TW201245468A - Highly corrosion-resistant austenite stainless steel well-suited to brazing - Google Patents

Abstract

The present invention provides an austenite stainless steel that not only is well-suited to brazing but is also highly resistant to corrosion in aqueous-solution environments containing chloride ions and environments in which low-pH condensed water containing nitrate ions and sulfate ions is produced via condensation of combustion exhaust gases. Said steel contains, by mass, up to 0.080% carbon, 1.2-3.0% silicon, 0.4-2.0% manganese, up to 0.03% phosphorus, up to 0.003% sulfur, 6.0-12.0% nickel, 16.0-20.0% chromium, 0.2-3.0% copper, 0.002-0.10% aluminum, 0.030-0.150% nitrogen, and 0.1-1.0% molybdenum, with the remainder comprising iron and unavoidable impurities. The mass percentages of copper, silicon, nickel, and molybdenum in said steel also satisfy relations (A) (1.6 = [Cu][Si] = 4.4) and (B) (0.16 = 2[N]+[Mo] = 1.0).

Description

201245468 VI. Description of the Invention: I: Field of the Invention 3 Field of the Invention The present invention relates to a Worthfield iron-based stainless steel which can be used for a structure welded by welding such as nickel welding or brazing. In particular, the present invention is a type of aqueous solution containing not only excellent hard solderability, but also low-pH condensed water containing nitrate ions or sulfate ions due to condensation of combustion exhaust gas; Worthfield iron-based stainless steel with excellent visibility in the environment. C 4s standard] Background of the Invention The hard soldering is a technique in which a solder material having a melting point lower than that of a structural material is used, and a material is bonded by heat treatment at a temperature slightly higher than a refining point of the hard solder material. Hard solder joints are widely used in the joining method of stainless steel. The brazing material used for the hard soldering of the stainless steel is an alloy of nickel or copper. In the hard soldering of stainless steel, the passive film of stainless steel hinders the hard solderability. Therefore, in order to reduce and remove the pure film, the hard soldering is carried out in a vacuum or in a hydrogen atmosphere. For example, in the case of using nickel welding, the temperature of the hard soldering is about 1100 ° C:. In the hard soldering, it is important to sufficiently fill the gap between the materials to be bonded to ensure the strength of the joint. Therefore, the wettability of the consumable material is important for the material to be joined, that is, for the stainless steel system. On the other hand, once the wettability state of the consumable material is too good, the consumable material flows out from the gap between the materials to be joined, and the gap cannot be filled with the consumable material to lower the joint strength. Therefore, it is important to have a moderate degree of wetness for stainless steels with excellent hardfacing of 201245468. - The general-purpose stainless steel is used as a stainless steel for hard soldering. In addition, JIS (Japan mdustdal standard) SUS3〇4 type material and SUS316 type material (hereinafter referred to as SUS3〇4 type material and just 16 series) are widely used as the Worthite iron-based non-mineral steel. material). The SUS304-based material and the &_6-based material are not only processable, but also have excellent resistance to purity in a general environment. The material of Fig. 04 and the material of SUS316 are resistant to stress. = (4) Corruption occurs when enchanting money (4) Stress cracking in the environment and the relationship between the material and the tensile stress residual H in the hard-wounded Vostian «Laigang affair, even if the surface is hard welded = broken = material The tensile stress remains on the top, and there is no need to worry about the occurrence of stress. The reason is that the hard soldering temperature of the Vosley-based stainless steel is performed at the temperature of the field-iron stainless steel, and the residual 70 is removed. For example, as described above, when using the recording, it will be: the same is true for the hard soldering of the left and right C. 100 rows two = different 'after the hard soldering will also be combined with other components into the gift material ^ H will be able to produce tensile stress after the combination of the material, and there is stress cracking, as a hard girl The cliffs of the cliff. Therefore, the button is. The Worthite iron used for joining does not have to have a stress-resistant corrosion environment, such as a right/^ component, and a water heater equipped with a latent heat recovery device. 