CN105543750A - Acid washing-free direct hot galvanizing method of hot-rolled strip steel - Google Patents
Acid washing-free direct hot galvanizing method of hot-rolled strip steel Download PDFInfo
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- CN105543750A CN105543750A CN201510903334.4A CN201510903334A CN105543750A CN 105543750 A CN105543750 A CN 105543750A CN 201510903334 A CN201510903334 A CN 201510903334A CN 105543750 A CN105543750 A CN 105543750A
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B15/00—Arrangements for performing additional metal-working operations specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
- B21B45/06—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing of strip material
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Coating With Molten Metal (AREA)
Abstract
The invention relates to an acid washing-free direct hot galvanizing method of hot-rolled strip steel, and belongs to the technical field of metallurgy; mainly aiming at the problems of weak hot galvanizing effect and low oxide scale reduction efficiency in a traditional galvanizing technology, the invention provides a method for improving a hot-rolled strip steel oxide scale reduction ratio; the oxide scale thickness and structure of the hot-rolled strip steel are adjusted in the hot rolling process: the hot-rolled strip steel is straightened in a straightener after being wound; after the surface of the strip is suffered from the bending stress, the strip is repeatedly bent and stretched; the huge difference of iron basal body and oxide scale covering layer material performances is used; the iron basal body is stressed to generate a certain plastic deformation; because of weaker plasticity and low breaking strength, a surface oxide scale layer cannot adapt to the deformation of the iron basal body to cause the internal stress to be higher than the breaking strength so as to finally generate different forms of scale cracks or stripping; the heating reduction is performed in a hydrogen atmosphere to improve the reduction efficiency; and then, the hot galvanizing is performed to obtain a more excellent acid washing-free reduction hot galvanizing effect.
Description
Technical field
The invention belongs to metallurgical technology field, be specifically related to a kind of method that the direct pot galvanize of pickling exempted from by hot rolled strip.
Background technology
Zinc-plated is the modal anti-corrosion method in metallic surface, pot galvanize is one of method of mainly adopting of the surface galvanizing of current steel plate, hot dip galvanizing process obtains large-scale development along with the develop rapidly of cold rolled strip, in recent years because its technology is increasingly mature, obtain coating performance is stable, the advantage such as long service life and economic benefit, be widely used in the various fields such as construction industry, household electrical appliance industry, mechanotronics, automobile making.
The substrate that traditional surface of steel plate pot galvanize adopts is cold-rolled substrate, cold-rolled substrate is by hot rolled strip rolling gained after overcooling, owing to being in hot environment in hot-rolled steel plate forming process, inevitably contact with the oxygen in air and be oxidized, one deck iron scale is produced at surface of steel plate, the existence of iron scale greatly reduces the zinc-plated performance of steel plate, and gained zinc coating stability is reduced; In common process, the iron scale of surface of steel plate is all through pickling removing, pickling can obtain good plate surface quality, but also bring a series of negative impact: acid cleaning process cost compare is high, and inevitably certain pollution is brought to environment after employing acid cleaning process, and waste acidity recovery and reclaiming process flow process complexity, cost significantly increases.
