CN1864917A - Method for manufacturing high-strength structured steel pipe - Google Patents

Abstract

The invention relates to a method for producing high-strength steel tube, which comprises following steps that: using high-strength low-carbon bainite steel to coil cylinder; cutting the strips; feeding material and bending the coil; mounting one drawing machine at the front of release machine, to draw the steel wire to guide the coil sheet into storage tank or shaping part of weld machine; jointing; shaping; the whole shaping machine reaches nine flat rollers or ten upright roller, while the distortion angles at first three or four curvatures are lower than 3%; the bottom diameter increases of last six curvatures are 1mm/each; welding; making the space between the high-frequency sensitive coil and the steel tube as 5mm; fixing the diameter; correcting; cutting; flattening the head; checking; packing; and storing. The invention has the advantages that; the yield strength of steel tube is 500MPa; the tensile strength is 650MPa; it is resistant to the impact at low temperature, while the impact adsorption power at -20Deg. C is higher than 40J to meet the demand of east sea bridge.

Description

The manufacture method of high-strength structured steel pipe

Technical field

The present invention relates to a kind of manufacture method of steel pipe, relate in particular to the manufacture method of the bridge spanning the sea structured steel pipe of a kind of high strength, low-temperature impact-resistant.

Background technology

At present along with the economic development of society, the construction of port and pier is also in develop rapidly, and the guard rail steel pipe of bridge (structured steel pipe a kind of) also all the more causes engineers and technicians' attention.For example: about 32 kilometers of Donghai Bridge total length is the designated lane that connects harbor district, and it is the van container truck that current vehicle has more than 85%.For guaranteeing traffic safety, need a kind of high strength, the steel pipe of low-temperature impact-resistant can prevent that as the anticollision barrier of bridge oversize vehicle from severing railing, routs up bridge floor and falls, and prevents dilly bump bounce-back causing second accident again.

The steel pipe that guardrail of the prior art generally all adopts common straightcarbon steel to make, the yield strength of common straightcarbon steel is 235Mpa, tensile strength is 375-500Mpa, 20 ℃ of normal temperature time 〉=27 of impact test joule; And the designing requirement of Donghai Bridge guard rail steel pipe is: Aldecor, material are that Q345 is 16Mn, yield strength 〉=345Mpa, and tensile strength is 470-630Mpa, impact test is 〉=34 joules in the time of 0 ℃.How producing such guard rail steel pipe is the problem of pendulum in face of the technical staff.

General manufacture of steel pipe is realized by following steps at present:

Reel;

Cut across itemize;

Material loading collapses;

Butt joint;

Moulding;

Welding;

Sizing;

Aligning;

The scale sawing

Tack;

Check;

Packing;

Warehouse-in;

Summary of the invention

The technical issues that need to address of the present invention have provided a kind of manufacture method of high-strength structured steel pipe, are intended to solve the above problems.

In order to solve the problems of the technologies described above, the present invention realizes by following steps:

Adopt high strength low-carbon bainitic steel material reel;

Cut across itemize;

Material loading collapses: by a hauling machine has been installed in coil opening machine the place ahead, with rope traction the roll bending material is drawn in material-storing box and welded tube mill composing type section;

Butt joint;

Moulding: whole shaping machine set has reached 9 road plain-barreled rolls or 10 road edger rolls, and the deformation angle branch is mixed slightly for a short time by about 3% in first three road or four road flexural deformations, and the end mass runoff recruitment of back on six roads is that per pass adds 1mm;

Welding: radio-frequency induction coil is close to the steel pipe gap about 5mm;

Sizing;

Aligning;

The scale sawing

Tack;

Check;

Packing;

Warehouse-in;

Compared with prior art, the invention has the beneficial effects as follows: the yield strength of structured steel pipe is about about 500Mpa, and tensile strength is about 650Mpa, low-temperature impact-resistant, impact absorbing energy 〉=40 during-20 ℃ of low temperature joule have reached the designing requirement of Donghai Bridge guard rail steel pipe fully.

