Modeling and Experimental Verification of Plastic Behavior of the Martensitic Transformation Plastic Behavior in a Carbon Steel

2006 ◽  
Vol 118 ◽  
pp. 369-374 ◽  
Author(s):  
Dong Ying Ju ◽  
Wei Min Zhang ◽  
Y. Matsumoto ◽  
Ryuji Mukai

The objective of this paper is to extend the capability of analyzing the time dependence and coupling of temperature, stress and strain effects on the macroscopic and microscopic structures subjected to quenching, and to introduce a theory of the kinetic of the phase transformation. Strain due to phase transformation, transformation plasticity and thermal expansion are the dominant factors that need to be included in the simulation of a quenching process. The evolution of the microstructure also influences the constitutive equations. In particular, as the temperature changes from the high to phase transformation, temperature and then room temperature, the stress-strain relationship changes from elastic-plastic strain. Therefore, in order to obtain a high strength and ductility in carbon steels, transformation plasticity often has a major effect in increasing of the residual stress during quenching process. In this paper, we measured temperature change and distortion occurring during the quenching process of a carbon steel(SCr420) by thermal simulation machine (Gleeble 1500) are used to determine the parameter of transformation plasticity due to the generation of martensite. The modeling of martensitic transformation plasticity is also verified by using of computational simulation of the quenching process.

2004 ◽  
Vol 120 ◽  
pp. 489-497
Author(s):  
R. Mukai ◽  
D.-Y. Ju

Predictions of deformation, residual stresses and hardness after heat treatment of gears by numerical simulation are very useful to determine optimum condition to decrease the distortion of machinery parts. In this paper, simulation on carburizing quenching of a helical gear made of carbon steel SCr420 was carried out using three-dimensional coupled analysis based on thermo-mechanical theory considering phase transformation. The expansion and latent heat due to phase transformation at various carburizing conditions were measured by TMA and DSC to determine the thermal physical properties of SCr420 carbon steel. The influence of the transformation plasticity strain on deformation, residual stress and hardness of a gear was clarified in the simulation. The accuracy of simulation also is verified by the comparison between the experimental data and the simulated result of the distortion and residual stress. From the predicted results, improvement of the hardness and strength on surface of the gear due to the carburizing-quenching process can be verified.


1997 ◽  
Vol 119 (3) ◽  
pp. 257-265 ◽  
Author(s):  
K. F. Wang ◽  
S. Chandrasekar ◽  
H. T. Y. Yang

An investigation of the quenching of 1080 carbon steel cylinders has been carried out to determine the validity of a quenching process model for carbon steels. The process model included a description of the austenite-pearlite and austenite-martensite transformations in carbon steels, temperature-dependent material properties, and an elastic-plastic stress analysis. The model was simulated using the finite element method (FEM). An experimental study of the quenching of 1080 steel cylinders in water and two types of polymeric quenchants has also been carried out. The temperatures at three points within the cylinder during quenching were measured using thermocouples. The hardness and residual stress distributions along a cross-section of the quenched cylinders were determined using a Rockwell hardness test and an X-ray diffraction technique, respectively. The temperature-time histories, residual stress, and hardness distributions predicted from the FEM simulation of the quenching model were found to be in good agreement with the corresponding measurements. The quenching process simulation described in the study appears to be a promising tool for the design of heat-treatment process parameters for carbon steels.


2011 ◽  
Vol 197-198 ◽  
pp. 375-382
Author(s):  
Shi Chun Zhu ◽  
Xiao Feng Lu ◽  
Jian Ming Gong

In this paper, effect of pre-deformation and ageing on compressive behavior of Ti-58.25wt%Ni was investigated at room temperature. Through range analysis of three factors and three levels on transformation temperature measured by DSC, ageing at 673K enhanced phase transformation temperature obviously, the As temperature could reach 308.02K. Transformations of B2-B19’ and B2-R-B19’ appeared after the treatments. Saw tooth shape phenomenon on the loading curves indicating the typical martensitic transformation was also observed. Dynamic balance due to compatible action among various phase under increased load kept the slope of the loading curves constantly. Pre-deformation by 0.2% resulted in higher compressibility (4.9%), and ageing at 523K caused better recovery (95.4%).


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