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75Cr hot-rolled plate coil produced from thin sheet billets through continuous casting and continuous rolling and production method thereof

A thin slab continuous casting and hot-rolled coil technology, which is applied in the field of high-grade saw blade steel production, can solve problems such as center segregation and center porosity, aggravated decarburization on the surface of 75Cr slab, and bonding accidents, etc., to achieve uniform structure and performance. good surface quality

Active Publication Date: 2014-03-19
HEBEI IRON AND STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The existing technology of 75Cr development and production has the following main problems: the carbon content in 75Cr steel is high, the manganese content is also high, and the alloy composition is complex. Uneven distribution; 75Cr has a low liquidus temperature and poor thermal strength, which is prone to slag inclusions and surface cracks on the surface of the slab; 75Cr solidifies at a high speed and has a thin shell, which is prone to bonding accidents; due to long-term Heating in the heating furnace will easily lead to aggravated decarburization on the surface of the 75Cr billet, thus affecting the surface hardness and quality of the finished product

Method used

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  • 75Cr hot-rolled plate coil produced from thin sheet billets through continuous casting and continuous rolling and production method thereof
  • 75Cr hot-rolled plate coil produced from thin sheet billets through continuous casting and continuous rolling and production method thereof
  • 75Cr hot-rolled plate coil produced from thin sheet billets through continuous casting and continuous rolling and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Embodiment 1: The 75Cr hot-rolled coil produced by continuous casting and rolling of thin slab adopts the following steps.

[0018] (1) It is smelted in a converter and alloyed by refining outside the furnace. Its chemical composition and weight percentage are: C 0.74%, Si 0.27%, Mn 0.68%, P≤0.015%, S≤0.005%, Cr 0.34% , Als 0.023%, the rest is Fe and unavoidable impurities.

[0019] (2) Carry out continuous casting with a superheat of 28°C, using 75Cr special mold powder, controlling the thickness of the slab to 65mm, and controlling the casting speed to 4.5m / min; the composition ratio of the mold powder is: CaO 22% 、Al 2 o 3 3.2%, SiO 2 27%, MgO 6.0%, F 11.5%, Na 2 O 13%, Fe 2 o 3 1.01%, MnO 2 0.1%, Li 2 0 3.46%, the balance of carbon and uncontrollable impurities; the temperature of the hemispherical point is 730-780°C, and the viscosity is 0.7-0.8Pa·s.

[0020] (3) Perform uniform heating in the heating furnace, reduce the heating time of the heating fur...

Embodiment 2

[0026] Embodiment 2: The 75Cr hot-rolled coils produced by continuous casting and rolling of thin slabs adopt the following steps.

[0027] (1) It is smelted in a converter and alloyed by refining outside the furnace. Its chemical composition and weight percentage are: C 0.75%, Si 0.26%, Mn 0.69%, P≤0.013%, S≤0.004%, Cr 0.36% , Als 0.022%, the rest is Fe and unavoidable impurities.

[0028] (2) Carry out continuous casting with a superheat of 25°C, using 75Cr special mold powder, controlling the thickness of the slab to 70mm, and controlling the casting speed to 4.4m / min; the composition ratio of the mold powder is: CaO 20% 、Al 2 o 3 3.3%, SiO 2 28%, MgO 6.5%, F 11%, Na 2 O 12.5%, Fe 2 o 3 1.58%, MnO 2 0.18%, Li 2 0 3.47%, the balance of carbon and uncontrollable impurities; the temperature of the hemispherical point is 730-780°C, and the viscosity is 0.7-0.8Pa·s.

[0029] (3) Perform uniform heating in the heating furnace, reduce the heating time of the heating f...

Embodiment 3

[0035] Embodiment 3: 75Cr hot-rolled coils produced by continuous casting and rolling of thin slabs adopt the following steps.

[0036] (1) It is smelted in a converter and alloyed by refining outside the furnace. Its chemical composition and weight percentage are: C 0.78%, Si 0.25%, Mn 0.65%, P≤0.020%, S≤0.006%, Cr 0.60% , Als 0.03%, the rest is Fe and unavoidable impurities.

[0037] (2) Carry out continuous casting with a superheat of 15°C, using 75Cr special mold powder, controlling the thickness of the slab to 80mm, and controlling the casting speed to 4.3m / min; the composition ratio of the mold powder is: CaO 24% 、Al 2 o 3 3.0%, SiO 2 26%, MgO 7.0%, F 11.5%, Na 2 O 14%, Fe 2 o 3 1.48%, MnO 2 0.07%, Li 2 0 3.0%, the balance of carbon and uncontrollable impurities; the temperature of the hemispherical point is 730-780°C, and the viscosity is 0.7-0.8Pa·s.

[0038] (3) Perform uniform heating in the heating furnace, reduce the heating time of the heating furnac...

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Abstract

The invention discloses a 75Cr hot-rolled plate coil produced from thin sheet billets through continuous casting and continuous rolling and a production method thereof. The 75Cr hot-rolled plate coil comprises the following chemical ingredients in percentage by weight: 0.73-0.78% of C, 0.25-0.40% of Si, 0.65-0.90% of Mn, not higher than 0.020% of P, not higher than 0.012% of S, 0.30-0.60% of Cr, 0.015-0.03% of Als and the balance of Fe and inevitable impurities. The production method has the advantages that the production problems of large liquid level fluctuation, caking, unstable heat flow and the like appearing during the continuous casting of thin sheet billets under the condition of high pulling rate and the quality problems of surface crackle, center segregation, center porosity and the like of casting blanks are solved, and a stable production technology for 75Cr steel in a thin-sheet continuous casting and continuous rolling production line is realized. The 75Cr plate coil has the advantages that the surface quality is good, cracks and slag inclusions are not discovered, the structure property is uniform, the tensile strength is 920-1010MPa, the yield strength is 490-820MPa, the elongation percentage is 13-24%, and the Brinell hardness is 270-320HBW.

Description

technical field [0001] The invention relates to the production field of high-grade saw blade steel, in particular to a 75Cr hot-rolled coil produced by continuous casting and rolling of thin slabs and a method thereof. Background technique [0002] 75Cr tool steel has extremely strong hardness and good wear resistance. It can be widely used in the production of high-grade saw blade substrates and other fields. It has high added value and broad market prospects. [0003] Thin slab continuous casting and rolling production technology conforms to the development of advanced technology in the iron and steel age, takes advantage of the short process, and can produce thin slab (strip) coils close to finished product specifications. The production situation has the following characteristics and advantages: Thin slab continuous casting and rolling technology can cover most types of hot-rolled coils, but it cannot fully produce some special properties and high value-added varieties o...

Claims

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Application Information

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IPC IPC(8): C22C38/18B22D11/18B22D11/111
Inventor 杨晓江郝占全张大勇王新东李一栋孙彩君王彬郝常鑫张连祝殷凯马永红付建军
Owner HEBEI IRON AND STEEL
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