CN107999760A

CN107999760A - A kind of method that diffusion-sintering prepares Fe-6.5%Si bands with powder hotforging

Info

Publication number: CN107999760A
Application number: CN201711367253.2A
Authority: CN
Inventors: 丁艺; 罗丰华; 朱警; 王柏钧; 贾吉祥; 周海铭
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2017-12-18
Filing date: 2017-12-18
Publication date: 2018-05-08

Abstract

A kind of method that diffusion-sintering prepares Fe 6.5%Si bands with powder hotforging, chooses reduction Fe powder and water atomization Fe powder, according to 4:6~6:4 ratio mixing, then HIGH-PURITY SILICON iron powder and bonding agent that Si contents are 50~70% are added, form Fe Si mixed powders.Squarely base is molded, 940~1010 DEG C is heated to and realizes Fe phase austenitizings, final forging temperature is 840~910 DEG C after repeatedly forging so that pressed compact is close complete fine and close；Powder hotforging base is carried out to vacuum or protection of reducing atmosphere sintering at 1020~1120 DEG C; after multiple cold rolling, low-temperature sintering, finally sintered in 1200~1300 DEG C of High temperature diffusions, realize homogeneous alloy; it is thick to obtain 0.1~0.5mm containing 4.5~6.7%Si, density >=7.40g/cm³High silicon steel band.

Description

A kind of method that diffusion-sintering prepares Fe-6.5%Si bands with powder hotforging

Technical field

The present invention principally falls into preparation and the manufacture field of metal material, and in particular to the powder hotforging of high silicon steel thin belt material With the method for rolling deformation.

Technical background

Remanent magnetism and coercive force all very littles of soft magnetic material, i.e. hysteresis curve is very narrow, it and fundamental magnetization curve are almost Overlap, be mainly used for the iron core of inductance coil, transformer, relay and motor.Fe-Si alloys maximum permeability is sent out with Si contents Changing, respectively Si mass percent it is (the same below) for 2% and 6.5% nearby there is the peak of two maximum permeabilities Value, respectively reaches 10000 and 25000.The maximum permeability of Fe-Si alloys does not have absolute predominance, such as slope in soft magnetic materials The maximum permeability of alloy can not reach 200000.But the Fe-Si lattens of Si ＜ 4.5% manufacture cost is low, therefore Silicon steel sheet is also known as electrical sheet or silicon steel thin slice, is a kind of very important magnetic material.

And Si>When 4.5%, below 540 DEG C of temperature B can occur for Fe-Si alloys₂The eutectoid decomposition reaction of ordered phase, it is raw Into the unordered phases of α-Fe and DO₃Ordered phase so that alloy becomes fragile and is difficult to deform.

For iron Si system alloy of the Si contents between 4.5~6.7%, commonly referred to as high silicon steel, wherein silicone content 6.5% High silicon steel it is mostly important.Its reason is Fe-Si alloy grains edge<100>The magnetostriction coefficient in direction is with the increase of Si contents And reduce, disappear substantially at about 6.3%, and<111>The magnetostriction coefficient in direction increases and increases with Si contents, about When 6.1% with<100>The magnetostriction coefficient in direction is equal so that high silicon steel shows excellent low in higher frequency operation Iron loss characteristic.

The transformer of normal operation can occur continuous uniform " drone " sound, this is because alternating current by transformer around Group when, in the core between generate periodically variable alternating flux, cause iron core magnetostriction and shake the sound sent.Greatly The sound that amount or large-scale iron core are sent in vibrations not only causes the loss of energy, also creates noise pollution.Especially It is to play particularly important role in the military aviation such as spacecraft, submarine and guided missile field, Fe-Si systems alloy.20th century 60 Age Mo, the alloy of Si contents 6.5% are appeared on No. 11 airships of Apollo as transformer material, are completed the mankind and are landed on the moon first Heroic undertaking.As it can be seen that high silicon steel is the environment-friendly type soft magnetic materials of a kind of consumption reduction of function admirable, noise reduction.

