Simulation and experimental investigation of strain rate impact on martensitic transformation in 304L steel through dome test

2016 ◽  
Vol 31 (14) ◽  
pp. 2136-2146 ◽  
Author(s):  
Hojjatollah Fathi ◽  
Esmaeil Emadoddin ◽  
Hamid Reza Mohammadian Semnani
Keyword(s):  
Experimental Investigation ◽  
Martensitic Transformation ◽  
Strain Rate ◽  
Image Position ◽  
304L Steel

Abstract

Investigation on Microstructure and Martensitic Transformation Mechanism for the Warm-Stamped Third-Generation Automotive Medium-Mn Steel

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Xiaodong Li ◽  
Ying Chang ◽  
Cunyu Wang ◽  
Shuo Han ◽  
Daxin Ren ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Strain Rate ◽  
Compressive Load ◽  
High Strength ◽  
Third Generation ◽  
Transformation Mechanism ◽  
Loading Method ◽  
Strain And Strain Rate ◽  
Medium Mn Steel ◽  
Mn Steel

With the development of the automotive industry, the application of the high-strength steel (HSS) becomes an effective way to improve the lightweight and safety. In this paper, the third-generation automotive medium-Mn steel (TAMM steel) is studied. The warm-stamped TAMM steel holds the complete and fine-grained martensitic microstructure without decarbonization layer, which contributes to high and well-balanced mechanical properties. Furthermore, the martensitic transformation mechanism of the TAMM steel is investigated by the dilatation tests. The results indicate that the effects of the loading method on the Ms temperature under different loads are different. The Ms temperature is hardly influenced under the tensile loads and low compressive load. However, it is slightly decreased under the high compressive load. Moreover, the effects of the strain and strain rate on the Ms temperature are insignificant and can be neglected. As a result, this research proves that the martensitic transformation of the TAMM steel is rarely influenced by the process parameters, such as stamping temperature, loading method, load, strain, and strain rate. The actual stamping process can be designed and controlled accurately referring to the continuous cooling transformation (CCT) curves to realize the required properties and improve the formability of the automotive part.

scholarly journals Longitudinal Stress Gradients and Basal Shear Stress of a Temperate Valley Glacier

1979 ◽  
Vol 24 (90) ◽  
pp. 507-508 ◽  
Author(s):  
Robert Bindschadler
Keyword(s):  
Shear Stress ◽  
Strain Rate ◽  
Field Data ◽  
Numerical Models ◽  
Lateral Strain ◽  
Longitudinal Stress ◽  
Base Shear ◽  
Stress Gradients ◽  
Valley Glacier ◽  
Image Position

AbstractFor the first time field data from a temperate valley glacier, the Variegated Glacier, are used to investigate the behavior of longitudinal stress gradients predicted by the relation(1)whereHis the local depth, andysandybare the surface and bed elevations respectively. This equation is similar to one derived by Budd (1970) for plane strain-rate, to evaluate the importance of longitudinal stress gradients, but a shape factorfis included to account approximately for lateral strain-rate gradients. Predictive numerical models of valley glaciers require the local base shear stress to be known as accurately as possible. It has been argued on theoretical grounds that whenTis averaged over distances of more than five to ten times the depth, this term is negligible. At larger averaging scales, 2Gcan then be considered a correction to the simple geometric expression of base stress due to the presence of longitudinal stress gradients. Field data of velocity and geometry are used to evaluate the terms of Equation (1), whereτband 2Gare estimated asandat intervals of 100 m,Usis the measured surface center-line velocity,Aandnare the flow-law parameters, andis the surface longitudinal strain-rate. The expression for 2Gis an approximation proposed by Budd (1970).

Effect of temperature and strain rate on the mechanisms of indentation deformation of magnesium

2015 ◽  
Vol 5 (3) ◽  
pp. 513-518 ◽  
Author(s):  
M. Haghshenas ◽  
V. Bhakhri ◽  
R. Oviasuyi ◽  
R.J. Klassen
Keyword(s):  
Strain Rate ◽  
Effect Of Temperature ◽  
Image Position

Abstract

scholarly journals Erebus Glacier Tongue, Mcmurdo Sound, Antarctica

1974 ◽  
Vol 13 (67) ◽  
pp. 27-35 ◽  
Author(s):  
G. Holdsworth
Keyword(s):  
Shear Stress ◽  
Strain Rate ◽  
Shear Strain ◽  
Longitudinal Strain ◽  
Strain Rates ◽  
Shear Strain Rate ◽  
Mcmurdo Sound ◽  
Glacier Tongue ◽  
The Past ◽  
Image Position

Examination of the past and present behaviour of the Erebus Glacier tongue over the last 60 years indicates that a major calving from the tongue appears to be imminent. Calculations of the regime of the tongue indicate that bottom melt rates may exceed 1 m a−1. By successive mapping of the ice tongue between the years 1947 and 1970, longitudinal strain-rates were determined using the change in distance between a set of 15 teeth, which are a prominent marginal feature of the tongue. Assuming a flow law for ice of the form where τ is the effective shear stress and is the effective shear strain-rate, values of the exponent n = 3 and B = 1 × 108 N m−2 are determined. These are in fair agreement with published values.

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