Influence of V and N on Transformation Behavior and Mechanical Properties of Medium Carbon Forging Steels

2010 ◽  
Vol 638-642 ◽  
pp. 3459-3464 ◽  
Author(s):  
Nenad Radović ◽  
Ankica Koprivica ◽  
Dragomir Glišić ◽  
Abdunnaser Fadel ◽  
Djordje Drobnjak
Keyword(s):  
Mechanical Properties ◽  
Acicular Ferrite ◽  
Bainitic Ferrite ◽  
Carbon Steels ◽  
High Potency ◽  
Medium Carbon ◽  
Nitrogen Steel ◽  
Ferrite Structure ◽  
Medium Carbon Steels ◽  
Low Nitrogen

The influence of vanadium and nitrogen on microstructure and mechanical properties of medium-carbon steels has been studied by means of metallography and mechanical testing. Vanadium addition to the low nitrogen steel suppresses the formation of ferrite-pearlite following the low reheating temperatures and microstructure consists of bainitic sheaves. Increasing nitrogen at the same vanadium level promotes the acicular ferrite formation. For high reheating temperatures, dominantly acicular ferrite structure in both the low nitrogen and the high nitrogen vanadium steels is obtained. The results suggest that vanadium in solid solution promotes the formation of bainite, whereas the effect of nitrogen is related to the precipitation of VN particles in austenite with high potency for intragranular nucleation of acicular ferrite and to the precipitation of V(C,N) particles in ferrite with high potency for precipitation strengthening. Addition of both vanadium and nitrogen considerably increases the strength level, while CVN20 impact energy increases on changing the microstructure from bainitic ferrite to the fine ferrite-pearlite and acicular ferrite.

scholarly journals Influence of Vanadium on the Microstructure and Mechanical Properties of Medium-Carbon Steels for Wheels

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 978 ◽  
Author(s):  
Pengfei Wang ◽  
Zhaodong Li ◽  
Guobiao Lin ◽  
Shitong Zhou ◽  
Caifu Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Grain Refinement ◽  
Carbon Steels ◽  
Precipitation Strengthening ◽  
Austenite Grain Size ◽  
Medium Carbon ◽  
Microstructure And Mechanical Properties ◽  
Medium Carbon Steels ◽  
The Impact

Steels used for high-speed train wheels require a combination of high strength, toughness, and wear resistance. In 0.54% C-0.9% Si wheel steel, the addition of 0.075 or 0.12 wt % V can refine grains and increase the ferrite content and toughness, although the influence on the microstructure and toughness is complex and poorly understood. We investigated the effect of 0.03, 0.12, and 0.23 wt % V on the microstructure and mechanical properties of medium-carbon steels (0.54% C-0.9% Si) for train wheels. As the V content increased, the precipitation strengthening increased, whereas the grain refinement initially increased, and then it remained unchanged. The increase in strength and hardness was mainly due to V(C,N) precipitation strengthening. Increasing the V content to 0.12 wt % refined the austenite grain size and pearlite block size, and increased the density of high-angle ferrite boundaries and ferrite volume fraction. The grain refinement improved the impact toughness. However, the impact toughness then reduced as the V content was increased to 0.23 wt %, because grain refinement did not further increase, whereas precipitation strengthening and ferrite hardening occurred.

Deformation, Mechanical Properties, and Fracture of Quenched and Tempered Carbon Steels

2015 ◽  
pp. 405-437
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Ductile Fracture ◽  
Carbon Steels ◽  
Low Carbon ◽  
Tempering Temperature ◽  
Medium Carbon ◽  
Low Carbon Steels ◽  
Deformation Properties ◽  
Medium Carbon Steels

Abstract Steels with martensitic and tempered martensitic microstructures, though sometimes perceived as brittle, exhibit plasticity and ductile fracture behavior under certain conditions. This chapter describes the alloying and tempering conditions that produce a ductile form of martensite in low-carbon steels. It also discusses the effect of tempering temperature on the mechanical behavior and deformation properties of medium-carbon steels.

scholarly journals The Influence of Vanadium Additions on Isothermally Formed Bainite Microstructures in Medium Carbon Steels Containing Retained Austenite

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 392 ◽  
Author(s):  
Irina Pushkareva ◽  
Babak Shalchi-Amirkhiz ◽  
Sébastien Yves Pierre Allain ◽  
Guillaume Geandier ◽  
Fateh Fazeli ◽  
...  
Keyword(s):  
Retained Austenite ◽  
Bainitic Ferrite ◽  
High Energy ◽  
Carbon Steels ◽  
Ex Situ ◽  
Transformation Rate ◽  
Medium Carbon ◽  
X Ray ◽  
Medium Carbon Steels ◽  
Carbon Mass Balance

The influence of V additions on isothermally formed bainite in medium carbon steels containing retained austenite has been investigated using in-situ high energy X-ray diffraction (HEXRD) and ex-situ electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis (EDX) techniques in the transmission electron microscope (TEM). No significant impact of V in solid solution on the bainite transformation rate, final phase fractions or on the width of bainite laths was seen for transformations in the range 375–430 °C. No strong influence on the dislocation density could be detected, although quantitative analysis was impeded by ferrite tetragonality. A reduction in the carbon content of retained austenite Cγ that is not believed to be due to competition with VC or cementite precipitation was observed. No influence of V on the carbon supersaturation in bainitic ferrite Cb could be directly measured, although carbon mass balance calculations suggest Cb slightly increases. A beneficial refinement of blocky MA and a corresponding size effect induced enhancement in austenite stability were found at the lowest transformation temperature. Overall, V additions result in a slight increase in strength levels.

scholarly journals Microstructure and Mechanical Properties of Austempered Medium Carbon Steels

2011 ◽  
Vol 97 (1) ◽  
pp. 26-33 ◽  
Author(s):  
Takeshi Suzuki ◽  
Yoshiki Ono ◽  
Goro Miyamoto ◽  
Tadashi Furuhara
Keyword(s):  
Mechanical Properties ◽  
Carbon Steels ◽  
Medium Carbon ◽  
Microstructure And Mechanical Properties ◽  
Medium Carbon Steels

Normalizing, Annealing, and Spheroidizing Treatments; Ferrite/Pearlite and Spherical Carbides

2015 ◽  
pp. 277-291
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Ferrite Matrix ◽  
Heat Treatments ◽  
Carbon Steels ◽  
Medium Carbon ◽  
Grain Structures ◽  
Medium Carbon Steels ◽  
Normalizing Annealing ◽  
Strength And Toughness

This chapter describes heat treatments that produce uniform grain structures, reduce residual stresses, and improve ductility and machinability. It also discusses spheroidizing treatments that improve strength and toughness by promoting dispersions of spherical carbides in a ferrite matrix. The chapter concludes with a brief discussion on the mechanical properties of ferrite/pearlite microstructures in medium-carbon steels.

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