Formable high strength cold-rolled steel sheet with excellent weather resistance and method manufacturing the same

A technology of cold-rolled steel sheet and weather resistance, applied in the field of formable high-strength cold-rolled steel sheet and its manufacture, can solve problems such as low tensile strength and achieve the effect of excellent workability

Inactive Publication Date: 2009-10-07
POHANG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the patent shows that the steel plate has a 60kg / mm 2 The tensile strength, which is lower than the tensile strength of the steel plate claimed in the present invention (80kg / mm 2 )

Method used

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  • Formable high strength cold-rolled steel sheet with excellent weather resistance and method manufacturing the same
  • Formable high strength cold-rolled steel sheet with excellent weather resistance and method manufacturing the same
  • Formable high strength cold-rolled steel sheet with excellent weather resistance and method manufacturing the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0056] The normalized corrosion resistance coefficient (CI) and weather resistance of steels having the compositions shown in Table 1 below were measured. The results are listed in Table 2 below.

[0057] As a weather resistance test, a salt spray test (SST) of steel was carried out in 5% salt water (NaCl solution) at 30° C. for 480 hours. The results are listed in Table 2 below.

[0058] The corrosion resistance coefficient is a coefficient obtained by evaluating the weather resistance of steel according to the ASTM G101 standard. It is known that the weather resistance of steel is optimized with increasing corrosion resistance coefficient. Here, the corrosion resistance coefficient is mainly calculated based on alloying elements and expressed by the following formula:

[0059] Corrosion Resistance Coefficient (CI)=26.01(%Cu)+3.88(%Ni)+1.2(%Cr)+1.49(%Si)+17.28(%P)-7.29(%Cu)(%Ni)-9.10(% Ni)(%P)-33.39(%Cu) 2

[0060] Table 1

[0061]

[0062] Table 2

[0063] ...

Embodiment approach 2

[0066] Each cold-rolled steel sheet was prepared from inventive steels 1 and 2 and comparative steels 1 to 4 shown in Table 1 of Embodiment 1 under the conditions shown in Table 3 below, and the mechanical properties and machining of the cold-rolled steel sheets were measured characteristic. The results are listed in Table 4 below.

[0067] table 3

[0068]

[0069] Table 4

[0070]

[0071]

[0072] As shown in Table 4, it can be seen that compositions 1 to 4 of the present invention—wherein the content ranges of the chemical components in the steel of the present invention and the manufacturing conditions of the steel of the present invention meet the requirements of the method of the present invention—have 80kgf / mm 2 or greater tensile strength, and have a volume fraction of the second phase including the martensite phase of 10% or greater after the annealing process. Therefore, cold-rolled steel sheets with weather resistance, high strength, and high workabilit...

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Abstract

There are provided a formable high strength cold-rolled steel sheet with excellent weather resistance and a tensile strength of 80 or more kgf / mm, a method for manufacturing the same. The formable cold-rolled steel sheet includes, by weigh: carbon (C): 0.10 to 0.20%, silicon (Si): 0.05 to 0.25%, manganese (Mn): 1.0 to 2.5%, phosphorus (P): 0.02% or less, sulfur (S): 0.01% or less, aluminum (Al): 0.02 to 0.07%, niobium (Nb): 0.02 to 0.08%, nickel (Ni): 0.05 to 0.30%, copper (Cu): 0.1 to 0.5%, chromium (Cr): 0.8 to 1.5% and cobalt (Co): 0.01 to 0.10%, and the balance of Fe and other inevitable impurities, wherein a low-temperature transformation structure is present in a volume of 10 to 30% and the balance is a ferrite structure.

Description

technical field [0001] The present invention relates to a formable high-strength cold-rolled steel plate with excellent weather resistance for buildings, railway vehicles, containers, etc. and a manufacturing method thereof. More specifically, the present invention relates to a weather-resistant cold-rolled steel sheet having high-strength characteristics and excellent workability capable of securing a low-temperature transformation structure in Cu-Co system components; and a method for manufacturing the steel sheet Methods. Background technique [0002] In the art, materials such as stainless steel or aluminum have been used to make containers or railcars lightweight and extend their life. The physical properties required for such products include not only strength properties but also bendability, weldability, durability, and the like. [0003] For the transportation structure, there is an urgent need for lightweight containers to increase the weight of goods that can be ...

Claims

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Application Information

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IPC IPC(8): C22C38/00
CPCC22C38/02C22C38/48C22C38/06C22C38/04C22C38/42C22C38/52
Inventor 金在翼郑琪朝金钟华李秀姬
Owner POHANG IRON & STEEL CO LTD
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