KR20100073409A - Method for pickling high chrome ferritic stainless steel - Google Patents

Method for pickling high chrome ferritic stainless steel Download PDF

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KR20100073409A
KR20100073409A KR1020080132075A KR20080132075A KR20100073409A KR 20100073409 A KR20100073409 A KR 20100073409A KR 1020080132075 A KR1020080132075 A KR 1020080132075A KR 20080132075 A KR20080132075 A KR 20080132075A KR 20100073409 A KR20100073409 A KR 20100073409A
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pickling
stainless steel
ferritic stainless
sulfuric acid
steel sheet
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KR101073242B1 (en
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김형준
한승용
김진석
오택수
이용헌
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주식회사 포스코
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling
    • C25F1/02—Pickling; Descaling
    • C25F1/04—Pickling; Descaling in solution
    • C25F1/06—Iron or steel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • 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
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F3/00—Brightening metals by chemical means
    • C23F3/04—Heavy metals
    • C23F3/06—Heavy metals with acidic solutions

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

Abstract

PURPOSE: An acid cleaning method of a high chrome ferritic stainless steel is provided to minimize the product defect of a stainless steel plate by improving the gloss of the steel sheet surface. CONSTITUTION: The acid cleaning method of the high chrome ferritic stainless steel comprises a step of pickling in a sulfuric acid electrolytic cell. The applied current of the sulfuric acid electrolytic cell to the maximum anode is 4.0A / dm^2 or greater. The concentration of the sulfuric acid electrolytic cell is 20~200g/l. The temperature of the solution of the sulfuric acid electrolytic cell is 20~70°C. The steel sheet comprises Cr 18~20 weight% and Si 0.5 weight%. The acid cleaning method operates a neutral salt electrolytic pickling process, a sulfuric acid electrolytic pickling process, a nitric acid electrolytic pickling process.

Description

고크롬 페라이트계 스테인리스강의 산세방법{Method for pickling high chrome ferritic stainless steel}Pickling method of high chrome ferritic stainless steel {Method for pickling high chrome ferritic stainless steel}

본 발명은 고크롬 페라이트계 스테인리스강의 산세방법에 관한 것이다. 보다 상세하게는 열간압연 또는 냉간압연 후 소둔열처리된 스테인리스강판에 대하여 황산 전해 산세공정을 추가하고 산세조건을 제어함에 따라 신속하게 산화스케일을 제거하여 우수한 표면광택도를 가지며 균일한 표면외관을 확보할 수 있는 고크롬 페라이트계 스테인리스강의 산세방법에 관한 것이다.The present invention relates to a pickling method of high chromium ferritic stainless steel. More specifically, sulfuric acid electrolytic pickling process is added to hot-rolled or cold-rolled annealing stainless steel sheets, and the oxidation scale is removed quickly to obtain excellent surface glossiness and uniform surface appearance. The present invention relates to a method for pickling high chromium ferritic stainless steel.

일반적으로, 18~20%의 크롬을 함유하는 페라이트계 슬라브는 가열로에서 2~3시간 가열 후 고온에서 열간압연을 행한 다음 산세공정을 거치며 이어서 소둔 열처리된다. 이후 상기 열연강판은 두께가 얇은 박판을 생산하기 위하여 최종적으로 냉간압연을 실시하고 이어서 소둔 열처리가 된다. 이후 다시 산세공정을 통해서 표면 스케일이 제거되어 매끄러운 표면상태를 갖는 스테인리스 강판으로 제조된다.In general, ferritic slabs containing 18 to 20% of chromium are subjected to hot rolling at a high temperature after heating for 2-3 hours in a heating furnace, followed by a pickling process, followed by annealing. After that, the hot rolled steel sheet is finally cold rolled to produce a thin plate, and then subjected to annealing heat treatment. After that, the surface scale is removed again through a pickling process to produce a stainless steel sheet having a smooth surface state.

종래 스테인리스강의 산세공정은 중성염전해산세, 질산전해산세 및 질산과 불산의 혼산침적에 의해서 이루어지고 있다. 이외에도 스테인리스강판을 산세처리 하기 위해 용융염에서 전처리 한 후 질산전해나 혼산조를 통과시키는 등 다양한 산세기술이 제공되고 있다.Conventionally, the pickling process of stainless steel is carried out by neutral salt electrolytic acid washing, nitric acid electrolytic acid washing and mixed acidic deposition of nitric acid and hydrofluoric acid. In addition, a variety of pickling techniques are provided, such as pretreatment in molten salt for pickling the stainless steel sheet, and then passing through nitric acid or a mixed acid bath.