Compared to other alloys, the research and development process of high silicon steel is relatively very long.Late 1920s A.Schulze studies discovery first, and the iron Si system alloy of silicone content 6.5% has the almost nil characteristic of magnetostriction coefficient. In the 1980s, professor K.I.Arail etc. has found the high silicon steel alloy low compared to traditional Si content in exchange dynamic magnetic field In there is the magnetic conductivity of lower iron loss and higher.Hereafter between many decades, in order to overcome the brittleness of high silicon steel, in technology of preparing side There are many trials in face.As the special rolled method of jacket or temperature control, rapid solidification method, chemical vapour deposition technique (CVD method), Plasma chemical vapor deposition (PCVD methods), hot dipping ooze a diffusion annealing method, powder metallurgic method, microalloying and are modified Etc. various methods.

Wherein CVD is the successful example of comparison.NKK companies of Japan in 1988 have produced thickness for the first time using CVD technology It is the No yield point 6.5%Si steel discs of 400mm to spend for 0.1~0.5mm, width.Phase early 1990s, global first commercialization Can realize that the CVD production lines of continuous siliconising are developed, the product size of production can reach 0.1~0.3mm × 600mm。

The principle of CVD is：Under specific temperature conditions, silicon-containing gas (SiCl₄) can react generation Fe- with silicon strip Si compounds, and alloy is reached required content to alloy diffusion inside by elevated furnace temperature.Although oneself uses this Technology realizes small-scale industrialized production, but its scale and yield all can not much meet the need in international soft magnetic materials market Ask, and this preparation method technical process is sufficiently complex, energy consumption and of high cost, operating environment and its severe, it is impossible to meet ring Guaranteed request.

High silicon steel is " the steel art work ", its technology of preparing is all always and everywhere state-of-the-art steel and iron manufacturing technology, and It is the hot spot of development and exploitation.For 6.5%Si high silicon steel, its excellent magnetic performance and wide application prospect are even more to inhale Draw scientific worker and carry out substantial amounts of research-and-development activity.The development of preparation process and ripe and can be cost-effectively Production, is that 6.5%Si high silicon steel move towards to be commercialized widely applied key, also the always emphasis of research work.Once grope Go out simple, economic, effective, ripe preparation process, will just produce huge economic benefit and social benefit.

The content of the invention

The method for preparing high silicon steel band is sintered the object of the present invention is to provide a kind of powder hotforging and High temperature diffusion, for Fe-4.5~6.7%Si alloy thin band materials are difficult to the problem of shaping, using technical pure Fe powder and Si contents as 50~70% it is high-purity Ferrosilicon powder is raw material, is molded into hot forging green compact after adding binder, then prepare certain thickness plate using powder hotforging method Base, is acted on using the large deformation of powder hotforging and causes green density raising, structure refinement, and realizes part under thermal diffusion effect Alloying, forms the α-Fe crystal grain of poor Si and the heterogeneous structure of the high Si phases of brittleness with plastic deformation ability.Follow-up warp is excessive Thin plate is obtained after passage cold rolling-sintering, is finally sintered using High temperature diffusion and obtains the high silicon steel band of homogeneous single phase.

The present invention is achieved by the following technical solutions：Reduction Fe powder and two kinds of Industrial iron powders of water atomization Fe powder are chosen, According to 4:6~6:4 ratio mixing, forms technical pure Fe powder basic materials, then it is 50~70% to add fine Si contents HIGH-PURITY SILICON iron powder is raw material, forms Fe-4.5~6.7%Si mixed powders.Will be fine by suitable bonding agent, dispersant HIGH-PURITY SILICON iron powder is adhered in mixed process in Fe powder surface or hole.Since technical pure Fe powder is with the thick of high-compressibility Bulky grain, occupies larger volume ratio in mixed powder, its plastic deformation ability, Ke Yitong are not significantly reduced after adding ferrosilicon powder Cross molding squarely base.It is heated to 940~1010 DEG C and realizes Fe phase austenitizings, then places into closed mould hot forging, it is more Final forging temperature is 840~910 DEG C after secondary forging so that pressed compact is about 6.91~7.23g/cm close to full densification³.Then by powder Last hot forging base carries out vacuum or protection of reducing atmosphere sintering in 1020~1120 DEG C of temperature ranges, makes Fe powder particles metallurgical bindings, And ferrosilicon powder particles realized with Fe it is partially-alloyed, formed densification, with the α-Fe crystal grain of the poor Si of plastic deformation ability and crisp The high silicon steel blank of heterogeneous structure of the high Si phases of property.Sintered subsequently through multiple cold rolling, low temperature diffusion, the density rise of slab, plate Thickness is reduced, and the alloying level of Si is also continuously improved.Finally vacuum or reducing atmosphere in 1200~1300 DEG C of temperature ranges Protection sintering, realizes the homogeneous alloy of high silicon steel with the help of thermal diffusion, obtain containing 4.5~6.7%Si 0.1~ 0.5mm is thick, density >=7.40g/cm³High silicon steel band.

