CN103215534A

CN103215534A - Production process of high strength hot dip galvanized sheet

Info

Publication number: CN103215534A
Application number: CN2013100913994A
Authority: CN
Inventors: 胡洪林; 李钢; 卢鹏程; 马孝娟
Original assignee: Baosteel Group Xinjiang Bayi Iron and Steel Co Ltd
Current assignee: Baosteel Group Xinjiang Bayi Iron and Steel Co Ltd
Priority date: 2013-03-21
Filing date: 2013-03-21
Publication date: 2013-07-24

Abstract

The invention provides a production process of a high strength hot dip galvanized sheet. The process adopts an ordinary low carbon chilled coil as a substrate, and controls the continuous annealing of hot dip galvanizing, thus obtaining the hot dip galvanized steel sheet with tensile strength. Specifically, the strip steel continuous annealing time, namely the unit rate is 40-50mpm, and the continuous annealing steel sheet temperature is 440-460DEG C. And the content of Al in liquid zinc is enhanced to 0.20% by adding high aluminum ingots.

Description

A kind of production technique of high-strength hot-dip zinc-coated plate

Technical field

The present invention relates to the production of heat zinc coating plate, the production of especially suitable high-strength hot-dip zinc-coated plate, this technology can significantly improve the tensile strength of pot galvanize, and it is splendid to make product be used for high strength strap effect.

Background technology

Usually be with steel annealed sheet temperature, in existing pot galvanize product TDC51D continuous annealing process, 680 ± 30 ℃ of the Wen Wenwei of plate; The high-strength hot-dip zinc-coated plate of this technology plate temperature in the continuous annealing process is limited to 450 ± 10 ℃; At 45 ± 5mpm, and the annealing time of high-strength hot-dip zinc-coated strip steel (being unit speed) is 50 ± 5mpm at existing pot galvanize product TDC51D strip speed; At existing pot galvanize product TDC51D, Al content is 0.16% in the zinc liquid, and high-strength hot-dip zinc-coated strip steel by adding the mode of high aluminium ingot, brings up to 0.20% with Al content in the zinc liquid,

It is substrate that the present invention adopts the chill volume of common low carbon, by reducing continuously annealing steel strip annealed sheet temperature, shorten the pot galvanize product of the tensile strength of annealing time acquisition, the production that is used for the high strength strap has one's own knack, for the industry energy conservation consumption reduction produces positive influence, has important promotional value.

Summary of the invention

The objective of the invention is to: adopting the chill volume of common low carbon is substrate, obtains high-tensile pot galvanize product by the control continuous annealing process and is used for the high strength strap.

The object of the present invention is achieved like this: a kind of production technique of high-strength hot-dip zinc-coated plate, and adopting the chill volume of common low carbon is substrate, by the continuous annealing of control pot galvanize, promptly gets the hot-dip galvanizing sheet steel of tensile strength; Wherein be with the steel continuous annealing time, promptly unit speed is 45 ± 5mpm, and the continuous annealing steel billet temperature is 450 ± 10 ℃, and by adding high aluminium ingot, Al content in the zinc liquid is brought up to 0.20%.

Know-why of the present invention: the hot dip galvanizing annealing process of influence band rigidity energy has two key factors: the annealed sheet of band steel in continuous annealing furnace gentle annealing time, i.e. unit speed.Existing pot galvanize product TDC51D substrate adopts the chill volume of common low carbon, the band steel will pass the continuous annealing furnace annealing before substrate enters the zinc pot to carry out pot galvanize, the band steel is when the plate temperature reaches 680 ± 30 ℃ in continuous annealing furnace, but Full Annealing, purpose is to make the substrate that very big internal stress is arranged through cold rolling crystal grain process crimp, and by annealing, the tissue process is replied, recrystallize, remove unrelieved stress, make substrate obtain certain intensity and unit elongation.

This technology makes plate temperature drop to 450 ± 10 of substrate in continuous annealing furnace ℃, temperature is lower than dead annealed temperature, make the substrate can not Full Annealing, can only finish a part of recrystallize and remove the part unrelieved stress, reach substrate intensity height, purpose that unit elongation is low, the intensity that makes heat zinc coating plate reaches the purpose that improves the pot galvanize product strength by being increased to below the 500MPa more than the 600MPa, shows technical progress.

Embodiment

Below in conjunction with embodiment invention is described further.

Embodiment

This technology with heating-hot continuous rolling-laminar flow cool off-batch-Steel Production Flow Chart of cold-rolling pickling-cold rolling mill-zinc-plated-packing is an example; To produce the trade mark is S550GD+Z, and the pot galvanize coil of strip of specification 0.9*1000mm is an example.

