The method of hot forming hollow articles

 

(57) Abstract:

The invention relates to the processing of metals by pressure, in particular a hot stamping hollow products with periodic cross-section of the outer side surface. Shaping the product produced by a single stroke of the punch. The outer side surface formed into a collapsible sleeve, housed in the container of a press. Shaping the product carried out due to redistribution of flow of the metal stream and simultaneous extrusion of metal into the main cavity and technological projections (radial and axial), and then remove the bottom. The technological dimensions of the projections appoint, subject to the conditions of deformation and tool life. The result is the reduction of thermal loads on products and tools, improved surface quality and dimensional stability presswork. Increased yield and reduced energy and labor costs. 4 C.p. f-crystals, 3 ill.

The present invention relates to the processing of metals by pressure and can be used for hot forming hollow articles with a variable diameter of the outer side surface mainly on pipetype psychosi placing the heated blank in the matrix with a tapered bore, facing a larger diameter in the direction of the punch, pre-shaping repressively blanks in the matrix and vipresume pipe with one stroke of the punch to the formation of the Donets, the tenderloin Donets and removing the pipe from the matrix in the direction of the punch. (The trough centuries, Zverev, I. metal Extrusion. M.: metallurgy, 1971, pp. 27-29).

The known method the same as the stated that pre-shaping, supressive items on the punch to the formation of the Donets one stroke of the punch, and then cutting the base plate.

There is a method of hot stamping products with a hole of cylindrical workpieces, comprising pre-forming of increased diameter at the end of the workpiece facing to the punch, and the formation process of a cylindrical projection, the diameter of which is larger than the diameter of a blind hole, forming a blind hole, backward extrusion, the formation of the bottom in the cylindrical protrusion and the removal of the bottom branch of the technological cylindrical protrusion. (The description of the invention the application 96101031/02, 1996 , BI 26) prototype.

In the known method hot forming is carried out in several different transitions punches on the way in the manufacture of products of hard alloys are great efforts deformation at the end of forming a blind hole in the extrusion of metal from the zone of the complicated deformation, leading to nedopostavku bottom and its high altitude, the destruction punch, overheating of the metal and the formation of its nonconforming structure.

The known method the same as the stated that the pre-shaping of increased diameter portion of the length of the workpiece, forming a blind hole is backward extrusion, formed the technological ledge and separates the bottom.

The problem to which this invention is directed, is to obtain hollow products with varying diameter of the outer side surface including pipetype presses, reducing thermal loads on the pressed product and tool, reducing the range of technological tools, the improvement of the quality of surfaces and stability of the geometrical sizes of products, lower quality requirements for procurement, increase yield, reduce energy and labor costs and increase opportunities universal press equipment.

This technical result is achieved by the fact that in the known method of hot forming hollow articles with a variable diameter of the outer side surface of the piece Qili is the author of the lateral surface of the product by increasing the diameter of the workpiece on the part of its length, forming a blind hole by means of reverse extrusion with getting the bottom with an axial technological ledge and remove the bottom, pre-shaping of the workpiece, forming a blind hole, and the receiving plate with axial technological ledge carried out in one move, punch in collapsible sleeve, which is placed in the container of the press, in the process of pre-forming of the workpiece, forming a blind hole, and a receiving plate with axial technological ledge on the part of the outer side surface of the workpiece to form an additional radial protrusions, and the axial technological ledge is formed over the workpiece material in the axial direction.

Axial technological ledge form a diameter, the value of which is chosen from the following mathematical expression:

< / BR>
where dB is the diameter of the cylindrical protrusion, mm;

d is the diameter of a blind hole in the product, mm;

[] - allowable stress in the material of the punch, MPa;

n - deformation resistance of the material of the workpiece with respect to temperature and strain rate, MPa;

CT=0,571,15 factor taking into account the friction force during extrusion of the cylindrical protrusion in the z is the instrument with the deformation portion of the workpiece, the corresponding height of the hindered zone of deformation at the end of the process of extrusion of the product and formation of the bottom.

When stamping products axial technological ledge form a diameter, the value of which is chosen from the following mathematical expression:

< / BR>
where [TV] - permissible temperature increment of the workpiece material during extrusion, TO;

- density of material, kg/m3;

C - specific heat capacity of the workpiece material, kJ/(KGC).

This prevents overheating of the unit, the height of which is equal to the height of the hindered zone of deformation at the end of the deformation process and the formation of the bottom.

When stamping products technological radial protrusions form with the total cross-sectional area, the value of which is chosen from the following mathematical expression:

< / BR>
where AV is the total cross - sectional area of technological radial protrusions, mm2;

KS - coefficient taking into account the amount of the additional fillings ledges, KS=0.5 to 0.8.