The method of the present invention specifically comprises the following steps：

(1) raw material powder prepares

Using -100 mesh reduced iron powders, Fe >=98.5% in Fe powder is reduced, remaining is Si, Mn, P, S and other are inevitable Impurity, using -100 mesh water-atomized iron powders, Fe >=99.0% in water atomization Fe powder, remaining for Si, Mn, P, S and other can not The impurity avoided, by reduction Fe powder and water atomization Fe powder according to 4:6~6:4 ratio is prepared, and is mixed using conical mixer, V-arrangement Material machine or drum mixer are mixed to form technical pure Fe powder basic materials, and incorporation time is 2~6h.

The Si contents of refining are used, with high-energy ball milling, to rush the methods of rotation method for 50~70% HIGH-PURITY SILICON iron powder and obtain grain The ferrosilicon powder of footpath≤6 μm, this ferrosilicon powder in addition to containing 50~70%Si, major impurity is~0.24%Al ,~ 0.07%Ca ,~0.02%C, remaining is Fe.

Reduced iron powder is a kind of widely used Industrial iron powder, has irregular porous pattern, micro- beneficial to storing, adhering to Fine silica powder, and in follow-up powder extrusion process also being mutually twisted for powder easy to implement and improve the intensity of pressed compact, be conducive to The stabilization of powder extrusion process.Water atomization Fe powder is also a kind of widely used Industrial iron powder, has subsphaeroidal pattern, and impurity contains Amount is less than reduction Fe powder, compressibility and mobility with higher, is conducive to the uniform flow of powder extrusion process course powder Dynamic, low impurity content is favourable to the soft magnetic characteristic of high silicon steel in water atomization Fe powder.Will two kinds of reduction Fe powder and water atomization Fe powder Industrial iron powder, according to 4:6~6:4 ratio mixing, forms technical pure Fe powder basic materials, and it is each to be conducive to two kinds of straight iron powders of performance From advantage, be also relatively common method in industrial production iron-base part.

Fe-50~70%Si high purity ferrosilicons in process of setting there are two eutectic reactions, when rich Si sides are at 1207 DEG C Form the β-FeSi with tP3 structures₂With Si phase eutectic structures, form when rich Fe sides are at 1212 DEG C and tied with tP3 β-the FeSi of structure₂With the FeSi eutectic structures of cP8 structures；At 982 DEG C and 937 DEG C, also there are β-FeSi₂Decomposition and oC48- FeSi₂Two solid-state phase changes processes of formation of phase.Therefore it is easy in process of setting of the Fe-50~70%Si after refining crisp Change, form trickle Fe-Si or Si heterogeneous structures, it is easy to refine by Mechanical Crushing technique.Fe-50~70%Si is high-purity Ferrosilicon is crushed to≤6 μm of ferrosilicon powder, the Si phases in its actual tissue, FeSi₂, FeSi phases it is more tiny, be conducive to subsequent high temperature The thermal diffusion homogenization of Si elements, forms homogeneous Fe-6.5%Si single-phase alloys during sintering.Meanwhile exist in high purity ferrosilicon powder 30~50%Fe can effectively reduce the degree of oxidation of Si, be conducive to improve the product quality of high silicon steel.

By Fe-50~70%Si high purity ferrosilicons Mechanical Crushing to particle diameter≤6 μm, be conducive to it and be adhered to technical pure Fe powder Surface is filled in the hole of technical pure Fe powder, tiny Si, FeSi₂, FeSi phases Dispersed precipitate in blank, play tissue The Strengthening and Toughening effect of refinement, is conducive to improve follow-up blank toughness, cracking is not easily caused in densification process is rolled.But Still contain a small amount of Si phases in Fe-50~70%Si high purity ferrosilicons, Si is easily absorbing oxygen, and SiO is formed in exposed Si phase surfaces₂ Film, therefore in the preparation, storage and transfer process of Fe-50~70%Si HIGH-PURITY SILICON iron powders, and follow-up batch mixing, hot forging, Inert gas shielding should be used in the operation of rolling, used instrument must also take dehydration, drying process in advance.

