Non-oriented silicon steel with good electromagnetic performance and hot rolling production method thereof

Abstract

The invention discloses non-oriented silicon steel with good electromagnetic performance and a hot rolling production method thereof. The non-oriented silicon steel comprises the following components in percentage by weight: less than or equal to 0.005% of C, less than or equal to 2.8% of Si, less than or equal to 0.8% of Mn, less than or equal to 0.1% of P, less than or equal to 0.8% of Al, less than or equal to 0.005% of S, less than or equal to 0.005% of O, less than or equal to 0.005% of N, less than or equal to 0.003% of Nb, less than or equal to 0.003% of V, less than or equal to 0.003% of Ti, less than or equal to 0.4% of Sb + Sn and the balance of Fe and inevitable impurities. According to the non-oriented silicon steel, through reasonable main component design of Si, Al and the like, proper trace elements are added, a heat preservation cover is immediately put into use after high-temperature discharging, high-temperature finish rolling, high-temperature coiling and hot rolling coiling are conducted, heat preservation is conducted through hot coiling waste heat, a thick and large hot-rolled structure and a favorable texture are obtained, the iron loss P15 / 50 of the manufactured non-oriented silicon steel product can be improved by 0.1-0.2 w / kg, and the iron loss P15 / 50 of the manufactured non-oriented silicon steel product can be improved by 0.1-0.2 w / kg. And the magnetic induction intensity B50 / 50 can be improved by 0.01 to 0.04 T. According to the method, the electromagnetic performance of the non-oriented silicon steel is effectively improved by investment of the heat preservation cover with extremely low cost.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to non-oriented silicon steel with good electromagnetic properties and a hot rolling production method thereof. Background Art

[0002] Non-oriented silicon steel is mainly used in the manufacture of compressor and motor cores. In recent years, more and more electrical equipment such as motors, compressors, EI cores, etc. have put forward strict requirements on the iron loss and magnetic induction of non-oriented silicon steel in order to improve the efficiency of compressors and motors, reduce the size, and reduce the weight. In order to improve the electromagnetic properties of non-oriented silicon steel products, it is usually necessary to increase the main elements Si+Al, improve the purity of molten steel, and put normalizing production lines into use to obtain coarse grains and favorable textures, but it requires a significant increase in manufacturing costs and further breakthroughs in technical barriers. Today, the market competition is fierce. Obviously, it is difficult to gain a foothold by significantly increasing manufacturing costs to improve electromagnetic properties. Improving the electromagnetic properties of products by increasing a small amount of investment or cost is the mainstream direction. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a non-oriented silicon steel with good electromagnetic properties and a hot rolling production method thereof.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] The invention discloses a non-oriented silicon steel with good electromagnetic performance. The silicon steel is a silicon steel coil. The weight percentage of the components of the non-oriented silicon steel is as follows: C≤0.005%, Si≤2.8%, Mn≤0.8%, P≤0.1%, Al≤0.8%, S≤0.005%, O≤0.005%, N≤0.005%, Nb≤0.003%, V≤0.003%, Ti≤0.003%, Sb+Sn≤0.4%, and the rest is Fe and unavoidable impurities.

[0006] The present invention also discloses a hot rolling production method of the non-oriented silicon steel with good electromagnetic properties, comprising the steps of adding segregation elements Sb and Sn to molten steel with Sb+Sn≤0.4%, casting the slab, rolling the slab into a hot coil at high temperature, coiling the hot coil at high temperature, insulating the hot coil with a heat preservation cover, cold rolling the hot coil into a cold coil without normalization, and finally obtaining the non-oriented silicon steel coil with good electromagnetic properties through annealing and coating processes.

[0007] Furthermore, the hot rolling production method specifically comprises the following steps:

[0008] Step 1) smelting and casting slab: during smelting, segregation elements Sb and Sn are added to the molten steel, and the slab with a thickness of 230 mm is continuously cast; Sb and Sn are grain boundary segregation elements, which will be segregated around the precipitates, hindering the solid solution of the precipitates, so that the precipitates remain in a coarse size state, thereby preventing the surface grains from being refined, effectively reducing the iron loss value, and promoting the formation of deformation bands within the grains, reducing the

[111] grains in the recrystallized structure, thereby improving the magnetic induction intensity of the non-oriented silicon steel; wherein, the heating furnace entry temperature is 200-600°C, the heating furnace heating time is 200-350min, and the furnace exit temperature is controlled in the range of 1100-1180°C;

