Shimko A. Improving of alitizing modes for maintenance of high refractoriness of products from the carbon steels.

The Thesis is dedicated to improvement of the technologies of pow-dered alitizing of low carbon steel for the reason development of the tech-nologies of production rigs for chemist-termal processing with high work-ing longevity. The principles of the choice of the material of the sheet sub-jecting to alitizing with provision of high refractoriness and minimum de-formation are designed. These characteristic are reached when ensuring the alike depth of layers with both sides on thickness of the sheet, herewith main metal between aluminized layers must gain after alitizing the eutec-toid structure. The influence of the mode of alitizing and parameters of thermo-cycling, imitating working the rig for chemist-termal processing, on struc-tured-phase changes in aluminized layer is explored. It is shown that in process of electro arc welding in air atmosphere of the aluminized sheet occurs the saturation of the metal of the seam by alu-minum as a result of dissolutions of FeAl2 and Fe2Al5. It is determined thepossibility of the reception of refractory and strong enough joins at welding of aluminized low carbon steel's sheet that allows to use the aluminized sheets under repair of the retorts of stoves for cementation. The new tech-nology of production of rigs for chemist-termal processing is designed. It includes the double-sided alitizing and following electro arc welding in at-mosphere of the air. The results of thesis are introduced in production of the rig for chemist-termal processing with real economic effect in size over 100 thous. grn.