A kind of production method of tin brass

Abstract

The invention discloses a production method of tin brass, comprising the following steps: smelting raw materials of tin brass and recycled materials in a ratio of 1:2.5-3.5 and then casting; hot rolling the ingot through 15 passes, applying vibration during rolling, and rolling the ingot into an ingot; milling the ingot; initial rolling; bell furnace annealing; trimming; rough rolling; bell furnace annealing; rough rolling; cushion furnace annealing; finished product rolling; cleaning and passivation. The invention obtains tin brass through low-cost production, and through the control of various production processes, stably produces tin brass with a tensile strength of 480-570Mpa, an elongation of ≥5%, a hardness of 150-190HV, and a high yield.

Description

Technical Field

[0001] The invention belongs to the technical field of tin brass production, and in particular relates to a production method of tin brass. Background Art

[0002] The multi-element alloy composed of other alloying elements added to ordinary brass is called special brass, which includes aluminum brass, lead brass, tin brass, manganese brass, etc. These brasses have some special properties. For example, the addition of tin in tin brass can significantly improve the corrosion resistance of brass in the atmosphere and the ocean, and can also improve the strength of brass. Tin brass is generally called naval brass. The tin content in general tin brass is 1%. Too much tin will reduce the plasticity of the alloy. According to the zinc content in the alloy, tin brass is divided into α tin brass, α + β tin brass, and β tin brass; single-phase tin brass α tin brass such as 70Cu-29Zn-1Sn has good mechanical properties, a soft tensile strength of 350MPa, an elongation of 60%, excellent cold working performance, can withstand hot rolling and hot extrusion, but cannot be hot punched and hot forged. It is widely used in high-strength corrosion-resistant condenser pipes in ships and thermal power plants. This alloy has a tendency to stress corrosion cracking, so the cold-processed pipes must be annealed at low temperature to eliminate stress. α+β tin brass, such as 62Cu-37Zn-1Sn, has good mechanical properties, a soft tensile strength of 380MPa, an elongation of 40%, can be processed by cold and hot pressure, is easy to cut, has good weldability, and has high corrosion resistance in seawater. It is suitable for ship parts and parts in contact with seawater, gasoline, etc.

[0003] CN102230105A discloses a high-strength tin brass, and specifically discloses that the composition of each component of the high-strength tin brass is respectively: 65.0-69.0% copper, 0.3-1.8% tin, and the balance is zinc and inevitable impurities with a total amount not exceeding 0.3% by weight percentage; the production method thereof is: firstly, the ingredients are prepared according to the above component proportions through alloy design, and a 15mm thick ingot is produced after horizontal continuous casting, and then it is homogenized annealed at 500-560°C for 4-5 hours, and then the surface is milled, and the thickness after milling is 12.5-13.5mm, and then it is roughly rolled to 3.0mm, and then it is subjected to multiple intermediate annealing and cold rolling. After each annealing of the thickness below 3.0mm, the surface is brushed, the annealing temperature is 480-560°C, the annealing time is 4-5 hours, and then the finished product is rolled, and the thickness of the finished product is determined by customer requirements, and finally it is finished and packaged into a finished product. This patent uses only metal raw materials as the production raw materials for tin brass, which results in high production costs, and does not disclose the properties of tin brass.

[0004] The production cost of tin brass can be reduced by adding recycled materials. However, if the process is not properly controlled when using recycled materials as raw materials, defects such as cracks, peeling, and white spots will easily appear on the surface of the tin brass, which will seriously affect the yield rate. Summary of the invention

[0005] The object of the present invention is to provide a production method of tin brass. In the production method, raw materials of tin brass and recycled materials are smelted and cast according to a ratio of 1:2.5-3.5, and the ingot is processed into a tin brass strip with a thickness of 0.1-1.5 mm through a subsequent process; the tensile strength of the tin brass in the H state is 480-570 MPa, the elongation is ≥5%, the hardness is 150-190 HV, and the yield rate is high.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for producing tin brass, the method comprising the following steps:

[0008] (1) Smelting and casting the raw materials of tin brass and the recycled materials in a ratio of 1:2.5 to 3.5;

[0009] (2) hot rolling the cast billet through 15 passes, applying vibration during rolling, and rolling the billet into an ingot;

[0010] (3) Milling the ingot;

[0011] (4) initial rolling;

[0012] (5) bell furnace annealing;

[0013] (6) trimming;

[0014] (7) Rough rolling;

[0015] (8) bell furnace annealing;

[0016] (9) Rough rolling;

[0017] (10) Air cushion furnace annealing;

[0018] (11) Finished product rolling;

[0019] (12) Cleaning and passivation.

