CN108044098A

CN108044098A - A kind of method that powder hotforging prepares high silicon steel thin belt material

Info

Publication number: CN108044098A
Application number: CN201711368386.1A
Authority: CN
Inventors: 罗丰华; 伍中华; 张德敏; 贾吉祥; 高翔; 李益民
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2017-12-18
Filing date: 2017-12-18
Publication date: 2018-05-18

Abstract

A kind of method that powder hotforging prepares high silicon steel thin belt material, for the present invention using reduction Fe powder, the HIGH-PURITY SILICON iron powder that Si contents are 50~70% is raw material, forms Fe Si mixed powders.HIGH-PURITY SILICON iron powder is adhered in the hole of reduced iron powder surface or filling ferrous powder by bonding agent and dispersant; it is molded squarely base; it is heated to 1000~1070 DEG C of realization Fe phase austenitizings; final forging temperature is 900~970 DEG C after multiple hot forging; powder hotforging base is carried out to vacuum or protection of reducing atmosphere sintering at 1020~1120 DEG C; subsequently through multiple cold rolling, low-temperature sintering; finally it is 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 >=7.36g/cm³High silicon steel band.

Description

A kind of method that powder hotforging prepares high silicon steel thin belt material

Technical field

Preparation and manufacture field the invention belongs to metal material, and in particular to the powder hotforging of high silicon steel thin belt material and roll The method for making deformation.

Technical background

Remanent magnetism and coercive force all very littles of soft magnetic material, i.e. hysteresis loop is very narrow, it and fundamental magnetization curve are almost It overlaps, is 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.There is no absolute predominances, such as slope in soft magnetic materials for the maximum permeability of Fe-Si alloys The maximum permeability of alloy can not reach 200000.However the manufacture of the Fe-Si lattens of Si ＜ 4.5% is at low cost, 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 increases with Si contents And reduce, it disappears substantially at about 6.3%, and<111>The magnetostriction coefficient in direction increases with Si contents and is increased, 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 the iron core of amount or large size is sent in vibrations not only causes the loss of energy, also creates noise pollution.Especially It is in the military aviations such as spacecraft, submarine and guided missile field, Fe-Si systems alloy plays particularly important role.20th century 60 Age Mo, the alloy of Si contents 6.5% are appeared in as transformer material on No. 11 airships of Apollo, are completed the mankind and are landed on the moon for the first time 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 is for the first time the study found that 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 have lower iron loss and higher magnetic conductivity.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 spends for 0.1~0.5mm, width is the No yield point 6.5%Si steel discs of 400mm.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 to alloy diffusion inside alloy is finally made to reach required content by raised 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 It asks, 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 ", and 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, 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 generate huge economic benefit and social benefit.

