CN104611713A - Mixed-acid acid washing liquid and acid washing method for 400-series stainless steel hot-rolled annealing wire - Google Patents
Mixed-acid acid washing liquid and acid washing method for 400-series stainless steel hot-rolled annealing wire Download PDFInfo
- Publication number
- CN104611713A CN104611713A CN201510025143.2A CN201510025143A CN104611713A CN 104611713 A CN104611713 A CN 104611713A CN 201510025143 A CN201510025143 A CN 201510025143A CN 104611713 A CN104611713 A CN 104611713A
- Authority
- CN
- China
- Prior art keywords
- acid
- stainless steel
- acid washing
- pickling
- wire rod
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
The invention relates to a mixed-acid acid washing liquid and an acid washing method for a 400-series stainless steel hot-rolled annealing wire. The acid washing liquid comprises hydrochloric acid, hydrofluoric acid, a corrosion inhibitor, an acid mist inhibitor and water. The acid washing liquid comprises the substances at a mass ratio as follows: 8wt%-22wt% of hydrochloric acid, 0.1wt%-2wt% of hydrofluoric acid, 0.01wt%-1wt% of the corrosion inhibitor, 0.1wt%-0.5wt% of an acid mist inhibitor and the balance of water. The acid washing method comprises steps as follows: the acid washing liquid is injected to an acid washing tank, the whole coil of the hot-rolled wire after annealing is directly placed in the acid washing tank for acid washing, the acid washing temperature is in a range from 45 DEG C to 85 DEG C, and the acid washing time is 10-40 min. The treated wire rod surface is clean, white and bright, oxide scale residues are avoided, and a wire rod can be normally used and stored without follow-up passivation.
Description
Technical field
The invention belongs to stainless steel surface processing technology field, particularly relating to 400 is stainless steel hot-rolling annealing wire rod nitration mixture pickle solution and acid washing method.
Background technology
400 is wire rod, the C content 0.001-0.4% that refers to, Cr content is at 12-18.5%, containing manganese about 0.5%, silicon content 0.5-2%, the wire rod of other element sums less than 1%, be equivalent to the steel grades such as 0Cr13,0Cr17,1Cr13, the 1Cr17 in GB, such steel grade does not contain or containing micro-nickel, scale on surface is very fine and close after annealing, and conventional acid washing method effectively can not remove iron scale.Use when the acid washing method nitric acid of 304 steel grades such as grade and hydrofluoric acid pickling and be very easy to overpickling, leave spot corrosion hole on surface.So the wire rod pickling after Cr13 and Cr17 type stainless steel annealing after annealing always is the technological difficulties of the industry.Particularly when client needs high temperature annealing (860 DEG C more than-900 DEG C), with the raising of annealing temperature, Cr and Si etc. are oxidized out more, add the difficulty of pickling.
Also have some in current industry about the research of this respect, wherein most not talkative be the acid washing method of annealing material, but the acid washing method of hot rolling material, and the complexity of the wire rod after high temperature annealing and normarzing annealing wire rod is short in understanding.Number of patent application 200710061665.3 is also a kind of technique of nitration mixture pickling, but the ratio of its hydrofluoric acid is up to more than 10%, the hydrofluoric acid of such concentration aborning use can have a strong impact on the health of workman, the inhibiter of the formula in its literary composition only uses one, actually shows that a kind of effect of inhibition does not have the composite effect of multiple inhibiter good.Number of patent application 20101032939.2 mentions a kind of wiredrawing wire rod pickling additive, but does not specify kind and the addition of the steel grade of pickling and the acid of pickling, and this additive does not have solution stabilizer and promotor.The patent No. 20081055045.3 mentions a kind of oxide skin minimizing technology of hot-rolled stainless steel, and pickle solution is pickling medium with sulfuric acid, and adds the inhibiter such as hydrochloride, thiocarbamide composition, and the pickling of inapplicable annealing material, and use sulfuric acid washing.