On the premise of oxygen content is controlled, influence of the impurity such as other Al, Ca, Mn to alloy magnetic property is little, during The possibility for introducing other alloying elements is also little.

(2) powder mixes

According to the ratio of Fe-4.5~6.7%Si, Fe powder and Fe-50~70%Si HIGH-PURITY SILICON iron powders are weighed；Protected in inertia Protect under atmosphere and mixed using low energy mixer, mixing velocity and time, the mitigation Fe powder that should try one's best existed depending on mixing uniformity Processing hardening occurs in mixed process.

(3) powder hotforging

Square pressed compact is prepared using compression-moulding methods, the green density of acquisition is 6.59~6.76g/cm³；Before hot forging Molding square billet is heated to 940~1010 DEG C under nitrogen protective effect, keeps the temperature 2~4h, the hot forging densification in square dies, Repeatedly final forging temperature is 840~910 DEG C after forging, and pressed compact is close complete fine and close, and density reaches 6.91~7.23g/cm³。

Under impact force action, hot forging pressed compact is close complete fine and close.Make the plasticity of plate after hot forging in order to avoid alloying Decline, relatively low heating-up temperature is have selected before hot forging.Fe phase and complexity FeSi phase composition of the alloy structure for high-ductility after hot forging Complex tissue, which possesses the high-ductility characteristic of simple substance Fe.

(4) cold rolling-sintering

By above-mentioned hot forged plate cold rolling-sintering, progressively it is thinned.

Single pass rolling reduction≤8%, after multi- pass rolling reaches 30~50% to total reduction, then in sintering furnace in 1020~1120 DEG C of 0.5~2h of heat preservation sintering, after multiple cold rolling-sintering, the thickness of plate reaches 0.1~0.5mm, with Si's Alloying is gradually completing, and strip density improves, and reaches 7.39~7.53g/cm³。

There are a large amount of deformable Fe phases in blank, slab can bear cold-rolling deformation.But there is also more in slab High Si phases, its performance is more crisp, therefore amount cannot be too high under every time rolling, and accumulation total reduction reaches 30~50%, takes around 8 ~25 passages.

Since existing hard crisp phase, cold deformation process can form some micro-cracks.In order to realize the closing of pores and crackle Repair, and the homogenization diffusion of a degree of Si elements.Cold rolling reduction accumulation needs to sinter 1 again to a certain extent afterwards It is secondary, 0.1~0.5mm is rolled down to from 36~54mm hot forging plates, takes around and sinters 12~20 times again.

Sintering temperature is too low, is unfavorable for metallurgical binding and the Si element thermal diffusions of Fe powder particles；And sintering temperature is excessive then Si elements can be caused quickly to spread, cause crystal grain excessive high hardness, embrittlement, follow-up rolling deformation is difficult to realize.

Take reproducibility, inert gas shielding or vacuum-sintering.W, Mo, heat resisting steel etc. can be used during sintering as support Plate (or burning boat), can also use the ceramic wafers such as corundum, zirconium oxide, but metallic plate thermal conductivity is good, and be beneficial to Even Sintering.

The texture of coarse crystal containing the second phase is formed after sintering.X-ray diffraction Discriminating materials are heterogeneous Fe (Si) Phase, body-centred cubic several characteristic peaks have obvious separating phenomenon, illustrate there are 2 kinds of different Fe phases of Si solid solubility, wherein must There are the Si contents in a kind of Fe phases low, there is plastic deformation ability.

(5) full alloying high temperature sintering

Vacuum or restitutive protection 1~4h of atmosphere sintering in 1200~1300 DEG C of temperature ranges, in the effect of thermal diffusion Under, to realize the full alloyings of Si, form single-phase alloy, obtain the high silicon steel of homogeneous, the thickness of plate is almost unchanged after densification sintering, For 0.1~0.5mm, density reaches 7.40~7.54g/cm³。

The HIGH-PURITY SILICON iron powder of particle diameter≤6 μm is by high-energy ball milling or rushes the acquisition of rotation method.