[0020] In step (1), the recycled material is baked at 500-700°C for 2.5-3.5 hours before entering the furnace to remove moisture that may be attached to the surface of the recycled material; when adding materials, first add part of the recycled material, then add the raw materials of tin and brass, and finally add the remaining part of the recycled material. This way of adding materials can fully mix the new and old materials during smelting. If this method is not followed, the composition of the ingot may be uneven.

[0021] In step (1), the casting temperature is 1050-1170°C, the ingot casting speed is 65-105mm / min, the primary cooling water inlet temperature is 20C-50°C, and the primary cooling water pressure is 0.2-0.4MPa; the secondary cooling water is 320mm away from the crystallizer outlet, the secondary cooling water inlet temperature is 20-50°C, and the secondary cooling water pressure is 0.2-0.4MPa; electromagnetic stirring is set 10mm away from the copper water, and the frequency is 15-25Hz. Avoid overburning. If overburning occurs, overburned structure will appear, which will reduce the force between crystals. In the subsequent casting and rolling process, peeling will occur.

[0022] In step (2), the zone temperatures of the heating furnace are: 850-920° C. in zones 1 to 4, 800-935° C. in zones 5 to 9, and 800-940° C. in zones 10 to 12. Heating by zones can make the temperature of the ingots uniform.

[0023] In step (2), in the hot rolling process, each rolling pass is controlled as follows: the processing rate of the 1st to 5th passes is 8.0-10.0%, and the rolling speed is 90-140 m / s; the processing rate of the 6th to 12th passes is 17.0-20.0%, and the rolling speed is 130-145 m / s; the processing rate of the 13th to 15th passes is 20.0-23.0%, and the rolling speed is 120-140 m / s. Multi-pass rolling can refine the grains and facilitate subsequent processing.

[0024] In step (2), the vibration frequency is 45 to 85 Hz to reduce defects in the ingot during the casting process.

[0025] In step (3), the single-sided milling amount is 0.8-1.0 mm, and the single-sided milling amount is 2-4 mm.

[0026] In step (5) and step (8), the bell-type furnace annealing conditions are: 500-600° C. for 7.5-8.5 hours to eliminate residual stress.

[0027] In step (10), the conditions for air cushion furnace annealing are: annealing temperature 600-700°C, annealing speed: 10-100 m / min. The strip is fully annealed, and the use of air cushion furnace annealing can reduce the contact between the strip and the roller, so that the strip shape can be better.

[0028] Compared with the prior art, the invention obtains tin brass through low-cost production, and through the control of various production processes, stably produces tin brass with a tensile strength of 480-570Mpa, an elongation of ≥5%, a hardness of 150-190HV, and a high yield. DETAILED DESCRIPTION

[0029] The present invention provides a method for producing tin brass, comprising the following steps:

[0030] (1) The raw materials of tin brass and recycled materials are smelted in a ratio of 1:2.5-3.5, and the recycled materials are baked at 500-700°C for 2.5-3.5h before entering the furnace to remove the water vapor that may be attached to the surface of the recycled materials; when adding materials, first add part of the recycled materials, then add the raw materials of tin brass, and finally add the remaining part of the recycled materials; the casting temperature is 1050-1170°C, the ingot casting speed is 65-105mm / min, the primary cooling water inlet temperature is 20C-50°C, and the primary cooling water pressure is 0.2-0.4MPa; the secondary cooling water is 320mm away from the outlet of the crystallizer, the secondary cooling water inlet temperature is 20-50°C, and the secondary cooling water pressure is 0.2-0.4MPa; an electromagnetic stirring is set 10mm away from the copper water, and the frequency is 15-25Hz;

[0031] (2) The ingot is heated in a heating furnace and then hot-rolled for 15 passes. During the rolling, a vibration with a frequency of 45 to 85 Hz is applied to the ingot to form an ingot. The temperatures of the zones of the heating furnace are: 850 to 920° C. for zones 1 to 4; 800 to 935° C. for zones 5 to 9; and 800 to 940° C. for zones 10 to 12. The control of each rolling pass is as follows: the processing rate of the 1st to 5th passes is 8.0 to 10.0%, and the rolling speed is 90 to 140 m / s; the processing rate of the 6th to 12th passes is 17.0 to 20.0%, and the rolling speed is 130 to 145 m / s; the processing rate of the 13th to 15th passes is 20.0 to 23.0%, and the rolling speed is 120 to 140 m / s.

[0032] (3) Mill the ingot surface, with a single-side milling amount of 0.8-1.0 mm and a single-side milling amount of 2-4 mm

[0033] (4) initial rolling;

[0034] (5) Bell furnace annealing: Annealing conditions are: 500-600℃ for 7.5-8.5h;

[0035] (6) trimming;

[0036] (7) Rough rolling;

[0037] (8) Bell furnace annealing: Annealing conditions are: 500-600°C for 7.5-8.5h;

[0038] (9) Rough rolling;

[0039] (10) Air cushion furnace annealing: Annealing conditions are: annealing temperature 600-700°C, annealing speed: 10-100 m / min;

[0040] (11) Finished product rolling;

[0041] (12) Cleaning and passivation.