4 201245468 Heat exchanger. The material members are used for condensing (four) ~ into containing ions or sulfate ions _ condensation =: - the atmosphere contains a large number - two have: rotted two: two correction compounds. And on her ^ submerged recovery (four) (four) steel made - into the set of materials, the secondary heat exchanger material, without the use of copper. Miscellaneous ^ The Voss shouting of the above-mentioned components is not important in the environment where low pH condensate containing == sulfate ions can be combined with both _ raw and hard entanglement. Regarding the hard solderability of stainless steel, it is proposed in the patent document i that a material is coated with a metal plate, and the material of the (4) ««显 m« is welded on a non-recorded steel surface and heated. Further, in the patent literature, there is proposed a method for producing a non-perforated steel sheet which has excellent hard solderability, and which is coated with a material such as a lung (10) and a consumable material which has been adjusted to have a surface roughness. However, in the patent document 丨 and the patent document 2, only the conventional SUS304-based material and the SUS3丨6-based material were examined for the fine-grained iron-based materials coated with the hard-welded material. Patent Document 3 proposes a stainless steel which can reduce μ and Ti and has excellent hard solderability. Further, Patent Document 4 proposes a stainless steel which is adjusted to have a river value represented by M = -〇.22T + 34.5Ni + l〇.5Mn + 13.5Cu - 17.3Cr - 17.3Si - 18Μο + 475·5. ~^. However, Patent Document 3 and Patent Document 4 only reviewed the ferrite-type iron-based stainless steel work, but did not review the Worthfield iron-based stainless steel. Patent Document 5 proposes a Worthfield iron-based stainless steel material having stress corrosion resistance and gap resistance 201245468 corrosiveness. However, the steel plate system proposed in Patent Document 5 is a member of the automobile fueling system member. Although the stress crack resistance is reviewed, the hard weldability is not described. Further, in the case of an exhaust system member for an automobile or a secondary heat exchanger provided with a hot water benefit of a latent heat recovery device, since the gas to be introduced contains vaporized gas, and particularly high salt near the coast Corrosion resistance is also a problem in environments containing vapor ions when used in hazardous areas. Japanese Patent Laid-Open Publication No. JP-A No. Hei. No. Hei. No. Hei. No. 2001-26855. Patent Document 3: Japanese Patent Laid-Open No. 2009-174046. Patent Document 4: Japan SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION The object of the present invention is to provide an excellent hard-gluing property, and Under the low pH test environment containing impurities or sulfuric acid ions due to the condensation of pure gas, the sand has an excellent resistance to the recording of the Wostian iron system. In order to obtain a problem to be solved by the inventors of the present invention, the inventors of the present invention have made an effort to review the Wostian Iron-based Stainless Steel, which has both hard solderability and purity resistance. 201245468 (4) When using the Worthite iron system, the above-mentioned Si and Cu are added and quantified, and the liquidity of the steel is too good, and the welding material will be from the joint materials. The gap flows out, so the joint will become insufficient. In order to prevent this situation, it is important not only to limit the upper limit of each content, but also to specify the upper limit of the [CuMSi] value. Further, in the following description, [Cu] and the net are Cu and Si contents expressed by mass %. (b) The Worstian Iron, which is hard-welded, is not side, and the suppression of stress cracking can be obtained by the multiplication effect of Cu and Si as shown by the value of 1]. (c) The recording of the low pH setting environment ητ containing _acid ions or sulfate ions due to the condensation of the combustion gas 4, and the corrosion resistance in the aqueous solution containing the vapor ions can be achieved by 2[N ] + [Μ0] is set to a certain value or more to increase. Further, in the following description, [Ν] and [Μ0] are the contents