Laboratory heat treatment method of steel plate for armor protection

Abstract

The invention discloses a laboratory heat treatment method of a steel plate for armored protection, which comprises the following steps: heat treatment quenching temperature is 880 + / -10 DEG C, heat preservation is carried out for 20-40 minutes, tempering temperature is 220-230 DEG C, heat preservation is carried out for 60-80 minutes, and finally a bainite structure is obtained; the steel plate for armor protection comprises the following chemical components in percentage by mass: less than or equal to 0.45% of C, less than or equal to 0.40% of S , less than or equal to 1.2% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, less than or equal to 1.80% of N , less than or equal to 1.0% of Cr, less than or equal to 0.7% of Mo, less than or equal to 0.005% of B, 0.030-0.050% of A < l > and the balance of Fe and impurities. The invention aims to provide the laboratory heat treatment method for the steel plate for armor protection, and aims to design and develop the armor protection steel plate meeting the requirements of a user, and the high-performance steel plate BTP500 is produced according to the performance standard requirements of relevant foreign and domestic products.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel heat treatment, and in particular to a laboratory heat treatment method for steel plates for armor protection. The bulletproof steel plate material of the present invention is mainly used for the protection of cash transport vehicles, riot control vehicles, and special vehicles, and the bulletproof plate used in such special vehicles is one of the important key materials. Background Art

[0002] At present, Patent 1, application number 202210862892.0, discloses a composite treatment method of laser shock and micro-arc oxidation for bulletproof steel, including pickling and rust removal, micro-arc oxidation treatment, washing and drying, and laser shock treatment of bulletproof steel. The invention effectively combines laser shock treatment with micro-arc oxidation to effectively improve the corrosion resistance and mechanical properties of the steel plate. However, the specific production method of bulletproof steel is not mentioned.

[0003] Patent 2, application number 201910160548.5, discloses a heat treatment method for civilian bulletproof steel, followed by quenching + two-phase zone quenching + tempering heat treatment. The invention also does not describe the specific smelting and rolling process, but only provides a heat treatment method.

[0004] Patent 3, application number 202211317381.7, proposes a gas shielded welding method for martensitic bulletproof steel with a hardness of 600 HBW. The method uses a melting inert gas shielded welding method, the power supply polarity is reversed, and an argon-rich mixed shielding gas is selected. The method also does not explain the specific production method of the steel plate. Summary of the invention

[0005] The purpose of the present invention is to provide a laboratory heat treatment method for armor protection steel plates, with the goal of designing and developing armor protection steel plates that meet user needs, benchmarking the performance standards of related foreign and domestic products, and producing high-performance micro-alloyed steel plates BTP500 through reasonable alloying composition design, smelting, rolling, heat treatment and other production process parameter design and small-scale industrial trial production.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention discloses a laboratory heat treatment method for a steel plate for armor protection, which adopts a process of molten iron pretreatment - converter steelmaking - LF refining outside the furnace - RH vacuum degassing - continuous casting - heating - dephosphorization - rough rolling - finishing rolling - cooling - straightening - offline heat treatment, and is characterized in that: the heat treatment quenching temperature is 880±10°C, the heat preservation is 20-40min, the tempering temperature is 220-230°C, the heat preservation is 60-80min, and a bainite structure is finally obtained;

[0008] The chemical composition of the armor protection steel plate in mass percentage is: C: ≤0.45%, Si: ≤0.40%, Mn≤1.2%, P: ≤0.015%, S: ≤0.010%, Ni≤1.80%, Cr≤1.0%, Mo≤0.7%, B≤0.005%, Al: 0.030-0.050%, and the rest is Fe and unavoidable impurities, with a total mass fraction of 100%.

[0009] Furthermore, the heating temperature is 1250±15°C to reach the complete austenitizing temperature, so that the slab structure is completely austenitized.

[0010] Furthermore, the rough rolling adopts high temperature and large reduction rolling to ensure that the columnar crystals are fully crushed; the final rolling temperature is 890±15℃ to ensure that the finishing rolling is carried out in a completely non-recrystallization temperature region, so that the austenite will not recrystallize and grow, but the grains will be elongated and fragmented, thereby obtaining uniform and fine austenite grains.

[0011] Furthermore, the chemical composition of the armor protection steel plate in mass percentage is: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.90%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest is Fe and unavoidable impurities, and the mass fraction totals 100%.

[0012] Furthermore, the chemical composition of the armor protection steel plate in mass percentage is: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.70%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest is Fe and unavoidable impurities, and the mass fraction totals 100%.

[0013] Furthermore, the chemical composition of the armor protection steel plate in mass percentage is: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.80%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest is Fe and unavoidable impurities, and the mass fraction totals 100%.

[0014] Compared with the prior art, the beneficial technical effects of the present invention are:

[0015] The present invention improves the microstructure of steel materials by adding microalloying elements alone or in combination, achieving high strengthening, high toughness and low cost. In particular, the influence of alloying elements on the hardness, cleanliness, structure and grain size of armor steel is explored. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings.