한편, 18~20%의 Cr을 함유하고 있는 고크롬 페라이트계 스테인리스강은 압연공정 또는 소둔 열처리를 행하는 동안 스테인리스강판의 표면에 Cr, Fe, Si 등의 산화물층이 형성된다. 이중 Cr, Fe 산화물층은 산세공정 동안 전처리 과정이나 전해 산세 방법을 통하여 제거될 수 있으나, 0.5% 이상의 Si을 함유하는 강판의 경우에는 계면에 형성된 Si산화물에 의해 Si 산화물층의 제거가 균일하지 못하거나, 완전 산세가 되지 않는 문제를 가지고 있다. 이러한 경우 내식성의 현저한 저하를 가져오게 되어, 제품의 가치가 떨어지는 문제를 가지고 있다.On the other hand, in the high chromium ferritic stainless steel containing 18 to 20% of Cr, oxide layers such as Cr, Fe, and Si are formed on the surface of the stainless steel sheet during the rolling process or annealing heat treatment. Among them, the Cr and Fe oxide layers may be removed through pretreatment or electrolytic pickling during the pickling process, but in the case of steel sheets containing 0.5% or more of Si, the removal of the Si oxide layer is not uniform due to the Si oxide formed at the interface. There is a problem that is not pickling. In this case, the corrosion resistance is remarkably lowered, and the value of the product is lowered.

본 발명은 상기한 종래의 문제점을 개선하기 위한 것으로, 열간압연 또는 냉간압연 후 소둔열처리된 페라이트계 스테인리스강판을 산세처리하였을 때 소둔산세 전 대비 85% 이상의 표면 광택도 회복률을 확보함과 동시에 균일한 표면외관을 갖는 고크롬 페라이트계 스테인리스강판의 산세방법을 제공하는데, 그 목적이 있다.The present invention is to improve the above-described problems, and when the pickling treatment of the annealing ferritic stainless steel sheet after hot rolling or cold rolling to ensure a more than 85% surface gloss recovery recovery rate before annealing SUMMARY OF THE INVENTION An object of the present invention is to provide a pickling method for a high chromium ferritic stainless steel sheet having a surface appearance.

상기 목적을 달성하기 위한 본 발명은, 열간압연 또는 냉간압연 후 소둔 열처리에 의해 표면에 형성된 스케일을 제거하기 위한 페라이트계 스테인리스강판의 산세방법에 있어서, 황산 전해조에서 산세하는 공정을 포함하여 이루어지고, 상기 황산 전해조의 인가전류는 최대 양극 기준으로 4.0A/d㎡이상, 농도는 20~200 g/l이며, 용액의 온도는 20~70℃인 것을 특징으로 하는 고크롬 페라이트계 스테인리스강의 산세방법에 관한 것이다.The present invention for achieving the above object, in the pickling method of a ferritic stainless steel sheet for removing the scale formed on the surface by annealing heat treatment after hot rolling or cold rolling, comprising a step of pickling in a sulfuric acid electrolytic cell, The applied current of the sulfuric acid electrolytic cell is 4.0A / dm 2 or more on the basis of the maximum anode, the concentration is 20 ~ 200 g / l, the solution temperature is 20 ~ 70 ℃ in the pickling method of high chromium ferritic stainless steel It is about.

또한, 본 발명에서 상기 강판은 중량%로, Cr: 18~20%, Si: 0.5% 이상을 함유하는 것이 바람직하며, 보다 바람직하게는 상기 Si의 함량은 0.5~0.6%이다. 또한, 본 발명에서 상기 산세방법은 중성염 전해산세-황산 전해산세-질산 전해산세-혼산침적의 순서로 행해지는 것이 바람직하다. In addition, in the present invention, the steel sheet is preferably contained by weight, Cr: 18 to 20%, Si: 0.5% or more, more preferably, the content of Si is 0.5 to 0.6%. In the present invention, the pickling method is preferably performed in the order of neutral salt electrolytic pickling-sulfuric acid electrolytic pickling-nitric acid electrolytic pickling-mixed acid deposition.

