CN105908196A - Nitric acid-free acid washing method of hot-rolled 304 austenitic stainless steel - Google Patents
Nitric acid-free acid washing method of hot-rolled 304 austenitic stainless steel Download PDFInfo
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- CN105908196A CN105908196A CN201610387027.XA CN201610387027A CN105908196A CN 105908196 A CN105908196 A CN 105908196A CN 201610387027 A CN201610387027 A CN 201610387027A CN 105908196 A CN105908196 A CN 105908196A
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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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/081—Iron or steel solutions containing H2SO4
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Abstract
The invention relates to a nitric acid-free acid washing method of hot-rolled 304 austenitic stainless steel. The method performs the acid prewashing, the first-period nitric acid-free acid washing and the second-period nitric acid-free acid washing for strip steel in sequence, wherein the two periods of nitric acid-free acid washing both adopt (H2SO4+Fe3++Fe2++H2SiF6+H2O2) mixed acid washing liquid. The method adopts the mixed acid washing liquid of concentrated sulfuric acid, hydrogen peroxide and fluosilicic acid, can satisfy the acid washing requirements of hot-rolled 304 austenitic stainless steel strip steel, realizes the nitric acid-free acid washing of the strip steel, prevents generation of high-pollution nitric oxides and nitrogen-contained waste water in acid washing by using nitric acid-contained mixed acid, and relieves the environmental pollution.
Description
Technical field
The invention belongs to acid-washing stainless steel technical field, be specifically related to a kind of hot rolling 304 austenitic stainless steel without nitric acid acidwashing method.
Background technology
At present, the hot rolling 304 austenic stainless steel belt steel capital be annealed after, strip steel is carried out machinery scale breading (descaling mill+
Dry type shot-blasting machine), carry out nitration mixture (HNO the most again3+ HF) pickling.But, in acid cleaning process, acid consumption is relatively big, simultaneously
Also can produce the nitrogen oxides of a large amount of high pollution and containing nitrate wastewater, bring seriously to natural environment and human being's production, activity
Harm, and purification of nitrogen oxides cost and the highest containing the processing cost of nitrate wastewater.
2012, national environmental protection portion formulated strict nitrogen pollutant discharge standard, wherein steel rolling industrial nitric acid for steel industry
Mist the highest permission concentration of emission is by original 420mg/m3Fall below 150mg/m3, total nitrogen concentration is not the most limited by sewage discharge
System, and new standard limits sewage discharge total nitrogen concentration and need to be less than 15mg/L, and need little at the local total nitrogen concentration that environmental requirement is higher
In 5mg/L, the nitrous oxides exhaust gas and the nitrogenous effluent treatment cost that produce during rustless steel nitration mixture pickling is caused to increase.
Summary of the invention
The embodiment of the present invention provides a kind of hot rolling 304 austenitic stainless steel without nitric acid acidwashing method, at least can solve prior art
Segmental defect.
The present embodiments relate to a kind of hot rolling 304 austenitic stainless steel without nitric acid acidwashing method, comprise the following steps:
Pre-acid pickling step: strip steel immerses pickling in pre-pickle；
First paragraph is without nitric acid acidwashing step: the strip steel after pre-acid pickling step processes immerses first without in nitric acid acidwashing liquid, and described the
One without in nitric acid acidwashing liquid, H2SO4Concentration is 40～90g/L, H2SiF6Concentration is 30～50g/L, Fe3+Concentration is 30～50g/L,
Fe2+Concentration is 0～40g/L, H2O2Concentration is 3～7g/L；
Second segment is without nitric acid acidwashing step: immerse second without nitric acid acidwashing liquid through first paragraph without the strip steel after nitric acid acidwashing step process
In, described second without in nitric acid acidwashing liquid, H2SO4Concentration is 40～90g/L, H2SiF6Concentration is 30～50g/L, Fe3+Concentration
It is 30～50g/L, Fe2+Concentration is 0～40g/L, H2O2Concentration is 3～7g/L.
As one of embodiment, in described pre-acid pickling step, described pre-pickle is sulfuric acid pickling solution；In described sulfuric acid pickling solution,
H2SO4Concentration is 150～170g/L, and concentration of metal ions is 30～40g/L.
As one of embodiment, in described pre-acid pickling step, the temperature of described sulfuric acid pickling solution is 75～85 DEG C
As one of embodiment, in described pre-acid pickling step, pickling time is 20～40s.
As one of embodiment, described first paragraph without nitric acid acidwashing step and second segment without in nitric acid acidwashing step, the temperature of pickle
Degree is 60～70 DEG C.
As one of embodiment, described first paragraph is without nitric acid acidwashing step and second segment without in nitric acid acidwashing step, and pickling time is equal
It is 20～40s.
