CS252642B1 - Steel mold for casting forging ingots - Google Patents

Abstract

The purpose of the proposed solution is to achieve the required conditions for solidification of forging ingots at an optimal weight of the mold, its dimensional stability and high service life. The stated purpose is achieved by making the wall thickness (W) along the circumference and height /H/ of the mold 13.5 to 16.5% of the diameter /D^/ of the inscribed circle in the inner space at the upper edge of the mold. At the upper edge of the mold, an outer circular bandage is created, the outer diameter of which /Djj,/ is equal to the sum of the diameter /Dyy/ of the circumscribed circle into the inner space at the upper edge of the mold and the value of double the thickness (S) of the wall up to the sum of the diameter /Dyy/ of the circumscribed circle into the inner space at the upper edge of the mold, then the value of double the thickness (sj of the wall and the value of 60 mm. At the lower edge of the mold, an outer circular bandage is created, the outer diameter of which /Djb^ is equal to the sum of the diameter /D22/ of the circumscribed circle into the inner space at the lower edge of the mold and the value of double the thickness (S) of the wall up to the sum of the diameter IB^I of the circumscribed circle into the inner space at the lower edge of the mold, then the value of double the

Description

The invention relates to the construction of the ingot mold for casting of forging ingots, and it solves the achievement of the required solidification conditions at an optimal weight of the ingot mold, its shape stability and high service life.

The internal shape of the ingot mold corresponds to the shape of the ingot _f given by the technological requirements of the forging. The basic requirements of the ingot are: body height, upper and lower cross-sections and thus the conicity of the ingots and the number of edges. Due to these assumptions and the different size of ingots, there are a number of molds of different construction made of hematite cast iron, pig iron and low carbon steel. The shape and functional inconsistency of the ingot molds is caused by the hitherto not introduced general procedure for the calculation of ingot molds for forging ingots.

To date, ingot molds with wedge wall thicknesses are used, in inverse proportion to the ingot mass, with greater thickness at the lower edge and vice versa. This type of ingot mold is designed to achieve a greater degree of rectification of solidification of the ingot from the bottom upwards. However, this construction is disadvantageous due to the inherent durability of the ingot mold. Against the large cross-section of the ingot at the top, the thinner wall is considerably thermally stressed, the specific stress in the ingot mold is high, resulting in longitudinal cracks.

There are also known molds for heavy forging ingots with external steel reinforcements - bandages. Their disadvantage is that they cannot achieve the initial perfect tightness of the massive bandage with the ingot mold and develop the necessary prestressing in the bandage. For this reason, this method of protection of the ingot mold against cracks is not effective because the bandage only becomes effective at the radial expansion of the ingot mold, when in many cases its wall is already broken.

Also, the design of the molds does not take into account the different properties of the materials used, such as steel, compared to traditionally used cast iron, not only in terms of higher strength but also linear expansion properties and stability at higher temperatures.

These drawbacks are eliminated by the steel forging casting ingot mold according to the invention, which has a wall thickness of 13.5 to 16.5% of the diameter of the inscribed circle into the inner space at the upper edge of the ingot mold. At the upper edge of the ingot mold, an outer circular bandage is formed, the outer diameter of which is equal to the sum of the diameter of the circumscribed circle into the inner space at the upper edge of the ingot. values 60 mm, expressed in terms of ^D 1b ^{= D} 11 ^{+ 2S to D} 11 + 2S + 60 mm.

an outer circular bandage is formed at the lower edge of the ingot, the outer diameter of which is equal to the sum of the diameter of the circumscribed circle into the inner space at the lower edge of the mold and values of 60 mm, expressed mathematically ° 2b ^{= d} 22 ^{+ 2S d} 22 ⁺ 2S + 60 mm, and the bandage width at the upper edge of the mold is, expressed mathematically ^h lb ⁼ ° < ^{15 H to} ° ^20H and the bandage width at the lower edge the molds are, expressed mathematically ^h 2b ^{= 0.10 H to 0.15 H}

The advantage of the ingot mold according to the invention is that the selected ingot cross-section always corresponds to the optimum wall thickness of the ingot mold, which is able to accumulate and transmit to the environment by radiation the necessary amount of heat while resisting thermal stresses resulting from uneven heating of its walls. The mold wall thus shows less permanent deformation of the inner walls in the longitudinal direction, which results in lower repair costs by milling and welding the upper edge of the steel mold.