The negative impact brought due to pickling is larger, people begin one's study the mode of clean surface of steel plate iron scale, current processing mode mainly concentrates on 3 aspects: scale structure control techniques in (1) course of hot rolling: magazine " steel rolling ", the article " present condition and developing tendency of hot rolling strip steel scale control techniques " of volume the 4th phase August the 29th in 2012 report, disclose and eliminate red iron sheet by optimizing the processing parameters such as dephosphorization process, hot-rolled temperature, coiling temperature, produce and exempt from the direct pot galvanize coiled sheet of pickling, the advantage of the method to reduce pickling operation, shortcoming is that processing parameter is wayward, because controlling improper, the defects such as the such as iron scale press-in that causes seriously hinder the lifting of product specification and cause great financial loss, also can cause adverse influence for cold rolling, color plating, the subsequent technique such as zinc-plated simultaneously, (2) anacidity machinery dephosphorization technique: if Chinese application number is the patent application of 200610086831.0 " processing method of cold-rolled steel strip acid-free de-scaling and production equipments ", provide a kind of processing method and production equipment of cold-rolled steel strip acid-free dephosphorization, mainly through multiple roll band tooth scale breaker, belt steel surface iron scale is broken, by steel brush machine, the firecoat left over is disposed, then the damp sand via the high pressure water flushing band water content 5% in De-scaling box carrys out wash zone steel, rinses after de-scaling with clear water, the advantage of this method is that the hot-rolled sheet produced both can as the raw material of cold rolling rear operation, also directly can be used for deep-draw or other deformation process, and shortcoming is that equipment is loaded down with trivial details, and operation sequence is complicated, (3) reducing atmosphere CO, H is utilized
2deng the technology of reacting with oxide compound heat reduction, as the patent application that Chinese application number is 201310714802.4 " pickling hot galvanizing method exempted from by a kind of hot rolled strip based on scale reduction ", a kind of hot rolled strip based on scale reduction is provided to exempt from pickling hot galvanizing method, the scale structure of hot rolled strip is adjusted by controlling to heat up, by the hot rolled strip of reduced anneal heat reduction in hydrogen atmosphere, then pot galvanize is carried out, while minimizing environmental pollution, eliminate the corrosion of pickling to production unit, reduce cost, shortcoming is the reduction through the short period of time under low-concentration hydrogen condition, reduction efficiency is low, China's application number is 201510277715.6 " a kind of direct hot galvanizing methods of hot rolled thin strip based on CO reduction ", there is provided a kind of before zinc-plated without the need to carrying out pickling and cold rolling, adopt the iron scale on CO reduction hot rolling thin strip surface, advantage is omitted pickling and cold rolling process, and CO gas is easy to obtain at metallurgy industry, cost is lower, shortcoming be CO the diffusion of surface of steel plate and transmittability weak, speed of reaction is slow, has requirement, the system of being of limited application to the thickness of hot-rolled steel sheet simultaneously.
Summary of the invention
The present invention is directed to the deficiency that prior art exists, provide a kind of method improving hot rolling strip steel scale reduction ratio: align at straightener after hot rolled strip batches, strip surface bears stress in bending, strip surface is through alternating bending and stretching, due to the greatest differences of iron-based body and iron scale covering layer material performance, the viscous deformation that the stressed rear generation of iron-based body is certain, scale on surface layer is then because plasticity is poor and strength at break is low, the distortion of iron-based body can not be adapted to and cause internal stress to be greater than its strength at break, the iron sheet crackle that final generation is multi-form or stripping, the heat reduction in hydrogen atmosphere again of iron scale thickness and the hot rolled strip of structure after adjustment, reduction efficiency improves, and then carries out pot galvanize, obtains the preferably zinc-plated effect of pickling-free reduction heat.
The method that the direct pot galvanize of pickling exempted from by a kind of hot rolled strip provided by the invention is carried out according to the following steps:
(1) slab hot rolling process is obtained hot rolled strip;
(2) hot rolled strip is aligned on stretching straightener;
(3) heat reduction is carried out to the hot rolled strip after aligning;
(4) directly pot galvanize in zinc pot is immersed;
The present invention for achieving the above object, preferred slab contains in mass %: C:0.08 ~ 0.15%, Si:0.01 ~ 0.5%, Mn:1.4 ~ 3.0%, Cr:0.10 ~ 0.80%, P≤0.015%, S≤0.01%, Nb≤0.01%, Ti≤0.01%, Al:0.01 ~ 0.14%, surplus is Fe and inevitable impurity;
As technological selection of the present invention, by heating of plate blank to 1150 ~ 1250 DEG C in above-mentioned steps, finish rolling start rolling temperature controls at 1000 ~ 1010 DEG C, and finishing temperature control is at 855 ~ 865 DEG C; Oiler temperature control is at 550 ~ 580 DEG C;
As technological selection of the present invention, finish to gauge speed >=3.5m/s in above-mentioned steps;
As technological selection of the present invention, steel plate in above-mentioned steps cools through multi-pass after completing finish to gauge, wherein the second passage is 30% ~ 80% to the interstand cooling water ratio of four-pass, and the interstand cooling water ratio of the 5th passage and the 6th passage is 15% ~ 50%;
As technological selection of the present invention, the coils of hot-rolled steel thickness obtained is 1 ~ 4mm, and iron scale thickness is 4 ~ 10um, and iron scale is Fe
3o
4or Fe
3o
4the microscopic metallographic structure structure of+Fe;
As technological selection of the present invention, above-mentioned steps is aligned in stretching straightener hot rolled strip, and aligning unit elongation is 0.8% ~ 7%;
As technological selection of the present invention, above-mentioned steps is aligned in stretching straightener hot rolled strip, and aligning unit elongation is not higher than 5%;
As technological selection of the present invention, in process furnace, hot rolled strip is warming up to 700 ~ 900 DEG C with the speed of 15 ~ 100 DEG C/s and carries out reduced anneal, then hot rolled strip is put into reduction furnace in above-mentioned steps, reducing atmosphere is H
2+ N
2, wherein H
2volumetric concentration is 10 ~ 100%, and it is 60 ~ 300s that the insulation recovery time controls;
As technological selection of the present invention, after above-mentioned steps heat treatment furnace through the hydrogen-cooled temperature that is but chilled to soon of height be in the zinc liquid of 450 ~ 460 DEG C, through being cooled to 410 ~ 430 DEG C after zinc-plated end; The air-cooled cooling after zinc-plated of described band steel, cooling tower top roll temperature 250 ~ 300 DEG C;
As technological selection of the present invention, in the iron scale tissue of hot rolled strip, the iron scale of 20% ~ 40% is reduced to iron, and the iron be reduced covers iron scale surface.