[0009] Step 2) High temperature rolling into hot coil

[0010] Reduce the water consumption during rough rolling and finishing rolling, ensure that the rough rolling RT2 outlet temperature is ≥980℃, the final rolling temperature is controlled at 860-920℃, and the hot coil is rolled into a thickness of 2.0-2.8mm;

[0011] Step 3) High temperature coiling

[0012] The laminar cooling of the coiling process adopts post-cooling method, and the final cooling temperature of laminar cooling is controlled at 600-780℃;

[0013] Step 4) Insulation cover

[0014] After the hot coil is unloaded, it is covered with a heat preservation cover, and the temperature entering the cover is controlled at above 400℃ and kept warm for 3-10 hours to obtain coarse hot-rolled metallographic structure and favorable texture. When the heat preservation cover is used in steel with added Sn and Sb elements, the improvement effect of the metallographic structure and favorable texture is greatly enhanced, achieving the goal of one plus one being greater than two.

[0015] Step 5) Cold rolling and coiling

[0016] The hot coil is cold rolled into 0.5mm cold coil without normalization, and then quickly annealed and coated at high temperature in a protective atmosphere to form a coil.

[0017] The beneficial effects of the present invention are as follows: the non-oriented silicon steel of the present invention is designed with reasonable main components such as Si and Al, proper trace elements are added, high-temperature furnace discharge, high-temperature final rolling and high-temperature coiling are adopted, and a heat preservation cover is used immediately after hot rolling into coils, and the residual heat of the hot coil is used for heat preservation, so as to obtain a coarse hot-rolled structure and a favorable texture, and the iron loss P15 / 50 of the manufactured non-oriented silicon steel product can be improved by 0.1-0.2w / kg, and the magnetic induction intensity B50 / 50 can be increased by 0.01-0.04T. The present invention effectively improves the electromagnetic properties of non-oriented silicon steel with a very low cost of heat preservation cover investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a metallographic structure diagram of the hot coil under the path of the heat preservation cover of the present invention;

[0019] Figure 2 It is the metallographic structure diagram of the hot coil under the conventional path of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the embodiments. Figure 1 As shown, the metallographic structure of the hot coil under the conventional path is as follows Figure 2 shown.

[0021] Embodiment 1:

[0022] The non-oriented silicon steel of this embodiment has the following components by weight: Si1.37%, Al0.41%, Mn0.22%, P≤0.1%, C≤0.005%, S≤0.005%, O≤0.005%, N≤0.005%, Nb≤0.003%, V≤0.003%, Ti≤0.003%, Sb+Sn≤0.4%, and the rest is Fe and unavoidable impurities.

[0023] The hot rolling production method of the present embodiment is as follows:

[0024] Step 1) smelting and casting slab: smelting molten steel according to the set composition, wherein the composition by weight percentage is Si1.37%, Al0.41%, Mn0.22%, P≤0.1%, C≤0.005%, S≤0.005%, O≤0.005%, N≤0.005%, Nb≤0.003%, V≤0.003%, Ti≤0.003%, Sb+Sn≤0.4%, and the rest is Fe and unavoidable impurities, and the slab is continuously cast into a 230mm thick slab by a continuous casting machine, the hot rolling heating furnace entry temperature is 200-600℃, the heating time of the heating furnace is 200-350 minutes, and the furnace outlet temperature is controlled in the range of 1120-1180℃.

[0025] Step 2) High temperature rolling into hot coil: reduce the water consumption during rough rolling and finishing rolling, ensure that the rough rolling RT2 outlet temperature is ≥980°C, control the final rolling temperature at 860-920°C, and roll into hot coil with a thickness of 2.0-2.8mm.

[0026] Step 3) High temperature coiling: The hot rolling laminar cooling adopts post-cooling method, and the final cooling temperature of the laminar cooling is controlled at 650-780°C.

[0027] Step 4) Insulation with insulation cover: After the hot coil is coiled and unloaded, cover it with insulation cover to ensure that the temperature entering the cover is controlled above 400℃ and keep it warm for 3-8 hours.

[0028] Step 5) Cold rolling and coiling: The hot coil is cold rolled into a 0.5 mm cold coil without normalization, and then quickly annealed and coated at high temperature in a protective atmosphere, and finally coiled. The electromagnetic properties of the finished product are tested using the Epstein square circle method.

[0029] Detailed process and product electromagnetic properties are shown in Table 1.

