TW201139701A - Duplex stainless steel material for vacuum vessels, and process for manufacturing same - Google Patents

Abstract

Provided is an Ni-saving type duplex stainless steel material which exhibits excellent gas desorption characteristics and can substitute for austenitic stainless steel. The duplex stainless steel material is characterized by: containing, by mass, 0.06% or less of C, 0.05 to 1.5% of Si, 0.5 to 10.0% of Mn, 0.05% or less of P, 0.010% or less of S, 0.1 to 5.0% of Ni, 18.0 to 25.0% of Cr, 0.05 to 0.30% of N, and 0.001 to 0.05% of Al; and having a hydrogen content of 3ppm or less, the balance being Fe and unavoidable impurities.

Description

201139701 VI. Description of the invention: t Ming 7s jin gen. = ^ phase hall 々 起 ^ 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 】 It has excellent gas desorption characteristics and is suitable for use as a vacuum container. L ^ BACKGROUND OF THE INVENTION In recent years, the production of semiconductor components, liquid crystal panels, and thin film solar cells has rapidly increased, and these products have also appeared to be large-scale. These products require vacuum treatment during the manufacturing process, and most of their vacuum containers are made of metal materials such as stainless steel, aluminum, and titanium. The stainless steel used in the vacuum container has always been made of Austenian iron material represented by SUS304 stainless steel. Further, with the increase in the size of vacuum equipment, stainless steel having a thickness of up to about 80 mm is also currently used. The material for the vacuum container must have some characteristics, which can be exemplified by the low gas emission. In particular, the influence of the surface polishing conditions and the baking treatment on the gas emission of materials such as Austenitic stainless steel, alloy, titanium, etc., which are materials for ultra-high vacuum, has been pointed out in the prior research (see Non-Patent Document 1). 'It has been known that the use of the grinding step can effectively reduce the surface roughness and reduce the surface oxide layer. Also, it is also known to be 1 to 450. (: This temperature is used for long-time baking to effectively solve the above problem (refer to Non-Patent Document 2). Further, the prior invention has pointed out that in order to improve the vacuum characteristics, it can be used in the Austenite stainless steel material containing 201139701 On top, it is formed into a high-content film (refer to the patent document 〇. The point of view provides us with the possibility of developing new materials. Another characteristic that needs to be possessed is strength and weldability. With the enlargement of vacuum vessels' It is also becoming more and more important. Especially for components such as pre-exhaust chambers, because it constantly repeats atmospheric pressure and vacuum, it is more economical to use high-strength materials with good fatigue properties. Since, Osfield Iron is not mine The lower limit of the drop strength is about MPa. If it is to be used as a material for large-scale vacuum vessels, this property must be improved. The characteristics of duplex stainless steel are that it contains more c^M〇, so it has a strength ratio of Austin Iron. The characteristics of stainless steel are higher; however, because the expensive material '10' is used less in vacuum containers. However, in recent years, it has gradually developed a reduction in the amount of can. Increase the _ content of duplex stainless steel, so even if the cost of steel is considered, it is also suitable for thinning through the material of the grain. However, if it is used in the duplex phase, it is economical and additive. The tongue is not only likely to damage its ductility and the property, but the influence of the presence of the ferrite phase and the Oss phase on its vacuum characteristics (gas desorption characteristics) has not yet been determined. Therefore, the inventors of the present invention have focused on Strength of N丨Conservative Duplex Stainless Steel|i7〖Life, surface characteristics, gas desorption characteristics, heat treatment and abrasiveness' are suitable for vacuum vessels. Duplex stainless steel is made of ferrite and iron phase and Osda The material composed of the structure of the iron phase 'has the strength, the ductility, the toughness and the weldability. Therefore, it can be said that it has the premise of replacing the Oswego iron-based stainless steel 4 201139701 steel. Basic characteristics. However, it is still necessary to understand the possible effects of a ferrite phase with a low toughness of about 50% and a small hydrogen solids limit. The characteristics are as follows: a smooth and clean surface can be obtained by mechanical, electrolysis, chemical polishing, etc., with good desorption characteristics of surface sorption gas such as water, and small amount of hydrogen emission in steel, etc. The system is to explain how to make the duplex stainless steel have the above characteristics, so that it can be developed as a practical material for vacuum containers. The inventors of the case investigated in the early stage of the invention to evaluate whether duplex stainless steel is suitable as the inventor of the case. For the purpose of vacuum container materials, but no specific related literature has been found so far. Since duplex stainless steel is rich in Cr and N, its corrosion resistance is extremely high, thus creating a problem, that is, the final acid of the steel surface. The washing step is inefficient. Under the premise of recognizing this subject, we focus on the important correlation between cold working and vacuum characteristics in duplex stainless steel, and carry out 0~20% cold working with the invention of duplex stainless steel. The