CN103074961A

CN103074961A - 1*3 type surface deformation low-relaxation prestress steel strand

Info

Publication number: CN103074961A
Application number: CN201310024154XA
Authority: CN
Inventors: 王文喜; 毛爱菊; 蔺秀艳; 王鸿利; 王莉; 韩文铎; 潘捷; 吕芳
Original assignee: TIANJIN METALLURGICAL GROUP FLOURISH STEEL INDUSTRIAL Co Ltd
Current assignee: TIANJIN METALLURGICAL GROUP FLOURISH STEEL INDUSTRIAL Co Ltd
Priority date: 2013-01-23
Filing date: 2013-01-23
Publication date: 2013-05-01

Abstract

The invention discloses a 1*3 type surface deformation low-relaxation prestress steel strand which can reduce stress concentration and improve the carrying capacity and mechanical performance indexes. The steel strand is formed by twisting three indented steel wires; three indents are formed on each indented steel wire in the radial direction; the indent shaped adopts an indent arc-shaped surface and is in a 'willow leaf' shape; each two of the three indents form 120 degrees; the direction of one indent is opposite to directions of the other two indents; all nominal diameters of the indented steel wires are 2.90mm; and the depth of the indent is 0.10 plus or minus 0.05mm, the length is 2.5 to 3.0mm, and the pitch is 3.70 to 3.90mm. The indented steel wires adopted by the steel strand reduce the length and the pitch of the indent, ensure that the density of indents on unit length is increased, the bond stress between the steel strand and concrete can be further improved, and the carrying capacity is improved. The depth of the indent of the indented steel wire is small, so that the stress concentration of the indent arc-shaped surface of the indent is reduced, and the comprehensive mechanical property of the indented steel wire is improved.

Description

1 * 3 body structure surface distortion low relaxed prestress steel strand

Technical field

The present invention relates to building material technical field, particularly relate to a kind of 1 * 3 body structure surface distortion low relaxed prestress steel strand.

Background technology

In recent years, generally make with light round steel twisted wire making prestressed concrete member.The steel strand that formed by the indented wire twisting, compare with the steel strand of round wire twisting, indenture on the steel wire has increased steel strand and concrete bond stress, thereby has improved the compressive pre-stress of prestressed concrete member, has the characteristics such as the strong and shock resistance of bearing capacity is strong." 1 * 3 body structure surface distortion low relaxed prestress steel strand " is with three three steel strand that the indented wire twisting forms.The precast plate that uses " 1 * 3 low relaxed prestress indented steel stranded wire " to make, have more from heavy and light, the advantage such as rigidity is large, compressive pre-stress is high, crack resistance is strong, be widely adopted in the engineering such as civilian construction and making road sound-proofing board abroad, the demand for exports amount is large, at home also great exploitation potential for its of market.

At present, the appearance and size of three indented wires of domestic production is generally carried out by standard GB/T/T5223 " steel wires for prestressed concrete ".This national Specification: the nominal diameter≤5.00mm of indented wire, width of nick a=0.12 ± 0.05mm, indentation length b=3.5 ± 0.5, pitch L=5.5 ± 0.5mm.

When carrying out above-mentioned standard, owing to the size and dimension reason of indentation, the root of the indentation of inscribing on the steel wire exists stress to concentrate, and the bending property of steel wire is relatively poor, and during follow-up manufacturing steel strand, twisting is very difficult, and the broken string frequency is higher.Therefore, produce the indentation prestress wire, need shape and the controlling dimension precision of reasonable design indentation, process impact on the steel strand mechanical property thereby reduce indentation, make the mechanical property of indented steel stranded wire reach the level of plain bar twisted wire fully.

Summary of the invention

The objective of the invention is for the technical deficiency that exists in the prior art, and provide a kind of stress that can reduce to concentrate, improve 1 * 3 body structure surface distortion low relaxed prestress steel strand of supporting capacity and mechanical performance index.

