Hot-rolled polyphase steel plate and method for manufacturing same

A steel plate and slab technology, applied in the direction of temperature control, etc., can solve the problems of steel cost increase, etc., and achieve the effects of short rolling cycle, economical composition design, and high rolling efficiency

Active Publication Date: 2008-09-24
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

A large number of precious alloy elements are also added, and the cost of steel increases

Method used

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  • Hot-rolled polyphase steel plate and method for manufacturing same
  • Hot-rolled polyphase steel plate and method for manufacturing same
  • Hot-rolled polyphase steel plate and method for manufacturing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Smelting and casting are carried out according to the chemical composition shown in Table 1 to form billets, and then the billets are heated to 1170°C. The thickness of the steel plate is 2.5mm. Rough rolling and hot deformation in the temperature range where austenite can recrystallize, and in the temperature range lower than austenite recrystallization but higher than the Ar3 transformation point, use one or more passes to fry the above steel plate to the final thickness of the steel plate. The finish rolling temperature was 800°C. Then enter the staged cooling process. The cooling rate in the first stage is 20°C / s, air cooling (intermediate stop) at 750°C for 10 seconds, the cooling rate in the second stage is 80°C / s, and the finished steel plate is obtained by cooling to the final cooling temperature of 230°C. Mechanical properties: see Table 11.

[0048] Table 1 Chemical composition of steel plate in Example 1

[0049]

Embodiment 2

[0051] Carry out steel plate manufacturing by the chemical composition shown in Table 2, manufacturing process is identical with embodiment 1. The billet heating temperature is 1170°C; the thickness of the steel plate is 3.0mm; the final rolling temperature is 820°C; the cooling rate in the first stage is 30°C / s, air cooling at 720°C (intermediate stay) for 6 seconds, and the cooling rate in the second stage is 58°C / s, has been cooled to the final cooling temperature of 330 ℃. Mechanical properties: see Table 11.

[0052] Table 2 The chemical composition of the steel plate in Example 2

[0053]

Embodiment 3

[0055] Steel sheets were manufactured with the chemical compositions shown in Table 3, and the manufacturing process was the same as in Example 1. The billet heating temperature is 1170°C; the steel plate thickness is 2.5mm; the finishing rolling temperature is 850°C; the cooling rate in the first stage is 40°C / s, air cooling at 689°C (intermediate stay) for 8 seconds, and the cooling rate in the second stage is 50°C / s, has been cooled to the final cooling temperature of 440 ℃. Mechanical properties: see Table 11.

[0056] Table 3 The chemical composition of the steel plate of Example 3

[0057]

[0058] Example 3 The typical metallographic structure of the steel plate is shown in figure 2 .

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Abstract

The invention provides a hot-rolled multiphase steel plate and a preparation method thereof. The invention has the advantages of the economical, reasonable, environmental-friendly design of steel component, being favorable for effective utilization and recycling of resources, being implemented and controlled easily, the simple and convenient process control, the high strength of steel plate and the good performance of cold bending and welding. The thickness of plate is 2.5 to 6 milimeter, the tensile strength of the hot-rolled steel plate is larger than 1000Megapascal, the yield strength is greater than or equal to 500Megapascal, the yield ratio is low, the minimum yield ratio is equal to 0.51 and the maximum is not higher than 0.80, the elongation A80 i.e. the sample of 80 milimeter of JIS13A standard distance is greater than or equal to 11 percent and the highest value reaches 20 percent, and the longitudinal direction and the transverse direction of cold bending meets the requirement of not cracking when d is equal to 4t. The microstructure is mainly Bainite and Martensite of higher than 90 percent and few ferrite of possible residual Austenite.

Description

technical field [0001] The present invention relates to steel plate material technology, more particularly, the present invention relates to steel plate material technology with a tensile strength exceeding 1000 MPa. Background technique [0002] With the development of the automobile industry, the requirements for vehicle safety are getting higher and higher. At the same time, the shortage of energy and the demand for environmental protection also require vehicles to reduce their own weight to reduce fuel consumption. Therefore, the strength requirements for steel plates used in vehicles are constantly increasing. The performance requirements of the part steel plate are also more and more detailed, and advanced high-strength steel (AHSS) or ultra-high-strength steel (Ultra-HSS) emerges as the times require. Generally, steels with a tensile strength greater than 700MPa can be classified as ultra-high-strength steels. Ultra-high strength has very high tensile strength and hi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/06C22C38/12C22C38/14C21D8/02B21B37/74
Inventor 郑磊郑芳
Owner BAOSHAN IRON & STEEL CO LTD
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