MASTER'S WORK
EXPLORATION OF PROCESS OF SOLIDIFICATION OF PIG-IRON GRINDING BODIES IN OPEN METAL MOLDS KONVEJERNO-KOKKILNOJ CARS
The purpose of the given job is improvement in quality of performance data of pig-iron grinding bodies ellipsoid moulding boxes on konvejerno-kokilnoj to the car.
On the Makeevsky foundry the "know-how" of grinding bodies of various standard sizes which are fabricated on konvejerno-kokilnoj to the car by разливки liquid pig-iron in open metal moulds is developed.
The basic requirements which are shown to grinding bodies, the high surface hardness and crash-worthiness are. Pig-iron grinding bodies, possessing sufficient hardness, have the lowered shock durability in comparison with steel grinding bodies.
To raise crash-worthiness of molten pig-iron bodies it is possible by change of internal structure of casts at the expense of change of a mode of solidification of liquid pig-iron on the conveyor кокильной cars with the subsequent controllable refrigeration of firm cast. In the spent explorations it has been shown, that if on a runout konvejerno-kokilnoj cars to provide temperature of a surface of cast in an interva 800-850 ˚С and then quickly to cool in flowing water the blanket will get sufficient hardness, and the internal volume will consist of a metastable austenitic. The cast having such internal structure, differs smaller fragility and prevents development of cracks of while in service grinding bodies in the globe mill.
The mathematical sample piece of solidification of casts has been developed for maintenance of such master schedule of manufacture of pig-iron grinding bodies in open metal moulds konvejerno-kokilnoj cars in the course of their movement on the car conveyor. The calculations spent on a sample piece, allow to fix corresponding speed of the conveyor at which the temperature of a surface of a washing body on a runout from cars will correspond in breaking points 800-900 ˚С. After achievement of such temperature fabricate the accelerated refrigeration of casts in flowing water that will lead to reception of necessary properties of a grinding body: a high surface hardness and less fragile structure in cast.
By results of the spent explorations reconstruction konvejerno-kokilnoj cars with adjustable speed of movement of the conveyor and with installation of the accelerated refrigeration of casts will be spent.
Conclusions:
- The mathematical sample piece of solidification of pig-iron grinding bodies ellipsoid moulding boxes is developed.
- Optimum speed of movement of a strap on konvejerno-kokilnoj to the car is defined.
- The internal structure of cast of a grinding body is investigated and conditions of reception of a metastable austenitic are defined.
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