Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
The comparison of microstructure and mechanical properties of a low carbon bainitic forging steel after isothermal transformation and direct cooling
Download
10464139.pdf
Date
2022-4-27
Author
Balcılar, Muhammed Mustafa
Metadata
Show full item record
This work is licensed under a
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
.
Item Usage Stats
335
views
319
downloads
Cite This
Bainitic forging steels have emerged in recent decades as an alternative to Quench and Temper steels due to their low cost and energy requirements and optimum combination of strength, ductility, and toughness. Although effect of continuous cooling on bainitic forging steels have been studied, the effect of isothermal transformation on microstructure and mechanical properties of microalloyed bainitic forging steels is an open field. A low carbon microalloyed bainitic forging steel is examined in this study, with a composition of 0.2C-1.3Si-1.5Mn-1.45(Cr+Mo), microalloyed with V-Ti-Nb. The steel is isothermally transformed at various temperatures and continuously cooled and compared in terms of microstructural features by optical microscopy and scanning electron microscopy, phase analysis by XRD measurements, and mechanical properties. Effect of isothermal holding time is also studied at each isothermal transformation temperature, varying from 15 minutes to 30 hours. Isothermal transformation just above Ms gives the maximum amount of bainite with the smallest lath thickness, which is proven by microstructural characterization. Retained austenite measurements demonstrated that in all samples, similar amounts of austenite remain in the system. Hardness measurements show that bainitic samples are similar in terms of hardness, but the specimen transformed at the lowest temperature gave the hardest microstructure ranging from 391-420 HV. The bainitic microstructure hardness values for other specimens range from 378HV to 421HV. The isothermal transformation just above the Ms temperature has given the most ductile and toughest steel, with an elongation of 17% and a UTS of 1264 MPa. The results show that isothermally transformed specimens have superior mechanical properties and isothermal transformation heat treatment routes should be designed to obtain materials with the best performance.
Subject Keywords
Bainitic steel
,
Steel
,
Bainite
,
Retained austenite
,
Bainitic forging steel
,
Isothermal transformation
URI
https://hdl.handle.net/11511/97323
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
Effects of heat input and thermal cycles to the fracture toughness of API 5L grade X70M steel welded by gas metal arc welding
Erol, Eren; Gür, C. Hakan.; Department of Metallurgical and Materials Engineering (2019)
High strength low alloy steels are widely used in line pipe applications since they have reasonably high strength and toughness due to their micro-alloying elements and production via thermomechanically controlled process. During welding of these steels, microstructures of the fusion zone and the heat affected zone consisting globular and acicular ferrite alter due to induced heat and thermal cycles. Consequently, changes in the microstructure affects the mechanical properties such as fracture toughness. Ga...
Investigation on the ballistic performance of a dual phase steel against 7.62 mm AP projectile
Ubeyli, Mustafa; DEMİR, TEYFİK; Deniz, Hueseyin; Yıldırım, Raif Orhan; KELEŞ, Ömer (2010-03-25)
Dual phase steels have the potential to reduce the weight of structural components because of the improved mechanical properties obtained from the two phases: soft ferrite and hard martensite. In this study, the ballistic performance of a low carbon and low alloy steel was investigated in intercritically annealed conditions. To do this, intercritical heat treatments at three different temperatures were applied to the steel samples separately to get three groups of samples having various martensite volume fr...
Analysis of forging for three different alloy steels
Civelekoğlu, Barış; Darendeliler, Haluk; Gökler, Mustafa İlhan; Department of Mechanical Engineering (2003)
Forging is a manufacturing process which is preferred among the others in that, the final product shows more enhanced properties. The properties of the final product are directly related with the material used in the forging process. Main parameters such as forging temperature, number of stages, preform design, dimensions of the billet, etc. may be affected by the forging material. Alloys are one of the main areas of interest in the forging industry. The use of alloy steels may bring superior properties, es...
Investigating the effect of deformation and annealing texture on magnetic anisotropy in low-C steel sheets by magnetic Barkhausen noise method
Akçaoğlu, Fehmi Ümit; Gür, Cemil Hakan; Department of Metallurgical and Materials Engineering (2013)
Deformation and annealing texture in the cold rolled low carbon steels is important for sheet metal forming operations and service performance. The aim of this study is to non-destructively investigate the effect of texture on magnetic anisotropy. Various samples having different textures and residual stress states, due to different % reduction in thickness, annealing and stress relieving treatment, were prepared. Texture maps were obtained by Magnetic Barkhausen noise measurements performed with 100 steps ...
The Influence of Additive Manufacturing Process Parameters on Residual Stress Of 17-4 PH Stainless Steel Parts Manufactured By Laser Powder Bed Fusion Additive Manufacturing System
Çelik, Gökhan; Gür, Cemil Hakan; Şimşir, Caner; Department of Metallurgical and Materials Engineering (2023-1-16)
Laser Powder Bed Fusion (LPBF) process is one of the most well-known additive manufacturing methods for the production of complex and functional parts from metal powder material. Residual stresses cause a major setback in the LPBF process and restrict the serviceability of the parts, particularly in advanced technology applications. Process parameters have a crucial impact on residual stress formation and residual stresses alter the reliability of material properties. Therefore, the influence of process par...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
M. M. Balcılar, “The comparison of microstructure and mechanical properties of a low carbon bainitic forging steel after isothermal transformation and direct cooling,” M.S. - Master of Science, Middle East Technical University, 2022.