The invention provides a kind of method that the direct pot galvanize of pickling exempted from by hot rolled strip, by iron scale thickness and the structure of course of hot rolling adjustment hot rolled strip, provide a kind of method improving hot rolling strip steel scale reduction ratio, bring following beneficial effect:
1, ferric oxide cortex produce in straightening process tiny crack and can not with matrix stripping, hydrogen is very easy to enter in the crack of zone of oxidation produce and reacts more fully, improves scale reduction efficiency, is conducive to obtaining preferably pot galvanize effect.
2, the iron scale of Surfaces of Hot Rolled Strip removes through hydrogen reducing, and owing to saving pickling process, pickling-free cost, ton steel reduces spent acid discharge 20kg, eliminates the environmental problem that pickling brings simultaneously.
3, the present invention is the technique being widely used in hydrogen reducing Surfaces of Hot Rolled Strip iron scale, and it overcomes the deficiency that existing technique exists, and does not increase extra facility and input, effectively increases scale reduction ratio, improve reduction efficiency; Less investment of the present invention, instant effect, easy to operate.
Accompanying drawing explanation
Fig. 1 tradition hot-rolled steel sheet galvanizing process flow schematic diagram;
The direct hot dip galvanizing process schematic flow sheet of pickling exempted from by Fig. 2 a kind of hot rolled strip provided by the invention;
Iron scale section structure micrograph in Fig. 3 embodiment of the present invention 1 after hot rolled strip tension leveling;
Fig. 4 is the section structure microtexture photo after the hot rolled strip reduction in the embodiment of the present invention 1.
Embodiment
The method that the direct pot galvanize of pickling exempted from by a kind of hot rolled strip provided by the invention is carried out according to the following steps:
(1) slab hot rolling process is obtained hot rolled strip:
(2) hot rolled strip is aligned on stretching straightener;
(3) heat reduction is carried out to the hot rolled strip after aligning;
(4) directly pot galvanize in zinc pot is immersed;
Embodiment 1
The composition content by weight percentage of the hot rolled strip adopted: C:0.08%, Si:0.01%, Mn:1.4%, Cr:0.10%, P:0.015%, S:0.01%, Nb:0.01%, Ti:0.01%, Al:0.01%, surplus is the slab of Fe and inevitable impurity;
By heating of plate blank to 1220 DEG C; Finish rolling start rolling temperature controls at 1000 DEG C, and finish rolling finishing temperature control is at 855 DEG C, and roll speed during finish rolling is 7.6m/s; Carry out multi-pass section cooling after finish rolling terminates, oiler temperature control is at 550 DEG C; Obtaining the firm thickness of hot-rolled strip is 2mm, and iron scale thickness is 8.9um, and scale structure is Fe
3o
4the coil of strip of+Fe;
Align in stretching straightener, unit elongation is 3%;
In process furnace, hot rolled strip is warming up to 900 DEG C of reduced anneals with the speed of 15 DEG C/s, during reduced anneal, the atmosphere of process furnace is be the hydrogen of 20% and the nitrogen of 80% in volumetric concentration; Then hot rolled strip enters in reduction furnace, insulation reduction 120s in atmosphere; In the iron scale tissue of hot rolled strip, the iron scale of 20% is reduced to pure iron, and the iron be reduced covers iron scale surface; After going out heat treatment furnace with steel through the hydrogen-cooled temperature that is but chilled to soon of height be in the zinc liquid of 460 DEG C, through being cooled to 410 DEG C after zinc-plated end; The air-cooled cooling after zinc-plated of described band steel, cooling tower top roll temperature is 250 DEG C;
Steel band through polishing and curling after adopt air cooling or force quenching to room temperature, adopt omnipotent test machine for mechanism to carry out 180 ° of cold bending tests, between coating and hot rolled strip matrix, there is good tack.