이하, 본 발명을 상세하게 설명한다.EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

본 발명자들은 Si을 0.5% 이상 함유하는 고크롬 페라이트계 스테인리스강을 산세처리하는 경우 Si 산화물층의 균일하고 완전한 제거에 대한 어려움을 해결하기 위한 방안을 연구하던 중, 기존의 산세처리 과정에서 황산 전해산세공정을 추가하고 그 산세조건을 제어함에 따라 신속하게 Si 산화물에 의한 스케일을 제거하여 우수한 표면광택도를 가지며 균일한 표면외관을 확보할 수 있음을 실험을 통해 확인하고, 그 실험결과를 기초로 하여 본 발명을 완성하게 되었다.The present inventors have been investigating a solution to solve the difficulty of uniform and complete removal of the Si oxide layer when pickling a high chromium ferritic stainless steel containing 0.5% or more of Si. By adding the pickling process and controlling the pickling conditions, we can quickly remove the scale by Si oxide and have excellent surface gloss and ensure the uniform surface appearance. The present invention was completed.

산화성 분위기에서 열처리시 스테인리스 강종별 크롬함량과 소둔온도가 상이하여 산화스케일의 조성과 두께 및 표면색상이 다르게 된다.When the heat treatment in an oxidizing atmosphere, the chromium content and annealing temperature of each stainless steel are different so that the composition, thickness and surface color of the oxide scale are different.

페라이트계 스테인리스 강판을 산화성 분위기에서 열처리하면 주로 Cr-rich 스케일이 형성되며 스케일 계면과 모재사이에 SiO2가 형성된다. 또한, 열처리 온도와 시간이 증가하면서 스케일 두께가 증가되며, 이때 소둔강판의 색상은 고크롬 페라이트계 스테인리스강의 경우 푸른색을 띄게 된다.When the ferritic stainless steel sheet is heat treated in an oxidizing atmosphere, a Cr-rich scale is mainly formed, and SiO 2 is formed between the scale interface and the base material. In addition, as the heat treatment temperature and time increases, the scale thickness increases, and the color of the annealed steel sheet becomes blue in the case of high chromium ferritic stainless steel.

이들 강종계에서 산화스케일을 제거할 경우 여러 경로의 산세공정이 있는데 각 공정별 특징을 정리하면 다음과 같다.When the scale is removed from these steel systems, there are several pickling processes. The characteristics of each process are as follows.

먼저, 상기 고크롬 페라이트계 스테인리스 냉연강판을 중성염 전해조를 통 과시킨다. 황산나트륨을 함유하고 있는 중성염 수용액에서 일정전류를 가하여 전해산세를 실시하는 경우 크롬-리치(Cr-rich) 스케일이 형성된 페라이트계 스테인리스강판의 경우 양극반응에 의해 Cr 산화물이 용해될 수 있으나 단시간 내에 크롬 산화물을 완전히 제거할 수는 없다. First, the high chromium ferritic stainless steel cold rolled steel sheet is passed through a neutral salt electrolytic cell. When electrolytic pickling is carried out by applying a constant current in an aqueous neutral salt solution containing sodium sulfate, in the case of ferritic stainless steel sheet having a chromium-rich scale, Cr oxide may be dissolved by anodization, but chromium may be dissolved within a short time. It is not possible to remove the oxide completely.

또한, Fe 산화물 역시 중성염수용액에서 전기화학반응에 의해 용해되지 않기 때문에 산화스케일 중의 Fe산화물을 제거하기 위해 질산전해과정을 거치게 된다. 아울러 스케일 중에 존재하고 있는 Si산화물은 중성염 및 질산전해로도 제거가 불가능하기 때문에 질산과 불산으로 구성되어 있는 혼산조에서 침적과정을 적용하고 있다.In addition, since the Fe oxide is not dissolved in the neutral saline solution by the electrochemical reaction, it undergoes the nitric acid electrolysis process to remove the Fe oxide in the oxidized scale. In addition, since the Si oxide existing in the scale cannot be removed by neutral salt and nitrate electrolyte, the deposition process is applied in a mixed acid tank composed of nitric acid and hydrofluoric acid.

하지만, 0.5% 이상의 Si을 함유하는 고크롬 페라이트계 스테인리스강의 경우에는 이것으로도 충분하지 않아 미산세가 발생하므로 본 발명에서는 기존 전해산세방법과 달리 황산 전해산세과정을 추가로 적용하여 산세처리를 행하는데 그 특징이 있는 것이다. However, in the case of high chromium ferritic stainless steel containing Si of 0.5% or more, even this is not enough, so that acid pickling occurs. In the present invention, unlike the existing electrolytic pickling method, sulfuric acid electrolytic pickling process is additionally applied to pickling treatment. It is characteristic.

