CN111251741A - Method for keeping surface height of steel plate constant and preventing hot-spraying coating particles from being pressed in - Google Patents

Abstract

The invention relates to a quality control technology of a thick plate steel plate thermal jet printer, in particular to a technology for eliminating the defect of pressing in of coating particles of the thick plate steel plate thermal jet printer. According to the invention, through the modification of the spray head bracket, the program modification of the jet printing machine and the transmission of jet printing height data, clear jet printing characters with few dispersed particles can be obtained, the press-in defect of the jet printing particles on the surface of the steel plate is effectively reduced, the waste time drop loss is reduced, the dispersion rate of the jet printing particles is controlled to be below 8%, and the compressed air blowing device of the jet printing machine is combined to effectively control the coating dispersed particles of the jet printing machine and eliminate the press-in defect of the coating particles of the hot jet printing machine of the steel plate in the thick plate finishing area.

Description

Method for keeping surface height of steel plate constant and preventing hot-spraying coating particles from being pressed in

Technical Field

The invention relates to a quality control technology of a thick plate steel plate thermal jet printer, in particular to a technology for eliminating the defect of pressing in of coating particles of the thick plate steel plate thermal jet printer.

Background

In the prior art, in order to distinguish the identity of each steel plate in the production of thick plates, and because the rolling termination temperature of the steel plates is 700-1000 ℃, a thermal printer is generally adopted to mark the steel plates, the thermal printer for the steel plates is a large character printer for printing characters with the height ranging from 5 mm to 67 mm, the working principle of the thermal printer is 'point spraying according to the requirement', and the character printer is widely applied to a series of industrial fields. The clear jet printing characters and the beautiful icons are ensured by using the paint type with proper high temperature resistance and viscosity. At present, the jet printing of a single character in a Zhanjiang steel 4200mm thick plate factory is 70 x 140 mm. The jet printing component of the steel plate thermal jet printer consists of a spray gun group arranged on the guide path block. The spray gun group independently controls spray guns with paint nozzles and pneumatic nozzles. The spray guns are independently driven, and the opening and closing of the spray needles are electromagnetically driven. When the spray gun is operated, a small amount of paint is mixed by compressed air and then is sprayed and printed on each point. Air, paint and cleaning agent enter through the guide block. The coating material circulates through the jet printing assembly and the spray gun. In order to keep the nozzle always clean, the nozzle is automatically cleaned after being mixed by compressed air and cleaning agent before and after each jet printing, and the gap can be preset in the production gap period. The mixed residue of compressed air and cleaning agent will be cleaned by the cleaning nozzle and its own nozzle. The cleaning solution and the clean compressed air are mixed and then pass through a solenoid valve installed on the guide block. And after the top spraying cart acts in place, the spray head performs spray printing operation. The main actions of the spray head comprise large arm rotation and small arm pressing; the paint supply system includes a paint pump that circulates through the jet printing assembly. The circulation of the coating material during the jet printing process is only briefly interrupted during the pause of the jet printing — meaning that the coating material pump maintains the dynamic pressure level required for the jet printing during the jet printing process at all times. A pilot shut-off valve is used to stop the flow of paint during the jet printing sequence, and the shut-off valve is fully open during the jet printing sequence.

The prior art method has the problems that the paint particles are scattered, the scattered paint particles have certain viscosity, are easy to adhere to the high-temperature steel plate, and can be pressed by a shear line pinch roll, a shearing machine and the like in the subsequent finishing area work, so that the press-in defects of the paint particles of the steel plate are caused.

In the existing method, the height of a spray head of a spray printing machine is set to be 350mm, namely, the height of the spray head is kept constant with the upper surface of a roller way. With the change of the thickness of the steel plate, particularly when the steel plate is in a limit thickness (the thickness of the steel plate is less than 8mm or more than 40mm), the character spray printing is incomplete, partial spray printing particles are sprayed outside, the particle spreading rate can be improved to 20%, and although the spray printing machine is provided with compressed air for blowing, spray printing particles on the steel plate are still remained. And because the surface of the thin steel plate of 5-8mm is far away from the spray head of the jet printer, the spreading area of the coating is rapidly increased, so that the coating forms particles to be spread outside the characters, and because the thick steel plate has slow temperature drop and high surface temperature, part of the coating loses moisture quickly to form particles, and the height of the thick steel plate is close to the spray head, the spraying pressure of the coating is high, and the particles are spread outside the characters under the action of air pressure.

