CN104422649A - Method for evaluating corrosion resistance quality of stainless steel products - Google Patents
Method for evaluating corrosion resistance quality of stainless steel products Download PDFInfo
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- CN104422649A CN104422649A CN201310401217.9A CN201310401217A CN104422649A CN 104422649 A CN104422649 A CN 104422649A CN 201310401217 A CN201310401217 A CN 201310401217A CN 104422649 A CN104422649 A CN 104422649A
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Abstract
The invention discloses a method for evaluating the corrosion resistance quality of stainless steel products. The method comprises the following steps: putting the stainless steel products into a neutral corrosion solution at a specified temperature for dipping; taking the stainless steel products out of the neutral corrosion solution after the dipping time reaches a first critical time, washing the stainless steel products with purified water, and airing the stainless steel products; putting the stainless steel products into a ferricyanide solution for dipping; and judging whether the corrosion resistance of the stainless steel products is qualified or not by observing whether blue points appear on the surfaces of the stainless steel products or not after the dipping time reaches a second critical time. By virtue of the method for evaluating the corrosion resistance quality of the stainless steel products, the corrosion resistance quality of the stainless steel products is tested; the processing method is simple and quick; a special device does not need to be independently developed again; the method is relatively economical; a solution dipping method is not limited by sizes and shapes of samples; the method is few in test influence factors and high in test result repeatability, and can be used for accurately, quickly and qualitatively judging the corrosion resistance quality of the stainless steel products at low costs.
Description
Technical field
The present invention relates to hardware corrosion resistance field of fast detection, particularly relate to a kind of stainless steel products corrosion stability grade estimation method.
Background technology
Stainless corrosion resistance mainly the fine and close chromium oxide passivation film of one deck very thin (about 1 μm) due to surface coverage, and this tunic can make metallic matrix and corrosive medium isolate, and is the basic barrier of stainless steel protection.Stainless steel work-piece is positioned in air self-passivation can form oxide film, but the passivating film formed under this condition is fine and close not, can not meet production and application requirement.Usually first thoroughly to clean, comprise alkali cleaning and pickling, use special passivator passivation, the integrality of guarantee passivating film and stability.One of object of pickling is for Passivation Treatment creates favorable conditions, and ensures the passivating film forming high-quality.Because make stainless steel surfaces on average have 10 μm of thick layer of surface to be corroded by pickling, the chemical activity of acid solution makes other position on the dissolution rate specific surface of rejected region high, therefore pickling can make whole surface be tending towards uniform balance, and some easily caused the hidden danger of corrosion to be eliminated originally.But the more important thing is, pass through acid wash passivation, iron is dissolved than the selective oxide of chromium and chromium with the oxide of iron, eliminate poor layers of chrome, cause chromium in stainless steel surfaces enrichment, the current potential of this rich chromium passivation film can reach+1.0V (SCE), close to the current potential of noble metal, improves erosion-resisting stability.Different Passivation Treatment also can affect the composition and structure of passivating film, thus the corrosion stability of Total Product is good and bad.As by electrochemical modification process, passivating film can be made to have sandwich construction, form CrO on restraining barrier
3or Cr
2o
3, or form the oxide film of glassy state, make stainless steel play maximum corrosion stability.
Stainless steel is owing to having excellent corrosion stability, wearing quality, obdurability and being widely used.If passivating film is destroyed, stainless steel is just in activation and easily occurs corrosion.Different stainless steels, the protective capability of its passivating film is different; The stainless steel of same model also may owing to there being different surface state, as roughness is different, or the surface film formed under different medium, different condition, its decay resistance also has obvious difference.Therefore, very important to the inspection of passivation for stainless steel film quality.
