DE1239912B - Process for the production of solid workpieces from cast blanks made of cast iron. Like. By hot extrusion - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EXPLOITATION PAPER 1239912 Int. Cl .:

B 21 j

German class: 49 h -11

Number: 1239 912

File number: Sch 340801 b / 49 h

Filing date: October 30, 1963

Open date: May 3, 1967

The invention relates to the production of solid workpieces, e.g. screw blanks or the like, from cast Blanks made of cast iron and similar heterogeneous crystallite mixtures by y_oiw_arts or backward working hot extrusion and has a particularly expedient process for the subject, through which a much simpler and cheaper production of the workpieces is made possible and get them better strength properties.

The hot forming of cast iron takes place mainly at around 900 ° C in multi-part forging dies. During the pressing and upsetting process of massive workpieces takes place under the effect of the pressure forces a flow of the crystallites takes place, and the excess material is as a burr in or against the ram direction discharged. During the further deformation process, this forging burr has to be continuously forged thinner in an energy-consuming manner will. The forging burr is therefore not only a loss of material, but also at the same time a big energy consumer. The existing need to improve the flowability of the materials during forward and backward extrusion is therefore always an occasion for new proposals.

To improve hot forming, it is known to start from a blank whose total surface differs from that of the molding to be produced. For example, for the production of Workpieces with round cross-section used blanks that have a rectangular cross-section, whereby the material initially flows sideways to the die wall during upsetting, then its The direction of flow changes and is pushed between the plunger and die wall against the direction of pressure will. For extrusion dies one has to reduce the formation of cracks at the front end of the pressed In some cases it is also proposed to place the blank in a closed die before the actual hot forming to compress and this in its front end, on which then the flat end face of the extrusion die acts to press in a dome-shaped depression. Even with this known method During the following hot forming, the pressing pressure initially only affects the one on the Crystallites stored on the surface. The surface crystals are pushing into the free space directed and initiate the flow process. Furthermore, by attaching special flow shoulders in the The extrusion tool tries to increase the flowability of the material to be pressed.

When extruding hollow shaft valves for processes for manufacturing solid workpieces
from cast blanks made of cast iron or the like.
by hot extrusion

Applicant:

Support fund of the country team

Thuringia e. V., Essen, Heymannsplatz 12

Named as inventor:

Dr.-Tng. Werner Schlegel, Düsseldorf

Internal combustion engines, it is also known to start from hollow blanks to introduce a mandrel to be able to take care of the calibration.

Compared to this prior art, the invention is based on the problem of upsetting further reduce the impact and pressure forces to be expended in order to reduce the production and maintenance costs for the complex closed-die forging

^a 5 reductions. The strength properties of the extruded workpieces should also be improved.

This object is achieved in that a central axis bore lying in the pressing axis is closed is extruded. This novel configuration of the blank enables a significantly improved flow process. In the first phase of the forming process, the Crystallites with a surface freedom approximately perpendicular to the surface outwards and inwards and are then deflected in the second phase against the direction of pressure. During the upsetting process is to determine a considerable relief of the pressing and upsetting process. But most of all they have workpieces produced according to the invention surprisingly show a strong increase in flexural strength, Transverse strength and long-term impact resistance. The hole closed during extrusion takes effect like a notch in the axis of the soul, and presumably contributes significantly to the increase in strength Reshaping process also includes the crystallites surrounding the hole or the notch in the direction of flow during the second deformation phase, i.e. parallel to the pressure direction. In contrast in addition to an increase in tensile strength, there was a sharp decrease in the The transverse and flexural strength of the briquettes can be observed.

