Verzugsarme Kaltmassivumformung*/Low distortion cold massive forming – Development of a new technology for the reduction of residual stresses

2019 ◽  
Vol 109 (10) ◽  
pp. 740-744
Author(s):  
A. Franceschi ◽  
P. Groche

Eigenspannungen, die während des Herstellungsprozesses in Bauteile eingebracht werden, sind oft Ursache von Verformungen und beeinträchtigen zudem die Ermüdungs- und Korrosionsbeständigkeit. In diesem Beitrag wird daher die Entwicklung einer neuen Technologie vorgestellt, die es ermöglicht, die Eigenspannungen bei kaltfließgepressten Teilen zu verringern. Zudem wird eine Wärmebehandlung numerisch simuliert, um zu zeigen, wie mit dieser Technologie Verformungen vermieden werden können.   Residual stresses stored in components during the manufacturing process often cause distortions besides negatively affecting fatigue and corrosion resistance. This paper reveals a new technology for residual stress reduction in cold extruded parts. The studied system can be implemented in conventional cold forging production and does not cause changes in the processing times. A heat treatment process is numerically simulated to show how distortions can be avoided by this technology.

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1303
Author(s):  
Fabian Mühl ◽  
Moritz Klug ◽  
Stefan Dietrich ◽  
Volker Schulze

Internal Quenching is an innovative heat treatment method for difficult to access component sections. Especially, the microstructure, as well as the residual stress state at inner surfaces, of thick-walled tubes can be adjusted with the presented flexible heat treatment process. Based on multiphysical FE-models of two different steels, a simulative optimization study, considering different internal quenching strategies, was performed in order to find the optimal cooling conditions. The focus hereby was on the adjustment of a martensitic inner surface with high compressive residual stresses. The simulatively determined optimal cooling strategies were carried out experimentally and analyzed. A good agreement of the resulting hardness and residual stresses was achieved, validating the presented Fe-model of the Internal Quenching process. The shown results also indicate that the arising inner surface state is very sensitive to the transformation behavior of the used steel. Furthermore, the presented study shows that a preliminary simulative consideration of the heat treatment process helps to evaluate significant effects, reducing the experimental effort and time.


2008 ◽  
Vol 571-572 ◽  
pp. 27-32 ◽  
Author(s):  
Volkan Güley ◽  
A. Erman Tekkaya ◽  
Turhan Savaş ◽  
Feridun Özhan

Experimental investigation of residual stresses after heat treatment and grinding processes in the production of ball bearing rings has been carried out. The residual stresses were measured by X-ray diffraction method utilizing chromium radiation, which has an average penetration depth of 5 μm incident on 100Cr6 (AISI-E52100) ball bearing steel. The process parameters of heat treatment and grinding processes were varied so as to represent the extreme values that can be applied in the respective processes. Hardness and percent retained austenite limit the heat treatment process parameters; while roundness, surface roughness and form the grinding process. Tensile surface residual stresses on the raceway of ball bearing rings changes to compression after grinding in both circumferential and axial directions. In grinding relatively higher compressive stresses were measured in axial direction compared to the circumferential direction. This experimental investigation also showed that the influence of heat treatment process parameters on the magnitude and distribution of residual stresses survived even after grinding process; i.e. heat treatment and grinding processes cannot be evaluated independently in process design for favourable residual stresses.


Author(s):  
Steve L. Dedmon ◽  
James Pilch ◽  
Jeffrey Gordon

Understanding how residual stresses develop during a typical rim spray quench and subsequent tempering operation is a fundamental objective necessary to gain knowledge of how wheels behave when under service loads. In this study, we have used specially modified and validated ANSYS software to calculate plastic deformations as they develop during the heat treatment process. Plastic deformations, including creep, were determined to follow stages which were both dependent on time of quench and depth from the taping line. Residual stresses developed from these deformations are also discussed.


2005 ◽  
Vol 490-491 ◽  
pp. 47-52 ◽  
Author(s):  
Clemens Franz ◽  
Gerhard Besserdich ◽  
Volker Schulze ◽  
Hermann Müller ◽  
Detlef Löhe

The field of heat treatment of steels offers a large variety of applications for the use of simulation tools. It always includes the development of residual stresses and distortions. The geometry of the part, the composition of the material, the heat treatment process as well as the initial state of the part interact with each other in complex ways and have an influence on the distortion of the part. Using simulation the temporal development of temperature, phases, stresses and distortions while quenching as well as the residual stress distribution and distortion after quenching can be calculated. Transformation plasticity has been proved to be very important for heat treatment simulation. Three steels with identical contents of alloying elements but different carbon contents of 0.2, 0.5 and 0.8 wt. % were analysed. The influence of transformation plasticity during the martensitic transformation on the distortions and residual stresses after quenching of cylinders made out of the three steels was analyzed in simulations and compared to experimental results.


2008 ◽  
Vol 3 (2) ◽  
pp. 63-69
Author(s):  
M. Sivapragash ◽  
◽  
V. Sateeshkumar ◽  
P.R. Lakshminarayanan ◽  
R. Karthikeyan ◽  
...  

1987 ◽  
Vol 19 (12) ◽  
pp. 79-83
Author(s):  
K. Bartoszewski ◽  
A. Bilyk

Rettery wastewaters were treated in anaerobic and aerobic ponds. Anaerobic treatment yielded efficiencies of BOD5 and COD removal as low as 20%. The treatment process conducted under aerobic conditions in aerated and stabilizing ponds arranged in series took from 18 to 20 days and gave efficiencies of BOD5 and COD removal amounting to 90%. The experimental results were interpreted by virtue of the Eckenfelder equation. Excess activated sludge was subjected to aerobic stabilization in a separate tank. A new technology was suggested for the existing obsolete industrial treatment plant.


Author(s):  
Karanbir Singh ◽  
Aditya Chhabra ◽  
Vaibhav Kapoor ◽  
Vaibhav Kapoor

This study is conducted to analyze the effect on the Hardness and Micro Structural Behaviour of three Sample Grades of Tool Steel i.e. EN-31, EN-8, and D3 after Heat Treatment Processes Such As Annealing, Normalizing, and Hardening and Tempering. The purpose of Selecting Tool Steel is Because Tool Steel is Mostly Used in the Manufacturing Industry.This study is based upon the empirical study which means it is derived from experiment and observation rather than theory.


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