SU1360883A1 - Mould for producing cast iron rolls - Google Patents

Abstract

The invention relates to a foundry, in particular, to a technology for producing mill rolls. The purpose of the invention is to increase the operational durability of the rolls and heat resistance of the chill mold. This goal is realized by making the outer layer 8 of the chill mold 2 of the metal-ceramic roll barrel placed between the needle protrusions 7 of the inner part 6 of the chill mold 2. The use of the invention makes it possible to reduce costs in the manufacture and operation of cast iron rolling rolls. 1 il. (L with SU5 oo oo with

Description

The invention relates to foundry, in particular, to the technology for producing mill rolls.

The purpose of the invention is to increase the operational durability of the rolls and heat resistance of the chill mold.

The drawing shows a mold for producing mill rolls.

Foundry form consists of consistently installed half-form 1 bottom

Rennected cast-iron part with needle protrusions and the outer of metal-ceramic, placed between the protrusions.

The metal is melted in induction furnaces and poured into pre-prepared molds in which chromel-alumel thermocouples are installed. According to the results of measurements, the rate of advance of the solidification front into the slurries, the chill mold 2 forming the barrel, the southern zone of the casting is determined and compared with the half-form 3 of the upper neck, the profits 4 with the speed of solidification in a known form,

siphon gating system 5. Kokil 2 consists of an inner cast-iron part b with needle protrusions 7 and an outer part 8 made of metal-ceramic placed between said protrusions 7. Semiforms 1 and 3, profit 4 and gating system 5 are made of sand 15

The results of a comparative study show that in the working layer of a roll with a thickness of 20 mm, the microstructures are identical, both in the known and proposed forms, and the area of the cementite component is 40-45%. In the axial zone of a roll cast in a known form, the area occupied by cementite is 18-20%, which is

clay mixture.

After filling the rolling mill form, the results of the comparative study show that in the working layer of the roll with a thickness of 20 mm the microstructures are identical, both in the known and proposed forms, and the area of the cementite component is 40-45%. In the axial zone of a roll cast in a known form, the area occupied by cementite is 18-20%, which is

ka liquid metal and heat removal 20 is a rejection feature for rolls

overheating, the surface working layer of the roll roll hardens, which is caused by the greater heat-accumulating capacity of the inner cast-iron part 6 of the chill mold 2 as compared to sand-clay

sheet rolling mills. A study of the density of samples by hydrostatic weighing in carbon tetrachloride shows the presence of porosity in the lower neck. In contrast to the remaining 9 parts of the casting 1, 3 and 4, which are known in this mixture, they are in the proposed form of casting rolls. The outer part 8 chill 2 reduces the heat-provide a dense bottom

retraction to the environment from the inner cheek and a decrease in the amount of the cementite component in the axial zone to 7–9%. This is because the speed of the advance

the cast-iron part 6, contributes to its heating and, consequently, slowing down the rate of solidification of the axial zone of the barrel. This ensures the elimination of shrinkage defects in the lower neck due to successively bottom-up hardening of the lower jersey and barrel, as well as reducing the amount of brittle cementite component in the axial

The setting of the solidification front in the axial zone of the barrel is 0.5-2.0 mm / min less than in the known form (3.0 mm / min).

Thermal cycling of the chill molds shows that through five filling in the outer part of the chill mold 8, cast in a known form, the barrel zone. In addition, a small, through-crack is formed, which the crack of the inner cast-iron part 6 slows down its normal operation.

The heat removal from the external surfaces of the protrusions 7 of the chill mold 2 contributes to a decrease in the temperature gradient along its thickness and a decrease in thermal stresses, which leads to an increase in the service life 40 of the chill mold.

They make a model of a double-layer chill mold of a known mold - a sector with an inner surface diameter of 315 mm. The internal part of the model is made

from steel, external from gray cast iron. The outer surface is exposed, which differs from the wall of a chill mold wall thickness of 60 mm. This is due to the fact that, in order to increase the operation of the lower neck with a diameter of 160 mm, the roll strength and heat resistance are

bits of sandy-clay mixture. chill molds, on its outer surface of the roll barrel barrel of the proposed lin-ing are made needle-like protrusions, and

The core form, also with a height of 315 mm, is a refractory material in the form of metallore-filled in the form of sectors, which are internally located in the cavities between them.

The use of the invention allows to reduce costs in the manufacture and operation of cast iron mill rolls.

Claims (1)

Invention Formula Casting mold for pig-iron rolls, containing molds under the roll cheeks and a chill mold for a roll barrel with a layer of refractory coating Compiled by O. Belkov Editor O. GolovachTekhred I. VeresKorrektor A. Tsko Order 5780/15 Circulation 741 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 1 13035, L 1oskva, Zh-35, Raushsk nab., 4/5 Production and Printing Enterprise, Uzhgorod, ul. Project, 4 Rennected cast-iron part with needle protrusions and the outer of metal-ceramic, placed between the protrusions. The results of a comparative study show that in the working layer of a roll with a thickness of 20 mm, the microstructures are identical, both in the known and proposed forms, and the area of the cementite component is 40-45%. In the axial zone of a roll cast in a known form, the area occupied by cementite is 18-20%, which is The thermal cycling of the chill molds shows that through five fillings in the outer part of the chill mold 8, cast in a known form, a through-crack forms, which excludes its normal operation. on the outer surface, characterized in that, in order to increase the utilization of the invention, it reduces the costs in the manufacture and operation of cast iron rolling rolls Invention Formula Casting mold for pig-iron rolls, containing molds under the roll cheeks and a chill mold for a roll barrel with a layer of refractory coating