A mathematical model has been developed to compute the thermomechanical state of the shell of continuously cast steels in a round billet casting mold. The model determines the temperature distributions, the stresses in and the gap between the casting mold and the solidifying strand. The effect of variations in steel carbon content and mold taper on the thermal, displacement, and stress fields a...

In the present study, M2 high speed steels were fabricated by using electro-slag rapid remelting process. Carbide structure was analysed and the fracture toughness and hardness were also measured after austenitization treatment at 1190 and 1210C followed by tempering treatment at 535C for billets with various diameters from 16 to 60 mm. Electro-slag rapid remelting (ESRR) process is an advanced...

At the Asiacrypt 2003 conference Billet and Gilbert introduce a block cipher, which, to quote them, has the following paradoxical traceability properties: it is computationally easy to derive many equivalent distinct descriptions of the same instance of the block cipher; but it is computationally difficult, given one or even up to k of them, to recover the so-called meta-key from which they wer...

Using a semi-discrete model that describes the heat transfer of a continuous casting process of steel, this paper is addressed to an optimal control problem of the continuous casting process in the secondary cooling zone with water spray control. The approach is based on the Hamilton–Jacobi–Bellman equation satisfied by the value function. It is shown that the value function is the viscosity so...

Near-stoichiometric NiTi with up to 18% closed porosity was produced by expansion at 1200 degrees C of argon-filled pores trapped by powder metallurgy within a NiTi billet. When optimally heat-treated, NiTi with 6-16% porosity exhibits superelasticity, with recoverable compressive strains up to 6% at a maximum compressive stress up to 1700 MPa. The apparent Young's modulus of NiTi with 16% poro...

A coextrusion process was used to fabricate macrochannelled hydroxyapatite (HA). To improve the powder characteristics, the HA powder was calcined at 900°C in air for 1 h. A feedrod composed of HA (shell) and carbon black (core) was coextruded at 120°C through a symmetric 8:1 square reduction die. After the first coextrusion, the individual pieces were bundled, warm-pressed, and then coextruded...

Ti–6Al–4V foams are produced by the expansion of pressurized argon pores trapped in billets created by powder metallurgy. Pore expansion during thermal cycling (840–1030 C, which induces transformation superplasticity in Ti–6Al–4V) improves both the foaming rate (by reducing the flow stress) and the final porosity (by delaying fracture of the pores and subsequent escape of the gas), as compared...

* Corresponding author. Tel.: +886 928722593; fax E-mail addresses: [email protected] (R.-C. (Y.-J. Chen), [email protected] (H.-C. Huang). In this paper, an artificial intelligent (AI) analyzer for mechanical properties of rolled steel bar by using neural networks was proposed. Based on the learning capability of neural network, the nonlinear and complex relationships among the steel bar...

In recent years, the fabrication of bulk materials with ultra fine grain sized materials processed by SPD methods. Different techniques have been used to introduce large plastic strains in to bulk metals such as Equal Channel Angular Pressing (ECAP) [1-3], Accumulative Roll Bonding (ARB) [4-7], Repetitive Corrugation and Straitening (RCS) [8,9], Constrained Groove Pressing (CGP) [5] and Constra...

In order to improve the quality of the billet continuous casting, a two-phase orthogonal power supply (TPOPS) for electromagnetic stirrer is researched, which is composed of three-phase PWM rectifier and three-leg inverter. According to the power analysis of system, the ripple of dc-link voltage is analyzed and its analytical expression is derived. In order to improve the performance of electro...