As one of embodiment, in described pre-acid pickling step, in described sulfuric acid pickling solution, H2SO4Concentration is 155～165g/L,
The temperature of this sulfuric acid pickling solution is 77～83 DEG C, and pickling time is 28～34s.
As one of embodiment, described first paragraph is without in nitric acid acidwashing step, and described first without in nitric acid acidwashing liquid, H2SO4Dense
Degree is 55～75g/L, H2SiF6Concentration is 35～45g/L, Fe3+Concentration is 38～42g/L, Fe2+Concentration is 0～30g/L, H2O2
Concentration is 4～6g/L；Described first is 62～67 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 28～34s.
As one of embodiment, described second segment is without in nitric acid acidwashing step, and described second without in nitric acid acidwashing liquid, H2SO4Dense
Degree is 55～75g/L, H2SiF6Concentration is 35～45g/L, Fe3+Concentration is 38～42g/L, Fe2+Concentration is 0～30g/L, H2O2
Concentration is 4～6g/L；Described second is 62～67 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 28～34s.
As one of embodiment, described first without nitric acid acidwashing liquid and described second without nitric acid acidwashing liquid all adopt with the following method preparation:
Adding concentrated sulphuric acid, hexafluosilicic acid and water in complex acid tank and obtain prefabricated mixed acid liquid with preparation, described prefabricated mixed acid liquid is in pickle supply
It is mixed to get without nitric acid acidwashing liquid with the hydrogen peroxide added by branch line in pipeline.
As one of embodiment, before described pre-acid pickling step, strip steel being carried out pretreatment, preprocess method includes entering strip steel
Row annealing and machinery scale breading process.
The embodiment of the present invention at least achieves following beneficial effect: the present invention uses the mixed acid of concentrated sulphuric acid, hexafluosilicic acid, hydrogen peroxide
Washing liquid, can meet the pickling requirement of hot rolling 304 austenic stainless steel belt steel, it is achieved strip steel without nitric acid acidwashing, it is to avoid use contain
Produce nitrogen oxides and the nitrogenous effluent of high pollution during the nitration mixture pickling of nitric acid, thus alleviate environmental pollution.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or prior art
In description, the required accompanying drawing used is briefly described, it should be apparent that, the accompanying drawing in describing below is only the one of the present invention
A little embodiments, for those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to according to these
Accompanying drawing obtains other accompanying drawing.
Hot rolling 304 austenitic stainless steel that Fig. 1 provides for the embodiment of the present invention is without the schematic flow sheet of nitric acid acidwashing method；
The structural representation of the stainless steel strip acid dip pickle that Fig. 2 provides for the embodiment of the present invention two；
The structural representation of the preheating device that Fig. 3 provides for the embodiment of the present invention three.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely retouched
State, it is clear that described embodiment is only a part of embodiment of the present invention rather than whole embodiments.Based on the present invention
In embodiment, all other embodiments that those of ordinary skill in the art are obtained on the premise of not making creative work,
Broadly fall into the scope of protection of the invention.
Embodiment one
Such as Fig. 1, the present embodiments relate to a kind of hot rolling 304 austenitic stainless steel without nitric acid acidwashing method, comprise the following steps:
(1) S101, pre-acid pickling step: strip steel immerses pickling in pre-pickle.Wherein, pre-pickle is preferably and uses sulphuric acid acid
Washing liquid, certainly, it is possible to use other acid solution, such as nitric acid, or the mixed acid solution etc. of sulphuric acid and nitric acid.As a example by sulfuric acid washing,
In described sulfuric acid pickling solution, H2SO4Concentration is 150～170g/L, and concentration of metal ions is 30～40g/L.Wherein, sulfuric acid washing
The temperature of liquid preferably controls in the range of 75～85 DEG C, can obtain preferable sulfuric acid washing effect.Pickling time is preferably and controls
In the range of 20～40s, strip steel can be controlled overpickling situation does not occur, (belt steel thickness, pickle can be included according to field working conditions
Temperature etc.) it is adjusted flexibly.
(2) S102, first paragraph is without nitric acid acidwashing step: the strip steel after pre-acid pickling step S101 processes immerses first without nitric acid
In pickle, described first without in nitric acid acidwashing liquid, H2SO4Concentration is 40～90g/L, H2SiF6Concentration is 30～50g/L, Fe3+
Concentration is 30～50g/L, Fe2+Concentration is 0～40g/L, H2O2Concentration is 3～7g/L.Wherein, above-mentioned first without nitric acid acidwashing liquid
Temperature preferably control, in the range of 60～70 DEG C, preferable pickling effect to be obtained.Pickling time preferably controls 20～40s
In the range of, it is ensured that strip steel does not occur to owe pickling or overpickling situation.