For realizing that the technical scheme that purpose of the present invention adopts is:

A kind of 1 * 3 body structure surface distortion low relaxed prestress steel strand, formed by three indented wire twistings, indented wire radially three has been worn indentation, indentation is shaped as the indent arcwall face, three indentations are mutually 120 °, in three indentations the indentation direction of one side and the indentation opposite direction on other two sides are arranged, and the nominal diameter average of indented wire is 2.90mm, the degree of depth of indentation is 0.10 ± 0.05mm on the indented wire, and the length of indentation is 2.5-3.0mm.The pitch of indentation is 3.70-3.90mm on the described indented wire.

The every described indented wire vertically plain line direction of the longitudinal centre line of the indent arcwall face of each indentation and described indented wire is at 45 °.

The root of each described indentation and Steel Wire Surface rounding off.

Compared with prior art, the invention has the beneficial effects as follows:

1, steel strand of the present invention have shortened indentation length and the pitch of indented wire, and the indentation density on the unit length is increased, and have increased the bond stress between steel strand and the concrete, improve supporting capacity.

2, steel strand of the present invention have reduced the width of nick of indented wire, make concentrated the reducing of stress of the indent arcwall face of indentation, fracture appears when avoiding the indented wire twisting, simultaneously, reducing of width of nick, improve tensile strength, the bending property of indented wire, improved the comprehensive mechanical property of indented wire.

3, in the steel strand of the present invention, the root of each indentation and Steel Wire Surface rounding off have reduced stress and have concentrated.

4, designed three indented wires in the steel strand of the present invention can adopt less lay pitch twisting steel strand, the fracture of wire situation do not occur, adopt larger tension force to carry out stabilization processes, reach the level of underrelaxation rate.

5, the indentation direction and the indentation opposite direction on other two sides of one side are arranged in designed three indentations in the steel strand of the present invention, and indentation is shaped as the indent arcwall face, is " wicker leaf shape ", has improved stress concentrated, has improved the crack resistance of member.

Description of drawings

Figure 1 shows that the sectional view of the present invention's 1 * 3 body structure surface distortion low relaxed prestress steel strand;

Figure 2 shows that the schematic diagram of indented wire.

Among the figure: 1. indented wire, 2. indentation.

The specific embodiment

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail.

The schematic diagram of 1 * 3 body structure surface distortion low relaxed prestress steel strand of the present invention as shown in Figure 1 and Figure 2, formed by three indented wire 1 twistings, every indented wire 1 radially three has been worn indentation 2, indentation 2 be shaped as the indent arcwall face, three indentations are mutually 120 °, in three indentations the indentation direction of one side and the indentation opposite direction on other two sides are arranged, form wicker leaf shape, the nominal diameter average of every indented wire 1 is 2.90mm, the degree of depth a of indentation 2 is 0.10 ± 0.05mm on every indented wire, and the length b of indentation is 2.5-3.0mm.The pitch L of indentation is 3.70-3.90mm on every described indented wire.

The every described indented wire 1 vertically plain line direction of the longitudinal centre line of the indent arcwall face of each indentation and described indented wire is at 45 °.The root of each described indentation and Steel Wire Surface rounding off.

Steel strand of the present invention have a following characteristics:

1, the indentation size design is by comparing with the indentation size that GB provides, and the nominal degree of depth reduces 0.02mm; The indentation length range shortens 0.5～1.0mm; The scope of pitch shortens 1.3～2.1mm, and the indentation density on the unit length is increased, and has increased the bond stress between steel strand and the concrete, improves supporting capacity.Reduce the width of nick of indented wire, made concentrated the reducing of stress of the indent arcwall face of indentation, occurred fracture when avoiding the indented wire twisting, simultaneously, reducing of width of nick improved tensile strength, the bending property of indented wire, improved the comprehensive mechanical property of indented wire.

