CN101537435B - Dieless drawing forming process for conical metal pipe - Google Patents

Abstract

The invention belongs to the field of thermal processing of metals, relates to a forming method for a variable section metal pipe piece, and particularly provides a dieless drawing forming process for a conical metal pipe. The process can be used for the forming of conical pipes of stainless steel, carbon steel, alloy steel, aluminum alloy, copper alloy, titanium alloy and the like. The formation of the conical metal pipe is realized by controlling process parameters of blank drawing speed, feeding speed (or cold-heat source moving speed), inductive heating temperature, cold-heat source distance and the like; and the defects of complex process, more procedure, large material loss and the like in a conventional method for producing the conical pipe can be solved. The process has the following advantages: by adopting an equal-diameter welded pipe blank or a seamless pipe blank as a raw material and directly forming the conical pipe without die drawing by heating and cooling, the process flow is short, and the production cost is low; wastes are not generated during processing, so the utilization rate of the material is high; the shape and specification of the product have large freedom degree, the size precision of the product is high, the shrinkage rate of the single section is large, and the production efficiency is high.

Description

A kind of Dieless drawing forming process for conical metal pipe

Technical field

The invention belongs to the metal fever manufacture field, the manufacturing process that relates to a kind of variable cross-section metal tube, a kind of Dieless drawing forming process for conical metal pipe is provided especially, has can be used for the shaping of conical pipes such as stainless steel, carbon steel, steel alloy, aluminium alloy, copper alloy, titanium alloy.

Background technology

Along with development economic and society, fields such as machine-building, oil, chemical industry, the energy, ocean, urban construction are increasing to the demand of conical metal pipe, adopt the conical pipe can the implementation structure optimal design, reach and save material and alleviate purpose such as construction weight.

The processing method of metal current conical pipe mainly contains that welding, variable cross-section have that die drawing pulls out, the variable cross-section extruding, push away the method for pulling out etc.Welding is according to the intensity of finished product conical pipe and dimensional requirement, selects the sheet material of different-thickness, and sheet material is processed into trapezoidal, curls welding forming then.There is weld seam in the conical pipe of this process forming, and overall aesthetics is relatively poor, has complex process, shortcomings such as waste of material is big, equipment investment is big, cost height; In addition because welding region needs certain thickness, and sheet material radius can not be too little when curling, thereby be difficult to produce the thin or little conical pipe of diameter of wall.Variable cross-section has that die drawing pulls out, the variable cross-section extruding, push away the method for pulling out all be adopt the method for die forming [Wang Sufen. push away the seamless conical pipe of the formula of pulling out [P]. Chinese utility model patent, grant number ZL200620168317.7, authorize day: 2008-02-06], processing to large diameter thin wall pipe is very difficult, and the use mould, production cost is higher; In addition, be subjected to the restriction of mould, limitation is also arranged when producing elongate articles.

Dieless drawing is a kind ofly not adopt mould and carry out the flexible near-net forming technology of metal forming, shortcomings such as other processing method long flow paths, cost height, single pass heavy deformation are little have been overcome, have that equipment scale is little, production flexibility height, be easy to realize advantage [Huang Zhenyi such as control automatically, Wang Ping, Kong Weibin, etc. no die drawing stretching process and development [J]. the Huadong Metallurgy College journal, 2000,17 (2): 118～120].

Dieless drawing is divided into discontinuous formula and two kinds of continous ways (seeing Fig. 1～3).The characteristics of discontinuous formula dieless drawing are: blank one end is fixed, and the other end is with certain speed drawing, and Cooling and Heat Source moves to the other end from an end of blank simultaneously, by control drawing speed (v _t) and Cooling and Heat Source translational speed (v _i) realize being shaped, the short product of big section, length is suitable for being shaped; The characteristics of continous way dieless drawing are: blank is sent to continuously from an end, and the other end is with certain speed drawing, at drawing speed (v _t) greater than charging rate (v _i) condition under realize progressive forming, be suitable for producing long size product.

Summary of the invention

The object of the present invention is to provide a kind of Dieless drawing forming process for conical metal pipe.Realize the shaping of conical metal pipe by controlling technological parameters such as blank drawing speed, charging rate (or Cooling and Heat Source translational speed) and induction heating temperature, Cooling and Heat Source distance, solved conventional method production conical pipe and had shortcomings such as complex process, operation is many, spillage of material is big.

A kind of conical metal pipe forming technology based on continuous dieless drawing is characterized in that:

(1) raw material are selected: diameter D ₀=(1～1.1) D ₁, wall thickness t ₀=(1～1.1) t ₁Seamless or the isometrical pipe of metals such as seam stainless steel, carbon steel, steel alloy, aluminium alloy, copper alloy, titanium alloy, D arranged ₁, t ₁Be respectively product outside diameter and wall thickness.