(3) S103, second segment is without nitric acid acidwashing step: the strip steel after first paragraph processes without nitric acid acidwashing step S102 immerses
Second without in nitric acid acidwashing liquid, and described second without in nitric acid acidwashing liquid, H2SO4Concentration is 40～90g/L, H2SiF6Concentration is
30～50g/L, Fe3+Concentration is 30～50g/L, Fe2+Concentration is 0～40g/L, H2O2Concentration is 3～7g/L.Wherein, above-mentioned second
The temperature of liquid without nitric acid acidwashing preferably controls, in the range of 60～70 DEG C, to obtain preferable pickling effect.Pickling time is preferred
For controlling in the range of 20～40s, it is ensured that strip steel does not occur to owe pickling or overpickling situation.
Further, before described pre-acid pickling step S101, strip steel being carried out pretreatment, preprocess method includes entering strip steel
Row annealing and machinery scale breading process.Before pickling, pretreatment operation can be effectively improved follow-up pickling effect and pickling efficiency, reduces pickling
Time, reduce the consumption of pickle.
It addition, during stainless steel strip pickling, the most all without preheating, the pre-descaling bath of direct passband to sulphuric acid carries out pickling,
When i.e. strip steel has just enter into acid tank, belt steel surface temperature is generally room temperature, and temperature only has 25 DEG C；Temperature during sulfuric acid washing it is generally required to
Being maintained at 75～85 DEG C, pickling effect can be only achieved most preferably, and the time that strip steel is in the pre-descaling bath of sulphuric acid only has tens seconds, time
Between shorter, within a short period of time, belt steel surface temperature was extremely difficult to 75～85 DEG C, and this will make pickling effect undesirable.And carry
When steel just enters pre-descaling bath, belt steel surface is relatively dry not to be moistened, and acid solution can be made to contact with belt steel surface uneven, also can
Cause pickling effect the best.It addition, strip steel is after shot-blasting machine de-scaling, belt steel surface still remains a part of oxide skin chip, when
When it brings pre-descaling bath into, also can consume acid solution.Therefore, in the present embodiment, above-mentioned preprocess method also include annealed and
The strip steel that machinery scale breading processes carries out the pre-heat treatment；Preferably, strip steel is preheated to 50～60 DEG C.
Above-mentioned first paragraph without nitric acid acidwashing step S102 and second segment without the operation principle of nitric acid acidwashing step S103 is:
Hydrogen peroxide (H2O2) by Fe2+It is oxidized to Fe3+, make Fe in solution3+Concentration keeps within the specific limits, H2SO4And Fe3+
Combination is equivalent to acid with strong oxidizing property, with HNO in nitration mixture3Effect suitable, can be permeated by oxide skin underbead crack and hole
To iron scale internal layer and chromium depleted layer surface, make belt steel surface oxide skin quickly peeling-off with metallic matrix by dissolving chromium depleted layer
With come off, H2SO4Also can react with Fe, the Mn in chromium depleted layer and produce a large amount of hydrogen, the release effect of hydrogen also can make
Oxide skin is peeling-off with metallic matrix and comes off.When chromium depleted layer has been dissolved, Fe3+Strong oxidation belt steel surface can be made to generate
One layer of fine and close passivating film, passivating film be mainly composed of Cr2O3, it is possible to prevent metallic matrix to be etched further.H2SiF6
There is activation, SiF6 2-The spot corrosion effect of ion can be accelerated acid solution and penetrate into oxidation by oxide skin underbead crack and hole
Iron sheet internal layer and chromium depleted layer surface, H+Also can react with Fe, Cr, Mn, the Si in chromium depleted layer and produce a large amount of hydrogen, make
Chromium depleted layer is dissolved, and iron scale is produced mechanical stripping effect.In acid cleaning process, SiF6 2-Ion is combined generation with metal ion
Silicofluoride salt dissolubility in the solution is relatively big, i.e. SiF6 2-Ion will not be combined generation precipitate with metal ion, thus with reaction
Carrying out, the SiF in solution6 2-Ion will not reduce, thus can maintain the activity of acid solution, is effectively improved pickling efficiency, and
The acid solution life-span is improved, and decreases acid solution waste discharge amount, reduces production cost；In acid cleaning process, due to not fluorination
Thing precipitation is combined generation stiff mud dirt with oxide skin, and what belt steel surface came off oxide skin is easily flush with water, no as sand
Pickling pipeline can be blocked, decrease maintenance shut-downs number of times.
By above-mentioned pre-acid pickling step S101, the most oxide skin of removable belt steel surface, make the structure of residue oxide skin simultaneously
Become more to loosen and be prone to come off.By above-mentioned first paragraph without nitric acid acidwashing step S102 and second segment without nitric acid acidwashing step
S103, removable belt steel surface residue oxide skin and chromium depleted layer, and make belt steel surface produce one layer of uniform passivating film.