Summary of the invention
For solving the problems of the technologies described above, for annealed material, especially the problem of pickling is not easy during high temperature annealing, the present invention proposes 400 is stainless steel hot-rolling annealing wire rod nitration mixture pickle solution and acid washing method, the method pickling effect is good, pickling rear surface is pure white, attractive in appearance, does not have the phenomenon of overpickling and deficient pickling.
It is stainless steel hot-rolling annealing wire rod nitration mixture pickle solution that an object of the present invention is to provide a kind of 400, and described pickle solution is made up of hydrochloric acid, hydrofluoric acid, inhibiter, acid fog inhibitor and water; Described each material mass ratio is as follows: hydrochloric acid 8-22wt%, hydrofluoric acid 0.1-2wt%, inhibiter-0.01-1wt%, and acid fog inhibitor addition is 0.1-0.5wt%, and surplus is water.
Inhibiter of the present invention be urotropine, Sodium Benzoate, quaternary ammonium salt, citric acid, thiocarbamide, Sodium Nitrite any one or a few.
Acid fog inhibitor of the present invention is any one or a few in sulfonate, benzene sulfonate, OP-10, fatty alcohol-polyoxyethylene ether.
Sulfonate of the present invention is sodium laurylsulfonate.
It is stainless steel hot-rolling annealing wire rod nitration mixture acid washing method that another object of the present invention is to provide a kind of 400, pickle solution is comprised the steps: to inject pickling tank, the whole dish of hot rolling wire after annealing is directly put into pickling tank and carries out pickling, pickling temperature 45-85 DEG C, pickling time 10-40min.
Pickle solution of the present invention is made up of hydrochloric acid, hydrofluoric acid, inhibiter, acid fog inhibitor and water; Described each material mass ratio is as follows: hydrochloric acid 8-22wt%, hydrofluoric acid 0.1-2wt%, inhibiter-0.01-1wt%, and acid fog inhibitor addition is 0.1-0.5wt%, and surplus is water.
Inhibiter of the present invention be urotropine, Sodium Benzoate, quaternary ammonium salt, citric acid, thiocarbamide, Sodium Nitrite any one or a few.
Acid fog inhibitor of the present invention is any one or a few in sulfonate, benzene sulfonate, OP-10, fatty alcohol-polyoxyethylene ether.
Sulfonate of the present invention is sodium laurylsulfonate.
Of the present invention 400 is wire rod, refers to C content 0.001-0.4%, Cr content 12-18.5%, and containing manganese about 0.5%, silicon content 0.5-2%, the wire rod of other element sums less than 1%, is equivalent to the steel grades such as 0Cr13,0Cr17,1Cr13, the 1Cr17 in GB.
Mentality of designing of the present invention is as follows: the iron scale of stainless steel hot-rolling wire surface, after softening annealing, and can containing a small amount of Cr
2o
3, SiO
2, XRD detects Fe
2o
3content can reach 50-80wt%, very large with the composition difference on the iron scale surface of plain carbon stool, in the iron scale of plain carbon stool, the content of FeO is very high.The iron scale formed after stainless steel annealing is very fine and close, pickle solution not easily through iron scale with steel substrate generation replacement(metathesis)reaction, so iron scale come off and occur little.Stainless iron scale can only lean on limited solvency action to remove, Fe
2o
3at the meltage in hydrochloric acid apparently higher than the meltage in sulfuric acid, so during pickling of stainless steel, preferably use hydrochloric acid.
But when high temperature pickling, iron scale is finer and close, and Si element is oxidized out more, easily form the fine and close SiO of contact in the bottom of iron scale
2tectum.SiO
2be insoluble to common bronsted lowry acids and bases bronsted lowry, be only dissolved in hydrofluoric acid.Oxide skin particularly compact in addition after high temperature annealing, pickle solution not easily through, add the difficulty of pickling.And F
-radius is little, easily enters less gap, so hydrofluoric acid can also use as permeate agent when pickling, effect is very good.But the addition of hydrofluoric acid is not easily too much, too much cause atmospheric pollution and harm workers ' health, preferably below 2%.
The beneficial effect adopting technique scheme to produce is: the wire rod surface light after aforesaid method pickling is pure white bright, does not have iron scale to remain, does not need to carry out follow-up passivation and just can normally use and deposit.
