High-manganese double-phase non-magnetic stainless steel as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of stainless steel materials, and discloses high-manganese double-phase non-magnetic stainless steel and a preparation method and application thereof. The material comprises, by mass, 0.07%-0.19% of carbon, 0.15%-0.45% of silicon, 11.8%-25% of manganese, 10.5%-14% of chromium, 0.75%-1.2% of nickel, 0.15%-0.51% of copper, 0.15%-0.25% of nitrogen, smaller than or equal to 0.05% of phosphorus, smaller than or equal to 0.005% of sulfur, 0.05%-0.5% of molybdenum, smaller than or equal to 0.0006% of lead, smaller than or equal to 0.003% of niobium, smaller than or equal to 0.0004% of antimony, smaller than or equal to 0.0002% of aluminum, smaller than or equal to 0.05% of cadmium and the balance iron and inevitable impurities. By adjusting the chemical composition, the problem that martensite formed after hot rolling and cold rolling has magnetism is solved, and the properties such as softness, strong stretching and ductility of the stainless steel are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of stainless steel materials, and in particular to a high-manganese duplex non-magnetic stainless steel and a preparation method and application thereof. Background Art

[0002] Austenitic stainless steel has typical non-magnetic properties. At the same time, the steel has good elongation and good formability. It also has good corrosion resistance and weldability, and has a wide range of applications.

[0003] However, ordinary austenitic stainless steel still has weak magnetism, especially after processing, its weak magnetic characteristics become more obvious, and the magnetic flux is usually greater than 1.01Wb, making it difficult to use in buttons, zippers, clothing accessories, mechanical hardware and deep-drawn products, which require absolute non-magnetic applications.

[0004] Therefore, how to provide a non-magnetic austenitic stainless steel material is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide a high manganese duplex non-magnetic stainless steel and a preparation method and application thereof, so as to solve the problem that the existing austenitic stainless steel has weak magnetism after processing.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The invention provides a high-manganese duplex non-magnetic stainless steel. The stainless steel comprises the following chemical composition, calculated by mass fraction: 0.07-0.19% carbon, 0.15-0.45% silicon, 11.8-25% manganese, 10.5-14% chromium, 0.75-1.2% nickel, 0.15-0.51% copper, 0.15-0.25% nitrogen, ≤0.05% phosphorus, ≤0.005% sulfur, 0.05-0.5% molybdenum, ≤0.0006% lead, ≤0.003% niobium, ≤0.0004% antimony, ≤0.0002% aluminum, ≤0.0002% cadmium, and the balance is iron and unavoidable impurities.

[0008] Preferably, in the above-mentioned high manganese duplex non-magnetic stainless steel, the total mass fraction of phosphorus and sulfur is ≤0.052%; the total mass fraction of lead and antimony is ≤0.001%.

[0009] Preferably, in the above-mentioned high manganese duplex non-magnetic stainless steel, the martensite temperature Md30 of the high manganese duplex non-magnetic stainless steel is ≤96° C.; and the high temperature solidification mode factor K of the high manganese duplex non-magnetic stainless steel is ≤1.15.

[0010] The present invention also provides a method for preparing high manganese duplex non-magnetic stainless steel, comprising the following steps:

[0011] (1) smelting and casting a slab according to the chemical composition of high manganese duplex non-magnetic stainless steel;

[0012] (2) The slab is heated, dephosphorized under high pressure after being taken out of the furnace, and then subjected to 5 passes of rough rolling and 7 passes of finish rolling to obtain a black steel coil;

[0013] (3) The black steel coil is heat treated, pickled, cut into different widths and cold rolled for 6 to 15 passes to obtain a semi-finished product;

[0014] (4) The semi-finished product is annealed, then subjected to 3 to 5 passes of finish rolling, and annealed again to obtain high manganese duplex non-magnetic stainless steel.

[0015] Preferably, in the above-mentioned method for preparing high manganese duplex non-magnetic stainless steel, the heating temperature in step (2) is 1250-1300° C.; and the heating time is 180-280 min.

[0016] Preferably, in the above-mentioned method for preparing high manganese duplex non-magnetic stainless steel, the thickness of the slab after rough rolling in step (2) is 30 to 50 mm; the thickness of the black steel coil after finish rolling is 2 to 6 mm; and the width of the black steel coil after finish rolling is 910 to 1530 mm.

