CN1303241C - Stainless steel for use under circumstance where organic acid and saline are present - Google Patents

Stainless steel for use under circumstance where organic acid and saline are present Download PDF

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CN1303241C
CN1303241C CNB028232623A CN02823262A CN1303241C CN 1303241 C CN1303241 C CN 1303241C CN B028232623 A CNB028232623 A CN B028232623A CN 02823262 A CN02823262 A CN 02823262A CN 1303241 C CN1303241 C CN 1303241C
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stainless steel
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CN1589334A (en
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小林裕
谷内俊彦
中尾喜有
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Nippon Yakin Kogyo Co Ltd
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Nippon Yakin Kogyo Co Ltd
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Priority claimed from JP2002020854A external-priority patent/JP4325141B2/en
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    • 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
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

The present invention provides a stainless steel which is suitable for use in the food manufacturing plant, particularly a soy sauce manufacturing plant. A stainless steel to be used in the environment which contains organic acid and common salt comprising, C; 0.05 wt % or less, Si; 1.00 wt % or less, Mn; 1.00 wt % or less, P; 0.040 wt % or less, S; 0.03 wt % or less, Ni; 40.0 wt % or less, 16.0 wt <=Cr<=26.0 wt %, 2.0 wt %<=Mo<=8.0 wt %, 0.05 wt %<=Al<=0.100 wt %, 0.10 wt %<=N<=0.30 wt %, Mg: 0.005 wt % or less, Ca; 0.0010 wt % or less and balance consisting of Fe and inevitable impurities, and satisfying equation (1), Cr+3.3Mo+20N<=38 (1) wherein, Cr, Mo and N show the content of each ingredients by weight %.

Description

Containing the stainless steel that uses under organic acid and the salt time-sharing environment
Technical field
This invention relates to stainless steel, its slit and corrosion resistant and anticorrosion stress-resistant crackle are good, be suitable for foodstuff manufacturing device, particularly in manufacturing processed, generate organic acid and the high food apparatus of contained common salt concn, particularly soy sauce producing apparatus such as amino acid, citric acid and acetic acid.
Background technology
Past in the producing apparatus of food, according to used food to contain composition different with operational conditions such as temperature, use the steel of stainless steel and coated inorganic or organic materials respectively, perhaps use FRP etc.The easy care of slave unit maintenance in recent years and reduction maintenance cost consider that from the angle of cleaning stainless use constantly increases especially.Usually in foodstuff manufacturing devices such as refreshment drink and beer or milk, the general stainless steels such as SUS304 and SUS316 that use more, it does not take place because of big problems such as sewing of causing of corrosion, even in addition in the food that contains salt, if near normal temperature, use, also needn't too much worry spot corrosion and crevice corrosion can take place, or the problem of local corrosion such as stress corrosion cracking, be enough to stand use.But, when manufacturing contains salinity flavouring like sauce how, even at normal temperatures, if use SUS304 and SUS316, also tangible local corrosion can take place under many circumstances, erosion resistance is insufficient.If using erosion resistance to be higher than above-mentioned stainless SUS329 is stainless steel, the possibility that produces local corrosion is less, but even so, when temperature is raise by normal temperature, also can worry to produce the stress corrosion cracking of crevice corrosion and welding portion, so its use is restricted.Therefore present situation is in the soy sauce producing apparatus of this particular surroundings, has to use the steel of coated inorganic or organic materials, perhaps uses FRP, also uses price to be higher than stainless nickelalloy and titanium etc., and does not use stainless steel.
Summary of the invention
The present invention studies in view of the above fact, and purpose is to provide and is applicable to and particularly generates organic acid during the fermentation by food apparatus, and contains the soy sauce producing apparatus of high density salt, or the stainless steel of vinegar (food double-fermented wine) equipment.
The present inventor is for being applicable to foodstuff manufacturing device, be applicable to that particularly the stainless steel in the foodstuff manufacturing device that comprises the fermenting processs such as flavouring like sauce that contain a large amount of salinities has carried out all research, the result has understood fully during the fermentation, during organic acids such as generation amino acid, citric acid and lactic acid, these acid, stainless corrosion speed is accelerated, the situation that crevice corrosion and stress corrosion cracking are quickened.
Quicken the mechanism of Corrosion of Stainless Steel as organic acid, can think during the fermentation, the amino acid that produces plays the effect as reductive agent, make the surperficial passive state epithelium of giving the stainless steel erosion resistance aging, on the other hand, citric acid, lactic acid etc. act on stainless steel surface as sequestrant, promoted not by the dissolving of oxide based inclusion in the so-called steel of water-soluble CaO, the MgO of surperficial passive state epithelium covering, form the starting point of crevice corrosion and stress corrosion cracking, make the erosion resistance variation.So distinguished in the environment that contains high density salt that organic acid exists,, at first must satisfy the condition in following (1) formula for the passive state epithelium that improves stainless steel surface and the erosion resistance of ground metal thereof.
Cr+3.3Mo+20N≥38(1)
(in the formula, Cr, Mo, N represent the content (weight %) of each composition)
If also understood fully simultaneously and reduced contained CaO, MgO in the stainless steel inclusion, it is formed with SiO 2, Al 2O 3Be main body, then can improve in the erosion resistance that contains under the organic acid high density salt environment.Just experimental result shows the condition of following by satisfying (2) formula:
Si+Al-100(Ca+Mg)≥0 (2)
And, the weight ratio of the CaO+MgO in the inclusion 20% or below, can suppress to produce in the stainless steel main corrosive crevice corrosion and stress corrosion cracking.Thereby finished the present invention.