Accompanying drawing explanation
Fig. 1 is 0Cr13 of the present invention annealing rear surface iron scale XRD detected result collection of illustrative plates.
Embodiment
Below in conjunction with specific embodiment, the present invention is further detailed explanation.
Embodiment 1:
The annealing and pickling technique of 0Cr13
The main component of 0Cr13: C content <0.05%, Cr content 13%, Si content 0.5%.The specification 5.5mm-42mm of wire rod, annealing temperature 700-800 DEG C.
Pickle solution is made up of hydrochloric acid, hydrofluoric acid, inhibiter, acid fog inhibitor and water; Each material mass ratio is as follows: hydrochloric acid 22wt%, hydrofluoric acid 0.1wt%, inhibiter-1wt%, and acid fog inhibitor addition is 0.5wt%, and surplus is water; Inhibiter be urotropine, quaternary ammonium salt, Sodium Nitrite etc. mass mixing thing; Acid fog inhibitor is sodium laurylsulfonate.
Acid cleaning process: pickle solution is injected pickling tank, directly puts into pickling tank by the whole dish of hot rolling wire after annealing and carries out pickling, pickling temperature 85 DEG C, pickling time 30min, carry out rinsing and neutralizing, can deposit after oven dry after pickling.
The 0Cr13 surface non-oxidation iron sheet of pickling remains in this way, and outward appearance is silvery white in color.Pickling loss (before the mass loss/pickling before and after pickling weight) is 0.8%, without overpickling.
Embodiment 2:
The annealing and pickling technique of 1Cr13
The main component of 1Cr13, C content <0.15%, Cr content 13%, Si content 0.5%.The specification 5.5mm-42mm of wire rod, high temperature anneal temperature 860-920 DEG C.
Pickle solution is made up of hydrochloric acid, hydrofluoric acid, inhibiter, acid fog inhibitor and water; Described each material mass ratio is as follows: hydrochloric acid 8wt%, hydrofluoric acid 2wt%, inhibiter-0.1wt%, and acid fog inhibitor addition is 0.1wt%, and surplus is water; Inhibiter be urotropine, thiocarbamide and Sodium Benzoate etc. mass mixing thing; Acid fog inhibitor be sodium laurylsulfonate, benzene sulfonate, fatty alcohol-polyoxyethylene ether etc. mass mixing thing.
Acid cleaning process: pickle solution is injected pickling tank, directly puts into pickling tank by the whole dish of hot rolling wire after annealing and carries out pickling, pickling temperature 70 DEG C, pickling time 40min, carry out rinsing and neutralizing, can deposit after oven dry after pickling.
The 1Cr13 surface non-oxidation iron sheet of pickling remains in this way, without residual acid (having residual acid to form macula lutea), without dust (dust place outward appearance is gloomy).Appearance off-white, pickling loss (before the mass loss/pickling before and after pickling weight) is 0.6%, without overpickling.
Embodiment 3:
The annealing and pickling technique of 0Cr17
The main component of 0Cr17, C content <0.05%, Cr content 17%, Si content 0.5%.The specification 5.5mm-42mm of wire rod, annealing temperature 780-820 DEG C.
Pickle solution is made up of hydrochloric acid, hydrofluoric acid, inhibiter, acid fog inhibitor and water; Described each material mass ratio is as follows: hydrochloric acid 17wt%, hydrofluoric acid 1.2wt%, inhibiter-0.05wt%, and acid fog inhibitor addition is 0.25wt%, and surplus is water; Inhibiter be thiocarbamide, Sodium Benzoate and citric acid etc. mass mixing thing; Acid fog inhibitor be sodium laurylsulfonate, fatty alcohol-polyoxyethylene ether etc. mass mixing thing.
Acid cleaning process: pickle solution is injected pickling tank, directly puts into pickling tank by the whole dish of hot rolling wire after annealing and carries out pickling, pickling temperature 65 DEG C, pickling time 30min, carry out rinsing and neutralizing, can deposit after oven dry after pickling.