Disclosure of Invention

The invention aims to obtain clear jet printing characters and few scattered particles, effectively reduce the press-in defects of the jet printing particles on the surface of a steel plate and reduce the waste time and loss.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

s1 spray head bracket modification: the bracket for fixing the spray head is reformed into a bracket with adjustable height, so that the position of the spray printing character is basically controllable. The device is connected with a jet printing machine manufacturer through mails, and the manufacturer is allowed to complete transformation for ensuring the reliability of the project, so that the device has the height adjusting capability on the mechanical structure.

S2 jet printer program modification: the jet printing machine has the capability of calculating the dynamic height, modifies the jet printing machine jet height setting program, combines the steel plate thickness data obtained from the thermal straightening machine, and adds the function of calculating the dynamic jet height.

S3 transfer of jet printing height data: the size of the steel plate is calculated by rolling the thickness of the target steel plate by a rolling mill L2, the information is sent to a hot straightener L2, a hot straightener L2 model machine calculates and sends the set values of roll gap and speed system to L1 according to the thickness requirement, the information of the size and the straightening speed of the steel plate is sent to a jet printing machine L1 by the hot straightener L2 before the hot straightener, and the jet printing machine receives, calculates and executes the height value of the jet head, namely the height value H +300mm of the jet head.

Has the advantages that: clear jet printing characters and few scattering particles can be obtained, the defect of pressing in of the jet printing particles on the surface of the steel plate is effectively reduced, the waste time loss is reduced, the scattering rate of the jet printing particles is controlled to be below 8%, and the coating scattering particles of the jet printing machine are effectively controlled by combining with a compressed air purging device of the jet printing machine, so that the defect of pressing in of the coating particles of the hot jet printing machine of the steel plate in a thick plate finishing area is eliminated.

Detailed Description

The invention is described in further detail below with reference to:

example one

Steel grade: Q345D, billet size: 227 multiplied by 1500 multiplied by 3168mm and the finished product size is 9.98 multiplied by 2443 multiplied by 44251 mm. The unevenness of the whole steel plate is controlled to be 1mm/m after the hot straightening machine straightens the steel plate, the jet printing characters are clear, and the particle scattering rate is 6 percent.

Example two

Steel grade: q420qD-Z15, billet size: 227X 1745X 3716mm, and the finished product size is 55.4X 2387X 11018 mm. The unevenness of the whole steel plate is controlled to be 0.7mm/m after the hot straightening machine straightens, the jet printing characters are clear, and the particle scattering rate is 5 percent.

EXAMPLE III

Steel grade: SS400, billet size: 227 multiplied by 2280 multiplied by 3463mm, and the finished product size is 24.32 multiplied by 2837 multiplied by 25651 mm. The unevenness of the whole steel plate is controlled to be 0.6mm/m after the hot straightening machine straightens, the jet printing characters are clear, and the particle scattering rate is 5 percent.

Claims (1)

1. A method for keeping constant surface height of a steel plate and preventing hot spraying coating particles from being pressed in comprises the following steps:

s1 spray head bracket modification: the bracket for fixing the spray head is reformed into a bracket with adjustable height, so that the position of the spray printing character is basically controllable. The method has the advantages that mail contact is carried out with a jet printing machine manufacturer, the manufacturer is allowed to complete transformation for ensuring the reliability of a project, and the mechanical structure has height adjusting capacity;

s2 jet printer program modification: the jet printing machine is set to have the capability of calculating the dynamic height, the jet printing machine nozzle height setting program is modified, and the dynamic nozzle height calculating function is added by combining the steel plate thickness data obtained from the thermal straightening machine;

s3 transfer of jet printing height data: the size of the steel plate is calculated by rolling the thickness of the target steel plate by a rolling mill L2, the information is sent to a hot straightener L2, a hot straightener L2 model machine calculates and sends the set values of roll gap and speed system to L1 according to the thickness requirement, the information of the size and the straightening speed of the steel plate is sent to a jet printing machine L1 by the hot straightener L2 before the hot straightener, and the jet printing machine receives, calculates and executes the height value of the jet head, namely the height value H +300mm of the jet head.