CN109570368A - A method of preparing ultra-high strength steel hot stamping forming die - Google Patents

A method of preparing ultra-high strength steel hot stamping forming die Download PDF

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Publication number
CN109570368A
CN109570368A CN201811478343.3A CN201811478343A CN109570368A CN 109570368 A CN109570368 A CN 109570368A CN 201811478343 A CN201811478343 A CN 201811478343A CN 109570368 A CN109570368 A CN 109570368A
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China
Prior art keywords
welding
mold
die
hot stamping
built
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CN201811478343.3A
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Chinese (zh)
Inventor
李永革
周杰
刘雪飞
汪义高
向科军
张建生
赵勇
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Chongqing Fostan Intelligent Equipment Co Ltd
CHONGQING JIEPIN TECHNOLOGY Co Ltd
CHONGQING JIANGDONG MACHINE Co Ltd
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Chongqing Fostan Intelligent Equipment Co Ltd
CHONGQING JIEPIN TECHNOLOGY Co Ltd
CHONGQING JIANGDONG MACHINE Co Ltd
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Priority to CN201811478343.3A priority Critical patent/CN109570368A/en
Publication of CN109570368A publication Critical patent/CN109570368A/en
Pending legal-status Critical Current

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21DWORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D37/00Tools as parts of machines covered by this subclass
    • B21D37/20Making tools by operations not covered by a single other subclass
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K31/00Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by only one of the preceding main groups
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18Hardening; Quenching with or without subsequent tempering
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0068Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/50Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints

Abstract

The invention discloses a kind of methods for preparing ultra-high strength steel hot stamping forming die, using cast steel as hot stamping forming die matrix, matrix has cast or has processed profile-followed water channel, by carrying out double-layer metal resurfacing welding on base layer, it is tempered destressing again, mold is finally machining.By analysis gradient-structure intensity and cooling optimum efficiency, seek the optimal value at the top of cooling water channel at a distance from die surface, to improve the cooling efficiency of drop stamping.The present invention provides one kind can increase substantially the abilities such as the wear-resistant, resistance to deformation in hot stamping forming die working region, improves die life, and can reduce die manufacturing cost, improves the preparation method of the hot stamping forming die of the production efficiency of drop stamping;Low cost, low energy consumption, short time, high usage and high performance manufacture and use mold are realized, there is very wide application prospect and scientific research meaning.

Description

A method of preparing ultra-high strength steel hot stamping forming die
Technical field
The present invention relates to a kind of preparation methods of hot stamping forming die, and in particular to a kind of double based on cast steel substrate The method that layer replating prepares hot stamping forming die.
Background technique
Currently, automobile-used high-intensitive and ultrahigh-strength steel plates have the characteristics that it is light and high-intensitive, it is more next in automobile industry It is more concerned, and oneself meets the important channel of automobile loss of weight and increase collision performance and security performance through becoming.And to realize High-intensitive or ultrahigh-strength steel plates punching press has good forming property, be unable to do without hot press-formed technique.Hot stamping die is set Meter is the core technology of hot press-formed technique, and the forming and quenching of plate are completed in hot stamping die, therefore drop stamping Mold will not only can satisfy the forming needs of part, but also have excellent cooling capacity, to guarantee that it is good that part obtains Good mechanical performance and dimensional accuracy.It can be seen that the design of hot stamping die occupy in heat forming technology it is extremely important Status, to also hot stamping die be required to possess higher wearability, thermal fatigue resistance, high temperature resistant etc. accordingly.However according to Hot stamping forming die is prepared by traditional method, even if possessing the comprehensive performances such as good strong hardness, toughness and high temperature resistant, Can satisfy the requirement of hot stamping forming die operating condition, but prevailing price is very high, preparation process flow is more, and the period is longer, and And the service life of mold cannot guarantee that.
In conclusion the performance and cost of mold tend not to obtain simultaneously very well in existing hot stamping forming die Satisfaction.The material price for being able to satisfy hot stamping forming die duty requirements is usually costly, and mold production process process is more. Therefore, seek a kind of requirement for being able to satisfy the performances such as hot stamping forming die intensity, toughness, thermal fatigue resistance, while can subtract again Method prepared by few die manufacturing cost and the hot stamping forming die for improving die life, becomes the art urgently It solves the problems, such as.