It is therefore an ingot mold with an optimal weight to the weight of the ingot, showing relatively high durability parameters and thus material savings per ton of cast steel.

The advantage of the outer natural bandage formed at both ends of the ingot mold is the reduction of the specific stress and an increase in the shape stability. This solution strengthens the wall, especially in the area of internal radii, which are the most thermally stressed from the ingot and thus prevents longitudinal cracks.

The attached drawing shows an exemplary embodiment of the ingot mold according to the invention, wherein in FIG. 1 its front view is in section, in FIG. 2 a cross section in its upper part and in FIG. 3 a cross section in its lower part.

The chill mold, in the exemplary embodiment of the invention, is intended for casting 43 ton octagonal ingot ingots, has a diameter D _{b of a} circle inscribed in the inner space of the upper edge of the chill mold D1 = 1518 mm and a circle p ₂ at the lower edge p ₂ = 1330 mm . The wall thickness S around the perimeter and the height of the ingot mold is 14.8% of the diameter D 4. It is:

S = 0.148. D _x = 0.148. 1518 = 225 mm

The cooling effect of the ingot mold wall is greater at the lower end of the ingot, which has a positive effect on rectified solidification and internal homogeneity in the ingot. The outer diameter D _{lb of the} bandage at the upper edge of the ingot mold was:

^D 1b ^{= D} 11 + 2 S = 1756 + 2. 225 = 2,206 mm

The outer diameter D _{2b of the} bandage at the lower edge of the ingot mold was:

^D 2b ^{= D} 22 + ^2S = ^{1539 + 2} · ²²⁵ = ¹ θ

The width hj _{b of the} bandage at the upper edge of the mold was:

h _1b = 0.15 H = 0.15. 2540 = 380 mm width h _2b bandage at the lower edge of the mold was:

h _2b = 0.10 H = 0.10. 2540 = 225 mm

The height H of the ingot mold was 2540 mm.

The ingot mold is provided with three pairs of oppositely located supporting pins 2 at three levels along the ingot height.

Claims (1)

SUBJECT OF THE INVENTION Steel ingot mold for forging ingots, characterized in that the wall thickness (S) around the perimeter and the height (H) of the ingot mold is 13.5 to 16.5% of the diameter (D ^) of the inscribed circle into the interior at the upper edge of the ingot an outer circular bandage (1) is formed at the upper edge of the ingot mold, whose outer diameter (D | _b ) is equal to the sum of the diameter (Djj) of the circumscribed circle into the inner space at the upper edge of the ingot; and a double wall thickness (S) up to the sum of ) circumscribed circles in the inner space at the upper edge of the ingot mold, further the values of double wall thickness (S) and the value of 60 mm, mathematically expressed ^D lb ^{= D} 11 ^{+ 2S D} 11 + ^{2S +} 60 mm (2) whose outer diameter (D _2b ) is equal to the sum of the diameter (D ₂₂ ) of the circumscribed circle into the interior at the lower edge of the ingot mold and the double wall thickness (S) up to the sum of the diameter (D ₂₂ ) circle into the inner space at the lower edge of the mold, as well as the double wall thickness (S) and the value of 60 mm, mathematically expressed D _2b - D ₂₂ + to ^ 22 + + ®0 mm, and the width (h _lb ) of the bandage at the upper edge of the ingot is expressed mathematically h _lb = 0.15 H to 0.20 H and the width (h _2b ) of the bandage at the lower edge of the ingot mold is expressed mathematically h _2b = 0.10 H to 0.15 H.