[0017] Figure 1 For example 1 organization;

[0018] Figure 2 For Example 2 organization;

[0019] Figure 3 Organized as in Example 3. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with specific embodiments.

[0021] Embodiment 1:

[0022] (1) The embodiment includes the following chemical components in weight percentage: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.90%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest are Fe and unavoidable impurities, with a total mass fraction of 100%.

[0023] (2) Hot metal pretreatment: After hot metal desulfurization pretreatment, the S content is ≤0.003%.

[0024] (3) Converter steelmaking: The converter adopts the single slag process to ensure the success of carbon extraction in one go. The steel tapping process adopts bottom blowing argon operation. To ensure the effect, the bottom blowing mode of nitrogen and argon switching is adopted. The steel tapping temperature is less than 1670℃.

[0025] (4) LF refining: mainly for the addition of Si, Mn, Nb, V, Ti, Cr, Mo, and the addition of appropriate amount of alloy according to the requirements of internal control components. LF refining is carried out for no less than 40 minutes.

[0026] (5) RH refining: The vacuum treatment time in the RH stage is not less than 30 minutes. The molten steel after RH treatment must first be soft-blown with argon to ensure uniform composition and sufficient floating of inclusions for more than 15 minutes, and then allowed to stand and steel is added. The standing time is Not less than 15 minutes.

[0027] (6) Continuous casting: Electromagnetic stirring and light pressure are used to ensure the quality of the casting.

[0028] (7) Heating process: The slab is cold loaded into the furnace, the time in the furnace is not less than 300 min, and the furnace temperature is 1250°C.

[0029] (8) Hot rolling process: The starting temperature of the rough rolling of the slab is 1230±15℃. Considering that the steel plate is relatively thin, two-stage controlled rolling is not adopted. The final rolling temperature of the steel plate is set to 890±15℃. In addition, the chemical composition design of this steel grade has ensured good hardenability, and the rolled steel plate will also obtain bainite structure under low cooling rate conditions. Considering that ACC acceleration is likely to cause poor shape of thin-gauge steel plates, the steel plate is not subjected to controlled cooling after rolling, and natural cooling in air is adopted.

[0030] (9) Heat treatment process: quenching heating temperature 880℃, keep warm for 30min. After quenching, the steel plate is tempered within 24 hours. Since this steel has high hardness and its microstructure is tempered martensite, the steel plate is tempered at low temperature. Tempering temperature 220℃, keep warm for 60min.

[0031] Embodiment 2:

[0032] (1) The embodiment includes the following chemical components in weight percentage: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.70%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest are Fe and unavoidable impurities, with a total mass fraction of 100%.

[0033] (2) Hot metal pretreatment: After hot metal desulfurization pretreatment, the S content is ≤0.003%.

[0034] (3) Converter steelmaking: The converter adopts the single slag process to ensure the success of carbon extraction in one go. The steel tapping process adopts bottom blowing argon operation. To ensure the effect, the bottom blowing mode of nitrogen and argon switching is adopted. The steel tapping temperature is less than 1670℃.

[0035] (4) LF refining: mainly for the addition of Si, Mn, Nb, V, Ti, Cr, Mo, and the addition of appropriate amount of alloy according to the requirements of internal control components. LF refining is carried out for no less than 40 minutes.

[0036] (5) RH refining: The vacuum treatment time in the RH stage is not less than 30 minutes. The molten steel after RH treatment must first be soft-blown with argon to ensure uniform composition and sufficient floating of inclusions for more than 15 minutes, and then allowed to stand and steel is added, with the standing time being not less than 15 minutes.

[0037] (6) Continuous casting: Electromagnetic stirring and light pressure are used to ensure the quality of the casting.

[0038] (7) Heating process: The slab is cold loaded into the furnace, the time in the furnace is not less than 300 min, and the furnace temperature is 1250°C.

[0039] (8) Hot rolling process: The starting temperature of the rough rolling of the slab is 1230±15℃. Considering that the steel plate is relatively thin, two-stage controlled rolling is not adopted. The final rolling temperature of the steel plate is set to 900±15℃. In addition, the chemical composition design of this steel grade has ensured good hardenability, and the rolled steel plate will also obtain bainite structure under low cooling rate conditions. Considering that ACC acceleration is likely to cause poor shape of thin-gauge steel plates, the steel plate is not subjected to controlled cooling after rolling, and natural cooling in air is adopted.

[0040] (9) Heat treatment process: quenching heating temperature 880℃, keep warm for 30min. After quenching, the steel plate is tempered within 24 hours. Since this steel has high hardness and its microstructure is tempered martensite, the steel plate is tempered at low temperature. Tempering temperature 220℃, keep warm for 80min.

[0041] Embodiment 3:

[0042] (1) The embodiment includes the following chemical components in weight percentage: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.80%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest are Fe and unavoidable impurities, with a total mass fraction of 100%.