Summary of the invention
The technical problem to be solved by the invention is to provide one kind to be both able to satisfy hot stamping forming die in intensity, tough The requirement of the performances such as property, thermal fatigue resistance, and manufacturing cost, manufacturing cycle are short, improve the hot stamping forming die of die life The method of preparation.
To achieve the above object, the invention provides the following technical scheme:
A method of preparing ultra-high strength steel hot stamping forming die, comprising the following steps:
(1), it is poured using cast steel as die matrix material and outpours die matrix (c) to be welded, die matrix (c) casting Out or conformal cooling channel (d) is processed, reserves built-up welding surplus thickness;
(2), on die matrix (c) to be welded along reserved built-up welding surplus the first high intensity of a built-up welding heat conduction efficiency Slightly good transition zone (b), is welded to mold working surface with a thickness of 4~6mm with toughness;
(3), the secondary built-up welding strengthening layer (a) on transition zone (b), the thickness of the strengthening layer (a) is within 4mm;The layer Strong hardness and toughness are higher than transition zone, and elongation percentage, shrinking percentage, impact flexibility and high-temperature behavior are good, are wear-resisting tired with heat resistanceheat resistant Labor performance layer plays a major role in hot stamping forming die work.Strengthening layer uses high-temperature alloy material, in room temperature and 500 DEG C when mechanical property difference be not it is very big, when being heated to 500 DEG C, be still able to maintain very high hardness.Each gradient layer bond strength Height, after forced working position is got off to temper brittleness and insensitive, from 500 DEG C of Slow coolings, impact flexibility only slightly drops It is low.Built-up welding reinforcing position harden ability is good, and each position hardness of the section of each gradient layer is almost consistent.
(4), the mold after secondary built-up welding is repeated into retarded cooling process after double tempering, wherein tempering temperature is 530 DEG C~570 DEG C, slow cooling temperature is to 180 DEG C;This is because mold can generate martensite, austenite etc. in welding heat affected zone Unstable tissue exists simultaneously larger internal stress.And if mold cooling velocity is too fast, it is easy to hardened structure is generated, from And the defects of cracked.So built-up welding rear mold will be tempered slow cooling processing, stable tempered martensite is obtained, improves tissue Stability makes mold that structural transformation no longer occur in use, so that its geometric dimension and property retention be made to stablize.Together When eliminate internal stress, to improve the service performance of mold and to stablize its geometric dimension.Also its ductility or toughness are improved, is adjusted The mechanical property of mold is to meet requirement.The generation of one-step temper embrittlement in order to prevent uses high tempering, i.e., Tempering temperature is controlled at 530 DEG C~570 DEG C;The generation of temper brittleness in order to prevent uses double tempering slow cooling work Skill.
(5), the mold after second of slow cooling is placed in air and carries out being air-cooled to room temperature;
(6), the mold after air-cooled is machined, makes mold portions size in place.The portion of Mold stack postwelding Position, hardness with higher, general machining process not can guarantee size.The mold working surface of heap postwelding is not perfectly flat It is whole, plane first can be processed with the dise knife of surface grinding machine or numerical control processing, pincers worker is crossed by drawing, first electricity consumption impulse interference wave machine Bed shapes, then the cutting of small surplus is carried out with numerical control milling, or directly uses grinder buffing, makes the size of each part of mold In place.
7~12mm built-up welding surplus thickness is reserved in above-mentioned steps (1);It is carried out to the die matrix (c) to be welded outpoured is poured 920 DEG C of quenchings and the processing being tempered at 650 DEG C, and oil is cooled to room temperature.In this way, remaining as-cast structure can be eliminated, and tissue can be made It will not overheat, avoid obtaining annealed structure, its comprehensive mechanical performance is made to meet product requirement.The die surface outpoured is poured simultaneously Out-of-flatness, the bond strength of wlding and basis material when can increase welding can greatly improve the whole of finally obtained forging die mold Body performance requirement.
The transition zone (b) that built-up welding heat conduction efficiency is high in above-mentioned steps (2), intensity and toughness are slightly good selects copper alloy material Material.Transition zone can be well combined with matrix, improve the solderable characteristic and intensity of cast steel substrate, effectively connect base layer with Thermal fatigue resistance ergosphere reduces wlding cost.
