CN103639223A

CN103639223A - Continuous equal circular channel warm extrusion method and die with prestressed structure

Info

Publication number: CN103639223A
Application number: CN201310610217.XA
Authority: CN
Inventors: 徐淑波; 李振东; 刘婷; 任国成; 刘鹏
Original assignee: Shandong Jianzhu University
Current assignee: Shandong Jianzhu University
Priority date: 2013-11-27
Filing date: 2013-11-27
Publication date: 2014-03-19

Abstract

The invention discloses an ECAP extrusion die with a prestressed combined concave die structure. Structurally, the die is characterized by adopting an inverted bell-shaped double-layer combined concave die prestressed structure, thereby not only effectively utilizing die materials, but also ensuring the carrying capacity. According to the invention, an optimized die geometrical shape and process parameters can be acquired firstly through finite element analysis of an ECAP extrusion process, an ECAP extrusion test die is designed according to the basic requirements of low carbon steel extrusion molding, and then the conventional structure of the concave die is improved. The strength and life time of a convex die are not only considered from the materials used, but also are ensured in terms of the structural design of the convex die. With the method and the die provided by the invention, concave die fracture can be effectively avoided, the life time of the die is prolonged, the experimental study efficiency is enhanced, and time and money can be saved.

Description

A kind of continuous circular channel Warm Extrusion method and mould of waiting with prestressed structure

Technical field

The present invention relates to a kind of continuous square circular passage temperature extension mould that waits, especially relate to a kind of employing and fall bell double-deck combined die prestressed structure, that greatly improves die life waits square circular passage temperature extension mould simultaneously.

Background technology

Traditional warm extrusion technology such as passage such as square circular such as grade is the pipeline that makes two angled iso-cross-sections of circular extrusion Multiple through then out under drift effect, thereby accumulates enough equivalent strains, reaches the object of grain refinement.

Yet extremely severe Deng square circular passage extrusion process condition of work, therefore, the extruding that realizes in advance hard material under normal temperature will propose higher requirement to mould and die accuracy, intensity, rigidity and life-span.According to requirement of experiment, by square circular passage Warm Extrusion processes such as finite element analyses, obtained mould geometry and the technological parameter optimized, by the basic demand of mild steel extrusion molding, designed and waited square circular passage Warm Extrusion experiment mould; Die and punch are to extrude the parts with ultra-fine grain structural material most critical, therefore in design process, should take into full account.

Because die deformation condition is extremely severe, and the conventional structure of die need to improve, and for effectively utilizing mold materials and guaranteeing its bearing capacity, selects prestressing combination cavity die structure.Because the size of punch is affected by the physical dimension of circular extrusion, thus the intensity of punch and life-span not only to consider from material used, more to guarantee from the structural design of punch.But be violent plastic deformation owing to waiting square circular passage warm extrusion technology, therefore, this technique is higher to mould and die accuracy, intensity, rigidity and life-span requirement, adopt traditional square circular passage temperature extension mould that waits to tend to the phenomenon that occurs that die breaks, the progress that has delayed experimental study and process exploitation, has wasted a large amount of time and moneys.

Summary of the invention

The object of the invention is: for the technical problem of above-mentioned existence, provide a kind of structure with two_layer pre_stress combined matrix, this structure can greatly improve die life, realize the cold extrusion and the Warm Extrusion that wait square circular passage warm extrusion technology of ferrous metal.

For solving above-mentioned technical matters, technical scheme of the present invention is: die adopts double-deck combined die prestressed structure.Die is divided into two parts to be made, and for fear of the larger phenomenon of circular extrusion burr, prestressing force lasso and die adopt down bell interference fit, and excessive swollen mould or the excessive phenomenon of burr of causing of die cavity expansive force in extrusion process can be effectively avoided in above-mentioned measure.Pushing concrete implementation step is

1. utilize line cutting technology that material is cut into diameter for 10mm, the sample that length is 80mm, and sample is carried out to full annealing;

2. before circular extrusion being put into die cavity, first mould is lubricated fully, put into after circular extrusion, mould and circular extrusion are preheating to uniform temperature simultaneously;

3. after having pushed, circular extrusion is carried out to stress relief annealing.

The invention has the beneficial effects as follows: waiting square circular passage bent angle extrusion process is violent plastic history, in extrusion process, mould will bear higher die cavity tension, therefore, Deng square circular passage warm extrusion technology, mould strength is had to higher requirement, some originally can cold-extruded material but adopted hot extrude or warm extrusion, yet temperature raises and has also caused a series of variation, there is growing up as crystal grain, the phenomenons such as scaling loss, be unfavorable for preparing block super fine crystal material, in actual process, die life is very low simultaneously.Therefore, on finite element analysis basis, wait square circular passage temperature extension mould design can effectively improve the intensity of mould, make the mould of design can meet the resistance of deformation of cold extrusion material, the deformation characteristics of square circular passage warm extrusion technology such as can meet again.The mould by improvement with prestressed structure, has realized the cold-extrusion technology that waits square circular passage bent angle ferrous metal, has widened the scope that waits square circular passage Warm Extrusion extrusion metal.

