scholarly journals Effect of Carbon Content in Retained Austenite on the Dynamic Tensile Behavior of Nanostructured Bainitic Steel

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 907 ◽  
Author(s):  
Wen Zhou ◽  
Tingping Hou ◽  
Cong Zhang ◽  
Lei Zhong ◽  
Kaiming Wu
Keyword(s):  
Strain Rate ◽  
Carbon Content ◽  
Tensile Properties ◽  
Retained Austenite ◽  
Carbon Film ◽  
Bainitic Steel ◽  
Low Carbon ◽  
Plasticity Effect ◽  
Bainite Steel ◽  
Dynamic Tensile Properties

Results of dynamic tensile testing of three-step low-temperature-transformed nanostructured bainitic steel and quenching and partitioning martensitic steel at different strain rates (0.1–500 s−1) are reported here. The results showed that the high carbon film-like austenite was much more stable than the low carbon blocky austenite during deformation. The nanostructured bainite steel exhibited the more remarkable dynamic tensile properties due to the better transformation-induced plasticity effect and strain rate hardening effect exhibited by stable film-like retained austenite. The big gap in engineering stress and strain curves occurred at a higher strain rate (100–200 s−1) for the nanostructured bainite steel because of the better stability of film-like austenite. Therefore, the present study is able to assist in explaining the effect of carbon content in retained austenite on the dynamic tensile properties and understanding the microstructure property relationship in complex steels.

Isothermal Transformation, Microstructure and Mechanical Properties of Ausformed Low-Carbon Carbide-Free Bainitic Steel

2018 ◽  
Vol 941 ◽  
pp. 329-333 ◽  
Author(s):  
Jiang Ying Meng ◽  
Lei Jie Zhao ◽  
Fan Huang ◽  
Fu Cheng Zhang ◽  
Li He Qian
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Bainitic Ferrite ◽  
Isothermal Transformation ◽  
Bainitic Transformation ◽  
Isothermal Treatment ◽  
Bainitic Steel ◽  
Low Carbon ◽  
Microstructure And Mechanical Properties

In the present study, the effects of ausforming on the bainitic transformation, microstructure and mechanical properties of a low-carbon rich-silicon carbide-free bainitic steel have been investigated. Results show that prior ausforming shortens both the incubation period and finishing time of bainitic transformation during isothermal treatment at a temperature slightly above the Mspoint. The thicknesses of bainitic ferrite laths are reduced appreciably by ausforming; however, ausforming increases the amount of large blocks of retained austenite/martenisite and decreases the volume fraction of retained austenite. And accordingly, ausforming gives rise to significant increases in both yield and tensile strengths, but causes noticeable decreases in ductility and impact toughness.

scholarly journals Mechanism of the Microstructural Evolution of 18Cr2Ni4WA Steel during Vacuum Low-Pressure Carburizing Heat Treatment and Its Effect on Case Hardness

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2352
Author(s):  
Bin Wang ◽  
Yanping He ◽  
Ye Liu ◽  
Yong Tian ◽  
Jinglin You ◽  
...  
Keyword(s):  
Low Temperature ◽  
Carbon Content ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Lath Martensite ◽  
Low Pressure ◽  
Low Carbon ◽  
High Carbon ◽  
Carburized Layer ◽  
Martensite Matrix

In this study, vacuum low-pressure carburizing heat treatments were carried out on 18Cr2Ni4WA case-carburized alloy steel. The evolution and phase transformation mechanism of the microstructure of the carburized layer during low-temperature tempering and its effect on the surface hardness were studied. The results showed that the carburized layer of the 18Cr2Ni4WA steel was composed of a large quantity of martensite and retained austenite. The type of martensite matrix changed from acicular martensite to lath martensite from the surface to the core. The hardness of the carburized layer gradually decreased as the carbon content decreased. A thermodynamic model was used to show that the low-carbon retained austenite was easier to transform into martensite at lower temperatures, since the high-carbon retained austenite was more thermally stable than the low-carbon retained austenite. The mechanical stability—not the thermal stability—of the retained austenite in the carburized layer dominated after carburizing and quenching, and cryogenic treatment had a limited effect on promoting the martensite formation. During low-temperature tempering, the solid-solution carbon content of the martensite decreased, the compressive stress on the retained austenite was reduced and the mechanical stability of the retained austenite decreased. Therefore, during cooling after low-temperature tempering, the low-carbon retained austenite transformed into martensite, whereas the high-carbon retained austenite still remained in the microstructure. The changes in the martensite matrix hardness had a far greater effect than the transformation of the retained austenite to martensite on the case hardness of the carburized layer.

scholarly journals Dynamic Tensile Properties of CFRP Manufactured by PCM and WCM: Effect of Strain Rate and Configurations

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1491
Author(s):  
Yujin Yang
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Tensile Properties ◽  
Strain Rate Sensitivity ◽  
Failure Strain ◽  
Dynamic Performance ◽  
Rate Sensitivity ◽  
Fracture Mechanisms ◽  
Reinforced Plastic ◽  
Dynamic Tensile Properties