The content of the invention

The object of the present invention is to provide a kind of method that powder hotforging prepares high silicon steel thin belt material, for Fe-4.5~ The problem of 6.7%Si alloy thin band materials are difficult to shape is former as 50~70% HIGH-PURITY SILICON iron powder to reduce Fe powder with Si contents Material is molded into hot forging green compact after adding binder, then prepares certain thickness slab using powder hotforging method, utilizes powder The large deformation of hot forging, which acts on, causes green density raising, structure refinement, and partially-alloyed, formation is realized under thermal diffusion effect The heterogeneous structure of the high Si phases of α-Fe crystal grain and brittleness of poor Si with plastic deformation ability.Subsequently pass through multi-pass cold rolling-burning Thin plate is obtained after knot, 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：Using the reduction Fe powder of irregular pattern, fine Si contents It is raw material for 50~70% HIGH-PURITY SILICON iron powder, forms Fe-4.5~6.7%Si mixed powders.By suitable bonding agent, divide Powder adheres to fine HIGH-PURITY SILICON iron powder in the hole of reduced iron powder surface or filling ferrous powder in mixed process.Due to also Former Fe powder is the big particle with high-compressibility, occupies larger volume ratio in mixed powder, is added after ferrosilicon powder not significantly Its plastic deformation ability is reduced, it can be by being molded squarely base.1000~1070 DEG C of realization Fe phase austenitizings are heated to, Then closed mould hot forging is placed into, repeatedly final forging temperature is 900~970 DEG C after forging so that green compact is close complete fine and close, about 6.80~7.12g/cm³.Then powder hotforging base is subjected to vacuum or protection of reducing atmosphere in 1020~1120 DEG C of temperature ranges Sintering, makes Fe powder particles metallurgical bindings, and ferrosilicon powder particles realized with Fe it is partially-alloyed, formed it is fine and close, there is plasticity change The high silicon steel blank of heterogeneous structure of the high Si phases of α-Fe crystal grain and brittleness of the poor Si of shape ability.Expand subsequently through multiple cold rolling, low temperature Sintering is dissipated, the density rise of slab, plate thickness are reduced, and the alloying level of Si is also continuously improved.Finally at 1200~1300 DEG C Vacuum or protection of reducing atmosphere sintering, the homogeneous alloy of high silicon steel is realized with the help of thermal diffusion, is obtained in temperature range 0.1~0.5mm containing 4.5~6.7%Si is thick, density >=7.36g/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 reduced iron powder, remaining is Si, Mn, P, S and other are inevitable Impurity, using the Si contents of refining, grain size≤6 μm, this ferrosilicon powder is except containing 50 for 50~70% HIGH-PURITY SILICON iron powder Beyond~70%Si, major impurity is~0.24%Al ,~0.07%Ca and~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 during follow-up powder hotforging also being mutually twisted for powder easy to implement and improve the intensity of green compact.

Fe-50~70%Si high purity ferrosilicons in process of setting there are two eutectic reactions, when rich Si one sides are at 1207 DEG C Form the β-FeSi with tP3 structures₂With Si phase eutectic structures, form when rich Fe one 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 subtle 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, Si phases, FeSi in actual tissue₂, 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 grain size≤6 μm, be conducive to it and be adhered to the table of reduction Fe powder Face is filled in the hole of reduction Fe powder, tiny Si, FeSi₂, FeSi phases Dispersed precipitate in blank, play structure refinement Strengthening and Toughening effect, be conducive to improve subsequent blank toughness, cracking do not easily caused in densification process is rolled.But Fe-50 Still containing a small amount of Si phases in~70%Si high purity ferrosilicons, Si is easily absorbing oxygen, and SiO is formed in exposed Si phase surfaces₂Film, 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, rolled Cheng Zhongying uses inert gas shielding, and 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, in the process The possibility for introducing other alloying elements is also little.

(2) powder mixes

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

(3) powder hotforging

Square green compact is prepared using compression-moulding methods, the green density of acquisition is 6.55~6.72g/cm³；Before hot forging Molding square billet under nitrogen protective effect is heated to 1000~1070 DEG C, keeps the temperature 2~4h, hot forging is fine and close in square dies Change, repeatedly final forging temperature is 900~970 DEG C after forging, and green compact is close complete fine and close, and density reaches 6.80~7.12g/cm³。

Under impact force action, hot forging green compact is close complete fine and close.Make the plasticity of plate after hot forging in order to avoid alloying Decline, relatively low heating temperature has been selected before hot forging.Alloy structure is the Fe phases of high-ductility and complexity FeSi phase compositions 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 7.35~7.49g/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, 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 It repairs and a degree of Si elements homogenization is spread.Cold rolling reduction accumulation needs to be sintered 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 is sintered 12~20 times again.

Sintering temperature is too low, is unfavorable for the metallurgical binding of Fe powder particles and Si element thermal diffusions；And sintering temperature is excessively high 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 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 apparent separating phenomenon, illustrate there are 2 kinds of different Fe phases of Si solid solubility, wherein must Have that the Si contents in a kind of Fe phases are 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, it realizes the full alloyings of Si, forms 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 7.36~7.50g/cm³。

The HIGH-PURITY SILICON iron powder of grain size≤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 green 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 123~210MPa.

Step (2) adds that cellulose, paraffin micro mist or zinc stearate are water-insoluble as binder, and binder adds when mixing 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 enhancing 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 elements such as grain size, crystal grain orientation, C etc. also has the magnetic behavior of high silicon steel Large effect can subsequently be annealed by wet hydrogen, the technological means such as normalizing treatment are controlled by.