The low energy mixer is conical mixer, V-arrangement batch mixer or drum mixer.

The square pressed compact prepared in step (3), length and width are respectively 100~300mm, are highly 40~60mm, using table The pressure that surface pressure is 400~600MPa is suppressed.The thickness of blank is 36~54mm after hot forging, and three point bending test shows to mould Property, bending strength reaches 142~248MPa.

Step (2) adds cellulose, paraffin micro mist when mixing or zinc stearate is water-insoluble adds as binder, binder Dosage total amount is no more than the 0.8% of mixed-powder gross mass, while adds grease and absolute ethyl alcohol does passivator, plays passivation Si Powder, bonding Fe-Si powder, the effect for strengthening powder flowbility and compact strength, the additive amount total amount of passivator are no more than mixed powder The 2% of last gross mass.

Support plate described in step (4) uses molybdenum plate, W plates, heat resisting steel, corundum or zirconia ceramics plate.

During high temperature sintering described in step (6), overlapping places sintering plate, and interlayer is laid with MgO powder, and plate tiling is placed, Tablet weight is placed on plate, prevents from deforming in sintering process.

In addition to Si contents, content of element such as grain size, crystal grain orientation, C etc. also has the magnetic behavior of high silicon steel Large effect, can subsequently be annealed, the technological means such as normalizing treatment is controlled by by wet hydrogen.

Essence of the invention is by with the addition of certain body in the technical pure Fe powder of the big volumetric portion with good plasticity Fine Fe-50~70%Si HIGH-PURITY SILICONs iron powder of product ratio, forms Fe-4.5~6.7%Si alloys basis powder.Using powder Hot forging obtains high green density into slab.Since hot forging is organized as incomplete alloying tissue, except small part is rich in tissue Outside Si phases, main constituent is yielding Fe phases, therefore subsequently can improve even tissue by multi-pass cold rolling and sintering Property and compactness, then high-temperature diffusion process, realize the homogenization of Si, so as to obtain the single-phase high silicon steel band of high quality.The party Method realizes Technics Process Automation, continuous production by technique and equipment Design, and can be mass-produced 0.1~0.5mm thickness, Density >=7.40g/cm³High silicon steel band.

Brief description of the drawings

Fig. 1 be the embodiment of the present invention 1 powder hotforging after blank three-point bending curve map；

Fig. 2 is metallographic structure figure after powder hotforging-cold rolling-sintering of the embodiment of the present invention 2；

Fig. 3 is XRD diffraction curve figures after powder hotforging-cold rolling-sintering of the embodiment of the present invention 2；

Fig. 4 is XRD diffraction curve figures after powder hotforging-cold rolling-high temperature sintering of the embodiment of the present invention 4.

Embodiment

The present invention is described in further detail with reference to the accompanying drawings and detailed description.

Embodiment 1

By the water atomization Fe powder of the reduction Fe powder of -100 mesh and -100 mesh according to 4:6 ratio is prepared, and is mixed using drum-type Material machine is mixed to form technical pure Fe powder raw materials, incorporation time 2h, is added in mixed process according to 200ml/ tons of ratio anhydrous Ethanol.

By well pre-mixed technical pure Fe powder and the Fe-70%Si high-purity powders of granularity≤6 μm according to 90.43:9.57 Ratio mixes, and forms the mixed-powder of Fe-6.7%Si.The paraffin micro mist of raw material total amount 0.6%, 0.1% machine are added during mixing Oil.Absolute ethyl alcohol is added according to 200ml/ tons of amount.Using V-arrangement batch mixer by above-mentioned powder mixing 4h.

Square pressed compact is prepared using compression-moulding methods, and pressed compact size is 100 × 100 × 40mm, surface pressing 600MPa, green density 6.59g/cm³。

Molding square billet is heated to 940 DEG C under nitrogen protective effect, keeps the temperature 4h.Using power forging machine, in square dies Middle hot forging densification, repeatedly final forging temperature is 840 DEG C after forging, and the thickness of blank is about 36mm, and density reaches 6.91g/cm³。 Three point bending test shows plasticity, sees Fig. 1, and bending strength reaches 148MPa.