basic experiment of the vacuum properties of the material. The result is a new issue in which cold working promotes the rate of hydrogen emissions in steel. That is, when we consider the use of the characteristics of the manufacturing steps, that is, relying on the chemical composition of the Ni-saving duplex stainless steel to develop a duplex stainless steel as a vacuum container, it is necessary to properly control the characteristics of the steel surface. PRIOR ART DOCUMENT PATENT DOCUMENT Patent Document 1 Japanese Patent Laid-Open No. 2003-13181 Non-Patent Document 201139701 Non-Patent Document 1 J. Vac. Soc. Jpn. v〇丨5〇, No. 1, 2007, p47-52 Non-Patent Literature 2 Vac_ Soc. Jpn· VoU9, No. 6, 2006, p335-338 Non-Patent Document 3 J. Vac. Soc. Jpn. Vol. 5〇, n〇.4 2007, p228 SUMMARY OF INVENTION Summary of the Invention The object of the present invention is to obtain a Ni-saving duplex stainless steel material for use in a vacuum vessel instead of Osbane iron-based stainless steel, and to describe the chemical composition, surface characteristics and manufacturing method of the steel. Means for Solving the Problems In order to solve the above problems, the inventors of the present invention conducted the following experiments. First of all, 'the duplex stainless steel containing various compositions is used in the experiment, and it is subjected to hot rolling, melt heat treatment, heat treatment of 1 〇〇〇K or less as appropriate, and then sandblasting and rusting and pickling under various conditions. A hot rolled steel sheet having a thickness of 10 mm to 40 mm is obtained. The obtained steel material was quantified, and the tensile strength was used to measure the strength 'measuring the surface roughness using the specification of JIS B0601, and the Vickers hardness was used to measure the sub-skin hardening depth>> and in order to evaluate the gas desorption characteristics, In the machining method, a gas analysis sample having a size of 3 mm thick x 14 mm x 14 mm is taken out from the surface of the steel material, and a part thereof is mechanically ground by smoothing the surface (#150 No. 6 201139701 type stone grinding to fine () wet grinding). The sample, in addition, is partially omitted from the mechanical grinding ^, there is a 1 wash 5 material. The above two samples were subjected to electrolytic polishing using a tannic acid solution, followed by desorption gas analysis. Desorption gas analysis system, the sample was placed on a transparent stone platform, and the vacuum vessel for analysis that has been exhausted by the human body was placed in a vacuum vessel of 1 2 < rr / l ^ ^ XK25 C / s to 2 Torr. eC, the desorbed water and the blue push; * fly into the helium ionization, using a quadrupole mass spectrometer (QMS) for the Dingli analysis. The same measurement was carried out for the SUS3Q4 as a comparative material, and the true time (gas desorption characteristic) of the double eye was evaluated based on the relative value. Through the above experiment, we have clearly found out the chemical composition, surface characteristics and manufacturing method of the duplex stainless steel having excellent gas desorption characteristics and being suitable as a vacuum vessel, so that the present invention can be produced. That is, the focus of the present invention will be as follows. (1) A duplex stainless steel material having excellent gas desorption characteristics, comprising: c: 0.06% or less, Si: 0.05% to 1.5%, Mn: 0.5-10.0%, p in terms of mass% : 〇_〇5% or less, s: 0.010% or less, Ni: 0.1-5.0% 'Cr: 18.〇~25.0%>N: 0.05-0-30%ΆΓ-0.001-0.05% or less; and steel The hydrogen content is 3 ppm or less. Further, if necessary, one or more of the following components are contained: Mo: 4.0% or less, Cu: 3.0% or less, Ti: 〇.05% or less, and Nb: 0.20%. Hereinafter, V: 0.5% or less, W: 1.0% or less, C〇: 2.0% or less, B: 0.0050%% or less, Ca: 0.0050% or less, Mg: 0 0030% or less, REM: 201139701 0.10% or less; It consists of Fe and unavoidable impurities. (2) For the duplex stainless steel of (1), the maximum cross-sectional height 玢 of the surface roughness is 40 μΐΏ or less, and the depth of the sub-skin hardened layer is 〇 i5 mm or less. (3) For duplex stainless steels of (1) or (2), the lodging strength is below 4 700 700 Mpa. (4) A method of producing a duplex stainless steel material according to (1) or (2), which comprises the step of performing heat treatment at a temperature ranging from 400 to 800K. (5) A method of producing a duplex stainless steel according to (3), characterized by comprising a step of performing heat treatment at a temperature ranging from 400 to 800K. Advantageous Effects of Invention At present, Aostian Iron and Steel is used as a material for a vacuum container in the manufacture of a semiconductor element, a liquid crystal panel, and a thin film solar cell. With this month, we can provide a kind of duplex stainless steel, which has excellent strength and gas desorption. It can be used instead. Some of the components of Aostian Iron and Steel are used, which can be more important than the traditional steel (four). . BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows the form of a sample which is not used to determine the depth of hardening under the skin. [Implementation of the cold type] The form for carrying out the invention The present invention will be specifically described. First, the main explanation will be (). The requirements have been planted, that is, the chemical group that defines duplex stainless steel and the reason for the hydrogen content in steel. : In order to ensure the corrosion resistance of stainless steel, the content is limited to 〇.〇60/0 8 201139701. If the content exceeds 0.06%, Cr carbide is formed to deteriorate the durability and toughness. The content is preferably 0.03% or less.