Above-mentioned steps (2) and (3) built-up welding front mold are preheated to 450~500 DEG C, and mold temperature is maintained in weld deposit process 300 DEG C or more.In this way, mold keeps certain temperature in built-up welding, make the shadow that temperature difference is reduced between deposited metal and base material It rings, avoids bringing many disadvantages from heat affected area.If weld is without preheating, since the sharp popular drama of sweating heat is cold, knot Fruit can make high carbon cast steel base material generate martensite, and weld hardens, and tissue, mechanical performance degenerate, or even generation crack etc. is fatal Accident.
Above-mentioned steps (2) and (3) butt welding die matrix (c) before built-up welding carry out surface cleaning processing, and secondary heap is soldered At the oxide skin and welding slag of rear removal overlay surface.Wherein the surface cleaning processing, which refers to, removes sand, oxide skin, greasy dirt, iron Rust, burr and casting flaw.Carbon arc air gouging can be specifically used to remove shrinkage cavity, the casting flaws such as cracking, then with pneumatic grinder rifle Remove sand, oxide skin, greasy dirt iron rust, burr etc. again, cleaning mold surface.
Above-mentioned steps (2) and (3) tap die matrix (c) by phased manner in weld deposit process and enable its vibration.
It taps die matrix (c) by phased manner in weld deposit process and enables its vibration, vibration frequency is 20~40 beats/min. Can reach in this way extends deposited metal, prevents hydrogen embrittlement, and position crystal grain is strengthened in refinement, and round and smooth corner angle reduce stress and concentrate, mention High dimensional accuracy stability eliminates the fine crack and slag defect on built-up welding surface layer, and the purpose for inhibiting crackle to occur makes built-up welding The metal fatigue service life improves.Wherein the intensity of material not only can be improved in refinement crystal grain, can also improve its plasticity and toughness. So that the stress that double-layer metal resurfacing welding strengthening process generates preferably is discharged, each overlay cladding competency, toughness combination are enabled More preferably.
Mold after secondary built-up welding is repeated into retarded cooling process after double tempering, wherein tempering temperature is 530 DEG C ~570 DEG C, the mold after second of slow cooling is placed in air to 180 DEG C and carries out being air-cooled to room temperature by slow cooling temperature.
CO need to be led to when above-mentioned steps (2) and (3) built-up welding2, Ar mixed gas protected, the gas ratio are as follows: Ar80%~90%, CO210%~20%, it takes and is passed through CO2, Ar mixed gas, molten bath and molten drop can be protected, by they and it is empty The defects of air bound is exhausted, prevents weld seam from generating stomata.Electric arc heat under the compression of protection air-flow is concentrated, and speed of welding is very fast, melts Pond is smaller, and heat affected area is narrow, and weldment post welding distortion is small.Splashing due to using rich argon mixed air mode, in welding process It significantly reduces, improves welding quality;Welding wire feeding speed is 5~8m/min, 360~440A of welding current, welding electricity when welding Press 35~36V.The selection of above parameter range is because when weldingvoltage is too low, having the tendency that adhesion base material.Voltage is too Height, arc phenomenon obviously increase, and molten bath is unstable, and splashing also increases;Welding current increases, fusion penetration, molten wide, the reinforcement of welding bead With this increase, and dilution rate is declined slightly, but electric current is excessive, and splashing will increase;And with the increase of speed of welding, welding bead Molten wide and reinforcement reduce, fusion penetration and dilution rate increase, and weldering speed is excessively high, arc generation ratio can be made to increase, certain dilute to control Rate is released, guarantees overlay properties, speed of welding general control is in 5~8m/min.Suitable welding parameter, can stabilised bath, prevent Only splash, control dilution rate etc., the overlay properties improved.
For the normal steel casting of selection after quenching ten temperings, microscopic structure is tempered sorbite and a small amount of bainite. 20~3OHRC of room temperature following table surface hardness or so, hardness and impact toughness decreased are serious under hot conditions, and harden ability, high temperature are strong Degree, heat-resistant anti-fatigue performance are poor, cannot be directly used as mould steel use.Therefore, using double-layer metal resurfacing welding technology, to its surface Carry out Strengthening and Toughening processing, working region made to meet or exceed the performance of common hot stamping forming die, realization reduce cost, Purpose that is energy-saving, improving die life.