Embodiment 2
The composition content by weight percentage of the hot rolled strip adopted: C:0.10%, Si:0.1%Mn:1.6%, Cr:0.3%, P:0.01%, S:0.001%, Nb:0.008%, Ti:0.01%Al:0.05%, surplus is the slab of Fe and inevitable impurity.
By heating of plate blank to 1250 DEG C; Finish rolling start rolling temperature controls at 1000 DEG C, and finish rolling finishing temperature control is at 855 DEG C, and roll speed during finish rolling is 3.5m/s; Carry out multi-pass section cooling after finish rolling terminates, oiler temperature control is at 550 DEG C; Obtaining the firm thickness of hot-rolled strip is 2.5mm, and iron scale thickness is 8.5um, and scale structure is Fe
3o
4the coil of strip of+Fe;
Align in stretching straightener, unit elongation is 3%;
In process furnace, hot rolled strip is warming up to 700 DEG C of reduced anneals with the speed of 20 DEG C/s, during reduced anneal, the atmosphere of process furnace is be the hydrogen of 10% and the nitrogen of 90% in volumetric concentration; Then hot rolled strip enters in reduction furnace, insulation reduction 60s in atmosphere; In the iron scale tissue of hot rolled strip, the iron scale of 30% is reduced to pure iron, and the iron be reduced covers iron scale surface; After going out heat treatment furnace with steel through the hydrogen-cooled temperature that is but chilled to soon of height be in the zinc liquid of 460 DEG C, through being cooled to 410 DEG C after zinc-plated end; The air-cooled cooling after zinc-plated of described band steel, cooling tower top roll temperature is 250 DEG C;
Steel band through polishing and curling after adopt air cooling or force quenching to room temperature, adopt omnipotent test machine for mechanism to carry out 180 ° of cold bending tests, between coating and hot rolled strip matrix, there is good tack.
Embodiment 3
The composition content by weight percentage of the hot rolled strip adopted: C:0.10%, Si:0.3%, Mn:2%, Cr:0.5%, P:0.006%, S:0.001%, Nb:0.005%, Ti:0.01%, Al:0.08%, surplus is the slab of Fe and inevitable impurity;
By heating of plate blank to 1210 DEG C; Finish rolling start rolling temperature controls at 1005 DEG C, and finish rolling finishing temperature control is at 860 DEG C, and roll speed during finish rolling is 4.0m/s; Carry out multi-pass section cooling after finish rolling terminates, oiler temperature control is at 560 DEG C; Obtaining the firm thickness of hot-rolled strip is 2.1mm, and iron scale thickness is 8.5um, and scale structure is Fe
3o
4the coil of strip of+Fe;
Align in stretching straightener, unit elongation is 3%;
In process furnace, hot rolled strip is warming up to 800 DEG C of reduced anneals with the speed of 30 DEG C/s, during reduced anneal, the atmosphere of process furnace is be the hydrogen of 10% and the nitrogen of 90% in volumetric concentration; Then hot rolled strip enters in reduction furnace, insulation reduction 80s in atmosphere; In the iron scale tissue of hot rolled strip, the iron scale of 35% is reduced to pure iron, and the iron be reduced covers iron scale surface; After going out heat treatment furnace with steel through the hydrogen-cooled temperature that is but chilled to soon of height be in the zinc liquid of 460 DEG C, through being cooled to 410 DEG C after zinc-plated end; The air-cooled cooling after zinc-plated of described band steel, cooling tower top roll temperature 250 DEG C;
Steel band through polishing and curling after adopt air cooling or force quenching to room temperature, adopt omnipotent test machine for mechanism to carry out 180 ° of cold bending tests, between coating and hot rolled strip matrix, there is good tack.
