Perfection of the equipment of electromagnetic stirring in moulds of billet and bloom CCM

To avoid defects of continuously casted billets, such as core porosity, shrink liquation, ingot developed dendrite structure and others, various methods of external physical impact on the crystallizing billet are used. One of the most technological and effective of them is the electromagnetic stirring (EMS) of the liquid melt of the crystallizing billet. An analysis of the experience of industrial EMS systems application at steel plants of Russia was accomplished. It was noted, that operating in Russia industrial CCM, intended for production of high quality billets, are equipped mainly by EMS systems of foreign production. The stator of the EMS is located outside a mould body and the bodies of the stator and the mould are manufactured of nonmagnetic steel of austenite class. Such systems are characterized by low reliability and high energy consumption because of their design features (location outside a mould body and necessity to use for them a separate circuit of cooling by a “boiler” water). Bessides, most of the EMS stators of foreign manufacturing are made in nonseparable bodies, hence in case of a failure the expensive rrepair of the stators should be carried out at the foreign plants-manufacturers. At present in Russia the EMS systems are being elaboorrated by specialists of AKKH “VNIIMETMASH”, Moscow. VNIIMETMASH within the frame of import substitution program elaboorated both built-in and external variants of EMS systems for moulds of billet and bloom CCM, the stator coil poles being cooled bby the water of the mould and its winding is made of immersible into water wire with a double insulation. Based on the results of thee study it was determined, that location of the elaborated EMS systems in a mould results in improving of the surface quality, as welll as quality of the subsurface layer and the billet macro-structure, decreasing of the point unevenness and decreasing of number of thee subshell bubbles.

P550

P550 is a fully austenitic Mn-Cr-N steel with 1.4% nickel minimum. The alloy is a special nonmagnetic steel with a high nitrogen content. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance. Filing Code: SS-1266. Producer or source: Schoeller-Bleckmann.

Microstructure and Properties of Laser Clad Nonmagnetic WC-FeNiCr Metal-Matrix Composite Coating

Nonmagnetic metal-matrix composite (MMC) coatings were fabricated by laser cladding with direct injection of WC-FeNiCr powder onto the N1310 nonmagnetic steel matrix. Laser cladding was conducted using a Trumpf6000 CO2 laser. The WC-FeNiCr MMCs coating was characterized using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The phase constitution in the laser cladding was identified by x-ray diffraction (XRD). No pores or macro-cracks have been found at the interface indicating good metallurgical bonding between the coating and the N1310 nonmagnetic steel matrix. Magnetic measurements were carried out with vibrating sample magnetometer (VSM) at room temperature. The MMC coating was nonmagnetic and with a relative permeability of 1.004. The XRD analysis confirmed the presence of an austenitic γ-(Fe, Ni), Cr0.19Fe0.7Ni0.11, Fe3W3C, WC and W2C phases in the laser clad layer.

Design and Strength Analysis of Ultra-High Speed Permanent Magnet DC Rotor

The sintered neodymium-iron-boron (Nd-Fe-B) material is used in most of PM machines. The kind of PM materials has small tensile strength and cannot withstand large centrifugal force due to high rotational velocity. A nonmagnetic steel enclosure is needed to cover the PM material. The tensile stress of the PM can reduced by pre-pressure applied to the outer surface of the PM through shrink-fitting into the enclosure. Based on the elasticity theory and the elastic-plastic contact theory, in soft ANSYS it is feasibility to establish a finite element mechanical model of interference fit between the enclosure and motor rotor PM at high rotating speed. This paper simulates the effects of the temperature and rotating speed (centrifugal force) on the displacement and the contact pressure on the interference-fitting surfaces .By finite element non-linear contact model analysis, if setting up right fit clearance, this paper could ensure the security of the PM rotor under rotational velocity up to 300,000 r/min high and temperature up to 150°C.