The main points of the 1st invention of the present invention are to comprise C:0.05 weight % or following, Si≤1.00 weight %, Mn:1.00 weight % or following, P:0.040 weight % or following, S:0.003 weight % or following, Ni:40.0 weight % or following, 16.0 weight %≤Cr≤26.0 weight %, 2.0 weight %≤Mo≤8.0 weight %, 0.005 weight %≤Al≤0.100 weight %, 0.10 weight %≤N≤0.30 weight %, Mg:0.0005 weight % or following, Ca:0.0010 weight % or following, rest part are Fe and unavoidable impurities, and satisfy the condition of following (1) formula, the stainless steel that can under the environment that contains organic acid and salinity, use;
Cr+3.3Mo+20N≥38 (1)
(in the formula, Cr, Mo, N represent the content (weight %) of each composition)
The main points of the 2nd invention of the present invention are to comprise C:0.05 weight % or following, Si≤1.00 weight %, Mn:1.00 weight % or following, P:0.040 weight % or following, S:0.003 weight % or following, 15.0 weight %≤Ni≤40.0 weight %, 16.0 weight %≤Cr≤26.0 weight %, 2.0 weight %≤Mo≤8.0 weight %, 0.005 weight %≤Al≤0.100 weight %, 0.10 weight %≤N≤0.30 weight %, rest part is Fe and unavoidable impurities, and satisfy the condition of following (1) formula, the austenitic stainless steel that can under the environment that contains organic acid and salinity, use;
Cr+3.3Mo+20N≥38(1)
(in the formula, Cr, Mo, N represent the content (weight %) of each composition)
The main points of the 3rd invention of the present invention are according to the stainless steel described in the 1st invention or the 2nd invention, and wherein, above-mentioned organic acid contains amino acid and is selected from the acid more than a kind or 2 kinds or 2 kinds in citric acid, acetic acid and the lactic acid;
The main points of the 4th invention of the present invention are to comprise C:0.05 weight % or following, Si≤1.00 weight %, Mn:1.00 weight % or following, P:0.040 weight % or following, S:0.003 weight % or following, Ni:40.0 weight % or following, 16.0 weight %≤Cr≤26.0 weight %, 2.0 weight %≤Mo≤8.0 weight %, 0.005 weight %≤Al≤0.100 weight %, 0.10 weight %≤N≤0.30 weight %, Mg:0.0005 weight % or following, Ca:0.0010 weight % or following, rest part is Fe and unavoidable impurities, and satisfies the food apparatus stainless steel of following (1) formula condition;
Cr+3.3Mo+20N≥38(1)
(in the formula, Cr, Mo, N represent the content (weight %) of each composition)
The main points of the 5th invention of the present invention are to comprise C:0.05 weight % or following, Si≤1.00 weight %, Mn:1.00 weight % or following, P:0.040 weight % or following, S:0.003 weight % or following, 15.0 weight %≤Ni≤40.0 weight %, 16.0 weight %≤Cr≤26.0 weight %, 2.0 weight %≤Mo≤8.0 weight %, 0.005 weight %≤Al≤0.100 weight %, 0.10 weight %≤N≤0.30 weight %, rest part is Fe and unavoidable impurities, and the food apparatus that satisfies following (1) formula condition is with formula body stainless steel difficult to understand;
Cr+3.3Mo+20N≥38(1)
(in the formula, Cr, Mo, N represent the content (weight %) of each composition)
The main points of the 6th invention of the present invention are according to the austenitic stainless steel described in～the 5 invention of above-mentioned the 1st invention, wherein, above-mentioned stainless steel satisfies the condition of following (2) formula, and the weight ratio that makes the CaO+MgO in the oxide based inclusion in the steel is at 20 weight % or following;
Si+Al-100(Ca+Mg)≥0 (2)
(in the formula, Si, Al, Ca, Mg represent the content (weight %) of each composition
The main points of the 7th invention of the present invention are that wherein, above-mentioned stainless steel can be used for soy sauce producing apparatus or vinegar producing apparatus according to the stainless steel described in～the 6 invention of above-mentioned the 1st invention;
The main points of the 8th invention of the present invention are according to the stainless steel described in～the 7 invention of above-mentioned the 1st invention, wherein, also contain and be selected from 0.01 weight %≤Cu≤1.0 weight %, 0.01 weight %≤W≤1.0 weight %, the material more than a kind or 2 kinds or 2 kinds among 0.01 weight %≤Co≤1.0 weight %;
The main points of the 9th invention of the present invention are according to the stainless steel described in～the 8 invention of above-mentioned the 1st invention, wherein, contain 0.001 weight %≤B≤0.010 weight %.
In the stainless steel of the 1st or the 2nd invention, preferably contain and be selected from 0.01 weight %≤Cu≤1.0 weight %, 0.01 weight %≤W≤1.0 weight %, 0.01 the material more than a kind or 2 kinds or 2 kinds among weight %≤Co≤1.0 weight % also preferably contains 0.001 weight %≤B≤0.010 weight %.
The simple declaration of accompanying drawing
Fig. 1 is illustrated in the AES analytical results curve of the specimen surface in 1 week of dipping in the testing liquid.
When Fig. 2 represents to be immersed in the testing liquid, flood current potential curve over time naturally to sample.
Fig. 3 represents the ratio of CaO+MgO in relational expression Cr+3.3Mo+20N and the inclusion and free from corrosion curve is arranged in corrosion test.
Fig. 4 represents the ratio curve of the CaO+MgO in relational expression Si+Al-100 (Ca+Mg) and the inclusion.
Implement preferred plan of the present invention
As mentioned above, stainless steel of the present invention is by (i) specified chemical composition and suitable content range thereof, (ii) help to improve Cr, the Mo of erosion resistance, the relation of N especially, (iii) steel inclusion forms and constitutes that the proper content range content of their Al, Si, Ca, Mg forms, and below describes for the experimental result that forms basis of the present invention.
Experiment 1
What kind of difference is situation when the present inventor has at first studied the environment that has fermenting process and generate organic acid soy sauce producing apparatuss such as amino acid and lactic acid in this process and do not had this type of organic acid have actually.Test adopts the thick SUS316L of 2mm that sells on the market as test materials, two samples that cut into 80mm * 25mm * 2mm and 60mm * 20mm * 2mm is overlapped, and carry out 4 some resistance welding, makes to have the corrosion sample that welds the slit.General soy sauce contains multiple organic acid, but be the simplification system, following 4 kinds of testing liquids have been prepared, L-glutamic acid and aspartic acid, non-amino acid whose lactic acid, citric acid and the acetic acid of one of organic acid amino acid that the conduct that interpolation generates during the fermentation is representative.