of Ν and Μ() shown by the mass °/〇. The present invention has been made based on the above findings, and the gist thereof is as follows. (1) A Worthfield iron-based stainless steel having excellent corrosion resistance and hard weldability, characterized by containing: C: 0.080% or less, Si: 1.2 to 3.0%, Μη: 0.4 to 2.0% by mass%, P : 0.03% or less, S: 0.003% or less, Ni: 6.0 to 12.0%, Cr: 16.0 to 20.0%, Cu: 0.2 to 3.0%, Α1: 0.002 to 0.10%, N: 0.030 to 0.150%, and Mo: 0_1 to 1.0%, and the remainder consists of Fe and unavoidable impurities, and satisfies the following formulas (A) and (B): (A) Formula: 1.6S[Cu]x[Si]S4.4 ; and (B) ^ : 〇.16^2[N] + [Mo]^1.0 ; Here, [Cu], [Si], [N], and [Mo] are each expressed in mass% 201245468 The content of the elements. (2) The Vostian iron-based stainless steel having excellent contact resistance and hard solderability as described in (1) above, which contains, in mass%, Nb: 〇丨~〇7〇/〇, Ti: One or two or more of 0.1 to 0.5%, V: 0.1 to 3.0%, and B: 〇〇〇〇2 to 〇〇〇3%. Advantageous Effects of Invention According to the present invention, it is possible to provide a Worthite iron having excellent corrosion resistance and hard weldability by adjusting (11 content and Si content, and further controlling N content and M content) in Vostian iron-based stainless steel. Further, according to the present invention, it is possible to improve the corrosion resistance of a structure obtained by hard welding of a gasoline, LNG, LpG, and stone exhaust heat recovery device and other heat exchange materials. The figure briefly illustrates the relationship between the content of Cl^Si and the hard solderability and the resistance to the surname in Fig. 1. Fig. 2 shows the relationship between the value of 2[N] + [M〇] and the maximum depth of rice. The relationship between the 2[N] + [Mo] value and the [Cu]x [Si] value and the hard solderability and the contact resistance is shown in the figure. t The implementation formula is used to implement the invention. In the following description of the present invention, the component "%" is a mass % as long as it has no particular %, and the results of the experiment are performed in order to obtain a composition having both hard solderability and button resistance. Explain that the production of 201245468 by vacuum dissolution has changed the Si Cu Mo and n The Worthfield iron-based stainless steel. In this case, the other elements are within the composition range of JISSUS 316. The steel is hot-rolled and subjected to heat treatment for 1 He XI minutes after the heat treatment of the steel. Further, it is cold-rolled into a cold-rolled plate. According to I, the cold-rolled sheet is heat-treated under the condition of 1G5G to li5G °C for 1 minute, and then subjected to dipping and pickling treatment in the Weiwei water-frequency towel to the king. The hard solder joint material was prepared to remove the dirt. The hard solder joint material was evaluated for hard solderability and stress _ (hard solderability evaluation) The hard solder joint material was cut into 4 〇 X 5 〇 mm & 25x30mm is used as a sample for evaluation of hard solderability. The thickness of the sample for evaluation of the hard solderability is 1 mm. The sample prepared as described above is hard-welded by silver soldering. On the overlapping portion where two samples have been stacked, 镍.3g is used as a welding material for the nickel bonding of JIS BNi5 in which the organic binder is mixed, and hard soldering is performed, and the hard soldering system uses a hydrogen reduction furnace. Performed in an environment of 11〇〇〇c and 100% hydrogen. Hard soldering The sample which has been subjected to the hard soldering is cut and evaluated by visual observation of the cross section. The results of the β parity are shown in Fig. 1. In the cross section of the sample which has been subjected to the hard soldering, the welding material is completely filled between the slits. In the case of an empty center (〇) or a black center (call), the case of remaining between the slits is represented by a cross (X). Here, the empty center (〇) and the black center (豢) are stress cracked as described later. The difference between the evaluation results and the good condition without stress cracking is indicated by the empty center (〇), and the bad condition of occurrence of stress cracking is indicated by the black center (#). Also, the 2 shown in Fig. 2 In the bar curve, the lower curve is [Cu]x[Si] value 1.6, and the upper side 201245468 Fig. 1 SCC means stress cracking.