This prevents distortion of the shape of the product during extrusion of the metal of the thickened part of the product during the formation of the axial otwartego mathematical expressions:

< / BR>
where d is the diameter of a blind hole in the product, mm;

D CR - diameter cylindrical workpiece, mm;

To is the temperature increment of the workpiece material during the formation of a blind hole, backward extrusion, K.

This prevents overheating of the unit when forming a blind hole.

The invention is illustrated by drawings, where Fig.1 shows the starting position after loading of the workpiece of Fig.2 - the end of the stamping process, in Fig.3 - compartment plate with a cylindrical ledge.

The method is as follows. Heated to the temperature of pressing the workpiece 1 with a diameter d CR is placed in the split sleeve 2, which is coupled by conical surface in the housing 3. The building is associated with the container 4 horizontal press. Then with one stroke of the punch 5 is made of sediment components (1) and forming the main section of the hollow product with an inner bore diameter d, the shaping is done by redistributing the flow of the metal stream during its simultaneous extrusion into the main cavity 9 in the radial and axial 6 technological protrusions with a diameter dB. Next, the punch 5, the container 4 is disposed on the axis of the pressing caps shall livania split sleeve 2 with item 8.

Section technological protrusions are assigned such that provide shaping of the main section of the product at an acceptable technological regimes. All this allows, on the one hand, to produce a product with variable wall thickness on the universal forging equipment, greatly increasing its capabilities, and on the other hand, to expand the range of manufactured products in form and alloys.

Example. Process batch in the amount of 10 pcs. cylindrical billets d CR= 143 mm and height H=235 mm, titanium alloy Ti-6Al-4V heated to a temperature of 40-50oC below the temperature of polymorphic transformation. As grease is applied glass 58. Geometrical product dimensions: inner diameter d=110 mm, the diameter of the protrusion on the side surface 172 mm, diameter of articles 144 mm, length 340 mm Limit forces on the plug match the diameter of the axial technological ledge dB=35 mm. Restrictions on local deformation overheating correspond to the diameter of the axial protrusion dB= 60 mm Selects the largest value dB=60 mm, the measurement Results show that in all cases, the products meet the requirements of the drawing, the microstructure after heat treatment - globuli side surface of the piece of cylindrical workpieces, includes pre-forming the workpiece into the press with the formation of the outer side surface of the product by increasing the diameter on part of its length, forming a blind hole by means of reverse extrusion with getting the bottom with an axial technological ledge and remove the bottom, characterized in that the preliminary shaping of the workpiece, forming a blind hole, and the receiving plate with axial technological ledge carried out in one move, punch in collapsible sleeve, which is placed in the container of the press, in the process of pre-forming of the workpiece, forming a blind hole, and a receiving plate with axial technological ledge on the part of the outer side surface of the workpiece to form an additional radial projections, and the axial technological ledge is formed over the workpiece material in the axial direction.

2. The method according to p. 1, characterized in that the axial technological ledge form a diameter, the value of which is chosen from the following mathematical expression:

where dB is the diameter of the cylindrical protrusion, mm;

d is the diameter of a blind hole in the product, mm;

[] - allowable stress in the material ISPs, MPa;

CT = 0,57-1,15 factor taking into account the friction force during extrusion of the cylindrical projection depending on the workpiece material and type of lubrication.

3. The method according to p. 1, characterized in that the axial technological ledge form a diameter, the value of which is chosen from the following mathematical expression:

< / BR>
where [TV] - permissible temperature increment of the workpiece material during extrusion, TO;

- density of material, kg/m3;

C - specific heat capacity of the workpiece material, kJ/(KGC).

4. The method according to p. 1, characterized in that the technological radial protrusions form with the total cross-sectional area, the value of which is chosen from the following mathematical expression:

< / BR>
where AV is the total cross - sectional area of technological radial protrusions, mm2;

KS - coefficient taking into account the amount of the additional fillings ledges, KS = 0.5 to 0.8.

5. The method according to p. 1, characterized in that the blind hole to receive the diameter, the value of which is chosen from the following mathematical expression:

< / BR>
where d is the diameter of a blind hole in the product, mm;

D CR - diameter cylindrical billet is observed K.

 

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FIELD: plastic working of metals in different branches of industry.

SUBSTANCE: apparatus includes supporting plate and housing with openings and duct. Punch, upper and lower stops are mounted in housing. Said stops may be in contact with blank by their flat notched surface. Movable lower stop is arranged in openings of housing and on supporting plate; it engages with said plate by its smooth surface. Hydraulic cylinder joined by its rod with lower stop is mounted on supporting plate. Upper stop is in the form of cylinder mounted in housing in such a way that it restricts together with punch inner cylindrical cavity of hydraulic system providing motion of lower stop. Said hydraulic system also includes duct of housing and hydraulic cylinder.

EFFECT: enlarged manufacturing possibilities of apparatus due to increased range of changing relation of shear deformation to compression deformation of blank.

2 dwg

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