Third-generation high-strength high-toughness automobile steel and preparation method thereof

Abstract

The invention provides third-generation high-strength high-toughness automobile steel and a preparation method thereof, and belongs to the technical field of metal material processing. The automobile steel comprises the following alloy components in percentage by weight: 0.40-0.60% of C, 1.00-2.00% of Si, 1.50-3.00% of Mn, 0-0.60% of Ni, 0.50-1.50% of Cr, 0.30-0.60% of Mo, 0-0.20% of V, 0-1.50% of Co, 0-1.50% of Al, and the balance of Fe and inevitable impurities. The preparation method comprises the following steps: carrying out casting after vacuum smelting, and then carrying out hot rolling at a total reduction rate of 80-95% to obtain a hot-rolled plate; heating the obtained hot-rolled plate to 900-970 DEG C at the speed of 5-20 DEG C / s, and carrying out austenitization for 10-20 min; and then, carrying out air cooling to 250-320 DEG C and carrying out heat preservation for 2-12 h. According to the automobile steel provided by the invention, the yield strength, the tensile strength and the elongation after fracture exceed 1000 MPa, 1500 MPa and 20% correspondingly, and both the strength and the plasticity are high; meanwhile, the preparation process is simple, the welding performance is good, and the formability is high; and accordingly, the automobile steel is suitable for industrialized production, and applicable to cross beams of front and rear bumpers in an automobile body structure, thereby guaranteeing the automobile safety.

Description

technical field

[0001] The invention belongs to the technical field of metal material processing, and relates to a structural steel with nano-scale lath-shaped bainitic ferrite and film-like distributed residual austenite at room temperature and a new third-generation automotive steel with high-strength plastic product and an efficient preparation method thereof. Background technique

[0002] With the development of the automobile industry, fuel economy, low carbon emissions and higher safety put forward higher requirements and challenges for the lightweight of the body. The development of lightweight body will be the main direction of the future development of the automobile industry, while the development and application of high-strength steel and advanced high-strength steel will be the future development direction of automobile steel and the core competitiveness of steel enterprises. According to statistics, as of 2015, the proportion of high-strength steel and advanced...

Examples

Embodiment 1

[0038] First, smelting and continuous casting are carried out according to the above composition range, and then the composition of the slab is detected, see Table 1.

[0039] Table 1 Slab composition (wt.%)

[0040]

[0041] Heat the 20-50mm thick billet to 1150°C for homogenization for 2 hours, and roll it at 1000°C to form a 1.5-3.5mm thick plate with a total reduction rate of 80-95%.

[0042] The specific heat treatment process parameters of the hot-rolled plate are shown in Table 2.

[0043] Table 2 heat treatment process parameters

[0044]

[0045] The mechanical properties of the high-strength automotive steel prepared according to Table 1 and Table 2 are shown in Table 3.

[0046] Table 3 mechanical properties

[0047]

[0048] Table 4 shows the dimensions of lath bainite and retained austenite in the thickness direction of the high-strength automotive steel prepared according to Table 1 and Table 2.

[0049] Table 4 Dimensions in the direction of tissue ...

Embodiment 2

[0056] First, smelting and continuous casting are carried out according to the above composition range, and then the composition of the slab is detected, see Table 6.

[0057] Table 6 Slab composition (wt.%)

[0058]

[0059] Heat the 20-30mm thick casting slab to 1150°C for 2h homogenization, and roll it at 1000°C to form a 1.5-3.5mm thick plate with a total reduction rate of 80-95%.

[0060] The specific heat treatment process parameters of the hot-rolled plate are shown in Table 7.

[0061] Table 7 heat treatment process parameters

[0062]

[0063] The mechanical properties of the high-strength automotive steel prepared according to Table 6 and Table 7 are shown in Table 8.

[0064] Table 8 mechanical properties

[0065]

[0066] Table 9 shows the lath bainite and retained austenite dimensions in the thickness direction of the high-strength automotive steel prepared according to Table 6 and Table 7.

[0067] Table 9 Dimensions in the direction of tissue thickn...

Embodiment 3

[0074] First, smelting and continuous casting are carried out according to the above composition range, and then the composition of the slab is detected, see Table 11.