이하 본 발명의 바람직한 산세조건에 대하여 상세히 설명한다.Hereinafter, the pickling conditions of the present invention will be described in detail.

본 발명에서는 Si: 0.5% 이상을 함유하는 18~20Cr 페라이트계 스테인리스 강판을 대상으로 열간압연 또는 냉간압연 후 소둔 열처리에 의해서 스테인리스 강판 표면에 형성된 표면 스케일을 제거하기 위해 중성염전해 - 황산전해 - 질산전해 - 혼산침지의 순서로 산세처리를 행할 수 있다. 상기 Si의 함량은 0.5~0.6%인 것이 보다 바람직하다.In the present invention, to remove the surface scale formed on the surface of the stainless steel sheet by hot-rolled or cold-rolled annealing on 18 ~ 20Cr ferritic stainless steel sheet containing 0.5% or more Si: neutral salt electrolyte-sulfate electrolyte-nitric acid Pickling treatment can be performed in the order of electrolysis-mixed acid immersion. More preferably, the content of Si is 0.5 to 0.6%.

먼저, 상기 페라이트계 스테인리스강판을 중성염 전해조에 통과시킨다. 이때 중성염 전해산세 조건은 통상적인 산세조건에 따라 실시될 수 있으며 특별히 한정하지 않는다. 일 실시예로서, 중성염 전해조는 셀(cell)당 6m 길이의 14셀(cell)로 구성되고, 중성염 전해시 전류는 7A/d㎡을 인가하며, 온도 및 농도는 통상의 조건으로 행할 수 있다.First, the ferritic stainless steel sheet is passed through a neutral salt electrolytic cell. At this time, the neutral salt electrolytic pickling conditions may be carried out according to conventional pickling conditions, and are not particularly limited. In one embodiment, the neutral salt electrolyzer consists of 14 cells 6 m long per cell, the current is 7 A / dm 2 during neutral salt electrolysis, and the temperature and concentration can be performed under normal conditions. have.

이후, 상기 중성염 전해산세를 거친 스테인리스 강판은 황산 전해조에서 산세하는 과정을 거치게 된다. 상기 황산 전해조는 최대 양극 기준으로 4A/dm2 이상으로 구성된 전해조에서 농도는 20~200g/l를 사용하고, 용액의 온도는 20~70℃로 한다. Thereafter, the stainless steel sheet subjected to the neutral salt electrolytic pickling is subjected to a process of pickling in a sulfuric acid electrolytic cell. The sulfuric acid electrolytic cell has a concentration of 20 to 200 g / l in an electrolytic cell composed of 4 A / dm 2 or more based on the maximum anode, and the temperature of the solution is 20 to 70 ° C.

상기 황산 전해조의 인가전류가 4.0 A/d㎡ 미만인 경우에는 미산세가 발생할 수 있으며, 4A/dm2 이상을 만족하는 경우에는 본 발명에서 목표로하는 광택도 회복률이 85%이상을 나타낼 수 있다. 여기서 미산세는 표면층에 Si 성분이 남아있지 않은 상태를 나타낸다. If the applied current of the sulfuric acid electrolytic cell is less than 4.0 A / dm 2 may cause acid pickling, when 4 A / dm 2 or more is satisfied, the glossiness recovery target of the present invention may represent 85% or more. The micro pickling here represents a state in which no Si component remains in the surface layer.

또한, 상기 황산 전해조의 온도가 20℃ 미만인 경우에는 미산세가 발생하는 반면, 70℃를 초과하는 경우에는 과산세가 발생하여 균일한 표면을 얻을 수 없다. 또한, 상기 용액의 농도가 20g/l 미만인 경우에는 미산세가 발생하는 반면, 200 g/l을 초과하는 경우에는 과도한 활성용해가 발생하여 표면이 불균일하게 될 수 있다.In addition, when the temperature of the sulfuric acid electrolytic cell is less than 20 ° C, acid pickling occurs, whereas when it exceeds 70 ° C, peracid washing occurs and a uniform surface cannot be obtained. In addition, when the concentration of the solution is less than 20g / l, the pickling occurs, whereas when it exceeds 200 g / l, excessive active dissolution occurs, the surface may be uneven.

