CN1006607B - Extraplastic forming technology of standard mould - Google Patents

Abstract

A steel die blank is treated by super thinning or directly heated to the temperature about AC-[1] by die steel under a supply state. At the strain rate of 10<-1> to 10<-3>/minute<-1>, a heat-resistant steel or alloy master die is used for once extruding and forming various standard part dies or other types of complicated and precise dies with large amount of deformation. Steel for making the die can be various types of cold die steel, hot die steel or matrix steel, the size precision of the die can reach 4 to 2 grades, and surface smoothness is from del7 to del9. The edges and the corners of slots of the die are clear, and the radium of a pure angle is smaller than 0.1mm. Cost can be reduced by more than 60%, and life time can be enhanced by 3 to 10 times.

Description

Extraplastic forming technology of standard mould

The present invention is a kind of technology of die manufacturing, is mainly used in to make the production steel mold.

Steel mold is cold-work die especially, in use mostly bear huge impact power and unit pressure, operating frequency height, serious wear, thereby require mould itself to have enough intensity, hardness, wearability, toughness and high fatigue life, and require to have high dimensional accuracy and surface smoothness.At present, the method that is used for the steel mold manufacturing mainly is to adopt machining or adopt EDM Technology such as electric spark, line cutting, and the mold materials utilization rate is low, and mould manufacturing process is many, the cycle is long, cost is high, and service life is lower.Adopt warm-extrusion forming can obviously save mold materials, simplify manufacturing process, forming speed is also very fast.But during warm-extrusion forming, metal deformation resistance is big, mobile poor, is difficult for being shaped, and improves the die life of formed thereby few for precision prescribed height, big, the complex-shaped steel mold of deflection.Utilizing metal material in the superplastic state method of mold for extruding and forming next time, is a kind of up-to-date few no cutting dies manufacturing technology.Metal material under superplastic state, resistance of deformation very little (the max-flow varying stress only has tens MPa), plasticity and mobile fabulous (percentage elongation can be brought up to percent hundreds of by common tens percent, even thousands of), and do not produce work hardening.The EWJMiller of Britain Cranfield Institute of Technology and RPearce once adopted super plastic compression seal legal system to produce shallow type cavity mould (" Metallurgia " 1981 of a kind of coin and small-sized " O " RunddichtringO, 5,206～210), tentatively superplastic forming technology is applied in the manufacturing of steel mold, but they have only realized that the impression of shallow die cavity die is shaped, die blank only produces a small amount of plastic deformation in the part, and mold materials also only limits to several middle carbon and low-alloy hot die steels.For matrix steel class high-strength toughness cold working die steel, because of its microstructure ultra-fining treatment difficulty, the superplastic deformation drag is bigger, and deformation temperature is higher, and its superplastic forming technology is still untapped., top layer impression darker, complex-shaped for die cavity can't be shaped and need the whole a large amount of moulds that could be shaped that are out of shape of blank, standard component cold heading die and edger that for example consumption is very big, because of deflection bigger, to guarantee after the shaping that enough dimensional accuracies, fineness and the demoulding are smooth etc., have a strong impact on the technological development and the application of superplastic extrusion processing steel mold.

Task of the present invention is to realize the superplastic deformation of matrix steel class steel, and development superplastic forming technology is with master mold and steel mold superplastic extrusion processing technology.