The specific embodiment

The following specific embodiment describes in further detail the present invention:

New steel grade " high strength low-carbon bainitic steel " the high strength ratio-frequency welded tube of being manufactured that adopts Mei Shan Steel stock Co., Ltd of Baoshan Iron and Steel Group to produce is used for the steel construction project of the crashproof railing of Donghai Bridge, this steel strength height, about the about 500Mpa of its yield strength, tensile strength is about 650Mpa, and the impact absorbing energy of low-temperature impact-resistant experimental performance when-20 ℃ of low temperature is more than 40 joules.The Ф 114 * 6 (about 4/5) of Q345C steel and the high strength welded tube of Ф 114 * 8 (about 1/5) are adopted in the Donghai Bridge design, and the present invention adopts the steel grade higher than Q345C intensity to make, this specification is the small-bore welded tube of heavy wall, since Ф 114 * 8 bainite mild steel yield strengths up to 500Mpa about, uses general welded tube unit rolling forming process and is difficult to realize shaping.General Ф 165 unit specifications processing thickest is 5.5mm (being suitable for general yield strength is 235Mpa), and the present invention with Ф 165 units in addition transformation:

Because hard especially (the yield strength height of high strength low-carbon bainitic steel material, reach 500MPa), when material loading collapses, flat roll bending material is difficult to loose winding and sends to forward, the present invention has installed a hauling machine in coil opening machine the place ahead, with rope traction the roll bending material is drawn in material-storing box and welded tube mill composing type section, welded tube forming is carried out;

Shaping machine set has increased by two road moulding plain-barreled roll frame and edger roll framves, thereby make molding roller (mould) increase by two road plain-barreled rolls and two road edger rolls, whole shaping machine set has reached 9 road plain-barreled rolls and 10 road edger rolls (being generally 7 road plain-barreled rolls and 8 road edger rolls) have increased rolling pass, reduced the deformation angle of every time roll (mould) roll-in bending, every time average deformation angle has reduced about 28% than original deformation angle, every time roll extrusion flexural deformation load of steel plate has reduced about 20%, makes welded tube thereby the heavy wall roll bending is shaped;

In roll (mould) design, owing to increased by two road plain-barreled rolls and two road edger rolls, the elongation of material will be significantly smaller than the elastic limit of materials elongation, and the elastic properties of materials recovery capacity strengthens; The present invention's deformation angle branch in first three road flexural deformation is mixed the bite condition that slightly smaller (per pass is little by about 3%) make flat roll bending enter unit and is improved, make every time transmission resistance of unit reduce about about 2%, end mass runoff recruitment on six roads, back is that per pass adds 1mm, makes the steel pipe that enters the profiled section roll keep suitable tension force.

Because reaching 8mm, steel plate surpasses the specified processing thickness of unit, it is (conventional 10～20mm) about 5mm that the present invention is close to the steel pipe gap with radio-frequency induction coil, make full use of high frequency electric kelvin effect and kindred effect, the kindred effect of high frequency coil and kelvin effect are brought into play to maximum effectiveness.

Claims (1)

1. the manufacture method of a high-strength structured steel pipe, realize by following steps:

Adopt high strength low-carbon bainitic steel material reel;

Cut across itemize;

Material loading collapses: by a hauling machine has been installed in coil opening machine the place ahead, with rope traction the roll bending material is drawn in material-storing box and welded tube mill composing type section;

Butt joint;

Moulding: whole shaping machine set has reached 9 road plain-barreled rolls or 10 road edger rolls, and the deformation angle branch is mixed slightly for a short time by about 3% in first three road or four road flexural deformations, and the end mass runoff recruitment of back on six roads is that per pass adds 1mm;

Welding: radio-frequency induction coil is close to the steel pipe gap about 5mm;

Sizing;

Aligning;

The scale sawing

Tack;

Check;

Packing;

Warehouse-in.