The curve is [Cu]x[Si] value 4 4 . B is the same in Figure 3. As is apparent from Fig. 1, a rr 1 Si Si is greater than 3.0%, Cll is greater than 3.0%, or [Cu]x[Si] value is greater than 4.4, then ^ 洚 阽 阽. * A gap is formed in the section of the sample that is hard-welded. On the right is Voss, and if you touch Lu π without recording steel, 'by adding Si and Cu, the wettability of the hard material will be Q- ΤΆ Γ, sub. However, once a certain amount or more is added

For the activity of Si and Cu, the wettability is ~, „ φ . ^ The extension is good, and the welding material will flow out from the material to be joined and the joint will not become. Brother i. Therefore, set [Cu]x The upper limit of the [Si] value is 4_4. The upper limit is preferably 4 〇. (Evaluation of stress cracking) No soldering is used. Hard soldering is used for the material, but the same condition as the hard soldering is used, even if the money is still « After heating, the hard-welded material is cut into 〇_ and 15x15 mm in size and polished to cut the end face. The two pieces of material of different sizes are overlapped and centered. The transfer was performed, and a gap between the two materials was used as a sample for evaluation of the fracture. The sample for evaluation of the stress evaluation was immersed in an aqueous solution of C1-containing 2 pm (Ppm) and kept in the solution. I〇〇u days. Seven days of inspection, the 'smelting material was perforated and separated, and evaluated whether there was any crack in the gap between the inner sides. Whether the rhyme was infiltrated into the flaw detection test (staining and flaw detection method) for confirmation. Figure 1. The case where no phase breakage occurs is indicated by the empty center (〇), and there is a case of stress cracking. The black center (Lu) is shown. In the first figure, it is found that the sample without stress cracking finds that the [Cu Na] value is above i6. On the other hand, the sample with the value of [[cuMSi] less than u has stress exposure 201245468 II Γ Γ 添加 添加 添加 添加 添加 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃 沃> can also be represented by the value of the Tao and the effect of multiplication. The lower limit of the [CU]x[Si] value is set to 2. It is also set to 2〇. Condensation of the exhaust gas of the miscellaneous (four) The result of the generated condensed water is explained. As described above, the hard-welded structure is the exhaust member of the vehicle or the hot-heated person who is equipped with the latent heat recovery device. Therefore, it is not enough for the Worthite iron which constitutes the structure for hard-welding to have excellent (four) hard weldability and stress cracking. (The condensate of the condensate due to combustion of the exhaust gas. Evaluation) The material used as the pattern is excellent in hard solderability and is resistant to stress. [W]x[Si] value is less than 6 and is less than 4 4 in the W&W area of the Worthfield iron non-mineral steel. The test liquid is a condensed water that can simulate the combustion of ordinary LNG or petroleum. Specifically, the composition of the test liquid is adjusted to have a _ ion of (10), a sulfate ion of 1 〇 Ppm, a pH of 2.5, and a gas of 100 ppm by weight in order to make the rot as fast as possible. The composition of the compound is not hard-welded to the material of the above-mentioned [CuWSi] value in the range of j 6 or higher and the value of 44 or less, and the same condition as the hard soldering is used. The furnace is on the 1st side. C and the hydrogen·% ring i is heated under the heating of the 16th material and cut into the coffee (9) hidden size as a record. #(四)(10) The evaluation sample was only immersed in the test tube to half of the test solution 201245468. In addition, the test solution in the test hall was 10 ml. After that, 14 dry-fishing repeated tests were carried out. The test tube was immersed in warm water of rib filling, kept for several hours to completely dry, and after drying, the test liquid was refilled to another test tube and kept completely dry. until. The evaluation of the corrosion resistance of the condensed water generated by the combustion of the exhaust gas gas was carried out by measuring the maximum corrosion depth on the