CN112342454B - 316L stainless steel and preparation method thereof - Google Patents
316L stainless steel and preparation method thereof Download PDFInfo
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- CN112342454B CN112342454B CN202011108299.4A CN202011108299A CN112342454B CN 112342454 B CN112342454 B CN 112342454B CN 202011108299 A CN202011108299 A CN 202011108299A CN 112342454 B CN112342454 B CN 112342454B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
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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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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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
- C22C38/18—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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- 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
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
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Abstract
The invention provides 316L stainless steel and a preparation method thereof. The preparation method comprises the following steps: carrying out EAF (easy open Filter) rough refining on a mixed material of 316L stainless steel; carrying out AOD pre-desulfurization on the mixed material subjected to EAF coarse refining; performing AOD refining on the mixed material subjected to AOD pre-desulfurization; performing LT slagging-off treatment on the mixed material subjected to AOD refining; performing VOD vacuum desulfurization on the mixed material subjected to LT slagging-off treatment; and continuously casting the mixed material subjected to VOD vacuum desulfurization to obtain 316L stainless steel. The 316L stainless steel prepared by the method can effectively improve the scale defects at the edges of cold (hot) rolled plates.
Description
Technical Field
The invention relates to a preparation method of stainless steel, in particular to a preparation method of 316L stainless steel, and belongs to the technical field of metallurgy.
Background
The 316L stainless steel is stainless steel with higher erosion resistance developed on the basis of 304 stainless steel, and is widely applied to the fields of pressure vessels, transportation, technical products, mechanical manufacturing, decoration, welded pipes and the like, so that the requirement on the surface quality of the 316L stainless steel cold-rolled plate is higher.
The edge line scale defects are the higher type of the surface defect occurrence probability of the cold-rolled sheet, and are more generated on the surface of the hot-rolled sheet, thereby having larger influence on the product quality and the rate of qualified products. The content of S in the continuously cast slab has a large correlation with the edge line scale defects on the surface of the cold (hot) rolled sheet because the inter-grain bonding force and plasticity are weakened by the concentration of sulfur between dendrites during solidification of austenitic stainless steel. Sulfur generally exists in steel materials, mainly exists in steel in a FeS form, the FeS melting point is 1190 ℃, can be infinitely dissolved in molten steel, but has low solubility in solid steel, and is easy to form a low-melting point eutectic compound FeO-FeS with Fe to be distributed on austenite crystal boundaries, and can be cracked along the crystal boundaries when being rolled at the temperature of above 988 ℃. In addition, when the sulfur content in steel is high, sulfide inclusions such as MnS and NiS are also increased, and plasticity of stainless steel at the inclusions is lowered, resulting in cracks during rolling.
Therefore, one of the factors influencing the solution of the edge line scale defect of the 316L stainless steel cold (hot) rolled plate is as follows: the content of S in the plain steel is reduced, the precipitation of sulfides at a crystal boundary is controlled, the plasticity of the stainless steel is improved, and the surface of the stainless steel is prevented from cracking under the rolling action. Therefore, how to deeply desulfurize is an urgent problem to be solved.
Disclosure of Invention
In order to solve the above-mentioned technical problems, it is an object of the present invention to provide a method of manufacturing 316L stainless steel that can effectively improve the line scale defect at the edge of a cold (hot) rolled plate.
It is yet another object of the present invention to provide 316L stainless steel having a low sulfur content.
