The comparison of bainitic transformations and mechanical properties of 60simn5 and 55cr3 steels

Download

index.pdf

Date

2019

Author

Bakır, Simg

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

341
views

203
downloads

In this study, lower bainitic and martensitic transformations in 55Cr3 and 60SiMn5 heavy duty spring steels were studied. 55Cr3 and 60SiMn5 steels are used in the production of springs that can withstand medium and high tensile and compression loads, especially as leaf springs, helical springs and ring springs in vehicles. A high elastic deformation behavior is expected in spring steels. Therefore, it is important that the spring steel has high yield strength. The transformation mechanisms and mechanical properties of lower bainite were compared with the tempered martensite of 55Cr3. The samples of both steels were austenitized at 860°C for 30 minutes. It was followed by isothermal treatment of 55Cr3 samples at just above Ms temperature, which is 270°C, for 80 minutes in order to obtain fully lower bainitic microstructure. Additionally, incomplete bainitic transformations at either 270°C for 8 minutes or at 270°C for 3 hours were also studied. Moreover, martensitic samples of 55Cr3 were tempered in the range 220°C-550°C. Another set of samples were also treated under Ms in order the obtain mixture of lower bainite and tempered martensite. Although the tempered martensitic samples yielded good impact toughness values, their tensile properties were lower than the lower bainitic samples of 55Cr3. It was seen from the results that the lower bainitic sample of 55Cr3 (270°C, 80min) had 583HV hardness,1645MPa yield strength, 1978MPa ultimate tensile strength, 9.7% elongation and 12,7J impact toughness values. Moreover, the carbide-free lower bainite of 60SiMn5 was seen to have 600HV, 1781MPa yield strength, 2107MPa ultimate tensile strength, 5,68% elongation and 9J impact toughness values.

Subject Keywords

Lower bainite., Lower bainite, carbide-free lower bainite, 55Cr3, 60SiMn5, tempered martensite

URI

http://etd.lib.metu.edu.tr/upload/12624253/index.pdf
https://hdl.handle.net/11511/45468

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

A Comparative Study of Effects of Additive Particle Size and Content on Wetting Behavior and Brazing Performance of C/SiC Composite Saltik, Simge; ESEN, ZİYA; Dericioğlu, Arcan Fehmi (2022-10-01) This study has focused on the influence of size and content of SiC particle incorporation on the wetting behavior of the Ticusil brazing filler alloy and on its brazing performance in C/SiC composite/Ti6Al4V alloy joints. The effect of the size and content of additive SiC particles on the variation of molten brazing filler alloy contact angle was recorded at various brazing time and temperatures. Moreover, the microstructural evolution and mechanical properties of the additive containing C/SiC composite/Ti6...
A Material Perspective on Consequence of Deformation Heating During Stamping of DP Steels ŞİMŞİR, CANER; Cetin, B.; Efe, Mert; Davut, K.; Bayramin, B. (2017-07-06) Recent studies showed that, during stamping of high strength steels at industrially relevant production rates, local temperature in the blank may rise up to 200°C – 300°C due to deformation heating. Moreover, die temperature may also rise up to 100°C – 150°C for progressive stamping dies. Based on the common assumption that the blank softens as the temperature increases, thermal softening creates a margin in Forming Limit Diagram (FLD) and therefore the FLD determined at room temperature can safely be used ...
The effect of SN content and isothermal transformation temperature on the mechanical properties of austempered ductile cast iron Özcan, Alper; Atala, Haluk; Department of Metallurgical and Materials Engineering (2003) In this study the effects of Sn content and isothermal transformation temperature on the ultimate tensile strength (UTS), elongation and hardness of austempered ductile cast iron (ADI) was investigated. To determine the possible effect of Sn on these properties the Sn content of standard GGG30, GGG40 and GGG50 materials were taken as reference, whose chemical compositions vary from 0,016 to 0,050% in terms of Sn. However the Sn content was increased to a maximum of 0,26% for investigating the effect of Sn o...
THE MECHANICAL CHARACTERIZATION AND IN VIVO EVALUATION OF POROUS TiNi AS GRAFT MATERIAL Arpak, Bertan; Araz, Kenan; Nakas, Ipek; Bor, Sakir; Nergiz, Ibrahim (2012-09-01) To obtain TiNi foams with interconnected pores that have surface quality necessary for bone growth in addition to required mechanical performance, sintering with the space holder technique was employed in this study, which aimed to evaluate the bone healing process of TiNi graft materials. For this purpose, processed TiNi foams with three different porosities were placed into the created defects in the femur of rats. Moreover, the mechanical properties of the processed TiNi foams were conducted via monotoni...
The effect of double austenitization on the microstructure and toughness of AISI M2 high speed steel Ögel, Bilgehan (1998-06-01) In this study, the effect of double austenitization on microstructure and toughness of AISI M2 high speed steel was investigated. For double austenitization treatment, the specimens, which are hardened initially at 1220 degrees C and quenched in air, were hardened for a second time in the temperature range 1150 - 1050 degrees C. For comparison purposes, another set of specimens is austenitized singly in the temperature range 1150 - 1050 degrees C. Tempering process was carried out between 500 - 640 degrees ...

Citation Formats

S. Bakır, “The comparison of bainitic transformations and mechanical properties of 60simn5 and 55cr3 steels,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Metallurgical and Materials Engineering., Middle East Technical University, 2019.