[0042] The present invention is described in detail below with reference to the embodiments.

[0043] The main components and weight percentages of the tin brass in each embodiment are shown in Table 1.

[0044] Table 1

[0045] Cu Pb Fe Sn Example 1 69 0.04 0.04 3.6 Example 2 65 0.04 0.04 4.3 Example 3 63 0.06 0.06 6.0 Example 4 60 0.09 0.06 9.0

[0046] The production process parameters of tin brass in each embodiment are shown in Table 2.

[0047] Table 2

[0048]

[0049]

[0050] The rolling thickness, processing rate and rolling speed of each pass in the hot rolling process are shown in Table 3.

[0051]

[0052]

[0053] Comparative Example 1

[0054] The rest is the same as in Example 1, except that the weight ratio of the raw material of tin brass to the recycled material is 1:4.

[0055] Comparative Example 2

[0056] The rest is the same as in Example 1, except that the casting temperature is increased by 20 degrees Celsius.

[0057] Comparative Example 3

[0058] The other steps are the same as those in Example 1, except that the two bell-type furnace annealing times are shortened by half an hour.

[0059] Comparative Example 4

[0060] The rest is the same as in Example 1, except that the annealing temperature of the air cushion furnace is increased by 50 degrees Celsius.

[0061] The properties of the tin brass in the embodiments and comparative examples are shown in Table 4.

[0062] Table 4

[0063] Thickness specification / mm Tensile strength / MPa Elongation / % Hardness / HV Yield / % Example 1 0.203 500 Min6 80 55.53 Example 2 0.203 570 Min6 81 54.53 Example 3 0.203 420 Min28 78 56.17 Example 4 0.203 490 Min15 80 55.26 Comparative Example 1 0.203 470 Min5 60 50.16 Comparative Example 2 0.203 550 Min5 65 49.16 Comparative Example 3 0.203 400 Min25 70 48.33 Comparative Example 4 0.203 450 Min10 68 50.48

[0064] The detailed description of a method for producing tin brass with reference to the above-mentioned embodiments is illustrative rather than restrictive, and several embodiments may be listed according to the limited scope. Therefore, changes and modifications without departing from the overall concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for producing tin brass, characterized in that: The production method comprises the following steps: (1) Smelting and casting the raw materials of tin brass and recycled materials in a weight ratio of 1:2.5~3.5; (2) hot rolling the cast billet through 15 passes, applying vibration during rolling, and rolling it into an ingot; (3) Milling the ingot; (4) Initial rolling; (5) Bell furnace annealing; (6) Trimming; (7) Rough rolling; (8) Bell furnace annealing; (9) Rough rolling; (10) Air cushion furnace annealing; (11) Finished product rolling; (12) Cleaning and passivation; In step (1), the recycled material is baked at 500-700°C for 2.5-3.5 hours before entering the furnace; when adding the materials, a portion of the recycled material is added first, then the raw material of tin brass is added, and finally the remaining portion of the recycled material is added; In step (1), the casting temperature is 1050-1170°C, the casting speed is 50-105 mm / min, the primary cooling water inlet temperature is 20°C-50°C, and the primary cooling water pressure is 0.2-0.4 MPa; the secondary cooling water is 320 mm away from the crystallizer outlet, the secondary cooling water inlet temperature is 20-50°C, and the secondary cooling water pressure is 0.2-0.MPa; an electromagnetic stirring is set 10 mm away from the copper water, and the frequency is 15-50 Hz; In step (2), the zone temperatures of the heating furnace are: 850-920°C for zone 1 to zone 4; 800-935°C for zone 5 to zone 9; and 800-940°C for zone 10 to zone 12. In step (2), in the hot rolling process, each rolling pass is controlled as follows: the processing rate of the 1st to 5th passes is 8.0-10.0%, and the rolling speed is 90-140 m / s; the processing rate of the 6th to 12th passes is 17.0-20.0%, and the rolling speed is 130-145 m / s; the processing rate of the 13th to 15th passes is 20.0-23.0%, and the rolling speed is 120-140 m / s; In step (2), the vibration frequency is 45~85Hz; In step (5) and step (8), the bell-type furnace annealing conditions are: 500-600°C for 7.5-8.5h; In step (10), the conditions for annealing in the air cushion furnace are: annealing temperature: 600-700° C., annealing speed: 10-100 m / min.

2. The production method according to claim 1, characterized in that In step (3), the single-sided milling amount is 0.8-1.0 mm, and the single-sided milling amount is 2-4 mm.

3. The production method according to claim 1, characterized in that The tin brass has a tensile strength of 480-570 MPa and an elongation of ≥5% in the H state.

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