission ◽  
Hot Rolled

Quenching and partitioning (Q&P) processes were applied to a cold-rolled high strength steel (0.19C-1.26Si-2.82Mn-0.92Ni, wt %). The effects of the prior hot-rolled microstructure on the optimum quenching temperature of the studied steels were systematically investigated. The microstructure was analyzed by means of transmission electron microscope (TEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). Compared with the ferrite pearlite mixture matrix, the lower martensite start (Ms) temperature and smaller prior austenite grain size in the cold-rolled martensite matrix are the main reasons for the optimum quenching temperature shifting to a lower temperature in the Q&P steels. We found that an empirical formula that only considers the influence of the alloy composition in the calculation of the Ms temperature will cause a certain interference to the pre-determined optimum quenching temperature of the Q&P steel.

Strengthening of Ferritic Steel by Interface Precipitated Carbides in Rows

2010 ◽  
Vol 638-642 ◽  
pp. 3218-3223 ◽  
Author(s):  
Yoshimasa Funakawa ◽  
Kazuhiro Seto ◽  
Haruo Nakamichi
Keyword(s):  
Electron Microscope ◽  
Efficient Method ◽  
Ferritic Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Bearing Steel ◽  
Precipitation Strengthening ◽  
Carbide Formation ◽  
Transmission Electron ◽  
Hot Rolled

Precipitation-strengthening is widely applied to high strength steel sheet for automotive use since several strength grades are easily achieved by controlling amount of microalloyed component. Recently, finer carbide dispersion has been required to obtain higher strength by smaller addition of carbide formers like titanium and niobium. Here, interface precipitation, one of the carbide formation phenomena during γ→α transformation, can be the efficient method to promote very fine carbides by lowering precipitation temperature. This study deals with relationship between transformation temperatures and hardness of ferritic steel strengthened by carbides generated by the interface precipitation. Two kinds of 0.04%C steels containing Ti and Nb of the same amount as carbon content in atomic were hot-rolled, followed by the soaking at various temperatures for 600s. The rapid-cooled samples before the soaking for 600s exhibited higher hardness than slow-cooled samples. Large carbides generated by interface precipitation were observed in slow-cooled Ti-bearing steel with a transmission electron microscope. In slow-cooled Nb-bearing steel, large NbC precipitated in austenite before γ→α transformation. The results are suggesting that lowering transformation temperature and suppressing carbides precipitation in austenite are important to obtain high strength by interface precipitation.

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.

ARMCO FORMABLE 70 HR

Alloy Digest ◽  
1979 ◽  
Vol 28 (5) ◽  
Keyword(s):  
Nonmetallic Inclusions ◽  
High Strength ◽  
Heat Treating ◽  
Rolled Steel ◽  
Low Carbon ◽  
Controlled Processing ◽  
High Strength Level ◽  
Hot Rolled ◽  
Hot Rolled Steel ◽  
Special Composition

Abstract ARMCO FORMABLE 70 HR is a hot-rolled steel with excellent ductility, weldability and edge-tear resistance at a minimum yield strength of 70,000 psi (483 MPa). For this relatively high strength level, it has unusually good fabricating properties that are the result of closely controlled processing of a fully killed, low-carbon, vacuum-degassed, columbium-alloyed steel. This special composition and processing practice minimize harmful nonmetallic inclusions that hamper formability. Typical applications include automotive reinforcements, truck parts and construction components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-359. Producer or source: Armco Inc., Eastern Steel Division.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

2011 ◽  
Vol 23 (7) ◽  
pp. 526-534 ◽  
Author(s):  
Yang Wang ◽  
Boming Zhang ◽  
Jinrui Ye
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Modified Epoxy ◽  
Scanning Electron

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

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