Improved relationship between Vickers hardness and yield stress for cold formed materials

Date

2001-08-01

Author

Tekkaya, AE

Metadata

Show full item record

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

Item Usage Stats

73
views

0
downloads

Cold-formed metal products are increasingly serving as high duty machine parts. Designers and users need to know their properties as accurately as possible. One such product property is the new yield strength, which can be approximated by the final flow stress of the workpiece material during forming. Vickers hardness measurements provide an easy and inexpensive method of evaluating the new local yield stress in cold-formed workpieces. The well-known available models given in literature to convert the measured hardness number into the corresponding yield stress have an error of up to 25%. This is basically due to the facts that cold formed material experiences large plastic strains in the main forming stage, the hardening behaviour is anisotropic and, moreover, the material properties are inhomogeneous especially at the workpiece surface. The purpose of this study is to improve the accuracy of the well-known available correlation models between Vickers hardness measurements and yield stress. This is achieved by utilizing finite element simulations of the indentation process. The models currently incorporate only the isotropic strain-hardening behaviour of the work material. The new suggested model decreases the theoretical conversion error to less than 10%.

URI

https://hdl.handle.net/11511/63553

Journal

STEEL RESEARCH

DOI

https://doi.org/10.1002/srin.200100122

Collections

Department of Mechanical Engineering, Article

Suggestions

OpenMETU
Core

An improved relationship between Vickers hardness and yield stress for cold formed materials and its experimental verification Tekkaya, AE (2000-08-26) Cold formed products are increasingly serving as high duty machine parts. Designers and users need to know their properties as accurate as possible. One such product property is the new yield stress, which can be approximated by the final flow stress of the workpiece material during forming. Vickers hardness measurements provide an easy and inexpensive method for evaluating the new local yield stress in cold formed workpieces. In this study, an improved relationship for the conversion of Vickers hardness va...
INVESTIGATION OF VIBRATION BASED FAULT DETECTION METHODS FOR SPINDLE BEARINGS Karakaş, Mert; Özşahin, Orkun; Department of Mechanical Engineering (2022-12) Spindles are hearth of the CNC lathes and condition of them are critical for the industry. In this thesis, effects of bearing defect on spindles are investigated and condition of spindles are determined using vibration data collected at working conditions. After a comprehensive literature survey, a bearing model including effects of defects is constructed. Afterwards, a finite element model of a spindle is created, and outputs of the bearing model are used as inputs for the FEM. Using the model, effects of ...
Analysis and design for aluminum forging process Öztürk, Hüseyin; Gökler, Mustafa İlhan; Department of Mechanical Engineering (2008) Aluminum forging products has been increasingly used in automotive and aerospace industry due to their lightness and strength. In this study, aluminum forging processes of a particular industrial part for the two different alloys (Al 7075 and Al 6061) have been analyzed. The forging part, forging process and the required dies have been designed according to the aluminum forging design parameters. The proposed process has been simulated by using the Finite Volume Method. In the simulations, analysis of the p...
Analysis and modeling of plastic wrinkling in deep drawing Yalçın, Serhat; Oral, Süha; Kaftanoğlu, Bilgin; Department of Mechanical Engineering (2010) Deep drawing operations are crucial for metal forming operations and manufacturing. Obtaining a defect free final product with the desired mechanical properties is very important for fulfilling the customer expectations and market competitions. Wrinkling is one of the fatal and most frequent defects that must be prevented. This study focuses on understanding the phenomenon of wrinkling and probable precautions that can be applied. In this study, dynamic – explicit commercial finite element code is used to s...
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

A. Tekkaya, “Improved relationship between Vickers hardness and yield stress for cold formed materials,” STEEL RESEARCH, pp. 304–310, 2001, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/63553.