[0030] Table 1: Hot rolling process and electromagnetic performance results

[0031]

[0032] Embodiment 2:

[0033] The non-oriented silicon steel of this embodiment has the following components by weight: Si 2.21%, Al 0.37%, Mn 0.21%, P ≤ 0.1%, C ≤ 0.005%, S ≤ 0.005%, O ≤ 0.005%, N ≤ 0.005%, Nb ≤ 0.003%, V ≤ 0.003%, Ti ≤ 0.003%, Sb + Sn ≤ 0.4%, and the rest is Fe and unavoidable impurities.

[0034] The hot rolling production method of the present embodiment is as follows:

[0035] Step 1) smelting and casting slabs: smelting molten steel according to the set composition, wherein the composition by weight is Si2.21%, Al0.37%, Mn0.21%, P≤0.1%, C≤0.005%, S≤0.005%, O≤0.005%, N≤0.005%, Nb≤0.003%, V≤0.003%, Ti≤0.003%, Sb+Sn≤0.4%, and the rest is Fe and unavoidable impurities; continuous casting into slabs with a thickness of 230 mm by a continuous casting machine, the hot rolling heating furnace entry temperature is 200-600° C., the heating time in the heating furnace is 200-300 minutes, and the furnace exit temperature is controlled at 1100-1160° C.

[0036] Step 2) High temperature rolling into hot coil: reduce the water consumption during rough rolling and finishing rolling, ensure that the rough rolling RT2 outlet temperature is ≥980°C, control the final rolling temperature at 860-920°C, and roll into hot coil with a thickness of 2.0-2.8mm.

[0037] Step 3) High temperature coiling: The hot rolling laminar cooling adopts post-cooling method, and the final cooling temperature of the laminar cooling is controlled at 600-700℃.

[0038] Step 4) Insulation with insulation cover: After the hot coil is coiled and unloaded, cover it with insulation cover to ensure that the temperature entering the cover is controlled above 400℃ and keep it warm for 3-8 hours.

[0039] Step 5) Cold rolling and coiling: The hot coil is cold rolled into a 0.5 mm cold coil without normalization, and then quickly annealed and coated at high temperature in a protective atmosphere, and finally coiled. The electromagnetic properties of the finished product are tested using the Epstein square circle method.

[0040] Detailed process and product electromagnetic properties are shown in Table 2.

[0041] Table 2: Hot rolling process and electromagnetic properties results

[0042]

[0043] The above contents are only used to illustrate the technical solution of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention made by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A non-oriented silicon steel with good electromagnetic properties, the silicon steel being a silicon steel coil, characterized in that: The weight percentage of the silicon steel components is: C≤0.005%, Si≤2.8%, Mn≤0.8%, P≤0.1%, Al≤0.8%, S≤0.005%, O≤0.005%, N≤0.005%, Nb≤0.003%, V≤0.003%, Ti≤0.003%, Sb+Sn≤0.4%, and the rest is Fe and unavoidable impurities.

2. The hot rolling production method of non-oriented silicon steel according to claim 1, characterized in that: The molten steel is smelted with segregation elements Sb and Sn added and Sb+Sn≤0.4%, cast into slabs, rolled into hot coils at high temperature, coiled at high temperature, and the hot coils are kept warm by heat-insulating covers. The hot coils are cold-rolled into cold coils without normalization, and finally the non-oriented silicon steel coils with good electromagnetic properties are obtained through annealing and coating processes.

3. The hot rolling production method of non-oriented silicon steel according to claim 2, characterized in that: The hot rolling production method specifically comprises the following steps: Step 1) Smelting and casting slab During smelting, segregation elements Sb and Sn are added to the molten steel, and the slab with a thickness of 230 mm is continuously cast; wherein, the heating furnace entry temperature is 200-600°C, the heating furnace heating time is 200-350 minutes, and the furnace exit temperature is controlled in the range of 1100-1180°C; Step 2) High temperature rolling into hot coil Reduce the water consumption during rough rolling and finishing rolling, ensure that the rough rolling RT2 outlet temperature is ≥980℃, the final rolling temperature is controlled at 860-920℃, and the hot coil is rolled into a thickness of 2.0-2.8mm; Step 3) High temperature coiling The laminar cooling of the coiling process adopts post-cooling method, and the final cooling temperature of laminar cooling is controlled at 600-780℃; Step 4) Insulation cover After the hot coil is unloaded, it is covered with a heat preservation cover, and the temperature entering the cover is controlled at above 400℃, and the heat preservation is carried out for 3-10 hours; Step 5) Cold rolling and coiling The hot coil is cold rolled into 0.5mm cold coil without normalization, and then quickly annealed and coated at high temperature in a protective atmosphere to form a coil.

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