In the present embodiment, owing to chromium in hot rolling 304 austenitic stainless steel, nickel content are of a relatively high so that belt steel surface oxide skin
Dense, the passivating film that during pickling, belt steel surface produces is the most dense, is not easily caused overpickling phenomenon, therefore, pickle
In (mainly first without nitric acid acidwashing liquid and second without nitric acid acidwashing liquid), the concentration of each acid can be more relatively high, to improve pickling
Efficiency, below for preferred embodiment:
As one of preferred embodiment, in above-mentioned pre-acid pickling step S101, in described sulfuric acid pickling solution, H2SO4Concentration is
155～165g/L, the temperature of this sulfuric acid pickling solution is 77～83 DEG C, and pickling time is 28～34s, can obtain preferably sulfuric acid washing
Effect.
As one of preferred embodiment, above-mentioned first paragraph is without in nitric acid acidwashing step S102, and described first without in nitric acid acidwashing liquid,
H2SO4Concentration is 55～75g/L, H2SiF6Concentration is 35～45g/L, Fe3+Concentration is 38～42g/L, Fe2+Concentration is 0～30g/L,
H2O2Concentration is 4～6g/L；Described first is 62～67 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 28～34s.In control
State parameter area and can obtain preferably oxide skin and chromium depleted layer removal effect.
As one of preferred embodiment, above-mentioned second segment is without in nitric acid acidwashing step S103, and described second without in nitric acid acidwashing liquid,
H2SO4Concentration is 55～75g/L, H2SiF6Concentration is 35～45g/L, Fe3+Concentration is 38～42g/L, Fe2+Concentration is 0～30g/L,
H2O2Concentration is 4～6g/L；Described second is 62～67 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 28～34s.In control
Stating parameter area better for the Passivation Treatment of belt steel surface, passivating film is the most uniform.
For above-mentioned first without nitric acid acidwashing liquid and second without the preparation of nitric acid acidwashing liquid, usually, can by concentrated sulphuric acid, industry water,
After hexafluosilicic acid and hydrogen peroxide are made into required pickle in being proportionally added into complex acid tank, then by acid solution supply line supply to descaling bath；
But during complex acid, amount of heat when concentrated sulphuric acid mixes with water, can be produced, the decomposition of hydrogen peroxide can be aggravated, and then cause double
Oxygen water lost efficacy, and therefore, in the present embodiment, used following optimal way: add in complex acid tank concentrated sulphuric acid, hexafluosilicic acid and water with
Preparation obtains prefabricated mixed acid liquid, and described prefabricated mixed acid liquid is mixed with the hydrogen peroxide added by branch line in pickle supply line
Conjunction obtains without nitric acid acidwashing liquid.For the manner of formulation of above-mentioned pickle, it is exemplified below a specific embodiment and illustrates.
Embodiment two
Such as Fig. 2, the embodiment of the present invention provides a kind of acid washing liquid for stainless steel organization of supply, in stainless steel strip pickling section
Nozzle 102 supply acid washing liquid, it includes that acid solution supply line 112, the connection of described acid solution supply line 112 have pickle to prepare
Structure, described pickle preparation structure includes concentrated sulphuric acid dispensing pipe 108, sparge pipe 110, hexafluosilicic acid dispensing pipe 109 and hydrogen peroxide
Dispensing pipeline 114；Above-mentioned concentrated sulphuric acid dispensing pipe 108 is used for supplying concentrated sulphuric acid, and sparge pipe 110 is used for supplying industry water, fluorine silicon
Acid dispensing pipe 109 is used for supplying hexafluosilicic acid, and hydrogen peroxide dispensing pipeline 114 is used for supplying hydrogen peroxide.Described acid solution supply line 112
Arrival end connects complex acid tank 111, described concentrated sulphuric acid dispensing pipe 108, described sparge pipe 110 and described hexafluosilicic acid dispensing pipe 109
All being connected with described complex acid tank 111 arrival end, described hydrogen peroxide dispensing pipeline 114 branch is connected to described acid solution supply line 112
On.During due to hydrogen peroxide by branch line 114 dispensing to acid solution supply line 112, concentrated sulphuric acid and water are in complex acid tank 111
It is sufficiently mixed, amount of heat will not be produced again, thus the thermal decomposition of hydrogen peroxide can be prevented, it is ensured that the pickling effect of pickle.Its
In, hydrogen peroxide dispensing pipeline 114 one end is connected with described acid solution supply line 112, and the other end connects hydrogen peroxide dispensing tank 116
Connect, be provided with hydrogen peroxide dispensing pump 115 in described hydrogen peroxide dispensing pipeline 114；Acid solution supply line 112 is provided with acid solution
Circulating pump 113, described acid cycle pump 113 is positioned at described complex acid tank 111 and described hydrogen peroxide dispensing pipeline 114 branch junction point
Between, certainly, above-mentioned acid cycle pump 113 may be alternatively provided at hydrogen peroxide dispensing pipeline 114 branch's junction point and acid solution supply line
Between 112 ports of export.
