Thermo-mechanical Processing for In-situ Cu-based Composites

In-situ Cu-based composites have been investigated extensively over the past decades because of their good conductivity and high strength. The preparation technologies of in-situ Cu-based composites mainly include casting of Cu alloys, initial heat treatment, hot deformation, cold deformation, intermediate and final heat treatment. This paper primarily researched the effect of thermo-mechanical processing such as initial heat treatment, hot deformation, cold deformation, intermediate and final heat treatments on the property and microstructure of in-situ Cu-based composites, analyzed the main role and mechanism of each thermo-mechanical processing, summarized the related research work and achievements, and prospected the future main research directions of the thermo-mechanical processing for in-situ Cu-based composites.

Effect of Design Modification on the Distortion Behavior of a Complex Counter Gear

A change in component design could help achieve objectives in lightweight construction. However, lightweight component design can incur serious distortion problems after the final heat treatment due to reduced stiffness or asymmetries in the mass distribution. The analysis of design modification through geometrical variations and their consequences on the distortion behavior through experiments can be costly and time consuming. In this paper, using 3D simulation models, different modified lightweight geometries are simulated. Using these simulation results, the authors try to understand the complex distortion behavior and correlate it with the effects of design modification.

EFFECT OF HEAT TRANSFER ON THE STRESS-STRAIN STATE OF THE MATERIAL CONSIDERING THE FINAL HEAT PROPAGATION VELOCITY

Анализируются результаты расчетов различных волновых задач. Показано, что деформационный нагрев материала интенсивен вблизи граничной поверхности и быстро уменьшается при незначительном удалении от нее. Делается вывод, что для получения точных решений волновых задач в неизотермической постановке необходимо учитывать перераспределение температуры в материалах из-за теплопередачи и его влияние на напряженно-деформированное состояние материалов различных конструкций. Приводятся результаты расчетов. Отмечена чувствительность решения к изменению удельной теплоемкости и коэффициента температуропроводности, входящих в волновое уравнение теплопроводности.

Effects of Pre-Crack Depth and Hydrogen Absorption on the Failure Strain of Zircaloy-4 Cladding Tubes Under Biaxial Strain Conditions

Fuel cladding may be subjected to biaxial tensile stress in axial and hoop directions during pellet-cladding mechanical interaction (PCMI) of a reactivity-initiated accident (RIA). Incipient crack in the hydride rim assisted by the scattered hydrides in the metal phase may lead to failure of the cladding at small hoop strain level during PCMI. To get insight of such phenomenon, biaxial-EDC tests under axial to hoop strain ratios ranging from 0 to 1 were performed with pre-cracked (outer surface) and uniformly hydrided Zircaloy-4 cladding tube samples with final heat-treatment status of cold worked (CW), stress relieved (SR) and Recrystallized (RX). Results showed dependencies of failure hoop strain on pre-crack depth, strain ratio, hydrogen content and final heat-treatment status on fabrication, but no apparent dependencies were observed on the distribution pattern of hydrides (with similar hydrogen contents and hydrides predominantly precipitated in hoop direction) and the heat-treatment process for hydrogen charging. J integral at failure seems to be available to unify the effect of pre-crack depth.

INDUSTRIAL TECHNOLOGY OF MANUFACTURING ULTRA-STRENGTH NANOBAINITIC STEEL PLATES

Nanobainitic steel grades are a new construction material with a strength in the range of 1.9–2.2 GPa, at the same time characterised by good plasticity. Currently, the works on the development of nanobainitic steels at Łukasiewicz – IMŻ have entered the commercialisation phase. One of the main applications of ultra-strength nanobainitic steel plates is armour systems. In order to optimise the parameters of the production process of nanobainitic steel plates, microstructure examination and measurement of mechanical properties were carried out at intermediate stages of production and after final heat treatment. The results of industrial steel and plate production operations were assessed, including smelting and casting into ingot moulds, preparation of the rolling mill charge, hot rolling, plate production as well as intermediate and final heat treatment. Critical technological operations that may adversely affect the quality and performance of plates were identified. The directions for technology modification that reduce or eliminate threats of plate deterioration were formulated.

ON NEW APPROACH TO DETERMINING HEAT-PRODUCING OF NATURAL GAS SUPPLIED TO CONSUMERS AND ITS CUBIC METROBAROMETRY

It is shown that with the change in pressure and temperature of natural gases in storages gas-holders, different installations one can separate water in necessary concentration from hydrates of hydrocarbon gases in their composition that forms its increased admixture in pipes and in the long run it influences the final heat-producing of the fuel. New approach was proposed as to the determing of heat-producing of natural gas supplied to consumers by the way of substantiation of the necessity to introduce such a unit as cubic metrobar (m3 bar). This would be conductive to determination of the correlation between heat-producing of produced natural gas and gas supplied to consumers, that is to say, determination of quality of consumed gas.