Carbon fiber-reinforced plastic (CFRP) is a promising material to achieve lightweight automotive components. The effects of the strain rate and configurations of CFRP on dynamic tensile properties have not yet been fully explored; thus, its lightweight benefits cannot be maximized. In this paper, the dynamic tensile properties of CFRPs, tested using two different processes with two different resins and four different configurations, were studied with a strain rate from 0.001 to 500 s−1. The tensile strength, modulus, failure strain, and fracture mechanism were analyzed. It was found that the dynamic performance enhances the strength and modulus, whereas it decreases the failure strain. The two processes demonstrated the same level of tensile strength but via different fracture mechanisms. Fiber orientation also significantly affects the fracture mode of CFRP. Resins and configurations both have an influence on strain rate sensitivity. An analytic model was proposed to examine the strain rate sensitivity of CFRPs with different processes and configurations. The proposed model agreed well with the experimental data, and it can be used in simulations to maximize the lightweight properties of CFRP.

SANDVIK 3R12

Alloy Digest ◽  
1995 ◽  
Vol 44 (9) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Carbon Content ◽  
Tensile Properties ◽  
Heat Treating ◽  
Low Carbon ◽  
Temperature Performance

Abstract Sandvik 3R12 is an austenitic chromium-nickel stainless steel with extra low carbon content. It is superior to Type 302 in corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-612. Producer or source: Sandvik.

scholarly journals A Comparative Study on the Dynamic Tensile Behavior of Nanostructured Bainitic and Quenched-Tempered Martensitic Steels

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 728 ◽  
Author(s):  
Wen Zhou ◽  
Kaiming Wu ◽  
Lei Zhong ◽  
Cong Zhang ◽  
Tingpin Hou ◽  
...  
Keyword(s):  
Low Temperature ◽  
Tensile Properties ◽  
Retained Austenite ◽  
Total Elongation ◽  
Tensile Behavior ◽  
Martensitic Steels ◽  
Martensitic Microstructure ◽  
Bainitic Microstructure ◽  
Dynamic Tensile Test ◽  
Dynamic Tensile Properties

In order to assess the dynamic tensile behavior of a newly developed three-step low-temperature-transformed bainitic microstructure, and a conventional one-step isothermal bainitic microstructure, and a quenched and tempered martensitic microstructure, a comparative research was conducted by using the dynamic tensile test. The results showed that more film-like retained austenite was obtained in the three-step low-temperature-transformed sample. The carbon content in the film-like retained austenite was found to be higher as compared to the blocky retained austenite. The dynamic tensile properties were all improved with an increase in strain rates (from 0.1 to 500 s−1). However, the three-step bainitic low-temperature-transformed sample showed the most remarkable dynamic tensile properties, including ultimate tensile strength and total elongation. This is attributed to a better transformation-induced plasticity effect that is exhibited by the higher stability of the film-like retained austenite. Therefore, the present study suggests that performing a three-step low-temperature bainitic transformation promotes grain refinement and the formation of film-like retained austenite and improves the dynamic tensile properties.

Strain rate effects on dynamic tensile properties of open-hole composite laminates

2020 ◽  
Vol 19 ◽  
pp. 226-232 ◽  
Author(s):  
Jin Sun ◽  
Zhen Jing ◽  
Jian Wu ◽  
Weibo Wang ◽  
Diantang Zhang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Tensile Properties ◽  
Composite Laminates ◽  
Strain Rate Effects ◽  
Rate Effects ◽  
Open Hole ◽  
Dynamic Tensile Properties

scholarly journals Static and dynamic response of ultra-fast annealed advanced high strength steels

2018 ◽  
Vol 183 ◽  
pp. 03017
Author(s):  
Florian Vercruysse ◽  
Felipe M. Castro Cerda ◽  
Roumen Petrov ◽  
Patricia Verleysen
Keyword(s):  
Strain Rate ◽  
Retained Austenite ◽  
High Strain ◽  
High Strength Steels ◽  
High Strength ◽  
Strain Rates ◽  
Low Carbon ◽  
Heating Rates ◽  
High Strain Rates ◽  
Advanced High Strength Steels

Ultra-fast annealing (UFA) is a viable alternative for processing of 3rd generation advanced high strength steels (AHSS). Use of heating rates up to 1000°C/s shows a significant grain refinement effect in low carbon steel (0.1 wt.%), and creates multiphase structures containing ferrite, martensite, bainite and retained austenite. This mixture of structural constituents is attributed to carbon gradients in the steel due to limited diffusional time during UFA treatment. Quasi-static (strain rate of 0.0033s-1) and dynamic (stain rate 600s-1) tensile tests showed that tensile strength of both conventional and UFA sample increases at high strain rates, whereas the elongation at fracture decreases. The ultrafast heated samples are less sensitive to deterioration of elongation at high strain rates then the conventionally heat treated ones. Based on metallographic studies was concluded that the presence of up to 5% of retained austenite together with a lower carbon martensite/bainite fraction are the main reason for the improved tensile properties. An extended stability of retained austenite towards higher strain values was observed in the high strain rate tests which is attributed to adiabatic heating. The extension of the transformation induced plasticity (TRIP) effect towards higher strain values allowed the UFA-samples to better preserve their deformation capacity resulting in expected better crashworthiness.

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