surface of the corrosion-resistant sample after the test. 5 parity results are shown in Figure 2. The case where the maximum invasive depth is less than a claw is represented by an empty center (〇), and the case of 100 vm or more is represented by (X). As clearly shown in Fig. 2, when the 2[N] + [Mo] value is 0.16 or more, the maximum corrosion depth is less than 100 // m. The reason for this is presumed to be that the effect of improving the pitting resistance by Mo and N can be obtained even in the case of a low-pH solution containing Ci·. Further, in Fig. 2, even if the 2[N] + [Mo] value is 0·16 or more, the maximum corrosion depth is 100 y m or more. When the sample of this case was investigated, it was found that the Cu content was outside the range described later. This is because Cu is eluted and ionized in a dry-wet repetitive environment containing an oxidizing agent such as a nitrate ion. Further, it is presumed that in this environment, Cu ions act as an oxidizing agent inside and outside the rotted hole, so that the depth of the rot is increased. Also, the value of 2 [N] + [Mo] increases while the depth of the maximum rot is reduced, and the decrease in corrosion depth above a certain value is saturated. It is presumed that once the N&Mo content exceeds a certain value, the corrosion depth becomes unaffected by elements other than N and Mo. In particular, in the presence of Cu, corrosion is promoted by Cu ions. For this reason, the upper limit of 2[N] + [Mo] is set to 1.0 or less. The upper limit is preferably 0.77, and the upper limit is 〇_74. Further, the lower limit of 2[N]+[Mo] is 〇_16 as described above, and the lower limit is preferably 0.20. 12 201245468 The results shown in Figures 1 and 2 above are [Cu]x and 2[N] + [M. After the state is stabilized, the axis is shown in the relationship of Figure 3. As shown in Figure 3, the sample [Culxfn estimate r. 1·] has a value in the range of 1.6 to 4.4, and the 2[n] + [Mo] value is in the range of 〇·16~Μ. Sex and _ sex. Also in this month, the contact resistance means the stress crack and the I of the exhaust gas. In the environment of low pH condensate water containing servant ions or mineral ions, the corrosion resistance of the water in the water riding environment containing the vapor ions: Therefore, the Vostian iron non-mineral steel of the present invention is Cu The Si, Mo, and MoAN systems must satisfy the following formulas (a) and (B). (A) Formula: 1.6$[cu]x[Sig4 4 (B) ^ : 〇·16^2[Ν] + [Μο]^1.0 Next, the elements contained in the Vostian iron-based stainless steel of the present invention The reasons for the individual limitations are explained. c曰 reduces the intergranular corrosion resistance and processability, so it is necessary to reduce the content, and the upper limit must be set to 〇__%. However, excessive reduction in C content can degrade refining costs. Therefore, a preferred C content is in the range of 0.005 to 0.060%. As described above, 8丨 is added in the same manner as (:11) in order to improve wettability and prevent stress cracking. If the Si content is less than 1.2%, such effects are not found. On the other hand, if Si is more than 3 〇% The wettability is excessively increased, and the hard solderability is lowered. Therefore, the Si content must be in the range of 1.2 to 3.0%, and preferably in the range of 1.4 to 2.5%. Μη is an important element of the deoxidizing element, but If it is excessively added, it is easy to generate MnS which will become the starting point of the rotten money. Therefore, the Μη content must be set to the range of 〇4 13 201245468 to 2.0%. It is also suitable for the range of 0.5 to 1.2%. Because P not only makes the weldability and processing The property is reduced, and intergranular corrosion is also likely to occur. Therefore, it must be reduced as much as possible. Therefore, the upper limit of the p content must be set to 0.03%. The more P content is in the range of 0.001 to 〇 〇 25%. The water-soluble impurity generated at the corrosion starting point of MnS or the like must be reduced as much as possible. Therefore, the content ratio of S is set to be 0.003% or less. However, excessively decreasing S increases the cost, so it is preferable to set the s content. It is in the range of 0.0002~0.002%.