2, the root of trace and Steel Wire Surface rounding off have reduced stress and have concentrated.

Because above-mentioned improvement, the steel strand lay pitch that obtains is little, and the minimum lay pitch can reach 11 times of nominal diameter; Steel strand stabilization processes tension force is large, and lax value is low, and 1000h reaches below 1.5%.

Embodiment 1

The diameter average 2.99mm of round wire before the indentation;

The nominal diameter 2.90mm of indented wire; Kerf width average 2.57mm; The degree of depth of indentation is 0.10 ± 0.05mm on the pitch of nick average 3.86mm, every indented wire;

The mechanical property of this indented wire is as follows:

The maximum, force average is 14.4kN;

The tensile strength average is 2040MPa;

Elongation rate (L ₀=100mm) average is 2.5%;

Number of bends m(R=10mm) average is 6～7 times/180 ⁰

Above-mentioned indented wire is made steel strand according to conventional method, and finished steel twisted wire performance is as follows:

The nominal diameter of steel strand: 1 * 3-φ 2.9mm;

The actual average of maximum, force is 41.8kN, and the maximum, force 〉=36.8kN that stipulates than standard GB/T/T5224 has improved 14%, and the maximum, force 〉=38.2kN that stipulates than Nippon Standard JIS G3536 has improved 9%.

The actual average of regulation disproportional extending force is 37.3kN, improves than the disproportional extending force of standard GB/T/T5224 regulation 〉=32.4 and knows clearly 15%, has improved 10% than the disproportional extending force of Nippon Standard JIS G3536 regulation 〉=33.8.

The actual average of tensile strength is 2020MPa, and is higher by 9% than the 1860MPa of standard GB/T/T5224 regulation.

Elongation rate Agt%(L ₀〉=500mm) actual average is 6.3%, than the elongation rate Agt%(L of standard GB/T/T5224 regulation ₀〉=500mm) 〉=3.5% improved 8%, than the elongation rate Agt%(L of Nippon Standard JIS G3536 regulation ₀〉=500mm) 〉=3.5% improved 8%.

1000h relaxation rate actual value 1.4% is not more than 2.5% standard value and compares with the 1000h relaxation rate of standard GB/T/T5224 and Nippon Standard JIS G3536 regulation, can reduce 1.1%.

Lay pitch actual value can reach 11D, less than (12-16) D of standard GB/T/T5224 regulation and (24-32) D of Nippon Standard JIS G3536 regulation.

Steel strand of the present invention have advantages of that intensity is high, good toughness, lax value are low, and the mechanical property of finished steel twisted wire is higher than Japanese JIS G3536:2008 " PC steel wire and PC steel strand " standard and GB/T5224 " steel strand for prestressed concrete " standard-required.

The above only is preferred embodiment of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims

1. a body structure surface is out of shape low relaxed prestress steel strand, formed by three indented wire twistings, every indented wire radially has three indentures, it is characterized in that, indentation is shaped as the indent arcwall face, three indentations are mutually 120 °, in three indentations the indentation direction of one side and the indentation opposite direction on other two sides are arranged, the nominal diameter average of indented wire is 2.90mm, and the degree of depth of indentation is 0.10 ± 0.05mm, the length of indentation is 2.5-3.0mm, and the pitch of indentation is 3.70-3.90mm.

2. 1 * 3 body structure surface according to claim 1 distortion low relaxed prestress steel strand is characterized in that, the every described indented wire vertically plain line direction of the longitudinal centre line of the indent arcwall face of each indentation and described indented wire is at 45 °.

3. 1 * 3 body structure surface distortion low relaxed prestress steel strand according to claim 1 and 2 is characterized in that the root of each described indentation and Steel Wire Surface rounding off.

4. 1 * 3 body structure surface distortion low relaxed prestress steel strand according to claim 3 is characterized in that, the minimum lay pitch of described steel strand is 11 times of nominal diameter.