1-is 1.: 17% salt solution
1-is 2.: 17% salt solution+1% L-glutamic acid
1-is 3.: 17% salt solution+1% L-glutamic acid+1% lactic acid
1-is 4.: 17% salt solution+1% L-glutamic acid+1% aspartic acid+1% lactic acid+0.2% citric acid+0.15% acetic acid
These 4 kinds of testing liquids are preserved down at 35 ℃, respectively said sample was flooded 1 month in each testing liquid.Dipping finishes the back and cuts with cutting machine, and the solder joint point that makes line of cut pass through to be formed by a resistance welding is examined the center at position.With its section of observation by light microscope, the length of the evaluation crevice corrosion degree of depth and stress corrosion cracking.Evaluation result is shown in table 1.Can confirm that the corrosion that takes place has only crevice corrosion, in contrast to this, in the solution (1-2.) that contains as amino acid whose L-glutamic acid, except crevice corrosion, also produces stress corrosion cracking in the solution that only contains salt (1-1.).On the other hand, contain promising non-amino acid at the same time but have the lactic acid of chelate structure and the solution of L-glutamic acid (1-3.) in, the degree of depth of crevice corrosion and stress corrosion cracking and length increase.And in salt, mix and contain in the various organic acid solution (1-4.), corrosion also obviously increases.By above result as can be known, though generate organic acids such as amino acid and lactic acid by fermenting process, contain in the soy sauce producing apparatus of high density salt environment with contain same high density salt but do not have organic acid environmental facies ratio, corrodibility obviously increases.
Table 1
Testing liquid Contain composition The maximum crevice corrosion degree of depth Maximum stress etching crack length
1-① 17% salt 14.5 μm -
1-② 17% salt+1% L-glutamic acid 15.5 μm 26.5μ m
1-③ 17% salt+1% L-glutamic acid+1% lactic acid 39.0 μm 45.0μ m
1-④ 17% salt+1% L-glutamic acid+1% aspartic acid+1% lactic acid+0.2% citric acid+0.15% acetic acid 70.0 μm 71.0μ m
Experiment 2
In order to verify the mechanism of the corrodibility increase that is caused by this class organic acid, the present inventor has carried out surface analysis to being immersed in the SUS316L that contains in the organic acid high density salt solution for a long time, and has carried out electrochemical gaging in its solution.Specifically be 3 kinds of testing liquids of modulation:
2-is 1.: 17% salt solution
2-is 2.: 17% salt solution+1% L-glutamic acid
2-is 3.: 17% salt solution+1% lactic acid
These solution are preserved down at 35 ℃, the SUS316L flat board sample that carries out wet grinding with No. 400 emery papers is flooded a week in above-mentioned 3 kinds of experimental liquids, its surperficial passive state epithelium structure is analyzed with auger electron spectroscopy instrument (below be designated as AES).With scanning electronic microscope (below be designated as SEM) specimen surface behind the same dipping is observed.Also further with saturated calomel as reference electrode, what be determined at each sample during the 1 week dipping floods current potential naturally.Before measuring nature dipping current potential,, make the dissolved oxygen state that reaches capacity in advance to various testing liquid bubbling airs 24 hours.
At first, the AES analytical results of the specimen surface after 1 week of dipping in each solution is shown in Fig. 1.Fig. 1 represents the Ar acceleration voltage is transferred to 1kV, at depth direction surperficial passive state epithelium is constituted element and analyzes, the numerical value of putting in order as [Cr]/[Cr]+[Fe] that forms passive state epithelium intensity index.Here [Cr], [Fe] expression atom % separately, this index is high more, illustrates that the passive state epithelium is solid more, and just erosion resistance is good more.Shown in Fig. 1 is clear and definite, 17% salt solution (2-1.), or in 17% salt solution, add the difference of not finding surperficial passive state epithelium structure in the solution (2-3.) of 1% lactic acid, but in 17% salt solution, add in the solution (2-2.) of 1% L-glutamic acid, 1. 3. compare with 2-with 2-, the value of [Cr]/[Cr]+[Fe] of top layer part decreases.This explanation L-glutamic acid has played the passive state epithelium aged effect that makes.Simultaneously the potential measurement of the dipping naturally result in each solution is shown in Fig. 2, can see solution 2-1. with 2-3. in, the dipping potential variation is very little naturally when beginning from measuring, but the solution 2-that contains L-glutamic acid 2. in, after mensuration had just begun, the dipping current potential sharply reduced at once naturally.Can think from above interpretation of result,, play effect, finally make surperficial passive state epithelium instability as reductive agent as amino acid whose L-glutamic acid even in organic acid.
On the other hand, when observing in each solution the specimen surface after 1 week of dipping with SEM, solution 2-1. with 2-2. in, and compare before the dipping, do not change.Only the solution 2-that contains lactic acid 3. in, the surface is formed with small hole.This part system just has the place of inclusion originally.Result by detailed observation as can be known, though be inclusion equally, with Al 2O 3Or SiO 2As the inclusion of main body, after dipping, still exist, but, but be to dissolve selectively to come off at CaO and the high inclusion of MgO content ratio.As the mechanism of this phenomenon, can think that because lactic acid has chelate structure so preferentially react with Ca with strong affinity and Mg, it is that inclusion dissolves selectively that the result causes CaO and MgO, forms the starting point of crevice corrosion and stress corrosion cracking.In view of above reason can draw as drawing a conclusion, even in organic acid, have the lactic acid of chelate structure and citric acid etc. and also have corrosive effect of increasing, in addition, and if when having CaO and MgO as the inclusion of main body, the erosion resistance variation.
Experiment 3
More than set forth and existed organic acid to contain singularity in the soy sauce producing apparatus environment of high density salt, and organic acid causes the aging of passive state epithelium, or inclusion based on CaO or MgO is dissolved selectively and increase corrosive mechanism, then under this environment, show good corrodibility in order to find, and the stainless steel moiety that might use, the present inventor has carried out following experiment.