Ni does not affect the stress crack resistance in the amount specified in JIS SUS316L. However, when exposed to the environment of exhaust gas in the case of LNG or petroleum combustion, the stress cracking property is lowered. Also, it is necessary to maintain the iron phase of Vostian and ensure processability. Therefore, the Ni content must be set in the range of 6 〇 to 12.0%. It is also suitable for the range of 6.5 to 11.0%.

Cr is the most important element in terms of ensuring the corrosion resistance of stainless steel. Therefore, the lower limit of the Cr content is set to be 16% by mass. However, the increase in Cr improves the workability, but the workability due to the workability is lowered. Therefore, the upper limit of the & content is 20.0%. A more preferable Cr content is in the range of 16 5 to 19 %. The addition of Cu and Si together reduces the hard solderability, but does inhibit the stress 1 crack. In addition, excessive addition of Cu reduces the corrosion resistance in the solution containing the oxalic acid ion. Therefore, it is necessary to set the Cu content to a range of 〇.2 to 3.0%. Also suitable for the range of 〜 5 to 2 5%. A1 is important as a deoxidizing element, and it is possible to control the composition of non-metallic inclusions and to refine the structure. However, if it is excessively added, there is a fear that coarsening of non-metallic inflammatory substances will occur, and it will become a starting point for product recording. 14 201245468 Therefore, the A1 content must be set in the range of 0.002 to 0.10%. It is also suitable for the range of 〇.〇〇5 to 0.08%. Although N can improve the pitting resistance, if it is excessively added, it will cause the resistance to intergranular rice cooking and workability as well as C. Therefore, the N content must be set to the range of 〇 〇 3 〇 to 0.150%. It is also preferably in the range of 0.037 to 0.10%.

Mo has an effect of repairing a pure film and is an element effective for improving the durability. Further, in the case of an environmental butyl containing a nitrate ion and a chloride ion, the combination with N has an effect of improving the pitting resistance, and therefore, it must contain at least 0.1 ° /. Mo. On the other hand, although the increase in M〇 improves corrosion resistance, excessive addition causes a decrease in workability and incurs an increase in cost. Therefore, the upper limit of the M〇 content must be set to 1·〇. /. . And the suitable content of M 〇 is in the range of 〇·2 to 0.8%. In the present invention, in addition to the essential elements described so far, one or two or more of Nb, Ti, V and 3 may be contained as needed. By adding N b , there is an effect of generating carbonitrides, sensitizing in the vicinity of the splicing portion, and increasing the high-temperature strength, so that it can be added as needed. However, excessive additions will incur an increase in costs. Therefore, the Nb content is preferably set to the range of 〇1 to 0.7%.

