A thin-gauge dual-phase steel with good hole expansion performance and its processing method

Abstract

The invention discloses thin double-phase steel with good broaching performance and a machining method of the thin double-phase steel and belongs to the technical field of steel rolling. The thin double-phase steel comprises the following chemical components in percentage by mass: 0.05% to 0.08% of C, 0.40% to 0.90% of Si, 1.10% to 1.60% of Mn, smaller than or equal to 0.015% of P, smaller than orequal to 0.004% of S, 0.30% to 0.60% of Cr, 0.015% to 0.040% of Nb, 0.020% to 0.060% of Als and the balance Fe and inevitable impurities. The thin double-phase steel is produced by adopting a thin slab continuous casting and rolling process; the machining method comprises the following steps: smelting; refining; thin slab continuous casting and rolling process; cooling; rolling; and flattening; and finally, batched stable manufacturing of the thin double-phase steel which is 1.0 mm to 3.0 mm in thickness and has good broaching performance is realized; the production cost is lowered; and the thin double-phase steel is excellent in comprehensive mechanical properties and can be used for replacing cold-rolled double-phase steel for manufacturing a body structural member of a passenger vehicle.

Description

technical field [0001] The invention relates to the technical field of steel rolling, in particular to a dual-phase steel with thin gauge and good hole expansion performance and a processing method thereof. Background technique [0002] In recent years, my country's automobile industry has continued to develop at a high speed, which has had a huge impact on social energy supply and environmental protection. In order to cope with the pressure of environmental protection, the state has promulgated a series of programmatic documents, clearly pointing out that my country's manufacturing industry should accelerate the pace of transformation of green manufacturing and ecological development. Existing research shows that lightweight is the most effective measure to achieve energy saving and emission reduction of automobiles, and high strengthening of steel materials is an important technical path to realize lightweight automobiles. Greening and high performance have become the dev...

AI Technical Summary

Problems solved by technology

[0003] Traditional advanced high-strength steel for automobiles, especially advanced high-strength steel with a thickness of less than 1.5mm, adopts a hot-rolled + cold-rolled manufacturing process, which has a long manufacturing process, complicated procedures, and high energy consumption. challenge

At present, the dual-phase steels used in automobile body structures mostly contain precious alloying elements such as Mo, Nb, and Cu in terms of composition, and the cost of alloys is relatively high; High, while the thinnest strip thickness produced by the hot rolling process is only 1.5mm, which cannot meet the use requirements of ultra-thin dual-phase steel with a thickness below 1.5mm

In addition, the hole expansion performance of existing dual-phase steels is generally low, and flanging cracking defects are prone to occur when stamping flanging formed parts

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