Press following compositing range with induction furnace (big mood dissolving stove), and the weight ratio that makes the CaO+MgO in the oxide based inclusion in the steel reaches various ratios, smelting stainless steel, obtain steel ingot, C:0.008～0.035 weight %, Si:0.02～0.24 weight %, Mn:0.13～0.92 weight %, P:0.017～0.034 weight %, S:0.001～0.003 weight %, Ni:6.44～34.83 weight %, Cr:16.51～25.12 weight %, Mo:2.06～7.47 weight %, Cu:0.01～0.86 weight %, W:0.01～0.73 weight %, Co:0.01～0.75 weight %, Al:0.006～0.092 weight %, N:0.02～0.30 weight %, Ca:0.0001～0.0052 weight %, Mg:0.0001～0.0018 weight %, B:0.0001～0.0036 weight %.Under 1250 ℃ condition, carry out 8 hours steel ingot thermal treatment, forging, cold rolling again, and under 1150 ℃, carry out the solution treatment of 30 minutes heating back water-cooleds, make the thick cold-reduced sheet of 2mm.Then from the 2mm cold-reduced sheet, take sample in the same manner, make by a resistance welding and have the sample that welds the slit with experiment 1.Corrosion test be with the fermented seasonings soy sauce that contains 17% salt of having an appointment as testing liquid, testing liquid is remained on 35 ℃, said sample was flooded 5 months in testing liquid.Behind the dipping, cut, make line of cut, its section is observed, the situation occurred of evaluation crevice corrosion or stress corrosion cracking with opticmicroscope by solder joint point nuclear portion center.Produce what the corrosion all be decided to be *, do not produce the corrosive material fully and be decided to be zero.
Fig. 3 is divided into 20% or following material and 20% above material to the weight ratio of the CaO+MgO in the oxide based inclusion in the steel, carries out the result of corrosion test respectively.The X-coordinate of Fig. 3 represents that the value of Cr+3.3Mo+20N is (in the formula, Cr, Mo, N represent the content (weight %) of each element), this value is in alloying constituent, chooses big Cr, Mo, the N of erosion resistance influence, consider from influence degree, make each element influence total amount about equally.Can be confirmed that by Fig. 3 the weight ratio of the CaO+MgO in the oxide based inclusion is 20% when above, the value of Cr+3.3Mo+20N is not just corroded after surpassing 44.In contrast, if the weight ratio of CaO+MgO 20% or when following, the value of Cr+3.3Mo+20N is not just corroded more than 38.The value of Cr+3.3Mo+20N is big more, and the good more this point of erosion resistance is conspicuous, must add corresponding high valence elements in alloy, certainly will cause cost to rise.If but the composition of controlled oxidation system inclusion, the weight ratio that makes CaO+MgO 20% or below, can reduce the lower value of the necessary Cr+3.3Mo+20N of erosion resistance.But also show simultaneously, even carry out this control, the desired value of Cr+3.3Mo+20N at least also 38 or more than, otherwise material might corrode in containing high density salt and organic acid soy sauce producing apparatus.
Then the present inventor further to for the weight ratio of CaO+MgO in the oxide based inclusion in the stable control steel 20% or following method carried out research repeatedly, the result shows, consider Ca, Mg that brick by induction furnace etc. is sneaked into, if the content of Si, the Al of deoxidation material composition is limited in a certain scope, then can reaches above-mentioned ratio.Just find as shown in Figure 4, if the content of Si, Al is each defined in the scope of 0.01～0.25 weight %, 0.005～0.100 weight %, and the relation with contents that makes Ca and Mg satisfies Si+Al-100 (Ca+Mg) 〉=0, then might stably make the weight ratio of the CaO+MgO in the inclusion reach 20% or below.As mentioned above, can draw such viewpoint, promptly, can be provided in and contain the austenitic stainless steel that has good corrosion resistance in high density salt and the organic acid soy sauce producing apparatus by control Cr, Mo, N and Si, the scope of Al composition and the composition of inclusion.
The reason that each composition is limited below is described.
C:0.05 weight % or following C when welding, are to bring out the element that sensitization reduces erosion resistance especially, thus wish that its content is lower, but extremely reduce its content, can cause intensity to reduce, increase manufacturing cost simultaneously.Because allowing, the content of C reaches 0.05 weight %, so be worth as higher limit with this.
Si:1.00 weight % or following
Si is for the deoxidation effective elements, and particularly in order to reduce the ratio of the CaO+MgO in the oxide based inclusion in the steel, with the common main body that constitutes oxide based inclusion of aluminium, Si is the ideal element.If but add excessive, then when reaching capacity, its effect can cause ductility to reduce and the intensity rising, but also can increase separating out of equal with the x mutually intermetallic compound of σ, make erosion resistance reduce, thus its amount must 1.0% or below, preferably 0.70% or below, 0.50% or below, 0.25% or below, 0.20% or below, more preferably 0.10% or below be advisable.
Mn:1.00 weight % or following
Mn is suppressing σ mutually and aspect the separating out of the equal intermetallic compound of x, reduce in order to suppress erosion resistance in addition, must reduce the element of its consumption as far as possible, therefore, its consumption must be at 1.00 weight % or following, preferably at 0.30 weight % or following, more preferably 0.20 weight % or following being advisable.
P:0.040 weight % or following P are the elements of unavoidably sneaking into as impurity, and the angle of segregation easily, erosion resistance and hot workability is considered from crystal boundary, wishes that its consumption is less.If but extreme reduces the content of P, then can cause manufacturing cost to increase.The permissible value of P content can reach 0.040 weight %, so be worth as higher limit with this.But, preferably 0.030 weight % or following being advisable.
S:0.003 weight % or following the same with P, S also is the element of unavoidably sneaking into as impurity, the angle of segregation easily, erosion resistance and hot workability is considered from crystal boundary, wishes that its consumption is less.When its content surpasses 0.003 weight %, its hazardous property can obviously appear, so its content is limited to 0.003 weight % or following particularly.But preferably 0.002 weight % or following being advisable.