Since the Si system deoxidizes the steel material during the melting of the steel, it is added in an amount of 0.05% or more. However, if it is added more than 1.5%, its toughness will deteriorate. Therefore, the upper limit is set to 1.5%. It is preferably 0.2 to 1.0%. The Μη system has a Μη content of 0.5% or more in order to improve the toughness and vacuum characteristics (gas desorption characteristics) of the steel. The addition of Μη is to increase the Aostian iron phase to improve toughness and to accumulate in the oxide film to improve the gas desorption characteristics after oxidation treatment. However, if the content exceeds 10.0 ° /. It will deteriorate the corrosion resistance and toughness. Therefore, the upper limit is limited to 10.0%. The ideal content is 3.0 to 8.0%. The lanthanum is an impurity, which causes the hot work of the steel and the toughness to deteriorate. Therefore, the content is limited to 0.05% or less. It is preferably 0.03% or less. The S system is an impurity and also deteriorates the hot workability, movability and corrosion resistance of the steel, so the content is limited to 0.010% or less. At 0.0020 ° /. The following is better.

In order to stabilize the Osbane iron structure, the Ni system improves the contact resistance and even toughness of various acids, and the content is 0.1% or more. However, since Ni is a high-priced alloy, in order to consider the cost, the content is limited to 5.0% or less. The ideal content is 1.5 to 4%.

In order to ensure the basic contact resistance of the steel, the Cr system is controlled to 丨8 〇0/. the above. However, if the content exceeds 25_0%, the ferrite iron phase fraction increases, which hinders the toughness and the corrosion resistance of the welded portion. Therefore, the Cr content was controlled at 18.0 ° /. Above '25.0% or less. The ideal content is 19 to 23%. 201139701 N is the solid phase of this material, which can effectively improve strength and resistance. Therefore, the content is controlled at 〇〇5〇/. the above. Although the solid-solution limit will be improved with the amount of Cr§, but the steel of the present invention contains more than 〇 above N, it will precipitate the ruthenium nitride and hinder its dynamicity and resistance, so the upper limit is imposed. Booked as 〇.30%. The ideal content is 0_10~〇.25%. A1 is an important element for deoxidizing steel. In order to reduce oxygen in steel, it is also added to Si. If the Si content exceeds 〇3%, it may not be necessary to add it as needed. However, in order to ensure the steel property, the oxygen content must be lowered, so the content must be controlled to 0.001% or more. On the other hand, A1 is an element with a higher affinity with N. If it is added excessively, A1N will be produced, which hinders the attractiveness of steel. Although the degree of influence is also based on the N content, but if it exceeds 〇, the steel quality will be significantly reduced, so the upper limit of the content is controlled at G. G 5 %. The upper limit is preferably 0.03%. Niobium (oxygen) is a major element constituting an oxide, and an oxide is a non-metallic intermediator. Further, if a large oxide cluster is formed, the surface deterioration is caused. Although the present invention does not specify an upper limit of its content, it is preferably controlled to be below 0010%. The amount of hydrogen in the steel is affected by the amount of hydrogen or water that is discharged from the vacuum capacity to the vacuum. In addition, it is known in the industry that hydrogen contained in the steel will become water due to oxidation of the surface of the steel, promoting water. Desorption. In particular, in a duplex stainless steel containing a ferrite phase, since hydrogen diffusion is very large, it is necessary to control the amount of hydrogen in the steel to a small amount in advance. The inventors of the present invention found that if the hydrogen content is controlled below 3 Ppm, it will have the same level of gas emission characteristics as the Osbane iron-based stainless steel. Therefore, the upper limit of the hydrogen content is set to be less than 201139701 ppm, especially Lppm 3ppm. The less hydrogen in the steel, the better, and it is better to control it below 2. The duplex stainless steel of the present invention is required as needed, and in addition to the above, one or more of the following components may be added: M〇, &, η, Nb, V, W, Co, B, Ca, Mg, and REM.

Mo is an effective element that can improve the corrosion resistance of stainless steel and can be added as needed. It is preferable to contain G. 2% or more. Under the consideration of cost ^ M of the invented steel. The content is limited to 4.0%, but Mq is a non-f expensive element, and it is preferable to further control it to 1.0% or less.

