Local stress and strain variations in the deformation zone can be ascertained by measuring hardness. Hardness is correlated with strain and stress. The expressions discussed later are useful in determining the local variations in stress and strain from hardness measurement. It is a simple method compared to visioplasticity. One can estimate the forces required for a forming process. It helps in the choice of equipment, design of tooling and selection of lubricant for the particular process.
(Indian Academy of Sciences, Hardness-stress-strain correlation in aluminium - A simpler alternative to visioplasticity in metal forming) Dharmaveera, N.; Srinivasan, K.
1996
A simple method of characterizing local stress and local strain variation in metal working is suggested. It is an alternative to complex and time consuming visioplastic technique. A power law expression exists for hardness and strain similar to that of stress and strain. A linear expression relating hardness and stress has been estahlished. These are valid not only for pure metals but also for their alloys. © Meshap Science Publishers.
(Hardness-stress-strain correlation in copper and brass through compression testing) Dharmaveera, N.; Srinivasan, K.
1996
This paper deals with an experimental investigation concerning the open die extrusion (ODE) of three materials of varying physical properties and mechanical properties. Two geometrical configurations (solid and tube) and two methods (by direct and indirect techniques) were considered to examine the influence of these variables in the generation and retention of heat in the deformation zone with the objective of ensuring a greater achievable strain. Studies reveal that solid configuration supports the retention of heat as against tubular configuration. Low thermal conductivity, density, specific heat and high flow stress which characterise 99Ti make this material an excellent candidate for ODE as opposed to AISI 1020 steel and aluminium, which fail to meet all the above physical and mechanical properties. The indirect technique reduces the friction factor and thus enables greater strains to be achieved. © 1997 Elsevier Science S.A.
(Elsevier BV, Adiabatic and friction heating on the open die extrusion of solid and hollow bodies) Srinivasan, K.; Venugopal, P.
1997
CP aluminium was subjected to axysymmetric compression testing at 303, 373, 473, 573 and 673 K. Strength coefficient and strain hardening exponent were determined from log-log plot of true stress and true strain at different temperatures. True stress vs temperature at different strains indicated that dynamic strain ageing (DSA) occurred between 473 and 673 K. Warm working is to be done between 423 K and 473 K, so that optimum substructure hardening and strain hardening can be achieved during mechanical processing. © Indian Academy of Sciences.
(Indian Academy of Sciences, High temperature compression testing and determination of warm working temperature for commercial purity aluminium) Rao, B.K.; Khadar, M.S.A.; Srinivasan, K.
1999
Open die extrusion (ODE) has been done on AISI 1020 steel, commercial purity aluminium and commercial purity titanium, in both direct and inverted modes. It was found that inverted extrusion requires lesser forces than direct extrusion. Limit strains are more for the former than for the later as measured experimentally and as calculated theoretically. Theoretical limit strains are lesser than experimental ones in both the case of rods and tubes. ODE is only for shorter components due to unsupported billet and interference from buckling. It is also only for smaller strains due to interference from upsetting of unsupported billet above the die rather than extrusion through the die. © 2004 Elsevier B.V. All rights reserved.
(Direct and inverted open die extrusion (ODE) of rods and tubes) Srinivasan, K.; Venugopal, P.
2004

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