709 578/170

Claims (1)

3 4 ten. In the extrusion according to the invention, only inclusions are not opposed. The portrayed a closing of the central axis bore without deformation taking place in a manner known per se a weld should occur, even if depending on the type of metal used marginal welding of the open areas at temperatures of about 900 ° C instead, can come. 5 The embodiment shown in Fig. 4 is According to the invention, it is finally provided that a die 11 meets for forward extrusion. to that the pressing on the front ends of the work- this purpose the die 11 has a lower drill piece suction cone formed a notch seal made of tion 12, whereas the pressure stamp 15 is made entirely of metal, Plastic, rubber or the like. Receives. This is done. The workpiece blank 13 has been invented Corrosion from the io according to a bore 14 is advantageously obtained. When the Soul notch turned off. Pressure stamp 15 finds the same transformation here The invention is shown schematically in the drawing to mung process, only that in contrast to that Hand of two exemplary embodiments explained in more detail, exemplary embodiment according to FIGS. 1 and 2 of namely shows material in the bore 12 of the die to the front Fig. 1, a reverse extrusion press with inserted 15 is pressed. The head shape of the workpiece with Blank in a central longitudinal section, the die according to FIG. 4 can be produced, has an et- F i g. 2 the subject of FIG. 1 in plan view what different version than that of the aforementioned Ausauf the counterbore, guide example. F i g. 3 the in the reverse extrusion according to By the attachment of the axial bore in F i g. 1 and 2 manufactured workpiece in a middle 20 blank and through the formation of the suction cone 9 Longitudinal cut, there is a danger at the front end of the workpiece F i g. 4 a forward extrusion with inlaid an increased corrosion. To such a corrosion A blank in a central longitudinal section and to be prevented is in the area of the suction cone 9 F i g. 5 a finished workpiece with notch lock. Drilled hole in which a notch lock 10 In which in FIGS. 1 and 2 it is introduced schematically. This notch lock 10 represents one provided die 1 is a cylindrical bore 2 plug made of metal, plastic, rubber or a plug provided, in which the pressure or ram 5 is another suitable material. The notch lock is introduced. The punch 5 has a hole 6, can be pressed in or glued in, so that the die works as a reverse extrusion press. The invention does not remain on the execution The blank 3 to be inserted into the die has limited 30 examples, but there are no problems a rectangular cross-section and in the middle numerous changes can be carried out without the Axis a small hole 4. The dimensions of the scope of the invention is exceeded. Sample pages this blank are such that the edges to wise there is the possibility of the holes too the wall of the bore 2 rest. To attach the hole 4 differently on the blank. Usually will In the blank 3, the position of these bores can be selected from a uniform cross section 35 so that be. But there is also the possibility of inserting them into the crystallites, which through the hole to fit to the shape of the workpiece to be manufactured stronger flow are stimulated to keep free in the Auskonisch. recesses or bores of the die flow When the stamp 5 acts on the blank 3, first the ones on the outer and inner 40 Crystallites located on the surface to the outside against claims:
the wall of the bore 2 or inwards into the Bore 4 flow. As soon as the existing 1st method for producing solid work cavities are filled, the flow direction pieces, e.g. screw blanks or the like, are deflected upwards, with the material being poured into the 45 cast iron blanks and similar bore 6 of the punch 5 flows in. This process of heterogeneous crystallite mixtures through forward mixing is presumably considerably facilitated by the fact that hot extrusion or reverse working, including the crystallites in the area of the blank axis, is characterized in that during the first phase, a center lying in the pressing axis is already caused to flow. This initiated flow process is capable of 50 telachsbohrung (4 or 14) is extruded.
then without further, additionally large pressure expenditure. with suction cone, characterized by a notch F i g. 3 is a workpiece 7 schematically shown closure (10) in the suction cone (9). made, as provided in the invention Procedure arises. The middle hole 4 of the raw 55 Documents considered: lings 3 is to an approximately linear notch 8 to- German Patent No. 1 105 254, 906777, pressed together, and 562 564 remains at the lower front end; a suction cone 9 in the usual way. pressing the bore is essentially only 918 820; to a closure without welding. 60 Journal "Das Industrieblatt", 4/1962, p. 221 he follows. But within certain limits it can happen up to 228; that in places in the area of the notch a small magazine "Der Maschinenbau", 7/1960, p. 200; open cross-section remains or else a magazine »Chemie-Ingenieur-Technik«, ring welding takes place, provided Oxyd- Juni 1962, pp. 401 to 403. 1 sheet of drawings 709 578/170 4.67 © Bundesdruckerei Berlin