The Cu system can additionally improve the acid-resistant and pure element of stainless steel, and also has the effect of improving steel properties. However, if the amount added exceeds 3 (%), the solid solubility is exceeded, and sCu is precipitated to cause embrittlement, so the upper limit is controlled to 3.0%. Cu has the function of stabilizing the Austin iron phase and improving the character of the character, so the building is added by 0.3% or more. In the case of containing Cu, the content is 〇3~u. /. It is better. Τι generates oxides, nitrides and sulfides in a very small amount, and helps the steel to solidify and refine the crystal grains of the high-temperature heating structure, as necessary. However, if more than 0.05% is added to the duplex stainless steel, coarse TiN is formed, which hinders the toughness of the steel. Therefore, the upper limit of the content is set to 〇·05%. The appropriate content of Ti is 0.003 to 0.020%.

Nb is an element which can effectively refine the crystal grains of the hot-rolled structure and has an effect of increasing the contact resistance. Nb nitrides and carbides can be formed during the hot working and heat treatment, suppressing the growth of crystal grains and strengthening the steel, so it is preferable to add 0.01% or more. However, if Nb is excessively added, 201139701 will precipitate unconsolidated precipitates during the heating stage before hot rolling, which hinders the toughness of the steel. Therefore, the upper limit of the content is set to 〇·2〇%. If it is to be added, the content range is preferably 0.03 to 0.10%. V and w are elements added for the purpose of additionally improving the corrosion resistance of the duplex stainless steel. V is to increase the touchability for this purpose, and can add 〇 05% or more. However, if it is added in excess of 0.5%, coarse v-based carbonitride will be generated to deteriorate the toughness. Therefore, the upper limit is set to 0.5. /. . If it is to be added, the desired content is in the range of 〇.1 to 0.3%. W has the same effect as Mo, and is an element that can improve the corrosion resistance of stainless steel, and has a higher solid solubility than V. In the steel of the present invention, in order to improve the resistance to enthalpy, the upper limit is 1 〇%. The ideal content is 0.05%~〇·50/〇 〇

Co is an element which can effectively improve the toughness and the resistance of the steel, and is selectively added as the case may be. The content is preferably 0.03% or more. Since c〇 belongs to the expensive element 'if more than 2.0% is added, the effect of controlling costs cannot be achieved'. The upper limit is set to 2.0%. If added, the content is preferably 0.03 to 1.0%. Elements such as B, Ca, Mg, and REM all improve the hot workability of steel. One or two or more are added for this purpose. However, if excessively added, each element of B, Ca, Mg, and REM will reduce hot workability and toughness, so the upper limit of the content is set as follows. 6 and 〇3 are 0.0050%, 1\^ is 0.0030%, and 1^1^ is 0.10%. The content of each item is 0.0005 to 0.0030% for B and Ca, 12 201139701 0.0001-0.0015% for Mg, and 0.005 to 0.05 °/ for REM. It is better. Here, REM refers to the sum of rare earth element contents of lanthanides such as La and Ce. (2) of the present invention is for specifying the maximum cross-sectional height Rt and the surface hardness of the surface roughness of the steel material. Rt and surface hardness are indicators of the mechanical grinding characteristics of steel. The surface is a hard duplex stainless steel. In order to obtain both a mechanical and electrical chemical polishing to obtain a smooth and clean surface, the surface properties of the ideal steel material are specified. As shown in the examples, Rt exceeds 40 μm, or the depth of the sub-skin hardened layer exceeds [丨. Umm of steel, if it is up to #150 belt sanding or even #600 wet sandpaper grinding and electrolytic grinding' Since the gas desorption characteristics are poor, the above regulations have been made. The reason why the gas desorption characteristic is lowered may be that the presence of the sub-skin hardening layer accelerates the desorption speed of hydrogen, and may also be caused by the residual microscopic surface defects which are invisible to the naked eye.