Further, above-mentioned acid solution supply line 112 is provided with the heating arrangements 117 for heating pickle, described heater
Structure 117 is between described hydrogen peroxide dispensing pipeline 114 branch's junction point and the described acid solution supply pipe port of export.Hydrogen peroxide with by
The mixed acid of complex acid tank 111 output enters above-mentioned heating arrangements 117 after mixing on acid solution supply line 112 and heats, then delivers to
Each nozzle 102, i.e. improves the temperature of pickle, can improve pickling effect.Preferably, described heating arrangements 117 includes heat exchange
Device 117, this heat exchanger 117 can be water-water heat exchanger or the shell-and-tube heat exchanger etc. using flue gas heat exchange.
The embodiment of the present invention further relates to a kind of stainless steel strip acid dip pickle, including descaling bath 101, sets in described descaling bath 101
Having the spraying and blowing organ 102 for spraying pickle, described spraying and blowing organ 102 connects above-mentioned pickle organization of supply.
Such as Fig. 2, being provided with overflow launder 103 in described descaling bath 101, connecting bottom described overflow launder 103 has acid solution return duct 105,
Connecting bottom described descaling bath 101 has acid solution evacuated tube 107, described acid solution evacuated tube 107 to be provided with exhaust-valve 106；Described acid
Liquid return duct 105 and described acid solution evacuated tube 107 are all connected with described complex acid tank 111.By said structure, form pickle
Circulation-supplied system, reduce pickle consumption.Wherein, typically descaling bath 101 two ends are provided with above-mentioned overflow launder 103,
When descaling bath 101 is longer, it also is provided with overflow launder 103 in the middle, is provided with refluxing opening bottom each overflow launder 103, in order to connect
Above-mentioned acid solution return duct 105；Between adjacent two overflow launders 103, the bottom of descaling bath 101 becomes V-structure, can be easy to spray
Pickle and pickling under the collecting of iron scale etc., above-mentioned acid solution evacuated tube 7 may connect to above-mentioned V-structure bottom or
The bottom of this V-structure a little higher than.When normally producing, the exhaust-valve 106 in above-mentioned acid solution evacuated tube 107 is to close, when
When stopping pickling work, above-mentioned exhaust-valve 106 can be opened, the pickle in descaling bath 101 is emitted in complex acid tank 111 and follows
Ring utilizes.Wherein, if the pickle through the discharge of above-mentioned acid solution evacuated tube 107 is dirtier, the impurity such as more iron scale are i.e. contained
Time, can be by arranging outside outer comb, i.e. the bottom at above-mentioned V-structure is also associated with outer comb, and outer comb is provided with discharging valve；
Or, above-mentioned dirtier pickle can recycling after solid-liquid separation, the most above-mentioned acid solution evacuated tube 107 connect have solid-liquid to divide
From device, the liquid outlet of equipment for separating liquid from solid is connected with complex acid tank 111.It addition, described descaling bath 101 top is provided with acid mist
Delivery pipe 118, above-mentioned acid mist emission pipe 118 can be respectively provided with at descaling bath 101 two ends.
The stainless steel strip acid dip pickle that the present embodiment provides can be used for the first paragraph in above-described embodiment one without nitric acid acidwashing step
S102 and second segment are without carrying out strip steel 1 in nitric acid acidwashing step S103 processing without nitric acid acidwashing.
Embodiment three
Such as Fig. 3, the present embodiment provides strip steel preheating device before a kind of pickling, can be used in above-described embodiment one carrying out strip steel 1
Preheating.This preheating device includes that preheating chamber 301, described preheating chamber 301 both ends open form the strip steel of this preheating chamber 301 through
Run passage, be provided with, in described preheating chamber 301, the preheating mechanism that strip steel 1 is preheated.This preheating chamber 301 is containment housing
Structure, only arranges opening at two, to ensure the strip steel 1 pre-heat effect in this preheating chamber 301；Limit via two openings and formed
Strip steel run passage be preferably horizontal channel, wherein, two groups of backing roll groups 304 can be set in this preheating chamber 301, wherein
One group of backing roll group 304 is arranged near this preheating chamber 301 arrival end, and another group is arranged near this preheating chamber 301 port of export；Often
Group backing roll group 304 includes roller and a lower roll on one, and two rollers are just slightly larger than strip steel 1 thickness, with to strip steel 1 to setting and spacing
Support and guide.
