Kuzmenko О. Recovery of the instrument for hot volumetric forging by an electroslag surfacing with noncompact materials. 5742

The thesis is dedicated to a solution of a problem of creation of effective technology of surfacing of the worn instrument for hot volumetric forging on the basis of electroslag process, provision of high operation stability and reliability of this instrument, and also decrease of its cost price. The metallurgical and technological features of an electroslag surfacing of the worn dies with applying of non-consumable graphitized rods and additives of noncompact materials in a slag pool, particularly shavings of steel 5ХНМ are learnt. It is established experimentally and by mathematical modeling method of ESS NM process by non-consumable rods, that for provision of even heating of a surface of a wide area die, the process must be carried on using power density (150...180) 104 W/m2, providing a temperature gradient on height of surfacing billet not less than 30 оС/sm. With the help of a designed mathematical model it is shown, that processes of move and melting of different types of noncompact materials(shawing, fraction, wire chaff) in slag and metal pools at ESS NM have complex and multiphase nature, and the main role in them is played by demarcation boundaries of phases air - melt of slag and melt of slag - melt of metal. On these boundaries at the expense of forces of boundary tension takes place anchoring of fragments of noncompact materials, their heating and, depending on the sizes and shape, partial or full fusion. The heat balance of process ESS NM is counted and the optimal mass rate of feeding of fragments of noncompact materials - 0.3...0.7 kg/h with 1 kWt of power input is determined. Results of the held studies and developments are put in a basis of new technology of recovery of dies by ESS NM. The basic requests to machinery for ESS NM are formulated in paper, which was used at designing of surfacing equipment and hardware. An inculcation of new technology at joint-stock company "Rostselmash" (Russia) and "Tokmak forging and stamping work" (Ukraine), where the specialized sites were created,allowed to almost completely utilize wastes of tool production for a surfacing (shavings, worn dies etc.), to increase stability of a dies at 1.5...3 times with simultaneous cost reduction near 30 %.