또한, 후속공정으로서 산화스케일 중의 Fe 산화물을 제거하기 위해 질산전해산세 과정을 거친 후 혼산침지 된다. 이때 질산 전해산세 조건은 통상적인 산세조건에 따라 실시될 수 있으며 특별히 한정되지 않는다. 또한, 상기 혼산침지시의 혼산조의 구성은 질산과 불산으로 이루어지며 전류밀도, 온도 및 농도는 통상의 조건으로 실시될 수 있으며 특별히 한정하지 않는다.In addition, as a subsequent step, the mixture is immersed after undergoing nitric acid electrolytic acid treatment to remove the Fe oxide in the oxide scale. At this time, the nitric acid electrolytic pickling conditions may be carried out in accordance with conventional pickling conditions and are not particularly limited. In addition, the composition of the mixed acid bath in the mixed acid immersion is made of nitric acid and hydrofluoric acid, the current density, temperature and concentration may be carried out under ordinary conditions, and is not particularly limited.

상술한 바와 같이, 본 발명에 따르면, 본 발명의 고크롬 페라이트계 스테인리스 강판의 산세방법은 단시간에 산세시킴과 동시에 우수한 표면광택도와 균일한 표면외관을 확보하여 스테인리스 강판의 제품 결함을 최소화하고 생산성을 향상시킬 수 있는 효과를 제공한다.As described above, according to the present invention, the pickling method of the high chromium ferritic stainless steel sheet according to the present invention minimizes product defects and improves productivity by securing pickling in a short time and ensuring excellent surface gloss and uniform surface appearance. It provides an effect that can be improved.

이하, 실시예를 통하여 본 발명을 보다 상세하게 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.

[실시예]EXAMPLE

본 실시예에서는 19Cr-0.5Si 강종을 대상으로 Na2SO4 중성염 전해조에서 전류밀도 10~20A/dm2를 인가하고, 온도는 70℃ 그리고 용액의 농도는 150g/l를 사용하 였다. 또한, 질산 전해 산세조건으로서, HNO3 질산 전해조에서 전류밀도 5~10A/dm2를 인가하고, 온도는 50℃ 그리고 용액의 농도는 100g/l를 사용하였다. 이후, 혼산 침지조건으로, 질산 농도는 90g/l이고, HF 농도는 10g/l이며, 이때 온도는 40℃로 하여 실시하였다.In this example, a current density of 10-20 A / dm 2 was applied in a Na 2 SO 4 neutral salt electrolyzer, and a temperature of 70 ° C. and a concentration of 150 g / l were used for 19Cr-0.5Si steels. In addition, as the nitric acid electrolytic pickling conditions, a current density of 5 to 10 A / dm 2 was applied in an HNO 3 nitric acid electrolyzer, a temperature of 50 ° C. and a concentration of a solution of 100 g / l were used. Thereafter, under mixed acid immersion conditions, nitric acid concentration was 90 g / l, HF concentration was 10 g / l, and the temperature was performed at 40 ° C.

하기 표 1에서는 황산 전해산세 조건 변화에 따라 측정된 산세성 결과를 나타내었으며, 광택도 회복률 및 백색도(표면 외관)를 측정하여 산세성을 평가하였다. 광택도 측정은 압연방향에 60도로 빛을 조사하여 측정하였다. 여기서, 광택도 회복율(%)은 열처리전의 광택도와 산세처리후의 광택도의 비율을 나타낸다.Table 1 shows the pickling results measured according to the electrolytic pickling condition of sulfuric acid, and the pickling properties were evaluated by measuring the gloss recovery rate and the whiteness (surface appearance). Glossiness measurement was measured by irradiating light to the rolling direction at 60 degrees. Here, glossiness recovery rate (%) represents the ratio of the glossiness before heat processing and the glossiness after a pickling process.