The 0Cr17 surface non-oxidation iron sheet of pickling remains, without residual acid in this way.Outward appearance silvery white, pickling loss (before the mass loss/pickling before and after pickling weight) is 0.9%, without overpickling.
Embodiment 4:
The annealing and pickling technique of 1Cr13
The main component of 1Cr13, C content <0.15%, Cr content 13%, Si content 0.5%.The specification 5.5mm-42mm of wire rod, high temperature anneal temperature 860-920 DEG C.
Pickle solution is made up of hydrochloric acid, hydrofluoric acid, inhibiter, acid fog inhibitor and water; Described each material mass ratio is as follows: hydrochloric acid 20wt%, hydrofluoric acid 1.6wt%, inhibiter-0.01wt%, and acid fog inhibitor addition is 0.4wt%, and surplus is water; Inhibiter be urotropine and Sodium Benzoate etc. mass mixing thing; Acid fog inhibitor be benzene sulfonate, fatty alcohol-polyoxyethylene ether etc. mass mixing thing.
Acid cleaning process: pickle solution is injected pickling tank, directly puts into pickling tank by the whole dish of hot rolling wire after annealing and carries out pickling, pickling temperature 45 DEG C, pickling time 10min, carry out rinsing and neutralizing, can deposit after oven dry after pickling.
The 1Cr13 surface non-oxidation iron sheet of pickling remains in this way, without residual acid (having residual acid to form macula lutea), without dust (dust place outward appearance is gloomy).Appearance off-white, pickling loss (before the mass loss/pickling before and after pickling weight) is 0.7%, without overpickling.
Above by embodiment to invention has been detailed description; but described content is only preferred embodiment of the present invention; utilize technical solutions according to the invention; or those skilled in the art is under the inspiration of technical solution of the present invention; design similar technical scheme; and reach above-mentioned technique effect, be all fall into protection scope of the present invention.
Claims (9)
1. 400 is a stainless steel hot-rolling annealing wire rod nitration mixture pickle solution, and it is characterized in that, described pickle solution is made up of hydrochloric acid, hydrofluoric acid, inhibiter, acid fog inhibitor and water; Described each material mass ratio is as follows: hydrochloric acid 8-22wt%, hydrofluoric acid 0.1-2wt%, inhibiter-0.01-1wt%, and acid fog inhibitor addition is 0.1-0.5wt%, and surplus is water.
2. according to claim 1 400 is stainless steel hot-rolling annealing wire rod nitration mixture pickle solution, it is characterized in that, described inhibiter is any one or a few in urotropine, Sodium Benzoate, quaternary ammonium salt, citric acid, thiocarbamide, Sodium Nitrite.
3. according to claim 1 400 is stainless steel hot-rolling annealing wire rod nitration mixture pickle solution, it is characterized in that, described acid fog inhibitor is any one or a few in sulfonate, benzene sulfonate, OP-10, fatty alcohol-polyoxyethylene ether.
4. according to claim 3 400 is stainless steel hot-rolling annealing wire rod nitration mixture pickle solution, and it is characterized in that, described sulfonate is sodium laurylsulfonate.
5. one kind 400 is stainless steel hot-rolling annealing wire rod nitration mixture acid washing method, it is characterized in that, comprise the steps: pickle solution to inject pickling tank, the whole dish of hot rolling wire after annealing is directly put into pickling tank and carries out pickling, pickling temperature 45-85 DEG C, pickling time 10-40min.
6. according to claim 5 400 is stainless steel hot-rolling annealing wire rod nitration mixture acid washing method, and it is characterized in that, described pickle solution is made up of hydrochloric acid, hydrofluoric acid, inhibiter, acid fog inhibitor and water; Described each material mass ratio is as follows: hydrochloric acid 8-22wt%, hydrofluoric acid 0.1-2wt%, inhibiter-0.01-1wt%, and acid fog inhibitor addition is 0.1-0.5wt%, and surplus is water.
7. according to claim 6 400 is stainless steel hot-rolling annealing wire rod nitration mixture acid washing method, it is characterized in that, described inhibiter be urotropine, Sodium Benzoate, quaternary ammonium salt, citric acid, thiocarbamide, Sodium Nitrite any one or a few.