[0043] (2) Hot metal pretreatment: After hot metal desulfurization pretreatment, the S content is ≤0.003%.

[0044] (3) Converter steelmaking: The converter adopts the single slag process to ensure the success of carbon extraction in one go. The steel tapping process adopts bottom blowing argon operation. To ensure the effect, the bottom blowing mode of nitrogen and argon switching is adopted. The steel tapping temperature is less than 1670℃.

[0045] (4) LF refining: mainly for the addition of Si, Mn, Nb, V, Ti, Cr, Mo, and the addition of appropriate amount of alloy according to the requirements of internal control components. LF refining is carried out for no less than 40 minutes.

[0046] (5) RH refining: The vacuum treatment time in the RH stage is not less than 30 minutes. The molten steel after RH treatment must first be soft-blown with argon to ensure uniform composition and sufficient floating of inclusions for more than 15 minutes, and then allowed to stand and steel is added, with the standing time being not less than 15 minutes.

[0047] (6) Continuous casting: Electromagnetic stirring and light pressure are used to ensure the quality of the casting.

[0048] (7) Heating process: The slab is cold loaded into the furnace, the time in the furnace is not less than 300 min, and the furnace temperature is 1250°C.

[0049] (8) Hot rolling process: The starting temperature of the rough rolling of the slab is 1230±15℃. Considering that the steel plate is relatively thin, two-stage controlled rolling is not adopted. The final rolling temperature of the steel plate is set to 900±15℃. In addition, the chemical composition design of this steel grade has ensured good hardenability, and the rolled steel plate will also obtain bainite structure under low cooling rate conditions. Considering that ACC acceleration is likely to cause poor shape of thin-gauge steel plates, the steel plate is not subjected to controlled cooling after rolling, and natural cooling in air is adopted.

[0050] (9) Heat treatment process: quenching heating temperature 880℃, keep warm for 30min. After quenching, the steel plate is tempered within 24 hours. Since this steel has high hardness and its microstructure is tempered martensite, the steel plate is tempered at low temperature. Tempering temperature 230℃, keep warm for 80min.

[0051] The mechanical properties of each embodiment are shown in Table 1, and the anti-ballistic properties are shown in Table 2.

[0052] Table 1 Mechanical properties of steel plates

[0053]

[0054] Table 2 Anti-ballistic properties of steel plates

[0055]

[0056] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A laboratory heat treatment method for steel plates for armor protection, which adopts the process of hot metal pretreatment - converter steelmaking - LF refining - RH vacuum degassing - continuous casting - heating - dephosphorization - rough rolling - finishing rolling - cooling - straightening - offline heat treatment, characterized in that: Heat treatment quenching temperature is 880±10℃, holding temperature is 20-40min, tempering temperature is 220-230℃, holding temperature is 60-80min, and finally bainite structure is obtained; The chemical composition of the armor protection steel plate in mass percentage is: C: ≤0.45%, Si: ≤0.40%, Mn≤1.2%, P: ≤0.015%, S: ≤0.010%, Ni≤1.80%, Cr≤1.0%, Mo≤0.7%, B≤0.005%, Al: 0.030-0.050%, and the rest is Fe and unavoidable impurities, with a total mass fraction of 100%.

2. The laboratory heat treatment method for armored steel plates according to claim 1, characterized in that: The heating temperature is 1250±15℃ to reach the complete austenitizing temperature, so that the slab structure is completely austenitized.

3. The laboratory heat treatment method for armor protection steel plate according to claim 1, characterized in that: The rough rolling adopts high temperature and large reduction rolling to ensure that the columnar crystals are fully crushed; the final rolling temperature is 890±15℃ to ensure that the finishing rolling is carried out in the completely non-recrystallization temperature area, so that the austenite will not recrystallize and grow, but the grains will be elongated and fragmented, thereby obtaining uniform and fine austenite grains.

4. The laboratory heat treatment method for armor protection steel plate according to claim 1, characterized in that: The chemical composition of the armor protection steel plate in mass percentage is: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.90%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest are Fe and unavoidable impurities, with a total mass fraction of 100%.

5. The laboratory heat treatment method for armor protection steel plate according to claim 1, characterized in that: The chemical composition of the armor protection steel plate in mass percentage is: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.70%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest are Fe and unavoidable impurities, with a total mass fraction of 100%.

6. The laboratory heat treatment method for armor protection steel plate according to claim 1, characterized in that: The chemical composition of the armor protection steel plate in mass percentage is: C: 0.40%, Si: 0.34%, Mn: 1.02%, P: 0.003%, S: 0.005%, Ni: 0.80%, Cr: 1.80%, Mo: 0.35%, Nb: 0.020%, Ti: 0.030%, B: 0.0011%, Al: 0.045%, and the rest are Fe and unavoidable impurities, with a total mass fraction of 100%.

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