In order to achieve any of the above objects, the present invention provides, in a first aspect, a method of manufacturing a 316L stainless steel, the method comprising:
performing EAF (easy open edge) rough refining on a mixed material of 316L stainless steel, wherein the soup outlet temperature of the EAF is more than 1500 ℃;
performing AOD pre-desulfurization on the mixed material after EAF rough refining, wherein the S content in the mixed material after AOD pre-desulfurization is less than or equal to 500 ppm;
performing AOD refining on the mixed material subjected to AOD pre-desulfurization;
performing LT slagging-off treatment on the mixed material subjected to AOD refining, wherein the S content in the mixed material subjected to the LT slagging-off treatment is less than or equal to 50 ppm;
performing VOD vacuum desulfurization on the mixed material subjected to LT slagging-off treatment, wherein the S content in the mixed material is less than or equal to 30ppm after the VOD vacuum desulfurization treatment;
and continuously casting the mixed material subjected to VOD vacuum desulfurization to obtain 316L stainless steel.
In a specific embodiment of the present invention, the AOD pre-desulfurization process sequentially comprises:
3 kg/ton steel-5 kg/ton steel fluorite is added, lime is added in batches for 2 to 4 times, 18 kg/ton steel-22 kg/ton steel is totally added, 4 kg/ton steel-7 kg/ton steel of silicon carbide is added, and bottom blowing stirring is carried out for 15 to 20 minutes.
In a specific embodiment of the present invention, the AOD refining process comprises:
and adding ferrosilicon (preferably, the silicon content in the ferrosilicon is 75%) for reduction, wherein the adding amount is 20 kg/ton steel-50 kg/ton steel, simultaneously adding lime and fluorite for slagging and desulfurization, the adding amount of the lime is 15 kg/ton steel-18 kg/ton steel, the adding amount of the fluorite is 2 kg/ton steel-4 kg/ton steel, blowing argon for stirring for more than or equal to 8min, and controlling the alkalinity (the alkalinity refers to the mass ratio of calcium oxide to silicon oxide) to be less than 2.2 (preferably less than 2.0). And observing the color condition of the slag after the operation is finished, wherein the whiter the color of the slag is, the better the reduction desulfurization is, 1-2kg of ferrosilicon is additionally added per ton of steel according to the whitening degree of the color of the slag, and the argon is blown for stirring for more than or equal to 2 min.
In one embodiment of the present invention, the VOD vacuum desulfurization process comprises:
and the VOD vacuum degree is 20mbar-30mbar (preferably 26mbar), lime and fluorite (the mass ratio of the fluorite to the lime is 20% -30%) are added for slagging and desulfurizing again, wherein the adding amount of the lime is 15 kg/ton steel-18 kg/ton steel, and the argon blowing stirring is not less than 30 min.
In one embodiment of the invention, when the EAF is subjected to rough smelting, the higher the temperature of the soup is, the better the temperature is, the more preferably 1540 ℃ is, on the basis of controlling the electric quantity of the EAF to be 45-55KWH per ton of steel. And after the molten liquid is filled into a transfer ladle, the molten liquid enters a slagging-off station for slagging-off, and after slagging-off is completed, the molten liquid is filled into an AOD refining furnace body.
In one embodiment of the present invention, the raw material composition of the mixed material of 316L stainless steel is:
C≤0.03％；Si≤0.75％；Mn≤2.00％；P≤0.045％；S≤0.030％；Ni：10.0％-14.0％；
cr: 16.0% -18.0%; mo: 2.0% -3.0%, and the balance of Fe.
In a specific embodiment of the invention, after AOD refining is finished, tapping is carried out to a casting ladle, the casting ladle enters an LT station for slagging-off treatment, and slagging-off needs to be carried out completely to prevent resulfurization in slag.
The invention also provides 316L stainless steel, and the 316L stainless steel is prepared by the preparation method of the 316L stainless steel.
In one embodiment of the invention, the 316L stainless steel (plain steel) S is less than or equal to 30ppm, and has high-temperature plasticity and rolling performance of the stainless steel and low edge line scale defects of a cold (hot) rolled plate.
According to the preparation method of the 316L stainless steel, the AOD pre-desulfurization and the VOD vacuum desulfurization are combined, the desulfurization effect is ensured, the S content of the plain steel is less than or equal to 30ppm, the high-temperature plasticity and the rolling performance of the stainless steel are improved, and the scale defect of the edge line of a cold (hot) rolled plate is overcome. Meanwhile, by combining AOD pre-desulfurization with VOD vacuum desulfurization, low alkalinity (alkalinity below 2.0) desulfurization can be achieved.
