A kind of 590mpa grade cold-rolled dual-phase steel with excellent hole expansion performance and production method thereof
A production method and technology of dual-phase steel, applied in the field of steel rolling, can solve the problem of low hole expansion performance of 590MPa cold-rolled dual-phase steel, achieve excellent hole expansion rate and elongation rate, improve welding performance, and reduce alloy costs.
Active Publication Date: 2020-08-11
MAANSHAN IRON & STEEL CO LTD
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Problems solved by technology
[0008] Aiming at the problem that the hole expansion performance of the 590MPa grade cold-rolled dual-phase steel in the prior art is not high, the present invention provides a 590MPa grade cold-rolled dual-phase steel with excellent hole expansion performance and its production method. On the basis of Nb micro-alloying and low-temperature coiling process to refine grains, adopt segmental cooling during continuous annealing to obtain an appropriate amount of bainite, thereby producing 590MPa grade cold-rolled dual-phase steel with a hole expansion rate ≥ 75%. steel
Method used
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Embodiment
[0053] After molten iron pretreatment, converter smelting, alloy fine-tuning, LF refining, and continuous casting, a dual-phase steel slab with the chemical composition shown in Table 1 below was prepared.
[0054] The chemical composition of table 1 embodiment
[0055]
[0056] Example 1 is used to illustrate: slag removal from molten iron, S content after desulfurization is 0.006%, steel scrap addition is 20 tons, argon blowing mode is adopted for the bottom blowing of the converter, the end point temperature of the converter is controlled at 1650°C, and the target tapping amount is 300 tons. The alloy fine-tuning station adds aluminum particles and carries out bottom blowing argon strong stirring, LF furnace white slag operation, refining exit temperature 1560°C, continuous casting tundish molten steel temperature 1538°C, stopper rod blowing argon operation, so that the crystallizer liquid level does not appear Tossing is appropriate.
[0057] 2) After heating, phosphor...
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Abstract
The invention discloses a 590MPa grade cold-rolled dual-phase steel with excellent hole expansion performance and a production method thereof, belonging to the technical field of steel rolling. It includes chemical composition and mass percentage: C: 0.06~0.09%, Si+Mn: 1.4~2.1%, Nb: 0.01~0.02%, Al: 0.03~0.06%, P≤0.020%, S≤0.010%, N : ≤0.006%, the balance is Fe and unavoidable impurities. In the microstructure of the dual-phase steel of the invention, the volume fraction of ferrite is 70-80%, the volume fraction of martensite is 10-25%, and the volume fraction of bainite is 5-10%. The invention adopts low Al content to improve the castability of smelting; the low-temperature coiling process at 540-600°C and Nb microalloying refines the grains and promotes the hard phase (martensite and bainite) Dispersed distribution; the sub-stage cooling process of "slow cooling-fast cooling Ⅰ-fast cooling Ⅱ" is adopted to obtain an appropriate amount of bainite and improve the hole expansion performance.
Description
technical field [0001] The invention belongs to the technical field of steel rolling, and more specifically relates to a 590MPa grade cold-rolled dual-phase steel with excellent hole expansion performance and a production method thereof. Background technique [0002] With economic development and social progress, energy saving, environmental protection and safety have become the development trend of the automobile industry. As the key material with the largest proportion of application in automobile manufacturing, steel has become an inevitable trend to develop towards high strength. Due to its good strong-plastic matching, dual-phase steel overcomes the problem of poor formability of traditional low-alloy high-strength steel products characterized by ferrite and pearlite. increasingly widely applied. [0003] With the increasing application of dual-phase steel, the structure of parts is becoming more and more complex, and the forming methods are becoming more and more div...
Claims
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IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/12C21D8/02C21D1/26
Inventor 郑笑芳詹华肖洋洋唐东东崔磊葛鑫涛张露星
Owner MAANSHAN IRON & STEEL CO LTD