8. according to claim 6 400 is stainless steel hot-rolling annealing wire rod nitration mixture acid washing method, it is characterized in that, described acid fog inhibitor is any one or a few in sulfonate, benzene sulfonate, OP-10, fatty alcohol-polyoxyethylene ether.
9. according to claim 6 400 is stainless steel hot-rolling annealing wire rod nitration mixture acid washing method, and it is characterized in that, described sulfonate is sodium laurylsulfonate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510025143.2A CN104611713B (en) | 2015-01-19 | 2015-01-19 | 400 be stainless steel hot-rolling annealing wire rod nitration mixture pickle and acid washing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510025143.2A CN104611713B (en) | 2015-01-19 | 2015-01-19 | 400 be stainless steel hot-rolling annealing wire rod nitration mixture pickle and acid washing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104611713A true CN104611713A (en) | 2015-05-13 |
| CN104611713B CN104611713B (en) | 2017-11-14 |
Family
ID=53146350
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510025143.2A Active CN104611713B (en) | 2015-01-19 | 2015-01-19 | 400 be stainless steel hot-rolling annealing wire rod nitration mixture pickle and acid washing method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104611713B (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104988517A (en) * | 2015-07-29 | 2015-10-21 | 河南红东方化工股份有限公司 | Acidic disincrustant and preparation method thereof |
| CN105369266A (en) * | 2015-12-14 | 2016-03-02 | 浙江大学 | Steel acid washing liquid based on Fenton oxidation reaction and acid washing process |
| CN106637244A (en) * | 2017-01-23 | 2017-05-10 | 上海应用技术大学 | Nano additive used for steel pipe pickling solution and preparation method for nano additive |
| CN108359911A (en) * | 2018-03-28 | 2018-08-03 | 浙江益宏不锈钢有限公司 | A kind of austenite stainless steel seamless steel tube and its preparation process |
| CN109055946A (en) * | 2018-09-27 | 2018-12-21 | 山西太钢不锈钢股份有限公司 | Carbon steel and low-alloy steel cut surface oxide layer pickling solution and acid washing method |
| CN112430818A (en) * | 2020-11-20 | 2021-03-02 | 德清县豪鹰金属制品有限公司 | Surface treatment process for steel wire |
| CN113088980A (en) * | 2021-04-02 | 2021-07-09 | 山西太钢不锈钢股份有限公司 | Production method of iron chromium aluminum alloy hot-rolled strip steel surface oxide skin through hydrochloric acid pickling |
| CN113736575A (en) * | 2021-09-28 | 2021-12-03 | 长沙艾森设备维护技术有限公司 | High-speed rail brake resistor sheet cleaning agent and preparation method thereof |
| WO2023000525A1 (en) * | 2021-07-23 | 2023-01-26 | 中冶南方工程技术有限公司 | Hot-rolled stainless steel annealing pickling process and pickling device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1041010A (en) * | 1988-09-09 | 1990-04-04 | 淮北矿务局科研所 | Steel derusting, passivation novel process |
-
2015
- 2015-01-19 CN CN201510025143.2A patent/CN104611713B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1041010A (en) * | 1988-09-09 | 1990-04-04 | 淮北矿务局科研所 | Steel derusting, passivation novel process |
Non-Patent Citations (2)
| Title |
|---|
| 喻亚非: "《锅炉化学清洗》", 31 October 2013, 中国电力出版社 * |
| 李佳: ""不锈钢线材盘卷的酸洗工艺"", 《轧钢》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104988517A (en) * | 2015-07-29 | 2015-10-21 | 河南红东方化工股份有限公司 | Acidic disincrustant and preparation method thereof |
| CN105369266A (en) * | 2015-12-14 | 2016-03-02 | 浙江大学 | Steel acid washing liquid based on Fenton oxidation reaction and acid washing process |
| CN106637244A (en) * | 2017-01-23 | 2017-05-10 | 上海应用技术大学 | Nano additive used for steel pipe pickling solution and preparation method for nano additive |
| CN106637244B (en) * | 2017-01-23 | 2019-01-01 | 上海应用技术大学 | A kind of acid cleaning of steel tube liquid nanometer additive and preparation method thereof |