(2) isometrical pipe forms one section softened zone under the acting in conjunction of induction coil heating and cooling device cooling, and induction heating temperature is T=(0.5～0.95) T _m, T _mFusing point (unit: K) for material; Cooling water flow is 10～200L/h; Distance between induction coil and the chilled water unit is 0＜S ₀≤ 5D ₀

(3) pipe one end is sent to, an end drawing, charging rate v _iEqual initial drawing speed v ₀, drawing speed v _tBeing non-linear gradual by the drawing speed model increases; Along with the increase of drawing speed, pipe diameter reduces continuously, forms the conical metal pipe (see figure 4) of external taper α, 0＜α≤1 °.

(4) reduction of area increases gradually in the drawing process, and single pass reduction of area maximum can reach 65%.

(5) wall thickness of dieless drawing form metal conical pipe attenuate gradually, its internal taper β is $\tan \mathrm{\β}=k(1-2\frac{t_0}{D_0})\tan \mathrm{\α},$ K=1.0～1.2 wherein.

(6) described dieless drawing speed v _tModel be

$v_t=(\frac{A_1}{A_2}-1)v_i$

In the formula, v _i-charging rate;

$A_1=2S_0+2\frac{D_0^2-{(D_0-2t_0)}^2}{[D_0-(D_0-2t_0)/k]\tan \mathrm{\α}};$

$A_2=\frac{S_0}{2}+\frac{D_0^2-{(D_0-2t_0)}^2}{2[D_0-(D_0-2t_0)/k]\tan \mathrm{\α}}+\sqrt{{\{\frac{S_0}{2}+\frac{D_0^2-{(D_0-2t_0)}^2}{2[D_0-(D_0-2t_0)/k]\tan \mathrm{\α}}\}}^2-2\frac{D_0^2-{(D_0-2t_0)}^2}{[D_0-(D_0-2t_0)/k]\tan \mathrm{\α}}{v}_{i}t};$

The t-time.

Conical metal pipe forming technology provided by the invention has the following advantages: adopting isometrical skelp or seamless tube blank is raw material, and by the direct dieless drawing shaping of heating and cooling conical pipe, technological process is short, and production cost is low; Process does not produce waste material, the stock utilization height; The shape of product specification free degree is big, product size precision height, and the single pass reduction of area is big, the production efficiency height.Be suitable for the processing of various conical metal pipes, as stainless steel, carbon steel, steel alloy, titanium alloy, aluminium alloy, copper alloy etc.

Description of drawings

Fig. 1 is a continous way dieless drawing principle schematic.Wherein 1 heater, 2 cooling devices.

Fig. 2 is v _iWith v _tReverse discontinuous formula dieless drawing principle schematic.

Fig. 3 is v _iWith v _tDiscontinuous formula dieless drawing principle schematic in the same way.

Fig. 4 is a dieless drawing shape of product schematic diagram.

The specific embodiment

Embodiment 1: big end is of a size of the shaping of 304 non-corrodible steel conical pipes of 0.4 ° of φ 6 * 1mm, tapering.

(1) blank is D ₀=6mm, t ₀The 304 stainless steel pipes of=1mm;

(2) cooling and heating process parameter: induction heating temperature is T=0.95T _m, the distance between induction coil and the chilled water unit is S ₀=5D ₀, cooling water flow is 50L/h;

(3) the pipe charging rate is 35mm/min; Drawing speed control model is $v_t=(\frac{24.0}{6.0+\sqrt{36.0-0.1t}}-1)\×35,$ Wherein initial drawing speed is 35mm/min;

(4) carry out dieless drawing under these conditions, the pipe diameter reduces continuously, forms external taper α=0.38 ° of conical pipe;

(5) after the drawing product wall thickness by 1mm attenuate gradually, the thinnest 0.7mm, $\tan \mathrm{\β}=1.12(1-2\frac{t_0}{D_0})\tan \mathrm{\α},$ Maximum reduction of area 60%.

Embodiment 2: big end is of a size of the shaping of the Ti-50.5mol%Ni alloy conical pipe of 0.5 ° of φ 6 * 1.5mm, tapering.

(1) blank is D ₀=6mm, t ₀The Ti-50.5mol%Ni alloy pipe stock of=1.5mm;

(2) cooling and heating process parameter: induction heating temperature is T=0.5T _m, the distance between induction coil and the chilled water unit is S ₀=0.8D ₀, cooling water flow is 10L/h;

(3) pipe charging rate 45mm/min; Drawing speed control model is $v_t=(\frac{17.7}{4.4+\sqrt{19.7-0.1t}}-1)\×45,$ Wherein initial drawing speed is 45mm/min;

(4) carry out dieless drawing under these conditions, the pipe diameter reduces continuously, forms external taper α=0.47 ° of conical pipe;

(5) after the drawing product wall thickness by 1.5mm attenuate gradually, the thinnest 1.0mm, $\tan \mathrm{\β}=1.2(1-2\frac{t_0}{D_0})\tan \mathrm{\α},$ Maximum reduction of area 55%.