The smaller the Rt, the better. It is better to use 2〇μπΐΗ, especially ι〇μηι. In order to control Rt to be less than 4 〇μηι and to control the depth of the sub-skinned layer to be 0 to 15 mm or less, it is preferable to appropriately control the particle size and the projection density of the blasting and rusting. (3) of the present invention is to specify the lodging strength of the duplex stainless steel. In order to reduce the thickness of the container material, the greater the strength, the better, and the lodging strength is preferably at least 400 MPa. However, if it exceeds 7 〇〇Mpa, its toughness will deteriorate. Therefore, the upper limit is set to 70 MPa. The fall strength can be adjusted in accordance with the chemical composition, the heat treatment conditions for melt treatment, or heat treatment conditions such as 400 to 800 K described in the inventions (4) and (5) to be described later. The present invention (4) and (5) relates to the manufacture of the duplex stainless steel according to the present invention. 13 201139701 The method is intended to improve the strength of the stainless steel surface material and reduce the hydrogen content in the steel. The purpose of this heat treatment is to increase the strength of the steel by age hardening of the duplex non-mineral steel. It also promotes the reduction of the gas content in the steel. Therefore, it is preferably carried out by a temperature range of ~8 〇〇 κ. Applying this heat treatment step reduces the hydrogen content of the steel to below 2 ppm, or even below 1 ppm. As the hydrogen content is reduced, the vacuum properties of the steel can be slightly improved, and the fall strength can be increased to 500 MPa or more, or even 600 MPa or more. The heat treatment time in the above temperature range is preferably 5 minutes or more. However, if the heat treatment time is too long and the lodging strength exceeds 7 〇〇Mpa, the toughness of the steel may be impaired. Therefore, the upper limit of the heat treatment time should be individually determined depending on the aging strengthening of the steel and the embrittlement characteristics. Further, after the vacuum vessel is manufactured, the heat treatment (heat treatment for baking) is carried out at a temperature range of 4 Torr to 8 Torr, which not only reduces the hydrogen content but also allows the water to be adsorbed on the surface of the container. Effectively improve its vacuum characteristics. The steel material of the present invention is used for the production of a vacuum vessel, and can be formed into a steel plate, a steel, a steel bar, a steel strip, a steel pipe, etc., but mainly a steel plate. The system containing the steel composition described in (1) is subjected to a continuous casting method to cause entanglement of the ruthenium, and then the steel is rolled into a steel sheet 1 and the casting can be compared with ordinary duplex stainless steel. Cast 1 . This steel sheet is heated and then hot rolled to obtain a steel material having a shape of > Here, the application conditions of the hot rolling are not particularly limited, and it is only necessary to compare the heating of the two materials (four). After the tempering heat treatment of the steel, if necessary, it can be subjected to dehydrogenation and heat treatment of 14 201139701 age hardening, and then the surface of the steel is subjected to sandblasting, rusting, grinding and pickling to make it necessary. The surface state is manufactured. EXAMPLES Hereinafter, the present invention will be specifically described by way of examples. Table 1 shows the chemical composition of the experimental steel. Further, in addition to the components described in Table 1, the components contained therein also contained Fe and unavoidable impurities. Further: Among the components described in Table 1, the portion not indicated in the content is an impurity grade. Further, the REM in the table indicates that the lanthanide element is a rare earth element and the content is the sum of its elements. The steel sheet of the steel type number T is obtained by melting a flat steel embryo from an actual machine and using a steel sheet having a thickness of 80 mm as a hot rolling material. The steel type A~Q is made up of a 50kg vacuum induction refining furnace in the laboratory. The steel of R is dissolved in a 50kg atmospheric melting furnace, and then cast into a flat steel block with a thickness of about 110mm, followed by heat. A steel sheet having a thickness of 80 mm obtained after forging treatment. Further, the steel sheet of the steel type number T2 is a portion in which the above-mentioned actual machine is melted into a flat steel, and corresponds to a portion having a hydrogen content of 4 ppm as a stage after pickling of the hot-rolled steel material. 15 REM Γ〇.