[0017] Preferably, in the above-mentioned method for preparing high manganese duplex non-magnetic stainless steel, the temperature of the heat treatment in step (3) is 1100-1200°C; the time of the heat treatment is 180-200min; and the TV value speed of the pickling is 80-150m / min.

[0018] Preferably, in the above-mentioned method for preparing high manganese duplex non-magnetic stainless steel, the pickling acid solution in step (3) comprises: 150-300 g / L sulfuric acid, 100-200 g / L nitric acid, and 5-15 g / L hydrofluoric acid.

[0019] Preferably, in the above-mentioned method for preparing high manganese duplex non-magnetic stainless steel, the temperature of the annealing treatment and the re-annealing treatment in step (4) is independently 1080-1200°C; the TV value of the annealing treatment and the re-annealing treatment is independently 18-25m / min.

[0020] The present invention also provides an application of high-manganese duplex non-magnetic stainless steel in clothing accessories or deep-drawn products.

[0021] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0022] By adjusting the chemical composition, the present invention avoids the magnetic martensite formed after hot and cold rolling, thereby enhancing the stainless steel's softness, tensile strength, and ductility. The stainless steel of the present invention, with manganese, nickel, and chromium as the main alloying elements, has a tensile strength of ≥600 MPa, a yield strength of 300 MPa, an elongation of >30%, and a hardness of <110 HRB or HV 235. DETAILED DESCRIPTION

[0023] The invention provides a high-manganese duplex non-magnetic stainless steel. The stainless steel comprises the following chemical composition, calculated by mass fraction: 0.07-0.19% carbon, 0.15-0.45% silicon, 11.8-25% manganese, 10.5-14% chromium, 0.75-1.2% nickel, 0.15-0.51% copper, 0.15-0.25% nitrogen, ≤0.05% phosphorus, ≤0.005% sulfur, 0.05-0.5% molybdenum, ≤0.0006% lead, ≤0.003% niobium, ≤0.0004% antimony, ≤0.0002% aluminum, ≤0.0002% cadmium, and the balance is iron and unavoidable impurities.

[0024] In the present invention, the total mass fraction of the phosphorus and sulfur is ≤0.052%; the total mass fraction of the lead and antimony is ≤0.001%.

[0025] In the present invention, the martensite temperature Md30 of the high manganese duplex non-magnetic stainless steel is ≤96° C.; and the high temperature solidification mode factor K of the high manganese duplex non-magnetic stainless steel is ≤1.15.

[0026] The present invention also provides a method for preparing high manganese duplex non-magnetic stainless steel, comprising the following steps:

[0027] (1) smelting and casting a slab according to the chemical composition of high manganese duplex non-magnetic stainless steel;

[0028] (2) The slab is heated, dephosphorized under high pressure after being taken out of the furnace, and then subjected to 5 passes of rough rolling and 7 passes of finish rolling to obtain a black steel coil;

[0029] (3) The black steel coil is heat treated, pickled, cut into different widths and cold rolled for 6 to 15 passes to obtain a semi-finished product;

[0030] (4) The semi-finished product is annealed, then subjected to 3 to 5 passes of finish rolling, and annealed again to obtain high manganese duplex non-magnetic stainless steel.

[0031] In the present invention, the heating temperature in step (2) is preferably 1250-1300°C, more preferably 1270-1300°C, and more preferably 1300°C; the heating time is preferably 180-280 min, more preferably 180-240 min, and more preferably 180 min.

[0032] In the present invention, the thickness of the slab after rough rolling in step (2) is preferably 30 to 50 mm, more preferably 32 to 45 mm, and even more preferably 40 mm.

[0033] In the present invention, the thickness of the black steel coil after finish rolling in step (2) is preferably 2-6 mm, more preferably 4-6 mm, and more preferably 5 mm; the width of the black steel coil after finish rolling is preferably 910-1530 mm, more preferably 950-1100 mm, and more preferably 980 mm.

[0034] In the present invention, the temperature of the finish rolling in step (2) is preferably 1250-1300°C, more preferably 1270-1300°C, and even more preferably 1290°C.

[0035] In the present invention, the temperature of the heat treatment in step (3) is preferably 1100-1200°C, more preferably 1100-1150°C, and more preferably 1100°C; the time of the heat treatment is preferably 180-200min, more preferably 180-190min, and more preferably 180min; the TV value speed of the pickling is preferably 80-150m / min, more preferably 85-120m / min, and more preferably 90m / min.