Embodiment 3: big end is of a size of the shaping of the Cu-12wt%Al alloy conical pipe of 0.6 ° of φ 10 * 2mm, tapering.

(1) blank is D ₀=10mm, t ₀The Cu-12wt%Al alloy pipe stock of=2mm;

(2) cooling and heating process parameter: induction heating temperature is T=0.95T _m, the distance between induction coil and the chilled water unit is S ₀=0.5D ₀, cooling water flow is 100L/h;

(3) pipe charging rate 60mm/min; Drawing speed control model is $v_t=(\frac{28.3}{7.0+\sqrt{49.9-0.2t}}-1)\×60,$ Wherein initial drawing speed is 60mm/min;

(4) carry out dieless drawing under these conditions, the pipe diameter reduces continuously, forms external taper α=0.58 ° of conical pipe;

(5) after the drawing product wall thickness by 2mm attenuate gradually, the thinnest 1.18mm, $\tan \mathrm{\β}=1.1(1-2\frac{t_0}{D_0})\tan \mathrm{\α},$ Maximum reduction of area 61%.

Embodiment 4: big end is of a size of the shaping of 304 non-corrodible steel conical pipes of 0.5 ° of φ 50 * 5mm, tapering.

(1) blank is D ₀=50mm, t ₀The 304 stainless steel pipes of=5mm;

(2) cooling and heating process parameter: induction heating temperature is T=0.7T _m, the distance between induction coil and the chilled water unit is S ₀=5D ₀, cooling water flow is 200L/h;

(3) pipe charging rate 30mm/min; Drawing speed control model is $v_t=(\frac{16.4}{4.1+\sqrt{16.8-0.008t}}-1)\×30,$ Wherein initial drawing speed is 30mm/min;

(4) carry out dieless drawing under these conditions, the pipe diameter reduces continuously, forms external taper α=0.48 ° of conical pipe;

(5) after the drawing product wall thickness by 5mm attenuate gradually, the thinnest 3.0mm, $\tan \mathrm{\β}=1.08(1-2\frac{t_0}{D_0})\tan \mathrm{\α},$ Maximum reduction of area 53%.

Claims (1)

1. conical metal pipe forming technology based on continuous dieless drawing is characterized in that:

(1) raw material are selected: diameter D ₀=(1～1.1) D ₁, wall thickness t ₀=(1～1.1) t ₁Seamless or the isometrical pipe of seam steel alloy, carbon steel, aluminium alloy, copper alloy or titanium alloy, D arranged ₁, t ₁Be respectively product outside diameter and wall thickness, D ₀, t ₀, D ₁, t ₁Unit be mm;

(2) isometrical pipe forms one section softened zone under the acting in conjunction of induction coil heating and cooling device cooling, and induction heating temperature is T=(0.5～0.95) T _m, T _mFusing point, unit for material: K; Cooling water flow is 10～200L/h; Distance between induction coil and the cooling device is 0＜S ₀≤ 5D ₀, S ₀Unit: mm;

(3) pipe one end is sent to, an end drawing, charging rate v _iEqual initial drawing speed v ₀, v ₀Unit: mm/min, drawing speed v _tBeing non-linear gradual by the drawing speed model increases; Along with the increase of drawing speed, pipe diameter reduces continuously, forms the conical metal pipe of external taper α, 0＜α≤1 °;

(4) reduction of area increases gradually in the drawing process, single pass reduction of area up 65%;

(5) wall thickness of dieless drawing form metal conical pipe attenuate gradually, its internal taper β is

K=1.0～1.2 wherein;

(6) described drawing speed v _tModel be

$v_t=(\frac{A_1}{A_2}-1)v_i$

In the formula, v _i-charging rate, unit: mm/min;

$A_1={2S}_0+2\frac{D_0^2-{(D_0-{2t}_0)}^2}{[D_0-(D_0-{2t}_0)/k]\tan \mathrm{\α}};$

$A_2=\frac{S_0}{2}+\frac{D_0^2-{(D_0-{2t}_0)}^2}{2[D_0-(D_0-{2t}_0)/k]\tan \mathrm{\α}}+\sqrt{{\{\frac{S_0}{2}+\frac{D_0^2-{(D_0-{2t}_0)}^2}{2[D_0-(D_0-{2t}_0)/k]\tan \mathrm{\α}}\}}^2-2\frac{D_0^2-{(D_0-{2t}_0)}^2}{[D_0-(D_0-{2t}_0)/k]\tan \mathrm{\α}}{v}_{i}t};$

T-time, unit: min.

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