At present, have following method to the detection of passivation for stainless steel film quality: water logging is tested, humidity measurement, boiling test, salt spray test, copper sulfate test, the potassium ferricyanide-nitric acid (Bluepoint method) is tested, ferric trichloride corrosion test etc.Current passivation film on stainless steel surface grade estimation is most widely used, industry degree of recognition is the highest be in emerging salt-fog test, simultaneously because Bluepoint method can test the presence or absence of passivating film fast, and the ease for operation of experiment, have also been obtained widespread use and the accreditation of industry.But, due to salt-fog test test period other longer (needing 48h-120h), need to use special equipment, safeguard that use cost is high, and front personnel can not be met to the corrosion proof fast mass evaluation requirements of stainless steel product.
Copper sulphate, tri-chlorination iron processes, Bluepoint method, when stainless steel is without passivating film, can directly be reacted with base material, reaction of formation product, thus reach object with presence or absence of identification stainless steel work-piece passivating film.But these methods, the threshold of inspection passivation film on stainless steel surface is lower, can only reflect passivating film with or without, and effectively cannot detect the quality (stability, integrality) of passivating film.Only rely on these several class methods to detect the many performances of qualified stainless steel work-piece and still can not meet product request for utilization.
For the problem of Fast Detection Technique development plan not having stainless steel corrosion stability quality in correlation technique, at present effective solution is not yet proposed.
Summary of the invention
For the problem of Fast Detection Technique development plan not having stainless steel corrosion stability quality in correlation technique, the invention provides a kind of stainless steel products corrosion stability grade estimation method, in order to solve the problems of the technologies described above.
According to an aspect of the present invention, the invention provides a kind of stainless steel products corrosion stability grade estimation method, wherein, the method comprises: neutral etchant solution stainless steel products being put into assigned temperature floods; After dipping duration arrived for the first marginal time, above-mentioned stainless steel products is air-dry after the cleaning of taking-up pure water in above-mentioned neutral etchant solution; Above-mentioned stainless steel products is put into ferricyanide solution at once flood; After dipping duration arrived for the second marginal time, whether there is Bluepoint by observing above-mentioned surface of stainless steel product, judging that whether the corrosion stability of above-mentioned stainless steel products is qualified.
Preferably, above-mentioned neutral etchant solution is sodium chloride solution.
Preferably, the sodium chloride massfraction in above-mentioned sodium chloride solution is 1% to 6%.
Preferably, above-mentioned ferricyanide solution contains the potassium ferricyanide, nitric acid, pure water.
Preferably, the collocation method of above-mentioned ferricyanide solution is: in fuming cupboard, gets the 7-14g potassium ferricyanide and 500ml pure water respectively, the two is stirred, then adds the nitric acid that 25-36ml content is 70%, after stirring by solution dilution to 1000ml.
Preferably, whether there is Bluepoint by observing above-mentioned surface of stainless steel product, judging that whether the corrosion stability of above-mentioned stainless steel products is qualified and comprising: if Bluepoint appears in above-mentioned surface of stainless steel product, then judging that the corrosion stability of above-mentioned stainless steel products is defective; If Bluepoint does not appear in above-mentioned surface of stainless steel product, then judge that the corrosion stability of above-mentioned stainless steel products is qualified.
Preferably, above-mentioned stainless steel products is 3XX series stainless steel goods or 4XX series stainless steel goods.
By the present invention, test the corrosion stability quality of stainless steel products, disposal route is simple, quick, develops specialized equipment no longer separately, good economy performance.The method of solution impregnation does not limit by sample size and shape, and tests affect factor is few, and test result is reproducible, can comparatively accurately, fast, the qualitative corrosion stability quality studying and judging stainless steel products of low cost.
Above-mentioned explanation is only the general introduction of technical solution of the present invention, in order to technological means of the present invention can be better understood, and can be implemented according to the content of instructions, and can become apparent, below especially exemplified by the specific embodiment of the present invention to allow above and other objects of the present invention, feature and advantage.
Accompanying drawing explanation
Fig. 1 is the process flow diagram of the stainless steel products corrosion stability grade estimation method according to the embodiment of the present invention;
Fig. 2 is the schematic diagram of the stainless steel products grade estimation according to the embodiment of the present invention.