" double-layer metal resurfacing welding technology " is to select the high temperature alloy for having very high red hardness, and heap is welded in mold and is easy to fatigue Position greatly improves intensity, hardness, wearability and the red hardness of the working region of hot stamping forming die all, is actually formed A kind of " double-level-metal reinforcing mold ".This technology greatly reduces mold using the new mold quantity of unit, product at Originally it is greatly lowered, energy conservation and consumption reduction effects are obvious, bring significant economic benefit and social benefit for enterprise and country, favorably In the saving of resource and recycling for mold materials, there is the effect of drive property to the structural adjustment of entire die industry.
Using on inexpensive cast steel substrate the built-up welding of bimetallic gradient prepare ultra-high strength steel hot stamping forming die edge The new method of block, by analysis gradient-structure intensity and cooling optimum efficiency, seek at the top of cooling pipe with die surface away from From Optimal Design Method, thus meet with brand-new hot stamping forming die equality strength effect under, can suitably reduce At the top of cooling pipe at a distance from die surface, increase the cooling efficiency of hot stamping forming die, hot press-formed part is quick The ability for obtaining martensitic structure is improved, and dwell time of the workpiece in hot stamping forming die shortens, so as to shorten every The production time of one stamping parts improves the production efficiency of entire punching production process.
Double-layer metal resurfacing welding technology has the advantage of the following aspects: 1, utilizing module material to greatest extent.Pass through Double-layer metal resurfacing welding can be such that module height remains unchanged, and can theoretically be repeated many times, realize " zero " report of module It is useless, to save mold materials.2, it can repair because of the inadequate and written-off mold of module size, make its " coming back to life ", accord with Close the requirement and policy guidance of " resource regeneration " that country advocates.3, processing charges is saved.Double-layer metal resurfacing welding is usually in mould The type cavity portion position of tool carries out, and other positions are not required to reprocess, so saving processing charges compared with whole whereabouts renovation method. 4, the service life of mold is improved.With the mold of double-layer metal resurfacing welding, there are one the unrivaled advantages of other methods, i.e., Different resurfacing welding materials can be selected respectively in one set of die, according to the different demands at each position of mold, make each portion of mold The service life of position matches, to greatly improve the service life of whole set of die.5, since double-layer metal resurfacing welding surface is strong Change improves the service life of mold, reduces mold changing number, reduces downtime, also mitigates the labor intensity of worker, Greatly improve utilization rate of equipment and installations.
Compared with the prior art, in summary, the present invention has the advantage that
1. using more cheap cast steel as die matrix material, entire die matrix to be fortified directly casts out or adds Work goes out conformal cooling channel, compared with original new molding jig, saves forging process and machining time, cost reduces, matrix Stock utilization is high, and brand-new mold developing cycle shortens.
2. after inexpensive cast steel substrate double-layer metal resurfacing welding surface peening, with currently used hot stamping forming die phase Than the comprehensive mechanical performance at die surface position is all relatively good.Simultaneously by each gradient function layer of double-layer metal resurfacing welding, often A gradient layer plays different efficacies, comprehensive to improve steel casting die, improves the performances such as its working region intensity, toughness.
3. inexpensive cast steel substrate double-level-metal gradient built-up welding, is meeting hot stamping forming die safe application performance Under the conditions of, since graded metal layer structure compares original hot stamping forming die intensity height, thus strong by analysis gradient-structure Degree and cooling optimum efficiency, seek the optimal value at the top of cooling pipe at a distance from die surface, increase cooling efficiency, because This improves hot press-formed production efficiency.
4. a kind of mold of heat-punch member can be restructured by the integral solder to hot stamping forming die working region For the mold of another heat-punch member, makes full use of and new module is no longer needed to out with regard to module.
5. the present invention will be manufactured and be remanufactured, key position reparation in hot stamping forming die, material preparation, resource It recycles and the fields such as green circulatory manufacture has wide application value and development prospect.