Essence of the invention is by being with the addition of certain volume in the reduction Fe powder of the big volumetric portion with good plasticity Fine Fe-50~70%Si HIGH-PURITY SILICONs iron powder of ratio forms Fe-4.5~6.7%Si alloys basis powder.Using powder hotforging Into slab, high green density is obtained.Since hot forging is organized as incomplete alloying tissue, except small part richness Si phases in tissue Outside, main constituent be yielding Fe phases, therefore subsequently can by multi-pass cold rolling and sintering, improve structural homogenity 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.This method is led to Technique and equipment Design are crossed, realizes Technics Process Automation, continuous production, can be mass-produced 0.1~0.5mm thickness, density ≥7.36g/cm³High silicon steel band.

Description of the drawings

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

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.

Specific embodiment

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

Embodiment 1

By the reduction Fe powder of -100 mesh and the Fe-70%Si high-purity powders of granularity≤6 μm according to 90.43:9.57 ratio Mixing forms the mixed-powder of Fe-6.7%Si.The paraffin micro mist of raw material total amount 0.6%, 0.1% machine oil are added during mixing. Absolute ethyl alcohol is added according to 200ml/ tons of amount.Using V-arrangement batch mixer by above-mentioned powder mixing 4h.

Square green compact is prepared using compression-moulding methods, and green compact size is 100 × 100 × 40mm, surface pressing 600MPa, green density 6.55g/cm³。

Molding square billet is heated to 1000 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 900 DEG C after forging, and the thickness of blank is about 36mm, and density reaches 6.80g/cm³。 Three point bending test shows plasticity, sees Fig. 1, and bending strength reaches 123MPa.

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, It is sintered through 13 cold rollings and 12 times.

For multi-pass cold rolling to after 30~50%, then in 1020 DEG C of heat preservation sintering 2h in vacuum sintering furnace, plate is thick Degree is thinned to 0.49mm, and density reaches 7.35g/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 7.36g/cm³, Si contents are 6.7%.

Embodiment 2

By the reduction Fe powder of -100 mesh and the Fe-50%Si high-purity powders of granularity≤10 μm according to 91:9 ratio mixing, 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.Anhydrous second Alcohol is added according to 400ml/ tons of amount.Using drum mixer by above-mentioned powder mixing 6h.

Square green compact is prepared using compression-moulding methods, and green compact size is 300 × 300 × 60mm, surface pressing 600MPa, green density 6.72g/cm³。

Molding square billet is heated to 1070 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 970 DEG C after forging, and the thickness of blank is about 54mm, and density reaches 7.12g/cm³。 Three point bending test shows plasticity, and bending strength reaches 210MPa.

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 is burnt 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 heat preservations 0.5h is tied, sheet metal thickness is thinned to 0.10mm, and density reaches 7.49g/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 apparent 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 are 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 7.50g/cm³, Si contents are 4.5%.

Embodiment 3

By the reduction Fe powder of -100 mesh and the Fe-60%Si high-purity powders of granularity≤6 μm according to 89.17:10.83 ratio Mixing forms the mixed-powder of Fe-6.5%Si.The paraffin micro mist of raw material total amount 0.4% is added during mixing, 0.2% methyl is fine Dimension element, 0.1% machine oil.Absolute ethyl alcohol is added according to 400ml/ tons of amount.Above-mentioned powder is mixed using drum mixer 6h。

Square green compact is prepared using compression-moulding methods, and green compact size is 200 × 200 × 50mm, surface pressing 500MPa, green density 6.57g/cm³。

Molding square billet is heated to 1020 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 920 DEG C after forging, and the thickness of blank is about 46mm, and density reaches 6.82g/cm³。 Three point bending test shows plasticity, and bending strength reaches 140MPa.

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 is sintered 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 1060 DEG C of heat preservations 1h is tied, sheet metal thickness is thinned to 0.27mm, and density reaches 7.36g/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 7.37g/cm³, Si contents are 6.5%,

Embodiment 4

By the reduction Fe powder of -100 mesh and the Fe-62%Si high-purity powders of granularity≤10 μm according to 90.64:9.36 ratio Mixing forms the mixed-powder of Fe-5.8%Si.The paraffin micro mist of raw material total amount 0.6%, 0.2% machine oil are added during mixing. Absolute ethyl alcohol is added according to 400ml/ tons of amount.Using drum mixer by above-mentioned powder mixing 3h.