Embodiment
In order to solve in correlation technique the problem of the Fast Detection Technique development plan not having stainless steel corrosion stability quality, the invention provides a kind of stainless steel products corrosion stability grade estimation method, below in conjunction with accompanying drawing and embodiment, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, do not limit the present invention.
In the inventive solutions, first by being impregnated into the marginal time to stainless steel products constant temperature in neutral etchant solution (such as NaCl solution), the passivating film of the stainless steel products of existing defects is totally disrupted, take out stainless steel products to flood in ferricyanide reagent, according to surface of stainless steel product whether react (there is Bluepoint) judge that fast whether the corrosion stability of stainless steel products qualified.Be described in detail below by embodiment.
The present embodiment comprehensively carries out the evaluation of the Chromating Film On Zn Deposits (i.e. corrosion stability) of stainless steel products by hot submersion and Bluepoint method, process is as follows: 1) by flooding stainless steel products certain hour in the NaCl solution of constant temperature, takes out stainless steel products; 2) adopt Bluepoint method to carry out Bluepoint test, observe surface of stainless steel product and whether occur Bluepoint; 3) whether there is Bluepoint by surface of stainless steel product, judge the quality of the quality of the passivating film of stainless steel products.
Present embodiments provide a kind of stainless steel products corrosion stability grade estimation method, Fig. 1 is the process flow diagram of the stainless steel products corrosion stability grade estimation method according to the embodiment of the present invention, and as shown in Figure 1, the method comprises the following steps (step S102-step S108):
Step S102, neutral etchant solution stainless steel products being put into assigned temperature floods.
Stainless steel products being put into object that neutral etchant solution floods is surface in order to corrode stainless steel products, prepares for the passivating film of follow-up stainless steel products and the ferricyanide carry out " Bluepoint is tested ".
In the specific implementation process of this step, neutral etchant solution can be sodium chloride solution or Klorvess Liquid etc.The present embodiment is introduced for sodium chloride solution.Sodium chloride massfraction in sodium chloride solution is 1% to 6%.Preferably, when the sodium chloride massfraction in sodium chloride solution is 5%, its corrosive effect is best.
Step S104, after dipping duration arrived for the first marginal time, takes out above-mentioned stainless steel products and cleans with pure water rear air-dry in above-mentioned neutral etchant solution.Or, also can dry with cotton swab.
Step S106, at once puts into ferricyanide solution by above-mentioned stainless steel products and floods.
Whether step S108, after dipping duration arrived for the second marginal time, there is Bluepoint by observing above-mentioned surface of stainless steel product, judging that whether the corrosion stability of above-mentioned stainless steel products is qualified.
By said method, test the corrosion stability quality of stainless steel products, disposal route is simple, quick, develops specialized equipment no longer separately, good economy performance.The method of solution impregnation does not limit by sample size and shape, and tests affect factor is few, and test result is reproducible, can comparatively accurately, fast, the qualitative corrosion stability quality studying and judging stainless steel products of low cost.
Fig. 2 is the schematic diagram of the stainless steel products grade estimation according to the embodiment of the present invention, and as shown in Figure 2, surface of stainless steel product has one deck passivating film, and the composition of this passivating film is chromium oxide, and namely chromium oxide is enclosed in stainless steel-based surface.After stainless steel products is put into neutral etchant solution, passivating film corrodes by neutral etchant solution (such as sodium chloride solution), and stainless steel base and sodium chloride solution carry out chemical reaction, generates iron protochloride.Then, put into ferricyanide solution again after stainless steel products is air-dry, now iron protochloride and ferricyanide solution react, and likely can form Bluepoint.
The ferricyanide solution be applied in the present embodiment contains the potassium ferricyanide, nitric acid, pure water.The collocation method of this ferricyanide solution can have multiple, embodiments provide following preferred disposition method: in fuming cupboard, get the 10g potassium ferricyanide and 500ml pure water respectively, the two is stirred, add the nitric acid that 30ml content is 70 percent again, after stirring by solution dilution to 1000ml.According to the ferricyanide solution of above-mentioned preferred disposition method configuration, the chemical reaction of stainless steel products and the ferricyanide can be realized preferably.