Embodiment 4
The composition content by weight percentage of the hot rolled strip adopted: C:0.10%, Si:0.4%, Mn:2.5%, Cr:0.6%, P:0.005%, S:0.001%, Nb:0.003%, Ti:0.01%, Al:0.1%, surplus is the slab of Fe and inevitable impurity;
By heating of plate blank to 1210 DEG C; Finish rolling start rolling temperature controls at 1010 DEG C, and finish rolling finishing temperature control is at 865 DEG C, and roll speed during finish rolling is 6.0m/s; Carry out multi-pass section cooling after finish rolling terminates, oiler temperature control is at 570 DEG C; Obtaining the firm thickness of hot-rolled strip is 2.3mm, and iron scale thickness is 8.0um, and scale structure is Fe
3o
4the coil of strip of+Fe;
Align in stretching straightener, unit elongation is 3%;
In process furnace, hot rolled strip is warming up to 900 DEG C of reduced anneals with the speed of 40 DEG C/s, during reduced anneal, the atmosphere of process furnace is be the hydrogen of 20% and the nitrogen of 80% in volumetric concentration; Then hot rolled strip enters in reduction furnace, insulation reduction 100s in atmosphere; In the iron scale tissue of hot rolled strip, the iron scale of 25% is reduced to pure iron, and the iron be reduced covers iron scale surface; After going out heat treatment furnace with steel through the hydrogen-cooled temperature that is but chilled to soon of height be in the zinc liquid of 460 DEG C, through being cooled to 410 DEG C after zinc-plated end; The air-cooled cooling after zinc-plated of described band steel, cooling tower top roll temperature 250 DEG C;
Steel band through polishing and curling after adopt air cooling or force quenching to room temperature, adopt omnipotent test machine for mechanism to carry out 180 ° of cold bending tests, between coating and hot rolled strip matrix, there is good tack.
Embodiment 5
The composition content by weight percentage of the hot rolled strip adopted: C:0.15%, Si:0.5%, Mn:3%, Cr:0.8%, P:0.005%, S:0.001%, Nb:0.001%, Ti:0.01%, Al:0.14%, surplus is the slab of Fe and inevitable impurity;
By heating of plate blank to 1150 DEG C; Finish rolling start rolling temperature controls at 1010 DEG C, and finish rolling finishing temperature control is at 865 DEG C, and roll speed during finish rolling is 7.0m/s; Carry out multi-pass section cooling after finish rolling terminates, oiler temperature control is at 580 DEG C; Obtaining the firm thickness of hot-rolled strip is 2.2mm, and iron scale thickness is 8.6um, and scale structure is Fe
3o
4the coil of strip of+Fe;
Align in stretching straightener, unit elongation is 3%;
In process furnace, hot rolled strip is warming up to 900 DEG C of reduced anneals with the speed of 50 DEG C/s, during reduced anneal, the atmosphere of process furnace is be the hydrogen of 20% and the nitrogen of 80% in volumetric concentration; Then hot rolled strip enters in reduction furnace, insulation reduction 120s in atmosphere; In the iron scale tissue of hot rolled strip, the iron scale of 30% is reduced to pure iron, and the iron be reduced covers iron scale surface; After going out heat treatment furnace with steel through the hydrogen-cooled temperature that is but chilled to soon of height be in the zinc liquid of 460 DEG C, through being cooled to 410 DEG C after zinc-plated end; The air-cooled cooling after zinc-plated of described band steel, cooling tower top roll temperature 250 DEG C;
Steel band through polishing and curling after adopt air cooling or force quenching to room temperature, adopt omnipotent test machine for mechanism to carry out 180 ° of cold bending tests, between coating and hot rolled strip matrix, there is good tack.
Claims (10)
1. a method for the direct pot galvanize of pickling exempted from by hot rolled strip, it is characterized in that: preparation process is as follows:
(1) slab chemical composition design, be: C:0.08 ~ 0.15%, Si:0.01 ~ 0.5%, Mn:1.4 ~ 3.0%, Cr:0.10 ~ 0.80%, P≤0.015%, S≤0.01%, Nb≤0.01%, Ti≤0.01%, Al:0.01 ~ 0.14% that surplus is Fe and inevitable impurity by percentage to the quality;
(2) described slab hot rolling process obtains hot rolled strip;
(3) described hot rolled strip is aligned;
(4) heat reduction is carried out to the hot rolled strip after aligning;
(5) described band steel is immersed pot galvanize in zinc liquid.
2. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 1, it is characterized in that: by heating of plate blank to 1150 ~ 1250 DEG C in above-mentioned steps (2); Finish rolling, start rolling temperature controls at 1000 ~ 1010 DEG C, and finishing temperature control is at 855 ~ 865 DEG C; Batch after six passage section cooling, oiler temperature control is at 550 ~ 580 DEG C.
3. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 2, it is characterized in that: described finish to gauge speed >=3.5m/s.
4. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 1 or 2, it is characterized in that: in described six passage coolings, the second passage accounts for 30% ~ 80% of total water coolant to the interstand cooling water ratio of four-pass, the interstand cooling water ratio of the 5th passage and the 6th passage accounts for 15% ~ 50% of total water coolant, and surplus is the first passage water coolant.
5. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 1, it is characterized in that: described coils of hot-rolled steel thickness is 1 ~ 4mm, and iron scale thickness is 4 ~ 10um, and iron scale is Fe
3o
4or Fe
3o
4the microscopic metallographic structure structure of+Fe.
6. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 1, it is characterized in that: in above-mentioned steps (3), hot rolled strip is aligned in stretching straightener, and aligning unit elongation is 0.8% ~ 7%.
7. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 6, it is characterized in that: described aligning unit elongation is not less than 5%.
8. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 1, it is characterized in that: the middle hot rolled strip of above-mentioned steps (4) is warming up to 700 ~ 900 DEG C with the speed of 15 ~ 100 DEG C/s and carries out reduced anneal in process furnace, and then put into reduction furnace, reducing atmosphere is H
2+ N
2, wherein H
2volumetric concentration is 30 ~ 100%, and it is 60 ~ 300s that the insulation recovery time controls.
9. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 8, it is characterized in that: after described band steel goes out heat treatment furnace through the hydrogen-cooled temperature that is but chilled to soon of height be in the zinc liquid of 450 ~ 460 DEG C, through being cooled to 410 ~ 430 DEG C after zinc-plated end; The air-cooled cooling after zinc-plated of described band steel, cooling tower top roll temperature 250 ~ 300 DEG C.
10. the method for the direct pot galvanize of pickling exempted from by a kind of hot rolled strip as claimed in claim 9, it is characterized in that: in the iron scale tissue of described hot rolled strip, the iron scale of 20% ~ 40% is reduced to iron, and the iron be reduced covers iron scale surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510903334.4A CN105543750A (en) | 2015-12-08 | 2015-12-08 | Acid washing-free direct hot galvanizing method of hot-rolled strip steel |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510903334.4A CN105543750A (en) | 2015-12-08 | 2015-12-08 | Acid washing-free direct hot galvanizing method of hot-rolled strip steel |
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| CN105543750A true CN105543750A (en) | 2016-05-04 |
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| CN201510903334.4A Pending CN105543750A (en) | 2015-12-08 | 2015-12-08 | Acid washing-free direct hot galvanizing method of hot-rolled strip steel |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105803331A (en) * | 2016-05-31 | 2016-07-27 | 武汉钢铁股份有限公司 | Direct hot galvanizing advanced high-strength steel sheet and manufacturing method thereof |
| CN107858619A (en) * | 2017-11-16 | 2018-03-30 | 宋德兴 | A kind of loose mail hot-dip galvanizing technique |
| CN110195202A (en) * | 2019-05-08 | 2019-09-03 | 沈阳大学 | A method of hot rolled steel plate surface oxidation iron sheet crackle is repaired based on hydrogen reducing |
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| CN104862629A (en) * | 2015-05-27 | 2015-08-26 | 武汉钢铁(集团)公司 | Hot rolling thin strip direct hot galvanizing method based on CO reduction |
| CN105032928A (en) * | 2015-06-15 | 2015-11-11 | 武汉钢铁(集团)公司 | Method and device for rolling metal composite plate strips |
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| CN102676938A (en) * | 2012-05-31 | 2012-09-19 | 武汉钢铁(集团)公司 | Pickling-free steel coil with even iron sheet on surface and manufacture method thereof |
| CN103726003A (en) * | 2013-12-20 | 2014-04-16 | 东北大学 | Hot rolled strip steel pickling-free hot galvanizing method based on scale reduction |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105803331A (en) * | 2016-05-31 | 2016-07-27 | 武汉钢铁股份有限公司 | Direct hot galvanizing advanced high-strength steel sheet and manufacturing method thereof |
| CN107858619A (en) * | 2017-11-16 | 2018-03-30 | 宋德兴 | A kind of loose mail hot-dip galvanizing technique |
| CN110195202A (en) * | 2019-05-08 | 2019-09-03 | 沈阳大学 | A method of hot rolled steel plate surface oxidation iron sheet crackle is repaired based on hydrogen reducing |
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