Realize that principle of the present invention is to utilize steel to have these characteristics of tissue (constant temperature) superplasticity under certain organization condition and deformation condition, the matrix steel class steel wool base that microscopic structure is met certain requirements places in the master mold, be placed on the press with heating and temperature controlling device and adjustable-speed, under certain temperature and speed, blank carried out extrusion molding one time.The fine grain structure such as axle such as grade that the superplasticity of steel will be aspired for stability, carbide size≤0.5 μ m, matrix grain size≤5 μ m.The matrix steel class base steel of supply status has originally satisfied the desired organization condition of superplasticity, gives processing directly at AC without super moulding ₁Carry out superplastic deformation under the deformation velocity that-(10～50) ℃ temperature and 0.5～5mm/ divide, the percentage elongation of steel can reach more than 200%, and the max-flow varying stress is less than 80MPa, and does not produce the work hardening phenomenon in deformation process.The approach that solves steel mold superplastic extrusion processing and demoulding difficulty is that the appropriate design by master structure realizes.This , the shaping master mold of standard component mould is made up of drift and die two parts.Die wherein The upper and lower mould structure is made up of upper die and lower die and push rod, and fixes and locate with overcoat.The back demoulding segmentation that is shaped is carried out.

Advantage of the present invention is, the resistance of deformation of steel is little during superplastic extrusion processing, and forming temperature is low, plasticity and good fluidity, master structure is reasonable, and the shaping and the demoulding are smooth, can go out mould complex-shaped, that precision is high, deflection is big at middle temperature once-forming on low tonnage press; Die size precision after the shaping can reach 4～2 grades, and surface smoothness is 7～

9, the groove corner angle are clear, clear angular radius＜0.1mm; Advantage with few nothing cutting; Die blank can be without giving processing; The be shaped microstructure ultra-fining treatment of back mould, the life-span can be improved 3-10 doubly, and can repair sth. old and make it as good as new by extrusion molding again to the mould that lost efficacy because of wearing and tearing or distortion; The present invention can produce the mould of precision unanimity in batches; The Mould Machining cycle is short, operation is few, equipment is few, material-saving material, energy-conservation source, production cost are low.

Embodiments of the invention are the superplastic extrusion processing of nut six side's cold upsetting punch (Fig. 1) and bolt six side's trim dies (Fig. 3).Mold materials is the matrix steel class steel 7Cr of high-strength tenacity ₇Mo ₂V ₂Si(code name LD) and 65Cr ₄W ₃Mo ₂VNb(code name 65Nb), also can use other cold work die steel.The superplastic forming technological process is: blank blanking → be coated with protection lubricant → pack into extrusion die → heating and extrusion molding → demoulding.After the blank blanking if give processing, then can be 950～1050 ℃ of circulating quenchings 1～3 time.Fig. 2 is six side's cold upsetting punch superplastic forming devices, and Fig. 4 is six side's trim die superplastic forming devices.Building mortion is made up of heating furnace (1), drift (3), patrix (2), counterdie (6), push rod (5) and overcoat (7), drift (3), patrix (2) and counterdie (6) are all made with heat resisting steel or heat-resisting alloy, and enough heat resistances are arranged under the superplastic forming temperature.Building mortion places on the press bench, and patrix (2) and counterdie (6) are contained in the overcoat (7), put into heating furnace (1).It is AC that the standard component die blank (4) that scribbles the protection lubricant is placed on temperature ₁In the counterdie (6) and patrix (2) of-(10～50) ℃, be incubated 3～15 minutes, the starting pressure machine, the speed isothermal extrusion blank (4) that drift (3) is divided with 0.5～5mm/ is until being shaped the standard component mould, then with the mould ejection device that is shaped.Extrusion molding of standard component mould also can be produced in batches continuously.Total shaping pressure＜24 tons, curring time＜20 minute.Compare with machining, mold materials can be saved more than 50%, reduces man-hour more than 80%, and cost reduces more than 60%, and die life can improve 3～10 times.

Claims (2)

1, a kind of technology of die manufacturing, pass through superplastic extrusion processing, feature of the present invention is that extrusion molding is made up of drift (3) and die with the master mold in the device, wherein die is upper and lower mode structure, form by patrix (2), counterdie (6) and push rod (5), adopt the segmentation demoulding behind the mould extrusion molding.

2, technology of die manufacturing according to claim 1 is characterized in that the die in the building mortion is contained in the overcoat (7), and fixes and the location by overcoat (7).

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