Ni:40.0 weight % or following
Ni is suppressing σ mutually and be effective elements aspect the separating out of the intermetallic compound that equates of x, and this is external when making tissue formation austenite, also is must obligato element.It is especially to improving anticorrosion stress-resistant crackle effective elements.If but its content surpasses 40.0 weight %, then can cause hot workability variation and thermal distortion impedance to increase.Therefore the content with Ni is limited to 40.0 weight % or following.The content of preferred Ni is at 18.0～30 weight %, and is if at 24.0～26 weight %, then even more ideal.
Cr:16.0 weight %≤Cr≤26.0 weight %Cr are for improving the slit and corrosion resistant effective elements, in order to obtain this effect, must contain the above Cr of 16.0 weight %.If but content surpasses 26.0 weight %, then can promote to form σ phase and the equal intermetallic compound of x, can reduce the slit and corrosion resistant performance on the contrary, so its consumption is defined as 16.0 weight %～26.0 weight %.The content of preferred Cr 20.0 weight % or more than, if 22.0 weight % or more than, then even more ideal.
Mo:2.0 weight %≤Mo≤8.0 weight %
Mo also is for improving the slit and corrosion resistant effective elements, in order to obtain this effect, its content must be more than 2.0 weight %, if but content surpasses 8.0 weight %, then can increase separating out of intermetallic compound, can reduce corrosion resistance nature on the contrary, so the content of Mo is limited to 2.0 weight %～8.0 weight %.The content of preferred Mo 3.0 weight % or more than, if at 5.0 weight % or above then even more ideal.
Al:0.005 weight %≤Al≤0.100 weight %
Al is strong reductor, as tests shown in 3, particularly in order to reduce the ratio of the CaO+MgO in the oxide based inclusion in the steel, makes itself and Si constitute oxide based inclusion main body, the interpolation of essential positive regard Al jointly.If but make its content surpass 0.10 weight %, then when its effect reaches capacity, also can encourage separating out of intermetallic compound, so its content is limited to 0.10 weight % or following.
N:0.10 weight %≤N≤0.30 weight %
N equally with Cr, Mo can improve slit and corrosion resistant, and suppresses the effective element that intermetallic compound is separated out simultaneously, in order to obtain this effect, must make its content 0.10 weight % or more than.If but its content surpasses 0.30 weight %, then the thermal distortion impedance is extremely risen, and can hinder hot workability, so the content of N is defined as 0.10 weight %～0.30 weight %.The content of preferred N 0.15 weight % or more than.
Mg:0.0005 weight % or following
Mg is the element that unavoidably will contain in the oxide based inclusion in the general steel, can obviously be found out by the result who tests 3, considers from the angle of erosion resistance, must make its content at 0.0005 weight % or following.If just surpass 0.0005 weight %, then easy formation dissolves in has chelate structure organic acid inclusion, causes erosion resistance to reduce.
Ca:0.0010 weight % or following
Ca is also the same with Mg, is the element that unavoidably will contain in the oxide based inclusion in the steel, can obviously be found out by the result who tests 3, considers from the erosion resistance angle, must make its content at 0.0010 weight % or following.If just surpass 0.0010 weight %, then easy formation dissolves in has chelate structure organic acid inclusion, causes erosion resistance to reduce.
Cu:0.01～1.0 weight %
W:0.01～1.0 weight %
Co:0.01～1.0 weight %
Among the present invention, on the basis of mentioned component, can also contain 0.10 weight %≤Cu≤1.0 weight %, 0.01 weight %≤W≤1.0 weight %, the element more than a kind or 2 kinds or 2 kinds of 0.10 weight %≤Co≤1.0 weight %.These elements are normally effective to improving erosion resistance.But in order to obtain this effect, must make its content 0.01 weight % or more than.On the other hand, if its content surpasses 1.0 weight %, then can hinder hot workability, so the content of various elements is decided to be 0.01 weight %～1.0 weight % respectively.
B:0.001 weight %≤B≤0.010 weight %
Among the present invention, on the basis of mentioned component, can also contain 0.001 weight %≤B≤0.010 weight %.B is for improving the very effective element of hot workability, but its content is when 0.001 weight % is following, and the non-constant of this effect if surpass 0.010 weight %, then can reduce hot workability on the contrary.Therefore, the content of B is defined as 0.001 weight %～0.010 weight %.
Cr+3.3Mo+20N≥38
Among the present invention Cr,, the relation of Mo, the N reason that is defined as following relational expression is because the result of experiment 3 shows, if Cr+3.3Mo+20N is lower than 38, even then reach the weight ratio that optimum extent is controlled the CaO+MgO in the oxide based inclusion in the steel of main composition key element of the present invention, in containing high density salt and organic acid soy sauce producing apparatus, do not have enough erosion resistances by the content that makes Si, Al, Ca, Mg yet.Preferred Cr+3.3Mo+20N 40 or more than, if 44 or more than, then even more ideal.
Cr+3.3Mo+20N≥38
(in the formula, Cr,, Mo, N represent the content (weight %) of each elemental composition) weight ratio of CaO+MgO in the steel in the oxide based inclusion is 20% or following Si+Al-100 (Ca+Mg) 〉=0
Among the present invention, the weight ratio of the CaO+MgO in the oxide based inclusion in the steel be limited to 20% or below, and the reason that the relation of Si, Al, Ca, Mg is defined as following relational expression is, the result of experiment 3 shows, if do not satisfy this relation, then in containing high density salt and organic acid soy sauce producing apparatus, there are not enough erosion resistances.
Si+Al-100(Ca+Mg)≥0
(in the formula, Si, Al, Ca, Mg represent the content (weight %) of each elemental composition)
Among the present invention, there is no need to make that all oxides is that inclusion is SiO in the steel 2, Al 2O 3, CaO, MgO one matter or composite oxides, no matter be what kind of inclusion, as long as the ratio that satisfies CaO+MgO is 20% or following.Certainly also can be the oxide compound that forms separately of other oxide compound sometimes or form composite oxides jointly with above-mentioned oxide compound.Can consider MnO, FeO, TiO as other oxide compound 2Deng.