Accompanying drawing explanation

Fig. 1 is assembly drawing of die of the present invention;

Fig. 2 is the prestressing combination cavity die structure in Fig. 1;

Fig. 3 is squeezing passage design details skill in prestressing combination die in Fig. 2;

Fig. 4 is die corner type cavity configuration in Fig. 1 assembly drawing of die;

Being labeled as in above-mentioned figure:

A kind of 1. lower bolster 2. guide pillar 3. soket head cap screw 4. guide pin bushing 5. cope match-plate pattern 6. punch retainer 7. setting circle pin 8. convex mould pad 9. soket head cap screw 10. punch 11. die pressing plate 12. die gland 13. die 14. cushion block 15. die backing plates that wait square circular passage Warm Extrusion extrusion die installation diagram with prestressing combination cavity die structure of Fig. 1.

The specific embodiment

From the prestressing combination cavity die structure of assembly drawing of die of the present invention, Fig. 2 shown in Fig. 1 and the prestressing combination die of Fig. 3, squeezing passage design details skill can be found out, the present invention mainly contains the compositions such as 1. lower bolster 2. guide pillar 3. soket head cap screw 4. guide pin bushing 5. cope match-plate pattern 6. punch retainer 7. cushion block 8. setting circle pin 9. convex mould pad 10. soket head cap screw 11. punch 12. die pressing plate 13. second layer die gland 14. ground floor die gland 15. die 16. die backing plates.In extrusion process, first extrusion experiment material therefor is passed through to line cutting stock, then by cutting process, being processed into diameter is 10mm, length is the sample of 80mm, after annealing in process, putting into a kind of square circular passage Warm Extrusion extrusion die that waits with prestressing combination cavity die structure pushes, Deng the design of square circular passage temperature extension mould, be different from conventional cold extrusion die, prodigiosin such as warm-extrusion die such as passage such as square circular such as grade of the present invention is realized circular extrusion side direction and is extruded continuously, need in combined die and prestressing force lasso, process circular extrusion and extrude passage.At mould, complete after a crush stroke, circular extrusion is put into die cavity again and push, so repeatedly can extrude continuously circular extrusion.Owing to adopting prestressing combination cavity die structure, be improved die life, improved success rate and the extruding efficiency of experiment.

Die corner type cavity configuration of the present invention, the prestressed structure of falling bell; all can adopt prior art; the present invention is not limited to above-mentioned cited concrete form of implementation; all those skilled in the art, without the getable improvement of creative work, all belong in protection scope of the present invention.

Equipment required for the present invention is punching machine or hydraulic press.

Claims

1. the ECAP extrusion die with prestressing combination cavity die structure comprises as lower member: a lower bolster, guide pillar, soket head cap screw, guide pin bushing, cope match-plate pattern, punch retainer, cushion block, setting circle pin, convex mould pad, soket head cap screw, punch, die pressing plate, second layer die gland ground floor die gland, die and die backing plate, is characterized in that:

(a) this mould adopts double-deck combined die prestressed structure, adopts the prestressed structure of interference fit can increase substantially mould strength, can realize repeatedly extruding of square blank material, and then obtains the material with nanometer microstructure;

(b) ECAP mould of the present invention can be realized circular extrusion side direction and extrudes continuously, in combined die and prestressing force lasso, process circular extrusion and extrude passage, at mould, complete after a crush stroke, circular extrusion is put into die cavity again and push, so repeatedly can extrude continuously circular extrusion;

(c) pre-stress die value of interference fit and physical dimension: D=275mm, d1=150mm, u1=0.984, d2=(2.45～3.25) d==223.75mm, considers gland perforate, d2=230mm, u2==0.4674, u is d place radial interference amount.

2. a kind of ECAP extrusion die with prestressing combination cavity die structure according to claim 1, it is characterized in that: die is divided into two parts to be made, the cavity structure having due to mould is two angled iso-cross-section pipelines, is divided into two parts makes for the ease of processing die.

3. a kind of ECAP extrusion die with prestressing combination cavity die structure according to claim 1, it is characterized in that: for fear of the larger phenomenon of circular extrusion burr, prestressing force lasso and die adopt down bell interference fit, along with the increase of extruding force can effectively increase the magnitude of interference of mould, improve prestressing force, improve die life.