Continue the structure of above-mentioned preheating device, and above-mentioned preheating mechanism can use Electromagnetic Heating, short flame to directly heat, hot-air
The preheating methods such as heat exchange；Such as Fig. 3, for a kind of optimal way of the present embodiment: described preheating mechanism includes that least one set steam sprays
Mouth group, often organizes described steam jet group and includes at least one steam jet 303 for blowing preheated steam, and each described steam sprays
Mouth 303 is all set up in described preheating chamber 301 by injection nozzle carrier.By steam, strip steel 1 is preheated, one side and strip steel
The contact heat-exchanging effect on 1 surface is preferable；On the other hand, strip steel 1 surface can effectively be moistened so that strip steel 1 enters pre-descaling bath
Time pickle contact uniformly with strip steel 1 surface, improve pickling effect further；Another further aspect, the condensed water that steam condensation produces
To a certain degree can walk the oxide skin chip on strip steel 1 surface by wash zone, lower the pickle consumption in follow-up acid cleaning process.
In above-mentioned preheating mechanism, it preferably comprises many group steam jet groups, and each described steam jet group is along strip steel 1 traffic direction
It is sequentially arranged.Wherein, often organize described steam jet group and include steam jet 303 at least one of strip steel 1 width layout
With at least one lower steam jet 303, each described upper steam jet 303 is respectively positioned on described strip steel and runs above passage and winding-up side
To down, each described lower steam jet 303 be respectively positioned on described strip steel run below passage and blowing direction upward.Usually, often
Group steam jet group includes steam jet group under the upper steam jet group of a row and a row, and often row's steam jet group includes along strip steel 1 wide
Multiple steam jets 303 that degree direction is arranged；Preferably, often in group steam jet group, the number of the quantity of upper steam jet 303
Amount, more than the quantity of lower steam jet 303, is on the one hand because steam and strip steel 1 lower surface of the winding-up of lower steam jet 303
The effect that liquidates is preferable, and heat transfer effect is better than upper steam jet 303, and on the other hand, strip steel 1 upper surface has condensation water loading,
This partial coagulation water can take away the heat of part strip steel 1.Above-mentioned each steam jet 303 is all connected with jet chimney 305, steam
Pipeline 305 is connected to steam generating system, can stablize supplying high temperature steam.
As one of embodiment, such as Fig. 3, connect bottom described preheating chamber 301 and have the discharge tube 306 for discharging condensed water,
Described discharge tube 306 is provided with the first control valve 307.Further, it is also associated with for leading to bottom described preheating chamber 301
Entering industry water and rinse the Backwash pipeline 309 of preheating chamber 301, described Backwash pipeline 309 is provided with the second control valve 308.Its
In, above-mentioned Backwash pipeline 309 can be independently arranged, and i.e. arranges with above-mentioned discharge tube 306 interval, it is possible to branch is connected to this
On discharge tube 306, between branch's junction point is bottom the first control valve 307 and preheating chamber 301.
Optimize said structure, V-shaped structure bottom described preheating chamber 301 further, include two sections of slopes, two sections described tiltedly
Slope extends to the two ends of described preheating chamber 301 respectively from the bottom of this V-structure.Above-mentioned discharge tube 306 is preferably connected to
Bottom bottom the preheating chamber 301 of described V-structure, it both as the discharge tube 306 of condensed water, also served as oxide skin broken
The discharge tube 306 of bits；Certainly, it is possible to the position that this discharge tube 306 connects is set to bottom a little higher than preheating chamber 301
Bottom, to improve the cleanliness factor of condensed water of discharge, now, need to additionally connect one and be used in the bottom bottom preheating chamber 301
Discharge the chip discharge pipe of oxide skin chip.By arranging slope, it is simple to collecting of condensed water and oxide skin chip.Produce one section
After time, a certain amount of condensed water and oxide skin chip can be accumulated bottom preheating chamber 301, for preventing oxide skin chip long-time
Be deposited on and cause being difficult to clear up bottom preheating chamber 301, can be by above-mentioned discharge tube 306 and Backwash pipeline 309 at
Reason, particularly as follows: the first control valve 307 first opened on discharge tube 306, condensed water elimination is clean, now there may be
The oxide skin chip of part residual is stayed bottom preheating chamber 301；Close above-mentioned first control valve 307, open Backwash pipeline 309
On the second control valve 308, be passed through industry water and rinse bottom preheating chamber 301 a period of time, be then shut off above-mentioned second control valve
308, open the first control valve 307, the industry water being passed through is emptied, turn off above-mentioned first control valve 307；Can basis
Backwash effect determines whether to carry out repeatedly backwash operation.
The condensed water of above-mentioned discharge is recyclable, after solid-liquid separation, delivers to steam generating system and recycles.It addition, it is described pre-
Top, hot cell 301 connects fog discharge pipeline 302, and the fog discharged through fog discharge pipeline 302 also can return to steam generating system recovery
Utilize.
Embodiment four
The present embodiment provides a kind of hot rolling 304 austenitic stainless steel without nitric acid acidwashing method, and the thickness of pending strip steel is 2mm；
The method comprises the following steps:
1) pickling during strip steel immerses sulfuric acid pickling solution, in this sulfuric acid pickling solution, H2SO4Concentration is 155g/L；This sulfuric acid pickling solution
Temperature be 77 DEG C；The pickling processes time is 34s.
