IMPROVING THE CONTINUOUS CAST BLANK STRUCTURE BY USING MICRO-COOLANTS
Paper intended to clarify some problems regarding the accomplishment of an improved crystalline of the continuously cast blanks using the micro-coolant addition during the continuous casting of the steel. The industrial experiments were made within a metallurgical plant having a continuous casting machine for blooms with a 240x270mm section. Micro-coolants as grains were added in the mould of the continuous casting machine, on a single thread. The conclusions got from analyzing the casting structure of the experimental blanks (with addition of micro-coolants in the mould) in comparison with the common casting structure (witness blank) are presented.
RESPECTS REGARDING THE USAGE MICRO-COOLERS TO CASTING STEEL
Basic problem, which must solve to casting steel, consists in the smooth ingots procurance insurance from chemical point of view, structural and of mechanical ownerships. For the defects mitigation to solidification classic, it is the needed adjustment to an efficient methods exhaust of warmth from the steel under solidification through the administration of micro-cooler under form of grains to casting. Micro-coolers you utilize with the view of process directing of solidification must achieve conditions series: to have a heaved purity respecting the content of oxide inclusions; the wet micro-coolers uttermost 0, 25%; to not have surface oxidant; to have a certain granulometric composition. The work clears the aspects related interaction micro-coolers you deal to casting steel over solidification to this. As parameters, which influence the process of solidification they were taken in the dimensions, study micro-coolers, the specific enlargement of micro-cooler, steel temperature in the enlargement moment while as the influenced parameter steel volume in which they acted microcoolers. Through analysis of regression by the agency of program Excel and Matlab they obtained dependence between meal micro-cooler you utilize to casting ingots from temperature and steel of casting, correlations which they allow the optimal areas establishment variation for temperature of casting, the quantity of micro-cooler dealt respective affected volume percent of cooling to the administration micro-coolers.
Preparation of hydrophilic poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation
Abstract Hydrophilic microporous hollow fiber membranes were prepared via thermally induced phase separation (TIPS). Poly(vinyl butyral) (PVB) and three kinds of polyethylene glycols (PEG) with the molecular weight of 200, 400 and 600 were used as polymer and diluents. In all cases, liquid–liquid (L–L) phase separation occurred and asymmetric cellular structures with the smaller pores at the outer surface were obtained. The properties of membranes such as pore size, water permeability, solute rejection and intensity were investigated by changing molecular weight of PEG, concentration of PVB, composition of the bath and air gap distance. The smaller molecular weight of PEG, the more PEG in the bath and the shorter air gap distance resulted in the higher water permeability, the lower solute rejection property and the lower mechanical strength.