By above-mentioned hot forged plate cold rolling-sintering, progressively it is thinned.Specifically pressure-annealing schedule is：36mm→24mm→17mm→ 12mm → 9.5mm → 7.2mm → 5mm → 3.5mm → 2.4mm → 1.6mm → 1.02mm → 1.02mm → 0.71mm → 0.49mm, Sintered through 13 cold rollings and 12 times.

Multi-pass cold rolling is thick in 1020 DEG C of heat preservation sintering 2h, plate to after 30~50%, then in vacuum sintering furnace Degree is thinned to 0.49mm, and density reaches 7.39g/cm³。

1h is sintered in 1300 DEG C of Temperature Vacuums, realizes the full alloyings of Si, forms single-phase alloy, thickness 0.5mm, density reaches 7.40g/cm³, Si contents are 6.7%.

Embodiment 2

By the water atomization Fe powder of the reduction Fe powder of -100 mesh and -100 mesh according to 5:6 ratio is prepared, and is mixed using drum-type Material machine is mixed to form technical pure Fe powder raw materials, incorporation time 3h, is added in mixed process according to 400ml/ tons of ratio anhydrous Ethanol.

By well pre-mixed technical pure Fe powder and the Fe-50%Si high-purity powders of granularity≤10 μm according to 91:9 ratio is mixed Close, form the mixed-powder of Fe-4.5%Si.The zinc stearate of raw material total amount 0.7%, 0.1% machine oil are added during mixing.Nothing Water-ethanol is added according to 400ml/ tons of amount.Using drum mixer by above-mentioned powder mixing 6h.

Square pressed compact is prepared using compression-moulding methods, and pressed compact size is 300 × 300 × 60mm, surface pressing 600MPa, green density 6.76g/cm³。

Molding square billet is heated to 1010 DEG C under nitrogen protective effect, keeps the temperature 2h.Using power forging machine, in square dies Middle hot forging densification, repeatedly final forging temperature is 910 DEG C after forging, and the thickness of blank is about 54mm, and density reaches 7.23g/cm³。 Three point bending test shows plasticity, and bending strength reaches 248MPa.

By above-mentioned hot forged plate cold rolling-sintering, progressively it is thinned.Specifically pressure-annealing schedule is：54mm→36mm→36mm→ 24mm→17mm→12mm→9.5mm→7.2mm→5mm→3.5mm→2.4mm→1.6mm→1.02mm→1.02mm→ 0.71mm → 0.49mm → 0.39mm → 0.25mm → 0.17mm → 0.13mm → 0.10mm, i.e., burn through 20 cold rollings and 19 times Knot.

Multi-pass cold rolling is to after 30~50% total reductions, then is burnt in hydrogen shield sintering furnace in 1120 DEG C of insulations 0.5h is tied, sheet metal thickness is thinned to 0.10mm, and density reaches 7.53g/cm³。

The texture of coarse crystal containing the second phase is formed after sintering, sees Fig. 2.X-ray diffraction Discriminating materials are heterogeneous Fe (Si) phase, as seen in Figure 3, body-centred cubic several characteristic peaks have obvious separating phenomenon, illustrate there are Si solid solubility it is different 2 Kind Fe phases, wherein must have the Si contents in a kind of Fe phases low, have plastic deformation ability.

4h is sintered in 1200 DEG C of Temperature Vacuums, realizes the full alloyings of Si, forms single-phase alloy, thickness 0.1mm, density reaches 7.54g/cm³, Si contents are 4.5%.

Embodiment 3

By the water atomization Fe powder of the reduction Fe powder of -100 mesh and -100 mesh according to 6:4 ratio is prepared, and is mixed using drum-type Material machine is mixed to form technical pure Fe powder raw materials, incorporation time 4h, is added in mixed process according to 500ml/ tons of ratio anhydrous Ethanol.

By well pre-mixed technical pure Fe powder and the Fe-60%Si high-purity powders of granularity≤6 μm according to 89.17:10.83 Ratio mixes, and forms the mixed-powder of Fe-6.5%Si.The paraffin micro mist of raw material total amount 0.4%, 0.2% first are added during mixing Base cellulose, 0.1% machine oil.Absolute ethyl alcohol is added according to 400ml/ tons of amount.Using drum mixer by above-mentioned powder Mix 6h.