In the present embodiment, Bluepoint test whether occurs Bluepoint by observing surface of stainless steel product, judges that whether the passivating film of stainless steel products is qualified, specifically comprise: if Bluepoint appears in surface of stainless steel product, then judge that the passivating film of stainless steel products is defective; If Bluepoint does not appear in surface of stainless steel product, then judge that the passivating film of stainless steel products is qualified.By above-mentioned preferred implementation, can judge that whether the passivating film of stainless steel products is qualified quickly and accurately.
In the present embodiment, above-mentioned stainless steel products can be 3XX series stainless steel goods or 4XX series stainless steel goods.Such as: 303 stainless steel products or 304 stainless steel products.303 stainless steels are Cutting free rust free, wear resistance acid steel that Austenitic contains sulphur and selenium respectively, and 304 stainless steels are stainless steel materials of a kind of versatility, and rustless property is eager to excel than the stainless steel material of 200 series.High temperature resistant aspect is also relatively good, and the general serviceability temperature limit is less than 650 DEG C.304 stainless steels have excellent stainless decay resistance and good anti intercrystalline corrosion performance.
In the actual mechanical process of the present embodiment, dipping temperature (or being called hot submersion temperature) and dip time are the key index of the superiority-inferiority evaluating stainless steel products Chromating Film On Zn Deposits, and whether the reference for judging passivation film on stainless steel surface quality good or not appears in the Bluepoint in Bluepoint test; After dipping temperature and dip time control dipping, during Bluepoint test, whether surface of stainless steel product there is Bluepoint.The good and bad criterion of the quality of passivation film on stainless steel surface is, flood certain hour in the NaCl solution of uniform temperature after, carrying out Bluepoint test, there is Bluepoint in surface of stainless steel product, this dip time is designated as the marginal time, and as the criterion of passivation film on stainless steel surface quality good or not.
Known based on above-mentioned analysis, the time that different stainless steel products floods in the sodium chloride solution of different temperatures is not identical yet.
The massfraction adopting NaCl in the NaCl solution of hot submersion is 5%; Test the quality of the quality of stainless steel and passivation film on stainless steel surface respectively; The Bluepoint liquid compounding medicine that Bluepoint method is carried out when Bluepoint is tested is: the potassium ferricyanide, pure water, and concentration is the nitric acid of 70%; The compound method of Bluepoint test fluid is: in ventilating kitchen, measures the 10g potassium ferricyanide and 500ml pure water respectively, stirs and evenly mixs, and adds the nitric acid that 30ml content is 70%, be diluted to 1000ml after stirring in this solution.The Bluepoint method test duration is not less than 30s.
The advantage of the present embodiment is: infusion process and Bluepoint method are combined; Adopt the effect of flooding during hot submersion method stronger; Can the quality of Fast Evaluation passivation film on stainless steel surface; The reactions change situation of stainless steel surfaces can be observed more intuitively by Bluepoint method; Testing cost reduces greatly.
Describe in detail below by preferred embodiment.
Embodiment 1
The present embodiment carries out constant temp. heating dipping to stainless steel sample, and process is as follows:
1. choose 200 with batch 303 stainless steel test specimens be immersed in and fill in the beaker of NaCl solution, and to put in the water-bath of 35 DEG C, make dipping solution keep 35 DEG C of constant temperature.
2. flood after 3h, take out test specimen, with distilled water cleaning and air-dry after carry out ferricyanide test, method is: wrap up with the absorbent cotton containing Bluepoint liquid on selected metal surface, after 30s, and records surface of test piece and whether occurs Bluepoint.
3. observe the Bluepoint whether test specimen occurs, do not occur that being designated as of Bluepoint is qualified; There is the test specimen of Bluepoint, be judged to defective.Above-mentioned 200 test specimens are to ensure that test specimen test failure rate can at 0-1%.
Embodiment 2
The present embodiment carries out constant temp. heating dipping to passivation film on stainless steel surface, and process is as follows:
1. choose 200 with batch 304 stainless steel test specimens be immersed in and fill in the beaker of NaCl solution, and in the water-bath put into, make dipping solution keep constant temperature.