[0036] In the present invention, the acid solution for pickling in step (3) includes: sulfuric acid, preferably 150-300 g / L, more preferably 180-270 g / L, more preferably 250 g / L; nitric acid, preferably 100-200 g / L, more preferably 110-160 g / L, more preferably 120 g / L; hydrofluoric acid, preferably 5-15 g / L, more preferably 10-13 g / L, more preferably 12 g / L.

[0037] In the present invention, the thickness after cold rolling in step (3) is preferably 0.6 to 1.5 mm, more preferably 0.9 to 1.5 mm, and even more preferably 1.5 mm.

[0038] In the present invention, the temperature of the annealing treatment and the re-annealing treatment in step (4) is independently preferably 1080-1200°C, more preferably 1090-1150°C, and more preferably 1100°C; the TV value of the annealing treatment and the re-annealing treatment is independently preferably 18-25 m / min, more preferably 19-22 m / min, and more preferably 20 m / min.

[0039] In the present invention, the thickness of the high manganese duplex non-magnetic stainless steel in step (4) is preferably 0.07 to 0.7 mm, more preferably 0.1 to 0.5 mm, and even more preferably 0.2 mm.

[0040] The present invention also provides an application of high-manganese duplex non-magnetic stainless steel in clothing accessories or deep-drawn products.

[0041] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0042] Example 1

[0043] This embodiment provides a high manganese duplex non-magnetic stainless steel, which comprises the following chemical composition, by mass fraction: 0.13% carbon, 0.25% silicon, 11.8% manganese, 13.3% chromium, 1% nickel, 0.41% copper, 0.17% nitrogen, 0.05% phosphorus, 0.001% sulfur, 0.05% molybdenum, 0.0002% lead, 0.003% niobium, 0.0004% antimony, 0.0002% aluminum, 0.05% cadmium, and the balance being iron and unavoidable impurities.

[0044] Martensite temperature Md30 = 96°C.

[0045] The method for preparing the high manganese duplex non-magnetic stainless steel comprises the following steps:

[0046] (1) smelting and casting a slab according to the chemical composition of high manganese duplex non-magnetic stainless steel;

[0047] (2) The slab is heated at 1300°C for 180 min, dephosphorized under high pressure after being taken out of the furnace, and then rough rolled to a thickness of 40 mm in 5 passes, and then finish rolled to a thickness of 5 mm and a width of 980 mm in 7 passes at 1290°C to obtain a black steel coil;

[0048] (3) The black steel coil was naturally cooled, then heat treated at 1100°C for 180 min, pickled in a solution of 250 g / L sulfuric acid, 120 g / L nitric acid, and 12 g / L hydrofluoric acid at a TV value speed of 90 m / min, and then cut into different widths and cold rolled in 8 passes to a thickness of 1.5 mm to obtain a semi-finished product;

[0049] (4) The semi-finished product was annealed at 1100°C with a TV value of 20 m / min, and then subjected to 5 passes of finish rolling, and annealed again at 1100°C with a TV value of 20 m / min to obtain a high manganese duplex non-magnetic stainless steel with a thickness of 0.2 mm.

[0050] Example 2

[0051] This embodiment provides a high manganese duplex non-magnetic stainless steel, which comprises the following chemical composition, by mass fraction: 0.17% carbon, 0.2% silicon, 15.5% manganese, 13.2% chromium, 1% nickel, 0.48% copper, 0.22% nitrogen, 0.045% phosphorus, 0.001% sulfur, 0.05% molybdenum, 0.0002% lead, 0.003% niobium, 0.0004% antimony, 0.0002% aluminum, 0.05% cadmium, and the balance being iron and unavoidable impurities.

[0052] Martensite temperature Md30 = 90°C.

[0053] The preparation method of the high manganese duplex non-magnetic stainless steel is specifically described in Example 1.

[0054] Example 3

[0055] This embodiment provides a high manganese duplex non-magnetic stainless steel, which comprises the following chemical composition, by mass fraction: 0.1% carbon, 0.45% silicon, 16.5% manganese, 13.1% chromium, 1.1% nickel, 0.51% copper, 0.22% nitrogen, 0.05% phosphorus, 0.0015% sulfur, 0.05% molybdenum, 0.0002% lead, 0.003% niobium, 0.0004% antimony, 0.0002% aluminum, 0.05% cadmium, and the balance being iron and unavoidable impurities.

[0056] Martensite temperature Md30 = 90°C.

[0057] The preparation method of the high manganese duplex non-magnetic stainless steel is specifically described in Example 1.