In short, can increase substantially the present invention provides one kind, hot stamping forming die working region is wear-resistant, resistance The abilities such as shape improve die life, and can reduce die manufacturing cost, improve the hot press-formed mould of drop stamping production efficiency The preparation method of tool;Low cost, low energy consumption, short time, high usage and high performance manufacture and use mold are realized, is had There are very wide application prospect and scientific research meaning.
Detailed description of the invention
Fig. 1 is die matrix structural schematic diagram in the present invention;
Fig. 2 is the A-A cross-sectional view of Fig. 1;
Fig. 3 is the structural schematic diagram of die matrix heap postwelding in the present invention;
Fig. 4 is the B-B cross-sectional view of Fig. 3.
Specific embodiment
Invention is further described in detail with reference to the accompanying drawings and detailed description.
A kind of preparation process of hot stamping forming die is taken below, to be described in further details to the present invention, Yin Ben The place that invention makes creative contribution to the prior art is each step of the method for the present invention, rather than be drop stamping at The selection of shape mold shape and type, therefore a kind of hot press-formed mould of specific structure is only listed in present embodiment Tool this method is described in detail, but each step in the method for the present invention for different shape and type drop stamping at Shape mold is regarded as being suitable.
Need the hot stamping forming die of preparation for the insert in common hot stamping forming die in present embodiment, Preparation method includes the following steps:
1) it, is poured using cast steel as die matrix material and outpours die matrix c to be welded, wherein working region part, reserved 7~10mm of built-up welding surplus thickness.Used cast steel selects high-carbon Chromador ZG25MnCrNiMo to be poured, using common Pouring technology stays machining allowance, and die matrix directly casts out or process conformal cooling channel, as shown in Figure 1, 2.Casting Hot stamping forming die insert out is after 920 DEG C of quenchings, 10 DEG C of temperings, and oil is cooled to room temperature, to improve its mechanical property Energy.
2), on die matrix c to be welded along reserved built-up welding surplus the first high intensity of a built-up welding heat conduction efficiency of shape The slightly good transition zone b with toughness, 4~6mm of transition zone b thickness.When it is implemented, it is optional close with cast steel substrate ingredient, or After identical heat treatment strong hardness and in terms of the high low hydrogen type copper alloy of the heat conduction efficiency that is not much different of performance Bead welding wire improves the solderable characteristic and intensity of cast steel substrate, effectively connects in this way, transition zone can be well combined with matrix Base layer and thermal fatigue resistance ergosphere are connect, reduces wlding cost, while increasing the thermal conductivity of mold.
3), the secondary built-up welding strengthening layer a on transition zone b welds strengthening layer a thickness within 4mm;In general, the secondary heap It welds strengthening layer and covers mold work region.When it is implemented, strong hardness height, the preferable high temperature alloy low hydrogen type of toughness may be selected Bead welding wire can make this layer of strong hardness and toughness higher than transition zone b, elongation percentage, shrinking percentage, impact flexibility and high-temperature behavior Well, it as wear-resisting and thermal fatigue resistance ergosphere, plays a major role in hot stamping forming die work.Strengthening layer a is in room temperature Mechanical property when with 500 DEG C is not much different, and when being heated to 500 DEG C, remains to maintain very high hardness.Each gradient layer combines Intensity is high, and after forced working position is got off to temper brittleness and insensitive, from 900 DEG C of Slow coolings, impact flexibility is only slightly There is reduction.Built-up welding reinforcing position harden ability is good, and each position hardness of the section of each gradient layer is almost consistent.
4) mold after secondary built-up welding, is repeated into retarded cooling process after double tempering, wherein tempering temperature is 550 DEG C, slow cooling temperature is to 180 DEG C.
5), the mold after second of slow cooling is placed in air and carries out being air-cooled to room temperature.
6), the mold after air-cooled is machined, makes mold portions size in place.The position of Mold stack postwelding, Hardness with higher, general one method of Machining Forces not can guarantee size.The mold working surface of heap postwelding is not perfectly flat It is whole, plane first can be processed with the dise knife of surface grinding machine or numerical control processing, pincers worker is crossed by drawing, first electricity consumption impulse interference wave machine Bed shapes, then the cutting of small surplus is carried out with numerical control milling, or directly uses grinder buffing, makes the size of each part of mold In place.