Embodiment and comparative example
Be base description situation of the present invention with embodiment shown below below.Here also write down the steel of the various compositions shown in the above-mentioned experiment 3 in the lump.
At first with induction furnace to steel of the present invention with relatively carry out melting with steel with moiety shown in table 2 and the table 3, obtain steel ingot.Under 1250 ℃, carry out 8 hours steel ingot thermal treatment, forging, cold rolling again, and the solution treatment of under 1150 ℃, carrying out 30 minutes heating back water-cooleds, the cold-reduced sheet that thickness is 2mm made.
Then get two samples, be of a size of 80mm * 25mm * 2mm and 60mm * 20mm * 2mm, carry out wet grinding, after the degreasing, make the sample that has soldered by a resistance welding with No. 400 emery papers from the 2mm cold-reduced sheet.
Corrosion test be with the fermented seasonings soy sauce that contains 17% salt of having an appointment as testing liquid, this testing liquid is kept under 35 ℃ the condition, sample was flooded 5 months in testing liquid.After dipping finishes, cut off along the solder joint point nuclear portion center that spot welding forms, with the section of this slotted section of observation by light microscope, the situation occurred of evaluation crevice corrosion or stress corrosion cracking.Observations is shown in table 3.
Zero mark: any corrosion of crevice corrosion, stress corrosion cracking does not take place in expression, demonstrates the material of good corrosion resistance.
* mark: crevice corrosion, two kinds of corrosive materials of stress corrosion cracking take place in expression.Evaluation result is shown in table 3.
Table 2
No. C Si Mn P S Ni Cr Mo Al N Ca Mg Cu W Co B
Steel of the present invention 1 0.035 0.12 0.23 0.021 0.001 15.17 16.51 4.77 0.012 0.29 0.0003 0.0002 - - - -
2 0.011 0.11 0.13 0.022 0.001 18.45 19.37 5.83 0.038 0.12 0.0007 0.0001 - - - -
3 0.008 0.02 0.18 0.019 0.001 18.84 20.26 6.09 0.092 0.21 0.0006 0.0002 - - - 0.0033
4 0.009 0.23 0.20 0.020 0.002 19.31 20.41 6.24 0.041 0.23 0.0002 0.0002 0.71 - - -
5 0.011 0.20 0.18 0.020 0.001 24.56 20.97 6.05 0.019 0.22 0.0002 0.0001 - - - 0.0026
6 0.010 0.18 0.26 0.021 0.001 24.98 21.02 6.76 0.026 0.20 0.0003 0.0001 0.32 - - -
7 0.010 0.24 0.20 0.019 0.001 29.23 23.03 7.47 0.044 0.22 0.0009 0.0002 - - - 0.0036
8 0.006 0.09 0.21 0.018 0.001 25.85 23.13 5.34 0.052 0.19 0.0003 0.0004 - - - 0.0031
9 0.007 0.06 0.20 0.020 0.001 25.78 23.31 5.53 0.017 0.20 0.0004 0.0003 - - - 0.0022
10 0.009 0.13 0.20 0.017 0.002 24.57 20.14 6.18 0.019 0.22 0.0006 0.0002 0.86 - - 0.0041
11 0.009 0.21 0.21 0.019 0.001 25.03 22.87 5.72 0.023 0.19 0.0008 0.0005 - 0.73 - -
12 0.010 0.17 0.17 0.022 0.001 25.11 20.63 6.02 0.034 0.22 0.0001 0.0003 - - 0.75 -
13 0.011 0.18 0.38 0.034 0.003 24.89 26.84 2.06 0.063 0.30 0.0003 0.0002 - - - -
14 0.009 0.23 0.23 0.019 0.001 6.55 24.60 3.22 0.035 0.17 0.0004 0.0002 - 0.16 - 0.0017
15 0.010 0.20 0.34 0.020 0.001 6.76 25.12 3.41 0.029 0.16 0.0005 0.0001 - 0.34 - -
Comparative steel 16 0.013 0.18 0.22 0.018 0.003 10.81 16.78 2.13 0.006 0.02 0.0008 0.0002 - - - -
17 0.010 0.17 0.19 0.019 0.002 15.04 18.13 3.98 0.008 0.15 0.0036 * 0.0004 - - - -
18 0.011 0.24 0.16 0.019 0.001 13.67 19.24 3.56 0.016 0.06 0.0009 0.0002 - - - -
19 0.012 0.17 0.20 0.018 0.001 25.46 20.74 5.02 0.009 0.15 0.0036 * 0.0004 - - - -
20 0.011 0.25 0.19 0.020 0.001 24.95 20.87 5.37 0.026 0.17 0.0052 * 0.0018 * - - - -
21 0.010 0.14 0.20 0.020 0.001 24.64 24.26 2.31 0.037 0.26 0.0006 0.0003 - - - -
22 0.008 0.21 0.18 0.017 0.001 6.44 24.72 3.16 0.037 0.17 0.0018 * 0.0009 * - - - -
Numerical value in the table is weight %, and rest part is an iron. *Situation beyond the expression scope of the invention.
Table 3
N o. Cr+3.3Mo +20N Si+Al -100(Ca+ Mg) CaO+MgO ratio (%) in the inclusion Corrosion test result in soy sauce
Steel of the present invention 1 38.05 0.082 15.1 ○
2 41.01 0.068 12.6 ○
3 44.56 0.032 13.5 ○
4 45.60 0.231 ＜0.1 ○
5 45.34 0.189 0.2 ○
6 47.33 0.166 1.6 ○
7 52.08 0.174 2.5 ○
8 44.55 0.072 18.3 ○
9 45.56 0.007 16.2 ○
10 44.93 0.069 9.4 ○
11 45.55 0.103 11.8 ○
12 44.90 0.164 4.0 ○
13 39.63 0.193 3.2 ○
14 38.63 0.205 ＜0.1 ○
15 39.57 0.169 6.8 ○
Comparative steel 16 24.21 * 0.086 14.9 ×
17 34.26 * -0.002 * 25.3 ×
18 32.19 * 0.146 6.0 ×
19 40.31 -0.221 * 36.3 ×
20 41.99 -0.424 * 95.1 ×
21 37.09 * 0.087 10.2 ×
22 38.55 -0.081 * 23.7 ×
*Situation beyond the expression scope of the invention.