〇12 1 CO | 0.0021 1 1 0.00141 | 0.0005 1 1 0.00091 | 0.00181 \ 0.0024 | 1 0.00161 | 0.08 | 1 0.34 1 | 0.15 1 1 0.32 1 > 丨0.12 1 I o.ii 1 | 0.06 1 1 0.12 I 1 0.07 1 | 0.023 1 | 0.048 | | 0.008 | | 0.006 1 d in rn | 0.32 | 0.33 | | 0.65 1 | 0.85 | 1 2.10 1 1 0.25 1 1 〇·21 1 | 0.22 1 | 0.02 | 0.23 | 1 3.25 1 0.31 | O 1 0.23 1 | 0.23 | 1 Q-31 1 | 0.30 1 | 0.23 | | 0.26 | 1 3.02 1 1 0.30 1 | 0.30 | | 0.25 | 丨3.02 | | 0.30 1 | 0.30 | 0.23 | 0.20 〇10.00361 1 0.0042 1 1 0.0026 1 | 0.00381 | 0.0043 1 | 0.0025 | 10.0033 | | 0.00241 10.0031 | | 0.0038 | 1 0.00341 1 0.00361 1 0.0036 1 1 0.0033 1 | 0.0035 | 10.0021 | | 0.00261 | 0.0033 1 | 0.00361 | 0.0033 1 0.0035 1 0.014 1 1 0.006 1 1 0.022 1 | 0.017 | I o.oii | | 0.018 | | 0.014 | | 0.022 1 | 0.016 | | 0.026 | 022 1 1 0.016 1 1 0.014 1 1 0.012 1 | 0.015 | | 0.023 | | 0.013 | | 0.014 1 | 0.065 | | 0.015 | 0.002 z 1 0.214 1 1 0.212 1 1 0.142 1 | 0.136 | | 0.178 | | 0.183 | 0.145 | | 0.143 1 | 0.178 | | 0.085 | 1 0.175 1 1 0.167 1 1 0.214 1 1 0.145 1 | 0.150 | | 0.035 | | 0.160 | | 0.065 1 | 0.150 | | 0.203 | 0.048 u 丨21.4 1 丨21.6 1 1 23.3 1 | 20.8 | 1 21.1 | 212| I 18.5 | 1 19.7 | 2I,4l 丨19.5 1 丨21.4 1 1 20.6 1 丨21.4 1 丨23.5 1 丨25.5 1 | 18.6 | 丨22.3 1 1 17.3 I 1 21.5 1 18.2丨 1.73 | 丨 4.20 | | 2.36 | | 2.02 | S 1-55 2.53 1 3.14 | 1 2.50 1 1 4.45 1 S — 2.01 1 4.63 | 1 6.23 I L62l\ | 0.82 1 (N 1 1-55 1 8.13 oo 10.0005 1 10.00091 10.00121 | 0.0005 | | 0.00071 | 0.0006 II 0.0008 I 1 0.0007 I 10.00051 | 0.0005 | 10.0007 I 1 0.00061 1 0.0005 I 丨0.0006丨10.0005 | 10.00041 10.00061 | 0.00061 | 0.00061 | 0.00081 0.0024 a. 1 0.023 1 | 0.022 1 I 0.023 | | 0.021 | | 0.002 II 0.035 II 0.024 ] I 0.025 I | 0.025 I 丨0.025 1 I 0.025 1 1 0.026 1 1 0.023 1 1 0.025 I | 0.024 1 | 0.025 | 1 0.021 I 1 0.025 I | 0.024 1 | 0.024 1 0.030 i 1 4.95 1 1 3.52 I 1 2.43 I 5.12 7.20 | 9.00 I 5.02 I 3.53 I 3.45 287 1 4.92 1 1 4.95 1 | I | 0.18 | 3^1| 0.75 丨0.73 I 1 3.25 1 | 4.99 | 0.85 1 0.45 1 | 0.62 1 L〇-46 1 | 0.35 | 1 0.48 I 1 0.62 II 0.33 II 0.48 II 0.36 II 0.38 1 0.42 1 0.36 1 1 0-45 1 I 0.35 I | 0.35 | 0.35 _ I 0.49 II 0.89 I | 0.35 | 1 0.52 | 0.40 u 1 0.025 1 | 0.022 | 1 0.019 I | 0.019 | I 0.025 II 0.025 II 0.035 II 0.025 II 0.022 I 1 0.026 1 1 0.019 1 10.026 1 1 0.025 1 | 0.020 I | 0.020 | I 0.009 1 I 0.016 II 0.072 I | 0.022 | | 0.022 | 0.055 X 10.0003 1 1 0.0001 I 1 o.oooi I 1 o.oooi II o. Oooi II 0.0001 II 0.0001 I 1 o.oooi II 0.0001 I 1 o.oooi 1 I o.oooi II 0.0001 I 1 0.00041 I 0.00011 | 0.0001 | 1 o.oooi II o.oooi II 0.0001 I [0.0001 I | 0.0004 | 0.0002 QF f W Comparative steel grade number Η < mu Q £JJ u. a X - P 2 〇 (X a QC tm (Π Ζ) ζ/3 201139701 Hot rolling step is to heat the above steel sheet to pre After the temperature of the 're-use two-stage chamber experiments Rolling mills and rolling operation is repeated. Finishing and rolling were carried out at 850 to 950 ° C to obtain a steel sheet (steel) having a thickness of 10 to 40 mm. In the melt heat treatment step, the steel sheet is placed in a heat treatment furnace having a predetermined temperature of 950 to 1050 ° C, and is heated after the soaking time of the steel sheet is adjusted, followed by water cooling. The hydrogen content and vacuum characteristics of the obtained hot rolled steel material (not subjected to pickling treatment) were measured in accordance with the following. After the surface of the steel material was ground for 5 mm, a sample for evaluating the hydrogen content having a thickness of 3 mm and a size of 3 mm x 14 mm was taken out, and a sample for evaluation of the vacuum property having a thickness of 3 mm and a size of 14 mm x 14 mm was taken. The hydrogen content was determined by an inert gas dissolution heat conduction method. The results are shown in Table 2. The vacuum property test sample was subjected to wet grinding until #600, and then subjected to phosphoric acid electrolysis. The slurry was subjected to electrolytic polishing in the range of 20 to 30 μm at a current density of 〇1 to 3 A/cm 2 and then immersed in a normal temperature of 35% nitric acid for 30 minutes. The vacuum characteristics were evaluated using a temperature-elevating desorption gas analyzer. The above sample was placed on the sample stage, and the temperature rise rate of the sample stage was controlled to 1 Torr. (: / min, quantitatively desorbed water and hydrogen during its heating to 200 ° C. It has been reported that 'the vacuum exhaust characteristics at room temperature are corresponding to the analysis of temperature-induced desorption gas 1 The ion current intensity desorbed from 〇〇13〇°C (refer to Non-Patent Document 3). According to this research report, we calculated the ionic current intensity of water and hydrogen at this temperature of SUS3〇4 steel. Then, the relative ratio of the ionic current intensity of the evaluation sample to the SUS304 steel was determined. The results are shown in the vacuum characteristic -1 block of Table 2. The good value is less than 2.0, and the ideal value 17 201139701 is less than 1.5. The tensile test of steel is to take out the round bar tensile test piece with the parallel portion of 8 from the thickness of the steel plate of the thickness ι〇_, and take the turn of the (four) mm diameter from the steel with the thickness of 20, 30 and 40 以 in the vertical rolling direction. The test piece is stretched. In addition, the steel bar with a thickness of 30 or 4 is taken as the center of the plate thickness of 1/4. The results of the drop strength are shown in Table 2. The impact of hot-rolled steel The test is to use the 2mmV type mechanical reinforcement groove in the direction of the milk extension_ No. sand sheet, two pieces are taken out in the direction in which the crack propagates in parallel in the rolling direction. Also, the steel of ι〇_ is evaluated by the 3M size "jin 彳·5*, 2G_ slab thickness is slab thickness The central part of the full-scale material test piece was evaluated, and the steel plate with the thickness of the plate was evaluated by a full-scale sand money piece centered on 1/4 of the plate thickness. The impact test/dishness was 20 C, which was the largest. The impact test was carried out by an impact tester with an impact energy of 5 嶋. Table 2 shows the average value (J/cm 2 ) of the k-shock values of the three plate thicknesses. 201139701 Table 2