In the specific implementation, it in step 1), pours the die matrix requirement to be welded outpoured and directly processes conformal cooling water Road.
In above-mentioned steps 2) built-up welding before, need to treat welding mould carry out built-up welding strengthen pre-treatment, comprising:
1. die surface cleaning treatment removes sand, oxide skin, greasy dirt, iron rust, burr and casting flaw;
2. whole preheated mold is to 450 DEG C.
3. the die surface to built-up welding is exposed thermal insulation material coating mould.Process temperature >=300 DEG C.
In the weld deposit process of step 2) and step 3), need:
1. using automatic CO2, Ar mixed gas (protective gas ratio: Ar80%, C0220%) double-layer metal resurfacing welding is protected Technique carries out built-up welding of transition zone b, welding wire feed speed along working surface on mold face to be fortified using Miller welding wire machine Degree is 7m/min, welding current 400A, weldingvoltage 36V.The layer is welded to 5mm under type chamber contour line.
2. strengthening process point multilayer carries out.Heap is burn-on after one layer of alloy material, and the oxide skin and weldering of overlay surface are removed Slag.
3. secondary built-up welding: the then special high-temperature alloy material a of built-up welding on a welding layer after removing surface.Welding Wire feed rate is 7m/min, welding current 400A, weldingvoltage 36V.Thickness degree 7mm.
4. the finally oxide skin and welding slag of removal overlay surface.
In entire welding process, mold temperature is lower than 300 DEG C, it is necessary to which shove charge preheats again.Weld ddge hammer in side firmly strikes It hits.Wherein, each overlay cladding structure is as shown in Figures 3 and 4, and in figure, a is that built-up welding is strengthened layer by layer, and b is built-up welding transition zone, and c is steel mould Have matrix (process conformal cooling channel), d is cooling water channel.
Above-mentioned steps 4) and step 5) be for completing post weld heat treatment, when specific implementation includes:
1. first time destressing is tempered: built-up welding, which finishes, to be carried out melting down heating at once, using equipment 13OKW well formula resistance furnace, Charging temperature≤450 DEG C, heating-up time 0.4h, 550 DEG C ± 20 DEG C of heating temperature, soaking time according to insert maximum geometry It calculates within size every 50 millimeters of heat preservations 1 hour, soaking time is it is ensured that mold preheats heat penetration.
2. first time slow cooling: after first time destressing tempering, insert being placed in heat preservation sand pit.Keep the temperature sand pit by The common river sand composition of grain average diameter 1mm, heat preservation sand pit temperature maintain 180 DEG C.Insert is buried completely with sand, is protected The warm time >=12h, insert is taken out into sand pit later.Temperature monitoring in the process is completed by infrared thermometer.
3. second of destressing is tempered: insert being taken out from heat preservation sand pit and enters second of destressing tempering, Process Planning Model such as first time destressing is tempered.
4. second of slow cooling: after insert completes second of destressing tempering, insert being placed in heat preservation sand pit and starts the Secondary slow cooling, technological specification such as first time slow cooling.
5. air-cooled: insert completes after second of slow cooling 180 DEG C of temperature, places in air after taking out in heat preservation sand pit It carries out being air-cooled to room temperature.Most of Transformation of Retained Austenite is martensite in die body at this time, and martensite is made to eliminate interior answer Power.At this point, surfacing part hardness is higher than die body hardness.
Through above-mentioned steps 4) and 5) after obtained die insert be finally machined again through step 6), it is final to be made Complete hot stamping forming die insert finished product (referring to Fig. 3,4).Its finished product die insert working surface hardness average out to 50HRC, flawless, the defects of being mingled with.Transition zone b is well combined with basis material, and mechanical performance index is quenched with cast steel substrate Compared to a little better after processing, transition connection function is played, while strengthening matrix mold.Strengthening layer a strong hardness is than transition zone b Improve very much, elongation percentage, shrinking percentage, impact flexibility and high-temperature behavior are good, and playing improves mold working surface competency, tough The purpose of property.It is comprehensive to improve hot stamping forming die by the collaboration compatibility effect of each gradient function layer, improve its workspace The performances such as domain intensity, toughness, it can instead the hot stamping forming die produced through solid forging.