The technological operation main points:

1) chemical ingredients of high strength galvanized sheet sees Table 1; The substrate chemical ingredients sees Table 2.

Table 1 high strength galvanized sheet composition

C	Mn	P	S
				<0.10	<0.50	<0.035	<0.035

Table 2 substrate chemical ingredients

Used substrate uses identical material substrate with existing procucts DC51D+Z, and meets Baosteel standard Q/BQB420-2009 " continuous hot galvanizing/zn-fe alloy coating steel plate and steel band " requirement.

2) plate shape: because yield strength, the tensile strength height of fully hard steel, zinc-plated unit does not have levelling machine, has only the straightening machine, the plate shape of straightening machine is improved limited in one's ability, therefore raw material plate shape requires be higher than the plate shape requirement of common zinc-plated raw material, anxious high degree＜2%, defectives such as no flounce; Width: because fully hard steel annealing temperature is low, the necking down amount is 0-1mm, so the raw material width is carried out according to the lower limit of zinc-plated raw material inner quality standard, promptly the raw material width is+2-+5mm.

3) fully hard steel continuous annealing furnace thermal regulation reference sees Table 3.

Table 3

4) 2.5 zinc-plated each section tension force configurations (KN) see Table 4.

Table 4

5) Composition Control is learned in zinc liquefaction, sees Table 5.

Table 5

Principal element	Al	Fe	Sb	Zn
					Content (%)	0.14-0.20	≤0.04	0.01-0.15	All the other

Wherein when aluminium content is on the low side in the pot, add high aluminium ingot, it is maximum that Al content in the zinc liquid is brought up to 0.20%(), stablizing the adding of roller place when adding ingot.

6) straightening machine control: because fully hard steel annealing temperature is low, the tensile strength height, the stressed increase of straightening roller, unit elongation is set at 0.2% or 0.3%.

7) furnace pressure is brought up to 100Pa or 120Pa from 70Pa or 80Pa, guarantee that density of hydrogen remains on 20%.

8) the transition volume that is used to lower the temperature, unit speed is controlled at 45MPM, operates in 59 minutes, and the annealed sheet temperature is reduced to 450 ℃ by 680 ℃; First transition volume has been produced, wind off the beginning from second transition unit speed brought up to 50MPM, with the annealed sheet temperature control at 450 ℃, keep stable unit speed, finish up to preceding 4 coil of strip productions, wind off from the 5th and begin to reduce unit speed, return to normal production.

Principle: produce high-strength steel, lick with the common zinc-plated commodity of the thickness DC51D+Z identical or close and to cross with width, before producing, use S550GD+Z the transition volume annealing furnace temperature, band steel plate temperature to be reduced to by the temperature of producing existing galvanizing production DC51D+Z to produce S550GD+Z temperature required, produce the back and use the transition volume annealing furnace temperature, band steel plate temperature to be risen to by the temperature of producing S550GD+Z to produce existing galvanizing production DC51D+Z temperature required, produce and finish the back transition and roll up and reduce to waste product.

9) production period, the annealing furnace operative employee strengthens the monitoring to caloric power of gas, and is less when caloric power of gas, by increasing the coal gas amount, regulates each section of annealing furnace temperature, guarantees the annealed sheet temperature; When caloric power of gas is big, reduce the coal gas amount, regulate each section of annealing furnace temperature, guarantee the annealed sheet temperature.

10) furnace temperature and speed control detect according to plate property, and Performance Detection is on the low side, can promote under the prerequisite in speed, preferentially gather way, and next reduces furnace temperature; Then preferentially underspeed as mechanical property is higher, next improves furnace temperature, above given parameter ± adjust in 20% scope.

Product performance of the present invention see Table 3.

Table 3 high strength galvanized sheet (S550GD+Z) performance index detect

Known to the data of last table, end properties has surpassed 600MPa.

The unit speed of this process using control stabilization, the successful batch process high strength galvanized sheet (S550GD+Z) of mode that keeps continuous annealing furnace plate temperature, product detect technique effect and the company standard that performance has reached expection finished product tensile strength and yield strength.

Claims

1. the production technique of a high-strength hot-dip zinc-coated plate is characterized in that: adopting the chill volume of common low carbon is substrate, by the continuous annealing of control pot galvanize, promptly gets the hot-dip galvanizing sheet steel of tensile strength; Wherein be with the steel continuous annealing time, promptly unit speed is 45 ± 5 mpm, and the continuous annealing steel billet temperature is 450 ± 10 ℃, and by adding high aluminium ingot, Al content in the zinc liquid is brought up to 0.20%.