[0075] Table 11 Composition of the slab (wt.%)

[0076]

[0077] Heat the 20-30mm thick casting slab to 1150°C for 2h homogenization, and roll it at 1000°C to form a 1.5-3.5mm thick plate with a total reduction rate of 80-95%.

[0078] See Table 12 for the specific heat treatment process parameters of the hot-rolled sheet.

[0079] Table 12 heat treatment process parameters

[0080]

[0081] The mechanical properties of the high-strength automotive steel prepared according to Table 11 and Table 12 are shown in Table 13.

[0082] Table 13 Mechanical properties

[0083]

[0084] Table 14 shows the dimensions of lath bainite and retained austenite in the thickness direction of the high-strength automotive steel prepared according to Table 11 and Table 12.

[0085] Table 14 Dimensions in the direction...

technical field

[0001] The invention belongs to the technical field of metal material processing, and relates to a structural steel with nano-scale lath-shaped bainitic ferrite and film-like distributed residual austenite at room temperature and a new third-generation automotive steel with high-strength plastic product and an efficient preparation method thereof. Background technique

[0002] With the development of the automobile industry, fuel economy, low carbon emissions and higher safety put forward higher requirements and challenges for the lightweight of the body. The development of lightweight body will be the main direction of the future development of the automobile industry, while the development and application of high-strength steel and advanced high-strength steel will be the future development direction of automobile steel and the core competitiveness of steel enterprises. According to statistics, as of 2015, the proportion of high-strength steel and advanced...

Examples

Embodiment 1

[0038] First, smelting and continuous casting are carried out according to the above composition range, and then the composition of the slab is detected, see Table 1.

[0039] Table 1 Slab composition (wt.%)

[0040]

[0041] Heat the 20-50mm thick billet to 1150°C for homogenization for 2 hours, and roll it at 1000°C to form a 1.5-3.5mm thick plate with a total reduction rate of 80-95%.

[0042] The specific heat treatment process parameters of the hot-rolled plate are shown in Table 2.

[0043] Table 2 heat treatment process parameters

[0044]

[0045] The mechanical properties of the high-strength automotive steel prepared according to Table 1 and Table 2 are shown in Table 3.

[0046] Table 3 mechanical properties

[0047]

[0048] Table 4 shows the dimensions of lath bainite and retained austenite in the thickness direction of the high-strength automotive steel prepared according to Table 1 and Table 2.

[0049] Table 4 Dimensions in the direction of tissue ...

Embodiment 2

[0056] First, smelting and continuous casting are carried out according to the above composition range, and then the composition of the slab is detected, see Table 6.

[0057] Table 6 Slab composition (wt.%)

[0058]

[0059] Heat the 20-30mm thick casting slab to 1150°C for 2h homogenization, and roll it at 1000°C to form a 1.5-3.5mm thick plate with a total reduction rate of 80-95%.

[0060] The specific heat treatment process parameters of the hot-rolled plate are shown in Table 7.

[0061] Table 7 heat treatment process parameters

[0062]

[0063] The mechanical properties of the high-strength automotive steel prepared according to Table 6 and Table 7 are shown in Table 8.

[0064] Table 8 mechanical properties

[0065]

[0066] Table 9 shows the lath bainite and retained austenite dimensions in the thickness direction of the high-strength automotive steel prepared according to Table 6 and Table 7.

[0067] Table 9 Dimensions in the direction of tissue thickn...

Embodiment 3

[0074] First, smelting and continuous casting are carried out according to the above composition range, and then the composition of the slab is detected, see Table 11.

[0075] Table 11 Composition of the slab (wt.%)

[0076]

[0077] Heat the 20-30mm thick casting slab to 1150°C for 2h homogenization, and roll it at 1000°C to form a 1.5-3.5mm thick plate with a total reduction rate of 80-95%.

[0078] See Table 12 for the specific heat treatment process parameters of the hot-rolled sheet.

[0079] Table 12 heat treatment process parameters

[0080]

[0081] The mechanical properties of the high-strength automotive steel prepared according to Table 11 and Table 12 are shown in Table 13.

[0082] Table 13 Mechanical properties

[0083]

[0084] Table 14 shows the dimensions of lath bainite and retained austenite in the thickness direction of the high-strength automotive steel prepared according to Table 11 and Table 12.

[0085] Table 14 Dimensions in the direction...

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