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Steel wire with excellent delayed fracture resistance

A technology of resistance to delayed fracture and steel wire, applied in the field of steel wire, can solve the problems of reduced resistance to delayed fracture and increased risk, etc.

Active Publication Date: 2020-10-23
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, especially in the high-strength region of 2000 MPa or more, even high-carbon steel wires have reduced delayed fracture resistance, increasing the risk of delayed fractures.

Method used

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  • Steel wire with excellent delayed fracture resistance
  • Steel wire with excellent delayed fracture resistance
  • Steel wire with excellent delayed fracture resistance

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0097] An ingot obtained by melting steels A to R having the chemical compositions shown in Table 1 and pouring them into a mold was heated to 1250° C. and hot forged into a round steel material (wire material) with a diameter of 20 mm.

[0098] Steels A to L and steels N to R in Table 1 are steels whose chemical compositions are within the range specified in the present invention. On the other hand, steel M is a steel whose chemical composition deviates from the conditions specified in the present invention.

[0099] [Table 1]

[0100]

[0101] The wire rod (round steel material) with a diameter of 20 mm obtained as described above was pickled in hydrochloric acid at room temperature, and after the phosphate coating treatment, a preliminary wire drawing process was carried out to make a steel wire with a diameter shown in Table 2 ( round steel).

[0102] Next, each of the above-mentioned steel wires obtained by preliminary wire drawing was heated at the temperature shown...

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Abstract

The steel wire according to the present invention, the chemical composition of which is, in terms of mass%, 0.60-1.1% C, 0.05-1.5% Si, 0.30-1.5% Mn, P ≤ 0.030%, S ≤ 0.030%, 0.005-0.05% Al, 0.001-0.006% N, 0-1.5% Cr, 0-0.02% Ti, and 0-0.005% B, the remainder comprising Fe and impurities, the metallographic structure of which comprises perlite, the degree of orientation of the {110} crystal face of a bcc phase of which is 0.95 or greater in a cross section perpendicular to a longitudinal direction thereof, and the wire diameter of which is 2.9 mm or greater, has a tensile strength of 2000 MPa or greater, and has excellent delayed fracture resistance even in an environment such as would cause localized corrosion. The present invention can therefore be applied to increasing the size of a civil engineering / construction structure.

Description

technical field [0001] The present invention relates to a steel wire excellent in delayed fracture resistance. Background technique [0002] The steel wire obtained by drawing the pearlite structure is used for PC (prestressed concrete) steel wire, steel wire rope, PWS (parallel wire strands) for bridges, etc. In recent years, civil and architectural structures using them have been increasing in size, and there has also been an increasing demand for cost reduction during construction. In order to realize such a strong demand, it is necessary to increase the strength of the steel wire. [0003] Conventionally, it has been known that high-carbon steel wires such as PC steel wires are superior in delayed fracture resistance compared to materials with a tempered martensitic structure. However, especially in the high-strength range of 2000 MPa or more, even high-carbon steel wires have reduced delayed fracture resistance, and the risk of delayed fractures increases. [0004] T...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/00C21D8/06C22C38/32
CPCC21D8/06C22C38/00C22C38/32C21D8/065C22C38/02C22C38/04C22C38/06C22C38/28C22C38/34C22C38/38
Inventor 千田徹志小此木真大村朋彦
Owner NIPPON STEEL CORP