Ti has the same effect as Nb, but excessive addition causes an increase in surface acne caused by nitride. Therefore, the Ti content must be set to the range of 〇1 to 0.5%. Since V can improve the resistance to contact and the corrosion resistance, if V is not added to the strands and m〇, the excellent workability can be ensured. Therefore, he added the demand. However, excessive addition will result in reduced processability. SUb, v content must be 15 201245468 set to the range of 0.1 to 3.0%. B is an intergranular strengthening element effective for hot workability, so it can be added as needed. However, excessive addition leads to a decrease in processability. Therefore, it is preferable to set the lower limit of the B content to 0.0002% and the upper limit to 0.003%. EXAMPLES Next, the present invention will be further described by way of Examples. However, the conditions of the present invention are used to confirm the implementation possibilities and effects of the present invention, and the present invention is not limited to the examples. The present invention can be applied to various conditions within the scope of the invention as long as it does not depart from the gist of the invention. Steel having the chemical composition shown in Table 1 was produced by a general method of manufacturing Worstian iron-based stainless steel. First, an ingot having a thickness of 40 mm was produced after vacuum melting, and it was hot rolled to have a thickness of 4.0 mm. Thereafter, after heat treatment at 1,150 ° C for 1 minute, the scale was removed by polishing, and a steel plate having a thickness of 1.0 mm was produced by cold rolling. This was heat-treated under various conditions of 1050 to 1150 ° C for 1 minute based on various recrystallization operations, and then subjected to a pickling and pickling treatment in an aqueous solution of nitric acid fluoride until the rust was completely removed, and the following three tests were provided. 16 201245468 (%¥«) 1--13⁄4 SM1珐许ri斛洚s^ 1i 66

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IZ 二9Ό rt ί °°,0 "3119i_010s Qu.ou.o -95 0 -3- 010 Ό uss sz 201245468 (hard solderability test) Cut all kinds of unrecorded steel of lmm into 4〇x5〇mm and 25x30mm And wet-grinding with #600 waterproof sandpaper (waterproof abrasive paper), and using it as a lap and performing a hard solderability test using silver soldering. Hard soldering is performed in the same manner as above, and two specimens are tested. Specifically, 0.3 g of the silver of JIS BNi5 in which the organic binder is mixed is placed on the overlapping portion of the sample and hard-welded. The hard-welded system uses a nitrogen reduction furnace at 11 GG ° C is carried out in an environment of 1 GG% of hydrogen. The evaluation method is based on the observation of the cross section of the sample which has been subjected to the hard soldering, and the case where the hard material is filled with το between the gaps is regarded as good, and remains. The gap is considered to be bad. (Currency test) Next, the dry-wet test method will be described in the test solution for simulating the condensed water produced by the combustion of LNG or petroleum. The sample system is not subjected to hard soldering. And the same conditions as when the hard soldering is performed, that is, In a hydrogen reduction furnace, various stainless steels were heated in an environment of ll〇〇eC and hydrogen 100%, and then tested by cutting into a size of 15×100 mm. Further, the thickness of the sample was 1 mm. The composition of the test solution was as described above. It simulates the composition of condensed water normally produced by the combustion of LNG or petroleum, and adjusts to 100 ppm of acid ions, 10 ppm of sulfate ions, ρΗ2·5, and simulated salt concentration to make the vapor ions 100 ppm. Half was immersed in the test tube containing the test solution, and placed in 8 (r warm water of rc. Keep until the test solution was completely dried) and after drying, transfer the sample to a new test tube filled with the test solution and dry again. After the drying was carried out 14 times, the maximum corrosion depth of 201245468 after the test was measured. (Stress Erosion Evaluation Test) The stress crack evaluation test system does not perform the hard solder joint, but the same conditions as when the hard solder joint is performed, that is, Using a hydrogen reduction furnace, the same material as the one used for the hard solderability test is heated in an environment of ll ° ° C and 100% hydrogen. The size of the material is cut out from 30 x 30 mm and 15 χ 15 mni. After the wet grinding treatment, the two sheets were overlapped and spot-bonded to form a gap. The sample having the gap was immersed in distilled water containing 2 〇〇ppm of C1· and continuously at 100 ° C. After 