Drawings
Fig. 1 is a process flow diagram of a method of making the 316L stainless steel of example 1.
FIG. 2a is a macroscopic image of the line scale defects at the edge of the cold rolled sheet in example 1.
FIG. 2b is an electron probe microanalysis EPMA image of the scale defects at the edges of the cold rolled sheet in example 1.
Detailed Description
The technical solutions of the present invention will be described in detail below in order to clearly understand the technical features, objects, and advantages of the present invention, but the present invention is not limited to the practical scope of the present invention.
Example 1
The embodiment provides 316L stainless steel which is prepared by the following steps, and the specific flow is shown in figure 1:
EAF soup (EAF raw materials are generally waste stainless steel, ferrochromium, nickel cold wash and lime) is at 1540 ℃. And after the molten liquid is filled into a transfer ladle, the molten liquid enters a slagging-off station for slagging-off, and after slagging-off is completed, the molten liquid is filled into an AOD refining furnace body.
After the AOD refining is started, firstly carrying out pre-desulfurization treatment, and sequentially adding fluorite: 4 kg/ton steel, 3 portions of lime are added in batches: total 20 kg/ton steel, silicon carbide: 5 kg/ton steel, bottom blowing and stirring for 20 minutes, and after pre-desulfurization is finished, S is less than or equal to 500ppm, so that the later-stage desulfurization pressure of AOD is reduced.
After the AOD pre-desulfurization treatment is finished, oxygen blowing and decarburization are carried out, after the decarburization is finished, ferrosilicon with the Si content of 75% is added for reduction, the adding amount is 30 kg/ton steel, lime and fluorite are simultaneously added for slagging and desulfurization, the adding amount of lime is 15 kg/ton steel, the adding amount of fluorite is 4 kg/ton steel, argon blowing and stirring are carried out for more than or equal to 8min, the alkalinity is controlled to be 2.0, the slag color condition is observed after the operation is finished, the more white the slag color indicates that the reduction and desulfurization are better, 1.5 kg/ton steel is additionally added according to the whitening degree of the slag color, and argon blowing and stirring are carried out for 5 min.
Tapping steel to a casting ladle after AOD refining is finished, and enabling the casting ladle to enter an LT station for slagging-off treatment, wherein slagging-off needs to be completely carried out, resulfurization in slag is prevented, and S is less than or equal to 50 ppm.
And the ladle enters VOD for vacuum desulfurization treatment after LT treatment to realize deep desulfurization, so that S in the molten steel is less than or equal to 30 ppm. VOD vacuum degree: 26mbar, adding lime and fluorite for slagging and desulfurizing, blowing argon and stirring for 30min, wherein the argon amount is preferably steel slag surging.
The images of the scale defects at the edges of the cold rolled sheet of this example are shown in FIGS. 2a and 2 b.
Table 1 shows the probability relationship between the elemental steel S and the edge line scale defects on the surface of the stainless steel sheet, the elemental steel S is less than or equal to 30ppm, and the line scale defect rate (the number of the line scale defects generated/316L total production number): from 15% to 5%.
TABLE 1
| Plain steel S (ppm) | Rate of defects |
| <20 | 4.2％ |
| 20-30 | 5.9％ |
| >30 | 14.9％ |
Table 1 shows that the preparation method of the invention can effectively reduce the S content of the plain steel, the S content of the plain steel is low, and the occurrence of defects is obviously reduced.