[0058] The high manganese duplex non-magnetic stainless steel prepared in Examples 1 to 3 was tested for mechanical properties, hardness, and magnetic flux. The results are shown in Table 1.

[0059] Table 1 Performance test results of high manganese duplex non-magnetic stainless steel

[0060]

[0061] The total lead content, total cadmium content, and nickel release of the high manganese duplex non-magnetic stainless steel prepared in Example 1 were measured. The results are shown in Table 2.

[0062] Table 2 Determination results of total lead content, total cadmium content and nickel release of high manganese duplex non-magnetic stainless steel

[0063]

[0064] Note: 1. “Not detected” means less than the detection limit (method detection limit).

[0065] 2. The basis for determining the total lead content is compliance with Entrance 63 of Annex XVII to (EU) No 2015 / 628 amending (EC) No 1907 / 2006 (i.e. REACH Regulation). The basis for determining the total cadmium content is compliance with Entrance 23 of Annex XVII to (EU) No 835 / 2012 amending (EC) No 1907 / 2006 (i.e. REACH Regulation). The basis for determining the nickel release is compliance with Entrance 27 of Annex XVII to (EC) No 1907 / 2006 (i.e. REACH Regulation).

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high manganese duplex non-magnetic stainless steel, characterized in that: Calculated by mass, it contains the following chemical composition: carbon 0.07-0.19%, silicon 0.15-0.45%, manganese 11.8-25%, chromium 10.5-14%, nickel 0.75-1.2%, copper 0.15-0.51%, nitrogen 0.15-0.25%, phosphorus ≤0.05%, sulfur ≤0.005%, molybdenum 0.05-0.5%, lead ≤0.0006%, niobium ≤0.003%, antimony ≤0.0004%, aluminum ≤0.0002%, cadmium ≤0.05%, and the balance is iron and unavoidable impurities.

2. The high manganese duplex non-magnetic stainless steel according to claim 1, characterized in that: The total mass fraction of the phosphorus and sulfur is ≤0.052%; the total mass fraction of the lead and antimony is ≤0.001%.

3. The high manganese duplex non-magnetic stainless steel according to claim 2, characterized in that: The martensite temperature Md30 of the high manganese duplex non-magnetic stainless steel is ≤96° C.; and the high temperature solidification mode factor K of the high manganese duplex non-magnetic stainless steel is ≤1.

15.

4. The method for preparing high manganese duplex non-magnetic stainless steel according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) smelting and casting a slab according to the chemical composition of high manganese duplex non-magnetic stainless steel; (2) The slab is heated, dephosphorized under high pressure after being taken out of the furnace, and then subjected to 5 passes of rough rolling and 7 passes of finish rolling to obtain a black steel coil; (3) The black steel coil is heat treated, pickled, cut into different widths and cold rolled for 6 to 15 passes to obtain a semi-finished product; (4) The semi-finished product is annealed, then subjected to 3 to 5 passes of finish rolling, and annealed again to obtain high manganese duplex non-magnetic stainless steel.

5. The method for preparing high manganese duplex non-magnetic stainless steel according to claim 4, characterized in that: The heating temperature in step (2) is 1250-1300° C.; the heating time is 180-280 min.

6. The method for preparing high manganese duplex non-magnetic stainless steel according to claim 4 or 5, characterized in that: The thickness of the slab after rough rolling in step (2) is 30-50 mm; the thickness of the black steel coil after finish rolling is 2-6 mm; and the width of the black steel coil after finish rolling is 910-1530 mm.

7. The method for preparing high manganese duplex non-magnetic stainless steel according to claim 6, characterized in that: The temperature of the heat treatment in step (3) is 1100-1200° C.; the time of the heat treatment is 180-200 min; and the TV value speed of the pickling is 80-150 m / min.

8. The method for preparing high manganese duplex non-magnetic stainless steel according to claim 7, characterized in that: The acid solution for pickling in step (3) includes: 150-300 g / L of sulfuric acid, 100-200 g / L of nitric acid, and 5-15 g / L of hydrofluoric acid.

9. The method for preparing high manganese duplex non-magnetic stainless steel according to claim 8, characterized in that: The temperatures of the annealing treatment and the re-annealing treatment in step (4) are independently 1080-1200° C.; the TV values ​​of the annealing treatment and the re-annealing treatment are independently 18-25 m / min.

10. Use of the high manganese duplex non-magnetic stainless steel according to any one of claims 1 to 3 in clothing accessories or deep-drawn products.

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