The index of Cr+3.3Mo+20N shown in the table 3 and Si+Al-100 (Ca+Mg),
The weight ratio (%) of average CaO+MgO in the oxide based inclusion in the steel also is shown simultaneously, Cr+3.3Mo+20N 〉=38, and Si+Al-100 (Ca+Mg) 〉=0, the weight ratio of adding the CaO+MgO in the inclusion is 20% or following steel of the present invention, in such containing in high density salt and the organic acid soy sauce environment, do not corrode, compare as can be known it is the material with excellent anticorrosive with comparative steel.
In addition, for the steel of the present invention and the comparative example of moiety shown in table 4 that changes the Mn amount and the table 5, use the method identical with table 2, make the thick cold-reduced sheet of 2mm, and, get two samples of 80 * 25 * 2mm and 60 * 20 * 2mm according to the identical method of previous example from this cold-reduced sheet.
And carry out the corrosion test identical, the result is shown in table 5 with precedent.Obtained same result.
Table 4
No. C Si Mn P S Ni Cr Mo Al N Ca Mg Cu W Co B
Steel of the present invention 1 0.03 0.12 0.50 0.021 0.001 15.17 16.51 4.77 0.012 0.29 0.0003 0.0002 - - - -
2 0.01 0.11 0.60 0.022 0.001 18.45 19.37 5.83 0.038 0.12 0.0007 0.0001 - - - -
3 0.00 0.02 0.70 0.019 0.001 18.84 20.26 6.09 0.092 0.21 0.0006 0.0002 - - - 0.0033
4 0.00 0.23 0.60 0.020 0.002 19.31 20.41 6.24 0.041 0.23 0.0002 0.0002 0.71 - - -
5 0.01 0.20 0.52 0.020 0.001 24.56 20.97 6.05 0.019 0.22 0.0002 0.0001 - - - 0.0026
6 0.01 0.18 0.53 0.021 0.001 24.98 21.02 6.76 0.026 0.20 0.0003 0.0001 0.32 - - -
7 0.01 0.24 0.52 0.019 0.001 29.23 23.03 7.47 0.044 0.22 0.0009 0.0002 - - - 0.0036
8 0.00 0.09 0.57 0.018 0.001 25.85 23.13 5.34 0.052 0.19 0.0003 0.0004 - - - 0.0031
9 0.00 0.06 0.92 0.020 0.001 25.78 23.31 5.53 0.017 0.20 0.0004 0.0003 - - - 0.0022
10 0.00 0.13 0.60 0.017 0.002 24.57 20.14 6.18 0.019 0.22 0.0006 0.0002 0.86 - - 0.0041
11 0.00 0.21 0.53 0.019 0.001 25.03 22.87 5.72 0.023 0.19 0.0008 0.0005 - 0.73 - -
12 0.01 0.17 0.51 0.022 0.001 25.11 20.63 6.02 0.034 0.22 0.0001 0.0003 - - 0.75 -
13 0.01 0.18 0.55 0.034 0.003 24.89 26.84 2.06 0.063 0.30 0.0003 0.0002 - - - -
14 0.00 0.50 0.52 0.019 0.001 6.55 24.60 3.22 0.035 0.17 0.0004 0.0002 - 0.16 - 0.0017
15 0.01 0.70 0.54 0.020 0.001 6.76 25.12 3.41 0.029 01.6 0.0005 0.0001 - 0.34 - -
Comparative steel 16 0.01 0.18 0.54 0.018 0.003 10.81 16.78 2.13 0.006 0.02 0.0008 0.0002 - - - -
17 0.01 0.17 0.54 0.019 0.002 15.04 18.13 3.98 0.008 0.15 0.0036 * 0.0004 - - - -
18 0.01 0.24 0.55 0.019 0.001 13.67 19.24 3.56 0.016 0.06 0.0009 0.0002 - - - -
19 0.01 0.17 0.57 0.018 0.001 25.46 20.74 5.02 0.009 0.15 0.0036 * 0.0004 - - - -
20 0.01 0.25 0.56 0.020 0.001 24.95 20.87 5.37 0.026 0.17 0.0052 * 0.0018 * - - - -
21 0.01 0.14 0.52 0.020 0.001 24.64 24.26 2.31 0.037 0.26 0.0006 0.0003 - - - -
22 0.00 0.21 0.45 0.017 0.001 6.44 24.72 3.16 0.037 0.17 0.0018 * 0.0009 * - - - -
Numerical value in the table is weight %, and rest part is an iron. *Situation beyond the expression scope of the invention.
Table 5
No. Cr+3.3Mo +20N Si+Al -100(Ca+M g) CaO+MgO ratio (%) in the inclusion Corrosion test result in soy sauce
Steel of the present invention 1 38.05 0.082 15.1 ○
2 41.01 0.068 12.6 ○
3 44.56 0.032 13.5 ○
4 45.60 0.231 ＜0.1 ○
5 45.34 0.189 0.2 ○
6 47.33 0.166 1.6 ○
7 52.08 0.174 2.5 ○
8 44.55 0.072 18.3 ○
9 45.56 0.007 16.2 ○
10 44.93 0.069 9.4 ○
11 45.55 0.103 11.8 ○
12 44.90 0.164 4.0 ○
13 39.63 0.193 3.2 ○
14 38.63 0.475 ＜0.1 ○
15 39.57 0.669 6.8 ○
Comparative steel 16 24.21 * 0.086 14.9 ×
17 34.26 * -0.002 * 25.3 ×
18 32.19 * 0.146 6.0 ×
19 40.31 -0.221 * 36.3 ×
20 41.99 -0.424 * 95.1 ×
21 37.09 * 0.087 10.2 ×
22 38.55 -0.O81 * 23.7 ×
*Situation beyond the expression scope of the invention.