Square green compact is prepared using compression-moulding methods, and green compact size is 220 × 220 × 55mm, surface pressing 450MPa, green density 6.65g/cm³。

Molding square billet is heated to 1020 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 920 DEG C after forging, and the thickness of blank is about 52mm, and density reaches 6.88g/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：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.It is 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 1050 DEG C of heat preservations 1h is tied, sheet metal thickness is thinned to 0.21mm, and density reaches 7.42g/cm³。

4h 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 final plate is shown in Fig. 4, are the high silicon steel of single-phase homogeneous.

Claims

1. a kind of method that powder hotforging prepares high silicon steel thin belt material, it is characterised in that comprise the following steps：

(1) raw material powder prepares

Using -100 mesh reduced iron powders, Fe >=98.5% in reduced iron powder, remaining is Si, Mn, P, S and other are inevitably miscellaneous Matter uses the Si contents of refining as 50~70% HIGH-PURITY SILICON iron powder, grain size≤6 μm, major impurity is~0.24%Al ,~ 0.07%Ca and~0.02%C, remaining is Fe；

(2) powder mixes

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

(3) powder hotforging

Square green compact is prepared using compression-moulding methods, green density is 6.55~6.72g/cm³；Square billet will be molded before hot forging 1000~1070 DEG C are heated under nitrogen protective effect, keeps the temperature 2~4h, repeatedly final forging temperature is 900~970 DEG C after forging, Green compact reaches 6.80~7.12g/cm close to full densification, density³；

(4) cold rolling-sintering

It by above-mentioned hot forged plate cold rolling-sintering, is progressively thinned, single pass rolling reduction≤8%, is reached through multi- pass rolling to total reduction To after 30~50%, then in 1020~1120 DEG C of 0.5~2h of heat preservation sintering, after multiple cold rolling-sintering, plate in sintering furnace Thickness reaches 0.1~0.5mm, and after the completion of the alloying of Si, strip density is increased to 7.35~7.49g/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 reaches 7.36~7.50g/cm³。

2. the method that powder hotforging as described in claim 1 prepares high silicon steel thin belt material, it is characterised in that：Grain size≤6 μm HIGH-PURITY SILICON iron powder is by high-energy ball milling or rushes the acquisition of rotation method.

3. the method that powder hotforging as described in claim 1 prepares high silicon steel thin belt material, it is characterised in that the low energy Mixer is conical mixer, V-arrangement batch mixer or drum mixer.

4. the method that powder hotforging as described in claim 1 prepares high silicon steel thin belt material, it is characterised in that：System in step (3) For the square green compact gone out, length and width is respectively 100~300mm, is highly 40~60mm, uses surface pressing as 400~600MPa Pressure compacting.The thickness of blank is 36~54mm after hot forging, and three point bending test shows plasticity, and bending strength reaches 123 ~210MPa.

5. the method that powder hotforging as described in claim 1 prepares high silicon steel thin belt material, it is characterised in that：Step (2) mixes When add cellulose, paraffin micro mist or the water-insoluble binder of zinc stearate, the additive amount total amount of binder is no more than mixed-powder The 0.8% of gross mass, while add grease and absolute ethyl alcohol does passivator, play passivation Si powder, bonding Fe-Si powder, enhancing powder The effect of mobility and compact strength, the additive amount total amount of passivator are no more than the 2% of mixed-powder gross mass.

6. the method that powder hotforging as described in claim 1 prepares high silicon steel thin belt material, it is characterised in that：Step (4) is described Support plate use molybdenum plate, W plates, heat resisting steel, corundum or zirconia ceramics plate.

7. the method that powder hotforging as described in claim 1 prepares high silicon steel thin belt material, it is characterised in that：Step (6) is described High temperature sintering when, overlapping place sintering plate, interlayer be laid with MgO powder, plate tiling place, on plate place tablet weight Object prevents from deforming in sintering process.