As shown in Table 2, the characteristics of any of the hot-rolled steels of the present invention are better than those of SUS304 steel, and not only exhibit good vacuum characteristics, but also have a strength of more than 400 MPa, and a toughness of up to 5 〇J/cm2 or more. It is an excellent property as a material for a vacuum barn. On the other hand, the comparative example of Table 2 is inferior to the strength and rhythm of the SUS304 steel of the comparative material if it is not good. Next, a hot-rolled pickled steel material was produced according to the following method.

Selecting three sizes of large, medium and small beads for the sandblasting and descaling step 'and then adjusting the projection density according to the speed of the hot rolled steel and the number of passes" to remove some of the surface rust of the above-mentioned duplex stainless steel hot rolled steel skin. The steel is then immersed in 4〇~60. C, in a mixture of 10 to 20 ° / 〇ΗΝ〇 3, 3 ~ 8 ° / 〇 HF 19 201139701 in a fluoroboric acid solution for 20 minutes to 24 hours, in order to completely remove the scale. A sample for the evaluation of the surface roughness and the depth of the hardened layer from the hot-rolled pickled steel. Quantification of the maximum section strength Rt and the Vickers hardness measurement of l〇〇gf were carried out in accordance with the surface roughness measurement standard prescribed in JIS B0601 to quantify the depth of sub-skin hardening. The evaluation length for measuring the surface roughness was set to 3.0 mm, and after each measurement three times, the maximum value was taken. When the depth of hardening under the skin is measured, since the area of the sample is narrow and has a thickness, in order to improve the precision of the measurement, the sample is cut as shown in the figure to form a slope, and the cut surface is turned upward. Fill in the resin. Thereafter, the hardness of the slope at 2 〇 was measured from a position corresponding to the surface of the steel material at a pitch of 〇.lmm. That is, the hardness corresponding to a depth of 1 mm under the skin of the steel was measured. Each measurement point was measured with n = 3, and the subcutaneous hardness distribution was determined based on the average value. The subepidermal hardening depth is obtained by determining the subepidermal thickness of the portion which is hardened by 50 or more with respect to the internal average hardness Hv, as shown in Table 3. The internal average hardness referred to herein is determined from the average value of the hardness of the sub-skin depth 〇 5 to 丨〇 mm. In the atmosphere, a part of the hot-rolled pickled steel is subjected to heat treatment (aging heat treatment) for ageing hardness and reduction of hydrogen content. The heat treatment at this time will form a thin oxide film on the surface of the steel. The hot-rolled pickled steel and the aging heat-treated steel were evaluated in the same manner as the hot-rolled steel which was not subjected to the pickling treatment, and the argon content and the vacuum characteristics were measured. However, the sample for evaluating the vacuum characteristics was first removed by the #15 带 belt sand mill to remove the unevenness of the steel surface, and then the sample of #3 mm, 14 mm x 14 mm was taken, and the wet grinding of #6〇〇 was similarly performed. 20 201139701 Electrolytic grinding and nitric acid immersion, which contains a part of the subepidermal hardening layer as a sample for temperature-dependent desorption gas analysis. - The tensile test and the impact test were carried out in the same manner as the hot-rolled steel which was not subjected to pickling treatment as described above. The evaluation results of the hot-rolled pickled steel are shown in Table 3 for the hydrogen content, vacuum characteristics _2, the drop strength and the impact characteristics. In the comparative example of the experimental number No. 15 of Table 3, since the blasting and rust removing step was short and the beads of small particles were used, it took a long time to carry out the slag washing. The results of the test showed that the hydrogen content was 〇 〇〇〇 4 mass%, and the vacuum characteristics were lowered. In the comparative example of the experimental number No. 16, the blasting and rust removing step of the granules for a long time was used to almost completely remove the scale, and the pickling step was completed in a short time. Therefore, the hardened layer is enlarged to 0 25 mm, and the vacuum characteristics are lowered. In the comparative example of the experimental number Π~20, large granules were used for the blasting and rinsing steps and pickling. The hardened layer is enlarged to 0.2 〇 mm. Therefore, the vacuum characteristics of the comparative examples of the experimental numbers 18 to 20 were not good. In the comparative example of the experimental number No. 17, since the aging heat treatment was performed for a long time, the lodging strength was excessively increased, and embrittlement was also caused. In contrast, the hot-rolled pickled steel in the examples of the present invention has good vacuum characteristics, lodging strength and punching characteristics. As is apparent from the above examples, the present invention can obtain a duplex stainless steel having good vacuum characteristics. 21 201139701 Impact toughness (J/cm2) § 1 Ο Ο Ο ο Ο (Ν § ο ο (Ν CN Ο m <Ν ο (Ν ο , * Ο § s (N 降 强度 intensity (MPa) § in 〇vo ο 00 νο Ο ο 00 κη ο ο ο CN ηη ο 〇〇«〇ο (Ν Ο g Ο CN Ο 00 〇〇〇•yj 〇<N VO 〇ON CN 1 Vacuum characteristics_2 p οο (Ν οο ο ρ 00 ο Ρ ON 〇ρ ρ ON Ο ρ m rn (Ν ν〇(Ν rn 寸 (N o Hydrogen content (mass%) 0.0003 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0004 0.0003 0.0001 0.0003 0.0002 0.0002 0.0002 Heat treatment 573Kxl2h 673Kx24h 573Kxl2h 473Kx6h 473Kx2h 姊 723Kx240h 573Kxl2h #. Hardening layer (mm) 〇〇ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο Surface roughness Rt ("m) 窆 窆 沄〇 沄沄 沄沄 沄沄 沄沄 Η Η 〇 〇 钢 钢 钢 钢 钢 钢 钢 钢 钢 钢 钢 C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C —> Ρ1 Η Η < QQ U SUS304 4锑Experimental number—(Ν寸ΙΤί VO 卜 〇 CN CN m 〇ν〇^—4 00 On ττ 201139701 Industrial Applicability The present invention can provide a high strength and a reduced Ni content, which is more economical. Duplex stainless steel for vacuum vessels can reduce the cost of large vacuum vessels and contribute greatly to the development of the industry. [Simplified illustration] Figure 1 shows the form of the sample used to determine the depth of hardening under the skin. 】"", 23