| CN108359911A (en) * | 2018-03-28 | 2018-08-03 | 浙江益宏不锈钢有限公司 | A kind of austenite stainless steel seamless steel tube and its preparation process |
| CN109055946A (en) * | 2018-09-27 | 2018-12-21 | 山西太钢不锈钢股份有限公司 | Carbon steel and low-alloy steel cut surface oxide layer pickling solution and acid washing method |
| CN109055946B (en) * | 2018-09-27 | 2021-02-02 | 山西太钢不锈钢股份有限公司 | Pickling solution and pickling method for oxide layers of cutting surfaces of carbon steel and low alloy steel |
| CN112430818A (en) * | 2020-11-20 | 2021-03-02 | 德清县豪鹰金属制品有限公司 | Surface treatment process for steel wire |
| CN113088980A (en) * | 2021-04-02 | 2021-07-09 | 山西太钢不锈钢股份有限公司 | Production method of iron chromium aluminum alloy hot-rolled strip steel surface oxide skin through hydrochloric acid pickling |
| CN113088980B (en) * | 2021-04-02 | 2022-09-20 | 山西太钢不锈钢股份有限公司 | Production method of iron chromium aluminum alloy hot-rolled strip steel surface oxide skin through hydrochloric acid pickling |
| WO2023000525A1 (en) * | 2021-07-23 | 2023-01-26 | 中冶南方工程技术有限公司 | Hot-rolled stainless steel annealing pickling process and pickling device |
| CN113736575A (en) * | 2021-09-28 | 2021-12-03 | 长沙艾森设备维护技术有限公司 | High-speed rail brake resistor sheet cleaning agent and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104611713B (en) | 2017-11-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104611713A (en) | Mixed-acid acid washing liquid and acid washing method for 400-series stainless steel hot-rolled annealing wire | |
| CN104611712A (en) | Hydrochloric-acid acid washing liquid and acid washing method for 400-series stainless steel hot-rolled annealing wire | |
| CN105297045B (en) | A kind of stainless steel pipe surface cleaning method | |
| CN102634806A (en) | Acid-wash additive for iron and steel | |
| JP6420251B2 (en) | Polishing and passivating stainless steel surfaces | |
| CN104611711A (en) | Pickling solution for high-alloy corrosion-resisting steel and pickling method | |
| US9580831B2 (en) | Stainless steel pickling in an oxidizing, electrolytic acid bath | |
| CN101922011A (en) | Pickling method of surface of 430 stainless steel | |
| CN103952711A (en) | Continuous online treatment technique for metal surface | |
| JP2007332416A (en) | Electrolytic solution for use in electropolishing process for stainless steel | |
| US20090148335A1 (en) | Process for surface treatment of metals | |
| CN105350005B (en) | A kind of compounding pickle containing passivator and preparation method thereof | |
| JP2007231413A (en) | Electrolytic solution to be used for electrolytic polishing method for stainless steel | |
| CN106521525A (en) | Stainless steel surface treating agent as well as preparation method thereof and using method thereof | |
| JPH11264087A (en) | Treating liquid for descaling stainless steel and its usage | |
| CN104480488A (en) | Degreasing agent for chemical equipment | |
| US1974570A (en) | Pickling solution | |
| CN105177604B (en) | A kind of compound hydrochloric acid pickling corrosion inhibitor and preparation method thereof | |
| CN110616436A (en) | Hydrochloric acid additive and preparation method thereof | |
| STREICHER | Synergistic inhibition of ferric ion corrosion during chemical cleaning of metal surfaces | |
| US1859736A (en) | Method of cleaning metal articles | |
| CN104532270A (en) | INCOLOY 825 nickel-base alloy oxides cleaning agent | |
| JP2017088726A (en) | Descaling promotion additive for alloy steel, acid cleaning liquid composition using the same, and acid cleaning method | |
| US1919624A (en) | Chrome scale softening process | |
| KR20190020948A (en) | Scale removing apparatus for ferritic stainless steel and method for removing scale using the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |