Forming annealing process

Abstract

The invention provides a forming annealing process, and relates to the technical field of glass manufacturing. The forming annealing process comprises the following steps: adding the use of edge fire guns, using a pair of edge fire guns at an inlet of an area A, using a pair of edge fire guns at an area R1, using a pair of edge fire guns at an area R3, using two pairs of edge fire guns at an area F, increasing the opening degrees of the edge fire at the area F and the area R, only burning a smooth edge by the edge fire, increasing the temperature of the smooth edge at an area C, adding a wind shield at the area F, adjusting the wind shield to protect the smooth edge, and reducing the blowing amount to the smooth edge. Increasing the blowing quantity of the glass on the inner side of the tooth mark, reducing the electric heating opening degree of the edge of the area B, reducing the outlet temperature of the tin bath, reducing the inlet temperature of the area A, correspondingly increasing the temperatures of the area B1, the area B2 and the area C, and reducing the temperature of the corresponding part of the crack of the area B or increasing the temperature of the corresponding part of the crack of the area C. Five sets of edge fire guns are arranged and used in different areas, electric heating and an F area wind shield are matched, the longitudinal temperature gradient and the transverse temperature difference of the annealing kiln are optimized, 15 mm glass annealing is continuous and stable, the number of split edges is small, and the cutting quality is stable and good.

Description

Technical Field

[0001] The invention relates to the technical field of glass manufacturing, in particular to a forming annealing process. Background Art

[0002] The development of float glass technology in China has been mature and stable. With the growth of personalized market demand, conventional 5mm and 6mm glass production can no longer meet the demand. At present, ultra-thick glass is widely used in high-end hotels, city signs, government projects, high-end exhibition halls and other places. Float glass production has moved towards large-scale production of multiple varieties of thick glass. The production of 15mm ultra-thick float glass must be carried out on the basis of stable production of 12mm float thick glass, because the thicker the glass, the greater the spreading force tends to balance the thickness, the more difficult it is to accumulate the thickness, the more difficult it is to control the stability of glass strip molding, and the more difficult it is to control the quality of continuous high-quality annealing.

[0003] In glass technology, annealing mainly refers to the process of reducing or eliminating the residual stress of glass. The purpose of glass annealing is to eliminate the residual stress and optical inhomogeneity of glass products and stabilize the internal structure of glass. Glass annealing is mainly divided into two main processes: one is the weakening and disappearance of internal stress, and the other is to prevent the regeneration of internal stress. The stable annealing process of ultra-thick plates (15mm glass plates) is the prerequisite for the stable production of ultra-thick plates and the basis for ensuring the reduction of plate explosion, splitting and cutting problems. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies of the prior art, the present invention provides a forming annealing process, which reduces a series of problems that may occur in the later stage of glass production under the premise of stable production of ultra-thick glass plates.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented by the following technical solutions: the forming annealing process includes the following processing steps:

[0008] S1, stress control: residual stress R = 1.86 × G × A × A. It can be seen from the formula that the residual stress is proportional to the cooling rate of zone B and the square of the glass thickness. When the stress value is too large, the temperature difference from the outlet of zone A to the outlet of zone B2 is reduced, and when the stress value is too small, the temperature difference from the outlet of zone A to the outlet of zone B2 is increased;

[0009] S2, increase the use of side muskets, use a pair of side muskets at the entrance of area A, 1 pair of side muskets in area R1, 1 pair of side muskets in area R3, and 2 pairs of side muskets in area F;

[0010] S3, increase the edge fire opening of F and R zones, the edge fire only burns the edges, increase the temperature at the light edge of C zone, add a windshield in F zone, and adjust the windshield to protect the light edge, reduce the air volume on the light edge, increase the air volume on the inner side of the tooth mark, and reduce the electric heating opening of the edge of B zone;

[0011] S4, lower the outlet temperature of the tin bath, so that the inlet temperature of zone A is lowered, and the temperatures of zones B1, B2 and C are increased accordingly;

[0012] S5, by lowering the temperature of the portion corresponding to the crack in zone B or raising the temperature of the glass portion corresponding to the crack in zone C;

[0013] S6, increase the edge temperature of zone B, reduce the opening of the edge air valve, increase the opening of the edge electric heating, or increase the edge fire of zone A.

[0014] Preferably, the R residual stress in S1 is in kg / ㎡, and the reference range of the residual stress of 15mm glass is: 1.81-2.54, and the target value is 2.17.

[0015] Preferably, in S1, G is the cooling rate of zone B of the annealing furnace, in units of °C / min, and A is the thickness of the glass sheet, in units of mm.

[0016] Preferably, the combustion condition of the blast gun in S2 is a carbonizing flame, and only the edges of the position are burned.

[0017] Preferably, the observation hole for placing the blaster in area A of S2 is not blocked.

[0018] (III) Beneficial effects

[0019] The present invention provides a forming annealing process. It has the following beneficial effects:

[0020] 1. This process optimizes the longitudinal temperature gradient and transverse temperature difference of the annealing furnace by configuring 5 sets of edge torches for use in different zones, and cooperates with electric heating and wind shield in zone F. The annealing of 15mm glass is continuous and stable, the number of split edges is low, and the cutting quality is stable and good. DETAILED DESCRIPTION

[0021] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The forming annealing process includes the following processing steps:

[0023] The annealing kiln area is divided into zone A (pre-annealing zone), zone B (annealing zone), zone C (post-annealing zone), zone D (transition zone), zone R (hot air circulation zone), zone E (transition zone) and zone F (forced cooling zone).

[0024] S1, stress control: residual stress R = 1.86 × G × A × A. It can be seen from the formula that the residual stress is proportional to the cooling rate of zone B and the square of the glass thickness.

[0025] R residual stress, unit is kg / ㎡, the reference range of residual stress of 15mm glass is: 1.81-2.54, the target value is 2.17.

[0026] G is the cooling rate of the annealing furnace B zone, in °C / min, and A is the thickness of the glass sheet, in mm.

[0027] When the stress value is too large, the temperature difference from the outlet of area A to the outlet of area B2 is reduced, and when the stress value is too small, the temperature difference from the outlet of area A to the outlet of area B2 is increased.

[0028] S2, use of side blasters: a pair of side blasters are used at the entrance of area A, 1 pair of side blasters are used in area R1, 1 pair of side blasters are used in area R3, and 2 pairs of side blasters are used in area F. The burning condition of the blasters is carbonization flame, and only the edges are burned. Use the side blasters in area A. When using the side blasters in area A, pay attention to the observation hole of the side blasters. The use of side blasters in area A is mainly to improve the cutting quality, and the use of side blasters in areas R / F is mainly to prevent the edge of the glass from exploding.

[0029] S3, splitting is caused by the edge of thick glass is thinner than the inner glass of tooth mark, the edge dissipates more heat than the middle part of the board, there is such temperature difference in the annealing zone, the edge will be subjected to tensile stress, the middle will be subjected to compressive stress, which is easy to cause splitting. By increasing the edge fire opening of F zone and R zone, the edge fire only burns the edge, and the temperature of the light edge of the annealing zone C is increased. The wind shield is adjusted to protect the light edge, the air blowing to the light edge is reduced, the air blowing to the glass inside the tooth mark is increased, and the electric heating opening of the edge of the annealing zone is appropriately reduced.

[0030] S4, the reason for the slag is that the surface stress curve is unreasonable, the core temperature is high, and the tensile stress of the core is too large. The main reason is that the cooling speed is too fast, which reduces the outlet temperature of the tin bath, reduces the inlet temperature of zone A, and correspondingly increases the temperature of zones B1, B2 and C.

[0031] The S5 crack is caused by a small crack extending into the plate at the knife edge when the glass plate is bent horizontally. The problem can be improved by lowering the temperature of the corresponding part of the crack in zone B or raising the temperature of the glass corresponding to the crack in zone C, or by reducing the temperature difference between the upper and lower plates.

[0032] S6, the edge of the horizontal bending does not follow the cutting line, and there are more or fewer corners. This is because the edge of the thick glass is thinner than the glass inside the tooth mark, and the edge dissipates more heat than the middle of the plate. The existence of such a temperature difference in the annealing zone will cause the edge of the glass to be subjected to compressive stress and the middle to be subjected to tensile stress after the temperature is uniform. This can be solved by increasing the edge temperature in the annealing zone, reducing the opening of the edge air valve, increasing the opening of the edge electric heating, or increasing the edge fire in zone A.

[0033] Among them, edge bending: manifested as more angles or fewer angles, incomplete bending, and increasing the edge fire to increase the temperature of the light edge.

[0034] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Forming annealing process, characterized in that: The processing steps include: S1, stress control: residual stress R = 1.86 × G × A × A. It can be seen from the formula that the residual stress is proportional to the cooling rate of zone B and the square of the glass thickness. When the stress value is too large, the temperature difference from the outlet of zone A to the outlet of zone B2 is reduced, and when the stress value is too small, the temperature difference from the outlet of zone A to the outlet of zone B2 is increased; S2, increase the use of side muskets, use a pair of side muskets at the entrance of area A, 1 pair of side muskets in area R1, 1 pair of side muskets in area R3, and 2 pairs of side muskets in area F; S3, increase the edge fire opening of F and R zones, the edge fire only burns the edges, increase the temperature at the light edge of C zone, add a windshield in F zone, and adjust the windshield to protect the light edge, reduce the air volume on the light edge, increase the air volume on the inner side of the tooth mark, and reduce the electric heating opening of the edge of B zone; S4, lower the outlet temperature of the tin bath, so that the inlet temperature of zone A is lowered, and the temperatures of zones B1, B2 and C are increased accordingly; S5, by lowering the temperature of the portion corresponding to the crack in zone B or raising the temperature of the glass portion corresponding to the crack in zone C; S6, increase the edge temperature of zone B, reduce the opening of the edge air valve, increase the opening of the edge electric heating, or increase the edge fire of zone A.

2. The forming annealing process according to claim 1, characterized in that: The R residual stress in S1 is in kg / ㎡, and the reference range of the residual stress of 15mm glass is: 1.81-2.54, and the target value is 2.

17.

3. The forming annealing process according to claim 1, characterized in that: In S1, G is the cooling rate of the B zone of the annealing furnace, in units of °C / min, and A is the thickness of the glass plate, in units of mm.

4. The forming annealing process according to claim 1, characterized in that: The combustion condition of the blast gun in S2 is a carbonizing flame, and only the edges are burned.

5. The forming annealing process according to claim 1, characterized in that: The observation hole for placing the musket in area A of S2 is not blocked.