2) strip steel is after the pre-pickling of persulfuric acid, immerses first without carrying out pickling in nitric acid acidwashing liquid.This is first without in nitric acid acidwashing liquid,
H2SO4Concentration is 55g/L, H2SiF6Concentration is 35g/L, Fe3+Concentration is 38g/L, Fe2+Concentration is 0, H2O2Concentration is 4g/L；
This first is 62 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 34s.
3) strip steel is after first without nitric acid acidwashing liquid pickling, immerses second and carries out pickling without nitric acid acidwashing liquid.This is second without nitric acid
In pickle, H2SO4Concentration is 55g/L, H2SiF6Concentration is 35g/L, Fe3+Concentration is 38g/L, Fe2+Concentration is 0, H2O2
Concentration is 4g/L；This second is 62 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 34s.
Hot rolling 304 austenic stainless steel belt steel is after above-mentioned sulfuric acid washing+two-stage nitration is without nitric acid acidwashing, and belt steel surface does not remain
Oxide skin, and belt steel surface fineness is higher, meets No.1 class requirement.
Embodiment five
The present embodiment provides a kind of hot rolling 304 austenitic stainless steel acid washing method, and the thickness of pending strip steel is 2mm；The method
Comprise the following steps:
1) pickling during strip steel immerses sulfuric acid pickling solution, in this sulfuric acid pickling solution, H2SO4Concentration is 165g/L；This sulfuric acid pickling solution
Temperature be 83 DEG C；The pickling processes time is 28s.
2) strip steel immerses first without carrying out pickling in nitric acid acidwashing liquid after sulfuric acid washing.This is first without in nitric acid acidwashing liquid,
H2SO4Concentration is 75g/L, H2SiF6Concentration is 45g/L, Fe3+Concentration is 42g/L, Fe2+Concentration is 30g/L, H2O2Concentration
For 6g/L；This first is 67 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 28s.
3) strip steel is after first without nitric acid acidwashing liquid pickling, immerses second and carries out pickling without nitric acid acidwashing liquid.This is second without nitric acid
In pickle, H2SO4Concentration is 75g/L, H2SiF6Concentration is 45g/L, Fe3+Concentration is 42g/L, Fe2+Concentration is 30g/L,
H2O2Concentration is 6g/L；This second is 67 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 28s.
Hot rolling 304 austenic stainless steel belt steel is through above-mentioned sulfuric acid washing+two-stage nitration without nitric acid acidwashing, and belt steel surface does not remain oxidation
Skin, and belt steel surface fineness is higher, meets No.1 class requirement.
Embodiment six
The present embodiment provides a kind of hot rolling 304 austenic stainless steel belt steel acid washing method, and the thickness of pending strip steel is 2mm；Should
Method comprises the following steps:
1) pickling during strip steel immerses sulfuric acid pickling solution, in this sulfuric acid pickling solution, H2SO4Concentration is 160g/L；This sulfuric acid pickling solution
Temperature be 80 DEG C；The pickling processes time is 30s.
2) strip steel immerses first without carrying out pickling in nitric acid acidwashing liquid after sulfuric acid washing.This is first without in nitric acid acidwashing liquid,
H2SO4Concentration is 65g/L, H2SiF6Concentration is 40g/L, Fe3+Concentration is 40g/L, Fe2+Concentration is 20g/L, H2O2Concentration
For 5g/L；This first is 65 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 30s.
3) strip steel is after first paragraph is without nitric acid acidwashing, immerses second and carries out pickling without nitric acid acidwashing liquid.This is second without nitric acid acidwashing
In liquid, H2SO4Concentration is 65g/L, H2SiF6Concentration is 40g/L, Fe3+Concentration is 40g/L, Fe2+Concentration is 20g/L, H2O2
Concentration is 5g/L；This second is 65 DEG C without the temperature of nitric acid acidwashing liquid, and pickling time is 30s.
Hot rolling 304 austenic stainless steel belt steel is after above-mentioned sulfuric acid washing+two-stage nitration is without nitric acid acidwashing, and belt steel surface does not remain
Oxide skin, and belt steel surface fineness is higher, meets No.1 class requirement.
In above-described embodiment four～embodiment six, can adjust pickling time according to belt steel thickness difference, belt steel thickness increases, and increases accordingly
Adding the pickling time of each section of pickling section, belt steel thickness reduces, the corresponding pickling time reducing each section of pickling section.
The foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all spirit in the present invention and former
Within then, any modification, equivalent substitution and improvement etc. made, should be included within the scope of the present invention.