2. flood after 7h, take out test specimen, clean air-dry after carry out Bluepoint test, method is: wrap up with the absorbent cotton containing Bluepoint liquid on selected metal surface, and after 30s, and record surface of test piece and whether occur Bluepoint, whether judgement test specimen qualified.
3. observe the Bluepoint whether test specimen occurs, do not occur that being designated as of Bluepoint is qualified; There is the test specimen of Bluepoint, be judged to defective.By above embodiment by the method for series of measures by hot submersion and Bluepoint method Comprehensive Assessment passivation for stainless steel film quality, achieve the object that passivation for stainless steel film quality is detected fast, compared with traditional test methods, have and test effect faster.
From above content, infusion process and Bluepoint method combine by the embodiment of the present invention; Adopt the effect of flooding during hot submersion method stronger; Can the quality of Fast Evaluation passivation film on stainless steel surface; The reactions change situation of stainless steel surfaces can be observed more intuitively by Bluepoint method; Testing cost reduces greatly.
Although be example object, disclose the preferred embodiments of the present invention, it is also possible for those skilled in the art will recognize various improvement, increase and replacement, and therefore, scope of the present invention should be not limited to above-described embodiment.
Claims (7)
1. a stainless steel products corrosion stability grade estimation method, is characterized in that, described method comprises:
Neutral etchant solution stainless steel products being put into assigned temperature floods;
After dipping duration arrived for the first marginal time, described stainless steel products is air-dry after the cleaning of taking-up pure water in described neutral etchant solution;
Described stainless steel products is put into ferricyanide solution at once flood;
After dipping duration arrived for the second marginal time, whether there is Bluepoint by observing described surface of stainless steel product, judging that whether the corrosion stability of described stainless steel products is qualified.
2. the method for claim 1, is characterized in that, described neutral etchant solution is sodium chloride solution.
3. method as claimed in claim 2, it is characterized in that, the sodium chloride massfraction in described sodium chloride solution is 1% to 6%.
4. the method for claim 1, is characterized in that, described ferricyanide solution contains the potassium ferricyanide, nitric acid, pure water.
5. the method for claim 1, is characterized in that, the collocation method of described ferricyanide solution is:
In fuming cupboard, get the 7-14g potassium ferricyanide and 500ml pure water respectively, the two stirred, then add the nitric acid that 25-36ml content is 70%, after stirring by solution dilution to 1000ml.
6. the method for claim 1, is characterized in that, whether occurs Bluepoint by observing described surface of stainless steel product, judges that whether the corrosion stability of described stainless steel products is qualified and comprises:
If Bluepoint appears in described surface of stainless steel product, then judge that the corrosion stability of described stainless steel products is defective;
If Bluepoint does not appear in described surface of stainless steel product, then judge that the corrosion stability of described stainless steel products is qualified.
7. the method according to any one of claim 1 to 6, is characterized in that, described stainless steel products is 3XX series stainless steel goods or 4XX series stainless steel goods.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101738365A (en) * | 2008-11-06 | 2010-06-16 | 北京有色金属研究总院 | Accelerated test method for simulating atmospheric corrosion of metal materials |
| CN103207139A (en) * | 2012-01-12 | 2013-07-17 | 中兴通讯股份有限公司 | Method for testing corrosion resistance of NCVM coating |
-
2013
- 2013-09-06 CN CN201310401217.9A patent/CN104422649A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101738365A (en) * | 2008-11-06 | 2010-06-16 | 北京有色金属研究总院 | Accelerated test method for simulating atmospheric corrosion of metal materials |
| CN103207139A (en) * | 2012-01-12 | 2013-07-17 | 中兴通讯股份有限公司 | Method for testing corrosion resistance of NCVM coating |
Non-Patent Citations (4)
| Title |
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| 宣卫芳等: "《钢制药筒丝状腐蚀加速试验方法研究》", 《装备环境工程》 * |
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