구분
division 황산조(H2SO4)Sulfuric acid bath (H2SO4) 광택도 회복률(%)Glossiness Recovery Rate (%) 표면외관
Surface appearance
온도(℃)Temperature (℃) 농도(g/l)Concentration (g / l) 전류밀도
(A/dm2)Current density
(A / dm 2 ) 발명예1Inventive Example 1 4040 6060 77 ○○ ○○ 발명예2Inventive Example 2 4040 3030 1717 ○○ ○○ 발명예3Inventive Example 3 4040 185185 1717 ○○ ○○ 발명예4Inventive Example 4 6060 4545 1717 ○○ ○○ 발명예5Inventive Example 5 6060 3030 77 ○○ ○○ 발명예6Inventive Example 6 6060 150150 44 ○○ ○○ 발명예7Inventive Example 7 3030 4040 1919 ○○ ○○ 발명예8Inventive Example 8 3030 150150 88 ○○ ○○ 발명예9Inventive Example 9 3030 100100 1313 ○○ ○○ 발명예10Inventive Example 10 2020 3535 2121 ○○ ○○ 발명예11Inventive Example 11 2020 100100 1515 ○○ ○○ 발명예12Inventive Example 12 2020 180180 88 ○○ ○○ 비교예1Comparative Example 1 -- -- -- XX XX 비교예2Comparative Example 2 7070 200200 33 XX XX 비교예3Comparative Example 3 8080 100100 1515 XX XX 비교예4Comparative Example 4 8080 190190 33 XX XX 비교예5Comparative Example 5 8080 2020 2121 XX XX 비교예6Comparative Example 6 1010 5050 1515 XX XX 비교예7Comparative Example 7 1010 190190 33 XX XX 비교예8Comparative Example 8 1010 205205 2121 XX XX 광택도 회복률: ○는 85% 이상으로서 광택 우수, X는 85% 미만으로서 광택 불량
표면외관 ○는 표면외관 우수, X는 표면외관 불량Glossiness recovery rate: ○ is more than 85%, excellent gloss, X is less than 85%, poor gloss
Surface appearance ○ is excellent surface appearance, X is poor surface appearance

상기 표 1에서 나타난 바와 같이, 본 발명의 범위를 만족하는 발명예(1~12)의 경우 광택도 회복률이 모두 85% 이상으로서 우수한 표면 광택도를 나타냄과 동시에 우수한 표면외관을 확보할 수 있었다.As shown in Table 1, in the case of Inventive Examples (1-12) satisfying the scope of the present invention, all of the glossiness recovery rate was 85% or more, showing excellent surface glossiness and excellent surface appearance.

반면, 비교예(1~8)의 경우 본 발명에서 목표로 하는 광택도 회복률 85% 이상을 확보하지 못할 뿐만 아니라 표면 외관도 불량한 제품을 얻었음을 잘 알 수 있다On the other hand, in the case of Comparative Examples (1 to 8) it can be seen that not only did not secure the glossiness recovery rate of 85% or more, but also obtained a poor surface appearance.

Claims (4)

열간압연 또는 냉간압연 후 소둔 열처리에 의해 표면에 형성된 스케일을 제거하기 위한 페라이트계 스테인리스강판의 산세방법에 있어서, 황산 전해조에서 산세하는 공정을 포함하여 이루어지고, 상기 황산 전해조의 인가전류는 최대 양극 기준으로 4.0A/d㎡이상, 농도는 20~200 g/l이며, 용액의 온도는 20~70℃인 것을 특징으로 하는 고크롬 페라이트계 스테인리스강의 산세방법.In the pickling method of a ferritic stainless steel sheet for removing the scale formed on the surface by annealing heat treatment after hot rolling or cold rolling, comprising a step of pickling in a sulfuric acid electrolytic cell, the applied current of the sulfuric acid electrolytic cell is based on the maximum anode 4.0A / dm 2 or more, the concentration is 20 ~ 200 g / l, the solution temperature is 20 ~ 70 ℃ pickling method of high chromium ferritic stainless steel. 제 1항에 있어서, 상기 강판은 중량%로, Cr: 18~20%, Si: 0.5% 이상을 함유하는 것을 특징으로 하는 고크롬 페라이트계 스테인리스강의 산세방법.The method of claim 1, wherein the steel sheet is in weight percent, Cr: 18 to 20%, Si: 0.5% or more characterized in that the pickling method of high chromium ferritic stainless steel. 제 1항에 있어서, 상기 산세방법은 중성염 전해산세-황산 전해산세-질산 전해산세-혼산침적의 순서로 행해지는 것을 특징으로 하는 고크롬 페라이트계 스테인리스강의 산세방법.The method of claim 1, wherein the pickling method is performed in the order of neutral salt electrolytic pickling, sulfuric acid electrolytic pickling, nitric acid electrolytic pickling, and mixed acid deposition. 제 2항에 있어서, 상기 Si의 함량은 0.5~0.6%인 것을 특징으로 하는 고크롬 페라이트계 스테인리스강의 산세방법.The method of claim 2, wherein the content of Si is in the pickling method of high chromium ferritic stainless steel, characterized in that 0.5 to 0.6%.
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KR100696850B1 (en) * 2005-10-27 2007-03-19 주식회사 포스코 A descaling method for low Cr ferritic stainless steel
KR100720278B1 (en) 2005-12-26 2007-05-22 주식회사 포스코 A high speed descaling method for stabilized ferritic stainless steel having nb and high cr

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