Practicality on the industry
As described above, in the stainless steel of the present invention, by make Cr, Mo, N amount separately with respect to its total amount reach requirement ratio or more than, and Si, Al, Ca, Mg are limited to the composition of oxide based field trash in the interior method control steel of prescribed limit, can develop for food apparatus, particularly contain high concentration salt and generate during the fermentation the stainless steel that the organic acid soy sauce has excellent anticorrosive.

Claims (11)

1. stainless steel, it is characterized in that comprising C:0.05 weight % or following, Si≤1.00 weight %, Mn:1.00 weight % or following, P:0.040 weight % or following, S:0.003 weight % or following, 6.55 weight %≤Ni≤40.0 weight %, 16.0 weight %≤Cr≤26.0 weight %, 2.0 weight %≤Mo≤8.0 weight %, 0.005 weight %≤Al≤0.100 weight %, 0.10 weight %≤N≤0.30 weight %, Mg:0.0005 weight % or following, Ca:0.0010 weight % or following, rest part is Fe and unavoidable impurities, and satisfies following (1) formula condition, comprise amino acid and be selected from citric acid containing, the organic acid more than a kind or 2 kinds or 2 kinds in acetic acid and the lactic acid and the environment of salinity use down
Cr+3.3Mo+20N≥38(1)
In the formula, Cr, Mo, N represent the content of each composition, in weight %,
And above-mentioned stainless steel satisfies the condition of following (2) formula, and the weight ratio that makes the CaO+MgO in the oxide based inclusion in the steel is at 20 weight % or following,
Si+Al-100(Ca+Mg)≥0(2)
In the formula, Si, Al, Ca, Mg represent the content of each composition, in weight %.
2. stainless steel, it is characterized in that comprising C:0.05 weight % or following, Si≤1.00 weight %, Mn:1.00 weight % or following, P:0.040 weight % or following, S:0.003 weight % or following, 15.00 weight %≤Ni≤40.0 weight %, 16.0 weight %≤Cr≤26.0 weight %, 2.0 weight %≤Mo≤8.0 weight %, 0.005 weight %≤Al≤0.100 weight %, 0.10 weight %≤N≤0.30 weight %, rest part is Fe and unavoidable impurities, and satisfies the condition of following (1) formula, comprise amino acid and be selected from citric acid containing, the organic acid more than a kind or 2 kinds or 2 kinds in acetic acid and the lactic acid and the environment of salinity use down
Cr+3.3Mo+20N≥38(1)
In the formula, Cr, Mo, N represent the content of each composition, in weight %,
And above-mentioned stainless steel satisfies the condition of following (2) formula, and the weight ratio that makes the CaO+MgO in the oxide based inclusion in the steel is at 20 weight % or following,
Si+Al-100(Ca+Mg)≥0(2)
In the formula, Si, Al, Ca, Mg represent the content of each composition, in weight %.
3. food apparatus stainless steel, it is characterized in that comprising C:0.05 weight % or following, Si≤1.0 weight %, Mn:1.00 weight % or following, P:0.040 weight % or following, S:0.003 weight % or following, 6.55 weight %≤Ni≤40.0 weight %, 16.0 weight %≤Cr≤26.0 weight %, 2.0 weight %≤Mo≤8.0 weight %, 0.005 weight %≤Al≤0.100 weight %, 0.10 weight %≤N≤0.30 weight %, rest part is Fe and unavoidable impurities, and satisfies the condition of following (1) formula
Cr+3.3Mo+20N≥38(1)
In the formula, Cr, Mo, N represent the content of each composition, in weight %,
And above-mentioned stainless steel satisfies the condition of following (2) formula, and the weight ratio that makes the CaO+MgO in the oxide based inclusion in the steel is at 20 weight % or following,
Si+Al-100(Ca+Mg)≥0(2)
In the formula, Si, Al, Ca, Mg represent the content of each composition, in weight %.
4. food apparatus stainless steel, it is characterized in that comprising C:0.05 weight % or following, Si≤1.00 weight %, Mn:1.00 weight % or following, P:0.040 weight % or following, S:0.003 weight % or following, 15.0 weight %≤Ni≤40.0 weight %, 16.0 weight %≤Cr≤26.0 weight %, 2.0 weight %≤Mo≤8.0 weight %, 0.005 weight %≤Al≤0.100 weight %, 0.10 weight %≤N≤0.30 weight %, rest part is Fe and unavoidable impurities, and satisfies the condition of following (1) formula
Cr+3.3Mo+20N≥38(1)
In the formula, Cr, Mo, N represent the content of each composition, in weight %,
And above-mentioned stainless steel satisfies the condition of following (2) formula, and the weight ratio that makes the CaO+MgO in the oxide based inclusion in the steel is at 20 weight % or following,
Si+Al-100(Ca+Mg)≥0(2)
In the formula, Si, Al, Ca, Mg represent the content of each composition, in weight %.
5. according to the stainless steel described in the claim 1～4, it is characterized in that above-mentioned stainless steel is used for soy sauce producing apparatus or vinegar producing apparatus.
6. according to the stainless steel described in the claim 1～4, it is characterized in that, also contain 0.01 weight %≤Cu≤1.0 weight %, 0.01≤W≤1.0 weight %, among 0.01≤Co≤1.0 weight % more than a kind or 2 kinds or 2 kinds.
7. stainless steel according to claim 5 is characterized in that, also contains 0.01 weight %≤Cu≤1.0 weight %, 0.01≤W≤1.0 weight %, among 0.01≤Co≤1.0 weight % more than a kind or 2 kinds or 2 kinds.
8. according to the stainless steel described in the claim 1～4, it is characterized in that, contain 0.001 weight %≤B≤0.010 weight %.
9. stainless steel according to claim 5 is characterized in that, contains 0.001 weight %≤B≤0.010 weight %.
10. stainless steel according to claim 6 is characterized in that, contains 0.001 weight %≤B≤0.010 weight %.
11. stainless steel according to claim 7 is characterized in that, contains 0.001 weight %≤B≤0.010 weight %.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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* Cited by examiner, † Cited by third party
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