In this hot stamping forming die actual experiment, die manufacturing cost can reduce 50% or more, save high-performance material Material;Die life is improved, reduces mold changing number, reduces downtime;The labor intensity of worker is also mitigated simultaneously, Greatly improve utilization rate of equipment and installations.
Because the place that the present invention makes creative contribution for the prior art is most importantly the sheet for being method and step Body, therefore in a specific embodiment, many data or numerical value are the optimal values announced, and there is no with regard to each specific numerical value Range is enumerated different numerical value and is illustrated.As long as should be regarded as these numerical value belongs to numerical value described in description of the invention Range, it will be able to implement the present invention and realize goal of the invention, only be merely that implementation result may be more relatively poor.

Claims (9)

1. a kind of method for preparing ultra-high strength steel hot stamping forming die, comprising the following steps:
(1), it is poured using cast steel as die matrix material and outpours die matrix (c) to be welded, die matrix (c) casts out or adds Work goes out conformal cooling channel (d), reserves built-up welding surplus thickness;
(2), on die matrix (c) to be welded along reserved built-up welding surplus the first high intensity and toughness of a built-up welding heat conduction efficiency Slightly good transition zone (b) is welded to mold working surface with a thickness of 4~6mm;
(3), the secondary built-up welding strengthening layer (a) on transition zone (b), the thickness of the strengthening layer (a) is within 4mm;
(4), the mold after secondary built-up welding is repeated into retarded cooling process after double tempering, wherein tempering temperature is 530 DEG C ~570 DEG C, slow cooling temperature is to 180 DEG C;
(5), the mold after second of slow cooling is placed in air and carries out being air-cooled to room temperature;
(6), the mold after air-cooled is machined, makes mold portions size in place.
2. a kind of method for preparing ultra-high strength steel hot stamping forming die according to claim 1, it is characterised in that: institute It states and reserves 7~12mm built-up welding surplus thickness in step (1);Quench simultaneously at 920 DEG C to the die matrix (c) to be welded outpoured is poured In the processing that 650 DEG C are tempered, and oil is cooled to room temperature.
3. a kind of method for preparing ultra-high strength steel hot stamping forming die according to claim 1, it is characterised in that: institute It states in step (2) transition zone (b) that built-up welding heat conduction efficiency is high, intensity and toughness are slightly good and selects Cu alloy material.
4. a kind of method for preparing ultra-high strength steel hot stamping forming die according to claim 1, it is characterised in that: institute It states step (2) and (3) built-up welding front mold is preheated to 450~500 DEG C, mold temperature is maintained at 300 DEG C or more in weld deposit process.
5. a kind of method for preparing ultra-high strength steel hot stamping forming die according to claim 1, it is characterised in that: institute It states step (2) and (3) the butt welding die matrix (c) before built-up welding and carries out surface cleaning processing, heap is removed after the completion of secondary built-up welding The oxide skin and welding slag on layer surface.
6. a kind of method for preparing ultra-high strength steel hot stamping forming die according to claim 1, it is characterised in that: institute It states step (2) and (3) and taps die matrix (c) by phased manner in weld deposit process and enable its vibration.
7. a kind of method for preparing ultra-high strength steel hot stamping forming die according to claim 6, it is characterised in that: Die matrix (c) is tapped in weld deposit process by phased manner and enables its vibration, vibration frequency is 20~40 beats/min.
8. a kind of method for preparing ultra-high strength steel hot stamping forming die according to claim 1, it is characterised in that: will Mold after secondary built-up welding repeats retarded cooling process after double tempering, and wherein tempering temperature is 530 DEG C~570 DEG C, delays Mold after second of slow cooling is placed in air to 180 DEG C and carries out being air-cooled to room temperature by cold temperature.
9. a kind of method for preparing ultra-high strength steel hot stamping forming die according to claim 1, it is characterised in that: institute CO need to be led to when stating step (2) and (3) built-up welding2, Ar mixed gas protected, the gas ratio are as follows: Ar80%~90%, CO210%~20%;When welding welding wire feeding speed be 5~8m/min, 360~440A of welding current, weldingvoltage 35~ 36V。
CN201811478343.3A 2018-12-05 2018-12-05 A method of preparing ultra-high strength steel hot stamping forming die Pending CN109570368A (en)

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