Square pressed compact is prepared using compression-moulding methods, and pressed compact size is 200 × 200 × 50mm, surface pressing 500MPa, green density 6.63g/cm³。

Molding square billet is heated to 980 DEG C under nitrogen protective effect, keeps the temperature 2h.Using power forging machine, in square dies Middle hot forging densification, repeatedly final forging temperature is 880 DEG C after forging, and the thickness of blank is about 46mm, and density reaches 6.94g/cm³。 Three point bending test shows plasticity, and bending strength reaches 160MPa.

By above-mentioned hot forged plate cold rolling-sintering, progressively it is thinned.Specifically pressure-annealing schedule is：46mm→36mm→24mm→ 17mm→12mm→9.5mm→7.2mm→5mm→3.5mm→2.4mm→1.6mm→1.02mm→1.02mm→0.71mm→ 0.49mm → 0.39mm → 0.27mm, i.e., sinter through 16 cold rollings and 15 times.

Multi-pass cold rolling is to after 30~50% total deformations, then is burnt in nitrogen protective sintering stove in 1100 DEG C of insulations 1h is tied, sheet metal thickness is thinned to 0.27mm, and density reaches 7.40g/cm³。

2h is sintered in 1280 DEG C of Temperature Vacuums, realizes the full alloyings of Si, forms single-phase alloy, thickness 0.27mm, density reaches To 7.41g/cm³, Si contents are 6.5%,

Embodiment 4

By the water atomization Fe powder of the reduction Fe powder of -100 mesh and -100 mesh according to 5:5 ratio is prepared, and is mixed using drum-type Material machine is mixed to form technical pure Fe powder raw materials, incorporation time 6h, is added in mixed process according to 500ml/ tons of ratio anhydrous Ethanol.

By well pre-mixed technical pure Fe powder and the Fe-62%Si high-purity powders of granularity≤10 μm according to 90.64:9.36 Ratio mixes, and forms the mixed-powder of Fe-5.8%Si.The paraffin micro mist of raw material total amount 0.6%, 0.2% machine are added during mixing Oil.Absolute ethyl alcohol is added according to 400ml/ tons of amount.Using drum mixer by above-mentioned powder mixing 3h.

Square pressed compact is prepared using compression-moulding methods, and pressed compact size is 220 × 220 × 55mm, surface pressing 450MPa, green density 6.69g/cm³。

Molding square billet is heated to 990 DEG C under nitrogen protective effect, keeps the temperature 2h.Using power forging machine, in square dies Middle hot forging densification, repeatedly final forging temperature is 890 DEG C after forging, and the thickness of blank is about 52mm, and density reaches 6.99g/cm³。 Three point bending test shows plasticity, and bending strength reaches 180MPa.

By above-mentioned hot forged plate cold rolling-sintering, progressively it is thinned.Specifically pressure-annealing schedule is：52mm→39mm→26mm→ 18mm→13mm→10.5mm→8.2mm→5mm→3.2mm→2.4mm→2.0mm→1.3mm→0.90mm→0.63→ 0.43mm→0.32mm→0.21mm.Sintered through 17 cold rollings and 16 times.

Multi-pass cold rolling is to after 30~50% total deformations, then is burnt in hydrogen shield sintering furnace in 1080 DEG C of insulations 1h is tied, sheet metal thickness is thinned to 0.21mm, and density reaches 7.42g/cm³。

2h is sintered in 1260 DEG C of Temperature Vacuums, realizes the full alloyings of Si, forms single-phase alloy, thickness 0.21mm, density reaches To 7.43g/cm³, Si contents are 5.8%, and the XRD analysis figure of its final plate is shown in Fig. 4, is the high silicon steel of single-phase homogeneous.