Claims (1)

201139701 VII. Patent application scope: 1. A duplex stainless steel material with better gas desorption characteristics, characterized by: ... 质量% by mass% C: 0.06% or less, Si: 0.05X4 5%, 5 Μη : 0.5~1〇·〇〇/0, P : 〇·05% or less, s : 〇〇1〇% or less,: 0.1 to 5.0%, 〇: 18.0 to 25.0%, N: 0.05 to 0.30%, A1: 0.001 to 0.05% or less; and the amount of hydrogen contained in the steel is 3 ppm or less; and further, if necessary, one or more of the following 10 components are contained: Mo: 4.0% or less, Cu: 3.0% or less, Ti : 0.05 ° /. Hereinafter, Nb: 0.20% or less, V: 0.5% or less, W: 1.0% or less, Co: 2.0% or less, B: 0.0050%% or less, Ca: 0.0050% or less, Mg: 〇.〇〇3〇〇/0 Hereinafter, REM: 0.10% or less; the remaining components are composed of Fe and unavoidable impurities. 15 2. In the duplex stainless steel of the first application of the patent scope, the maximum cross-sectional height Rt of the surface roughness is 4 〇μηι or less, and the depth of the sub-skin hardened layer is 0.15 mm or less. 3. If the duplex stainless steel material of the first or second patent application scope is applied, its lodging strength is below 400 〇〇Mpa. A method of producing a duplex stainless steel material for producing a duplex stainless steel according to the first or second aspect of the patent application, characterized in that it comprises a step of performing heat treatment at a temperature ranging from 400 to 800K. A method for producing a duplex stainless steel material for use in the manufacture of a duplex stainless steel according to the third aspect of the patent application, characterized in that it comprises a heat treatment step of a temperature range of 25 400 to 80 〇K. twenty four