Claims (10)
1. hot rolling 304 austenitic stainless steel is without nitric acid acidwashing method, it is characterised in that comprise the following steps:
Pre-acid pickling step: strip steel immerses pickling in pre-pickle；
First paragraph is without nitric acid acidwashing step: the strip steel after pre-acid pickling step processes immerses first without in nitric acid acidwashing liquid, and described the
One without in nitric acid acidwashing liquid, H2SO4Concentration is 40～90g/L, H2SiF6Concentration is 30～50g/L, Fe3+Concentration is 30～50g/L,
Fe2+Concentration is 0～40g/L, H2O2Concentration is 3～7g/L；
Second segment is without nitric acid acidwashing step: immerse second without nitric acid acidwashing liquid through first paragraph without the strip steel after nitric acid acidwashing step process
In, described second without in nitric acid acidwashing liquid, H2SO4Concentration is 40～90g/L, H2SiF6Concentration is 30～50g/L, Fe3+Concentration
It is 30～50g/L, Fe2+Concentration is 0～40g/L, H2O2Concentration is 3～7g/L.
Hot rolling 304 austenitic stainless steel the most according to claim 1 is without nitric acid acidwashing method, it is characterised in that: described pre-pickling
In step, described pre-pickle is sulfuric acid pickling solution；In described sulfuric acid pickling solution, H2SO4Concentration is 150～170g/L, metal
Ion concentration is 30～40g/L.
Hot rolling 304 austenitic stainless steel the most according to claim 2 is without nitric acid acidwashing method, it is characterised in that: the acid of described sulphuric acid
The temperature of washing liquid is 75～85 DEG C, and pre-pickling time is 20～40s.
Hot rolling 304 austenitic stainless steel the most according to claim 1 is without nitric acid acidwashing method, it is characterised in that: described first paragraph
Step without nitric acid acidwashing and second segment are without in nitric acid acidwashing step, and the temperature of pickle is 60～70 DEG C.
Hot rolling 304 austenitic stainless steel the most according to claim 1 is without nitric acid acidwashing method, it is characterised in that: described first paragraph
Step without nitric acid acidwashing and second segment are without in nitric acid acidwashing step, and pickling time is 20～40s.
6. according to the hot rolling 304 austenitic stainless steel acid washing method described in Claims 2 or 3, it is characterised in that: described pre-pickling walks
In Zhou, in described sulfuric acid pickling solution, H2SO4Concentration is 155～165g/L, and the temperature of this sulfuric acid pickling solution is 77～83 DEG C, acid
The time of washing is 28～34s.
Hot rolling 304 austenitic stainless steel acid washing method the most according to any one of claim 1 to 5, it is characterised in that: described
First paragraph is without in nitric acid acidwashing step, and described first without in nitric acid acidwashing liquid, H2SO4Concentration is 55～75g/L, H2SiF6Concentration
It is 35～45g/L, Fe3+Concentration is 38～42g/L, Fe2+Concentration is 0～30g/L, H2O2Concentration is 4～6g/L；Described first nothing
The temperature of nitric acid acidwashing liquid is 62～67 DEG C, and pickling time is 28～34s.
Hot rolling 304 austenitic stainless steel acid washing method the most according to any one of claim 1 to 5, it is characterised in that: described
Second segment is without in nitric acid acidwashing step, and described second without in nitric acid acidwashing liquid, H2SO4Concentration is 55～75g/L, H2SiF6Concentration
It is 35～45g/L, Fe3+Concentration is 38～42g/L, Fe2+Concentration is 0～30g/L, H2O2Concentration is 4～6g/L；Described second nothing
The temperature of nitric acid acidwashing liquid is 62～67 DEG C, and pickling time is 28～34s.
Hot rolling 304 austenitic stainless steel the most according to claim 1 is without nitric acid acidwashing method, it is characterised in that described first nothing
Nitric acid acidwashing liquid and described second all adopts preparation with the following method without nitric acid acidwashing liquid: add concentrated sulphuric acid, hexafluosilicic acid in complex acid tank
Obtaining prefabricated mixed acid liquid with water with preparation, described prefabricated mixed acid liquid is double with added by branch line in pickle supply line
Oxygen water is mixed to get without nitric acid acidwashing liquid.
Hot rolling 304 austenitic stainless steel the most according to claim 1 is without nitric acid acidwashing method, it is characterised in that: described pre-acid
Before washing step, strip steel being carried out pretreatment, preprocess method includes that strip steel carries out annealing and machinery scale breading processes.
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| CN107574448A (en) * | 2017-08-10 | 2018-01-12 | 武汉众登科技有限公司 | A kind of series austenitic stainless steel acid washing method of environment-friendly hot rolling 300 |
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| CN110528009A (en) * | 2019-09-23 | 2019-12-03 | 中冶南方工程技术有限公司 | A kind of 304 austenitic stainless steel of cold rolling is without nitric acid acidwashing technique |
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