Claims

1. a kind of method that powder hotforging prepares high silicon steel band with High temperature diffusion sintering, it is characterised in that include the following steps：

(1) raw material powder prepares

Using -100 mesh reduced iron powders, Fe >=98.5% in Fe powder is reduced, remaining is Si, Mn, P, S and other are inevitably miscellaneous Matter, using -100 mesh water-atomized iron powders, Fe >=99.0% in water atomization Fe powder, remaining is Si, Mn, P, S and other are inevitable Impurity, will reduction Fe powder and water atomization Fe powder according to 4:6~6:4 ratio is prepared, using conical mixer, V-arrangement batch mixer Or drum mixer is mixed to form technical pure Fe powder basic materials, incorporation time is 2~6h；

Si contents are used as 50~70% HIGH-PURITY SILICON iron powder, particle diameter≤6 μm, major impurity is~0.24%Al ,~0.07% Ca ,~0.02%C, remaining is Fe；

(2) powder mixes

According to the ratio of Fe-4.5~6.7%Si, Fe powder and Fe-50~70%Si HIGH-PURITY SILICON iron powders are weighed；Gas is protected in inertia Mixed under atmosphere using low energy mixer；

(3) powder hotforging

Square pressed compact is prepared using compression-moulding methods, green density is 6.59~6.76g/cm³；Square billet will be molded before hot forging 940~1010 DEG C are heated under nitrogen protective effect, keeps the temperature 2~4h, repeatedly final forging temperature is 840~910 DEG C after forging, pressure Base reaches 6.91~7.23g/cm close to full densification, density³；

(4) cold rolling-sintering

By above-mentioned hot forged plate cold rolling-sintering, progressively it is thinned, single pass rolling reduction≤8%, is reached through multi- pass rolling to total reduction To after 30~50%, then in sintering furnace after 1020~1120 DEG C of 0.5~2h of heat preservation sintering, multiple cold rolling-sintering, plate Thickness reaches 0.1~0.5mm, and after the completion of Si alloyings, strip density brings up to 7.39~7.53g/cm³；

(5) full alloying high temperature sintering

Vacuum or restitutive protection 1~4h of atmosphere sintering in 1200~1300 DEG C of temperature ranges, it is real under the action of thermal diffusion The existing full alloyings of Si, form single-phase alloy, obtain the high silicon steel of homogeneous, and the thickness of plate is 0.1~0.5mm after densification sintering, Density brings up to 7.40~7.54g/cm³。

2. the method that diffusion-sintering as claimed in claim 1 prepares Fe-6.5%Si bands with powder hotforging, it is characterised in that： Mixing iron powder per ton adds 200~500ml absolute ethyl alcohols in step (1) mixed process.

3. the method that diffusion-sintering as claimed in claim 1 prepares Fe-6.5%Si bands with powder hotforging, it is characterised in that： The ferrosilicon powder of particle diameter≤6 μm is by high-energy ball milling or rushes the acquisition of rotation method.

4. the method that diffusion-sintering as claimed in claim 1 prepares Fe-6.5%Si bands with powder hotforging, it is characterised in that The low energy mixer is conical mixer, V-arrangement batch mixer or drum mixer.

5. the method that diffusion-sintering as claimed in claim 1 prepares Fe-6.5%Si bands with powder hotforging, it is characterised in that： The square pressed compact prepared in step (3), length and width are respectively 100~300mm, are highly 40~60mm, use surface pressing for The pressure compacting of 400~600MPa；The thickness of blank is 36~54mm after hot forging, and three point bending test shows plasticity, bending Intensity reaches 142~248MPa.

6. the method that diffusion-sintering as claimed in claim 1 prepares Fe-6.5%Si bands with powder hotforging, it is characterised in that： Add cellulose, paraffin micro mist or zinc stearate water-insoluble binder during mixing, the additive amount total amount of binder is no more than mixing The 0.8% of powder gross mass, while add grease and absolute ethyl alcohol does passivator, play passivation Si powder, bonding Fe-Si powder, enhancing The effect of powder flowbility and compact strength, the additive amount total amount of passivator are no more than the 2% of mixed-powder gross mass.

7. the method that diffusion-sintering as claimed in claim 1 prepares Fe-6.5%Si bands with powder hotforging, it is characterised in that： Support plate described in step (4) uses molybdenum plate, W plates, heat resisting steel, corundum or zirconia ceramics plate.

8. the method that diffusion-sintering as claimed in claim 1 prepares Fe-6.5%Si bands with powder hotforging, it is characterised in that： During high temperature sintering described in step (6), overlapping places sintering plate, and interlayer is laid with MgO powder, and plate tiling is placed, on plate Tablet weight is placed, prevents from deforming in sintering process.