Claims (8)
1. A method of making a 316L stainless steel, the method comprising:
performing EAF (easy open edge) rough refining on a mixed material of 316L stainless steel, wherein the soup outlet temperature of the EAF is more than 1500 ℃;
performing AOD pre-desulfurization on the mixed material after EAF rough refining, wherein the S content in the mixed material after AOD pre-desulfurization is less than or equal to 500 ppm; the AOD pre-desulfurization process sequentially comprises the following steps: 3 kg/ton steel-5 kg/ton steel fluorite is added, lime is added in batches for 2 to 4 times, 18 kg/ton steel-22 kg/ton steel is totally added, 4 kg/ton steel-7 kg/ton steel of silicon carbide is added, and bottom blowing stirring is carried out for 15 to 20 minutes;
performing AOD refining on the mixed material subjected to AOD pre-desulfurization;
performing LT slagging-off treatment on the mixed material subjected to AOD refining, wherein the S content in the mixed material subjected to the LT slagging-off treatment is less than or equal to 50 ppm;
performing VOD vacuum desulfurization on the mixed material subjected to LT slagging-off treatment, wherein the S content in the mixed material is less than or equal to 30ppm after the VOD vacuum desulfurization treatment; the VOD vacuum desulfurization process comprises the following steps: the VOD vacuum degree is 20mbar-30mbar, lime and fluorite are added for slagging and desulfurizing again, wherein the adding amount of the lime is 15 kg/ton steel-18 kg/ton steel, and argon blowing stirring is carried out for more than or equal to 30 min;
and continuously casting the mixed material subjected to VOD vacuum desulfurization to obtain the 316L stainless steel.
2. The production method according to claim 1, wherein the AOD refining process is:
and adding ferrosilicon for reduction, wherein the adding amount is 20 kg/ton steel-50 kg/ton steel, simultaneously adding lime and fluorite for slagging and desulfurization, the adding amount of the lime is 15 kg/ton steel-18 kg/ton steel, the adding amount of the fluorite is 2 kg/ton steel-4 kg/ton steel, blowing argon and stirring for more than or equal to 8min, and enabling the alkalinity to be lower than 2.2.
3. The production method according to claim 2, wherein the silicon iron has a silicon content of 75%.
4. The method according to claim 1, wherein the mass ratio of fluorite to lime is 20 to 30%.
5. The method of claim 1, wherein the EAF has a broth temperature of 1540 ℃.
6. The method of claim 1, wherein the 316L stainless steel has a composition of:
c is less than or equal to 0.03 percent; si is less than or equal to 0.75 percent; mn is less than or equal to 2.00 percent; p is less than or equal to 0.045%; s is less than or equal to 0.030 percent; ni: 10.0% -14.0%; cr: 16.0% -18.0%; mo: 2.0% -3.0%, and the balance of Fe.
7. A 316L stainless steel produced by the method of producing the 316L stainless steel of any of claims 1-6.
8. A316L stainless steel according to claim 7, wherein S is less than or equal to 30ppm in the 316L stainless steel.
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| CN113215503A (en) * | 2021-05-13 | 2021-08-06 | 江苏申源集团有限公司 | Preparation process of high-strength high-toughness 316LF stainless steel |
| CN115044839B (en) * | 2022-08-12 | 2022-11-15 | 浦项(张家港)不锈钢股份有限公司 | Stainless steel band with high-temperature oxidation resistant surface, manufacturing method and application |
| CN115537638B (en) * | 2022-09-15 | 2023-06-23 | 山西太钢不锈钢股份有限公司 | Method for solving scale defect of 304 series BA plate for precise strip steel |
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| JP2009144244A (en) * | 2007-12-12 | 2009-07-02 | Posco | Refining method of high-chromium ferritic stainless steel for reducing carbon |
| CN102787196A (en) * | 2012-08-24 | 2012-11-21 | 北京首钢国际工程技术有限公司 | Method for smelting stainless steel by direct reduced iron |
| CN102943148A (en) * | 2012-11-30 | 2013-02-27 | 张家港浦项不锈钢有限公司 | Method for producing high-purity stainless steel |
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