7 days of treatment, the spot-bonded portion of the treated sample was perforated and separated by a drill, and then cracked was observed in the dye penetration test (staining flaw detection method). Good, cracking occurred as a defect. The results are shown in Table 1. Further, the hard solderability test results and the stress cracking evaluation test results are indicated by A and the defects by B. As is apparent from Table 1, it was confirmed that the inventive examples of Nos. 1 to 13 were excellent in the maximum corrosion depth and the stress corrosion resistance evaluation test in the hard solderability test, the corrosion resistance test (dry-dry test). the result of. On the other hand, it was confirmed that the [〇1;^[8丨] value was greater than 4.4>1〇.14 to 18, and the 21 system did not have sufficient hard solderability. Further, it was confirmed that the [Cu]x[Si] value was less than 1.6. Although 19, 23, 24, and 25 had good hard solderability, cracking occurred in the stress cracking test, and 2 [n] The value of +[Mo] is No. 20, 21, 23, and 24 outside the lower limit of the present invention. The maximum decay depth in the corrosion resistance test (dry and wet repeat 5 test) is 100# m or more. Although the value of N〇22i[Cu]x [Si] and the value of 2[N] + [Mo] are within the scope of the present invention, since Cr is in the limit of the circumference of the present invention, it is in the corrosion resistance. The maximum corrosion/woodiness in the test (dry fishing repeated test) is greater than 1 〇〇"m. Moreover, even if N 〇 i4~i8 has a value of [Μ 〇 值 于 于 于 于 于 值 值 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Cu is outside the scope of the present invention, and exerts the effect of promoting the rot of the eluted & ion. #1上一~, the Worslai 纟 钢 steel of the present invention is in the combustion gas of:::fuel In the environment inside the heat exchanger, it also has the nature of 'there is no stress (4). Also, it is confirmed that (4) j '夭斯田铁系不铁钢 will produce a sulphuric acid ion or sulphur The low-pH condensed aqueous solution of ions is also rich in money. (IV) The availability of the aquaculture industry. The present invention is a method of producing a hard-weld material, and is applicable to a structure which generates an eight-star L-series stainless steel. On the way to the bottom of the world, the Tiansitian iron-based stainless steel system is not the same as the kerosene or LNG fuel _ +, the material for the converter. At this time, the (four)..., U-two of the present invention The hot father exchanges $m for the 埶. Not only can the material be used: = 二Γ: as the external and diaphragm etc. It is also suitable for use as a heat recovery member. It is also suitable for use as a heat recovery member. 20 201245468 In addition, the Worthite iron stainless steel of the present invention is particularly suitable for use in containing nitrate ions. And the low ρ Η solution of sulphate ion in the dry and wet environment. Specifically, it is an exterior exterior material, building materials, roofing materials, outdoor equipment, etc. Further, the Worthfield iron-based stainless steel plate of the present invention can be used for fear The general indoor water machine for stress cracking is specifically applicable to water storage, water storage tanks, home appliances, bathtubs, kitchen equipment, and other outdoor equipment. As described above, the present invention is industrially high. Use value. I: Simple description of the figure 3 The first figure shows the relationship between CU and S i content and hard solderability and corrosion resistance. Figure 2 shows the value of 2[N] + [Mo] and the maximum corrosion depth. Fig. 3 shows the relationship between the values of 2[N] + [Mo] and [Cu]X[Si] and the hard solderability and the silver property. [Description of main component symbols] (none) 21

Claims (1)

201245468 VII. Patent application scope: 1. A Worthfield iron-based non-mineral steel with excellent buttability and hard solderability, characterized by containing: C: 0_080°/. Hereinafter, Si: 1.2 to 3.0%, Μη: 0.4 to 2.0%, P: 0·03ο/〇 or less, S: 0.003% or less, Ni: 6.0 to 12.0%, Cr: 16.0 to 20.0%, and Cu: 0.2 to 3.0. %, A1 : 0.002 to 0.10%, N: 0.030 to 0.150%, and Mo: 0.1 to 1.0%, and the remainder is composed of Fe and unavoidable impurities, and satisfies the following formula (A) and (B) Formula: (A) Formula: 1.6S[Cu]x[Si]S4.4; and (B) Formula: 0.16S2[N] + [M〇]S 1.0 ; Here, [Cu], [Si], [N] and [Mo] are the contents of each element expressed by mass%. 2. The Worth Iron-based stainless steel having excellent corrosion resistance and hard solderability as in the first paragraph of the patent application, which contains, in mass%, Nb: 0.1 to 0.7%, Ti: 0·1 to 0.5%, V: 0.1 to 3.0%, and B: 0.0002 to 0.003%, one or more. twenty two