CN103930579A

CN103930579A - Alloy cast iron and manufacturing method of vane using the same

Info

Publication number: CN103930579A
Application number: CN201280055816.3A
Authority: CN
Inventors: 朴载奉
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2011-11-14
Filing date: 2012-11-14
Publication date: 2014-07-16
Anticipated expiration: 2032-11-14
Also published as: EP2780486B1; EP2780486A1; JP5926396B2; JP2015504481A; WO2013073817A1; US20130118651A1; KR20130052977A; CN103930579B; AU2012337617B2; EP2780486A4; KR101409877B1; AU2012337617A1

Abstract

The present disclosure relates to an alloy cast iron, a method of manufacturing a vane for a rotary compressor, and a vane for a rotary compressor using the alloy cast iron. The alloy cast iron according to one exemplary embodiment comprises, by weight, 3.2 to 3.8% C, 2.0 to 2.6% Si, 0.5 to 1.0% Mn, 0.2 to 0.6% Cr, 0.1 to 0.6% Mo, 0.04 to 0.15% Ti, P less than 0.3%, S less than 0.1%, and the rest percentage of Fe and foreign materials, wherein the alloy cast iron comprises a martensitic matrix structure, flake graphite, and 15 to 30% carbide in volume ratio.

Description

The manufacture method of the blade of cast alloy iron and this cast alloy iron of employing

Technical field

The present invention relates to the manufacture method of the blade for rotary compressor of a kind of cast alloy iron and this cast alloy iron of employing.

Background technology

Conventionally, compressor comprises that one produces the compression set (compression unit) that drives the CD-ROM drive motor and of power to be connected in CD-ROM drive motor and compressed refrigerant in casing internal space.According to refrigerant compression method, compressor can be divided into broad variety.For example, with regard to the situation of rotary compressor, compression set comprises the cylinder (cylinder) of a formation compression space, the compression space of cylinder is divided into the blade of an induction chamber and an exhaust chest by one, multiple load bearing components that form compression space for support blade and together with cylinder, and one by being rotatably installed in the rotory piston (rolling piston) in cylinder.

Blade is inserted in the blade groove of cylinder, and because the end of blade is fixed in the peripheral part of rotory piston, compression space is divided into two portions.In compression process, blade slides constantly in blade groove.Here, blade should have high strength and high-wearing feature (abrasion resistance), because it need to contact the refrigeration agent of high temperature and high pressure constantly, and keeps connection state to prevent leakage of refrigerant with rotory piston and bearing.

Particularly, substitute the Chlorofluorocarbons (CFCs) (CFC) because ozone-depleting is prohibited from using such as the new refrigerant of hydrogen fluorohydrocarbon (HFC), it has the lubricity lower than CFC, and compared with prior art demonstrate more the wear resistance strengthening, this is owing to using frequency transformer (inverter) to reduce energy consumption but blade is needed.

In order to meet these conditions, recently by high speed steel or stainless steel is processed into predetermined shape, carry out subsequently aftertreatment, blade is manufactured in such as surface treatment etc.

Summary of the invention

Technical problem

But these blades are too much containing Gr, the W of the rare earth metal of promising costliness, Mo, V, Co etc., and be processed to predetermined shape by forging, thereby there is poor efficiency and high price.Particularly, this blade has high rigidity to improve wear resistance, but this makes it be difficult to implement process operation by forging.

Technical scheme

Therefore, in order to overcome the defect of prior art, an aspect of of the present present invention is in order to provide one can boost productivity and reduce manufacturing cost, meets the cast alloy iron that the required intensity of blade and wear resistance require simultaneously.

Another aspect of the present invention is the manufacture method for this blade is provided.

In order to reach the advantage of these and other, with object according to the present invention, as embodied in this article with generalized description, a kind of cast alloy iron is provided, it comprises: by weight, 3.2～3.8% C, 2.0～2.6% Si, 0.5～1.0% Mn, 0.2～0.6% Cr, 0.1～0.6% Mo, 0.04～0.15% Ti, be less than 0.3% P, be less than 0.1% S, and the iron of surplus and tramp material (foreignmaterial), wherein, this cast alloy iron can comprise martensitic matrix structure, flake graphite and volume ratio are 15%～30% carbide.

This cast alloy iron can be added into nucleating agent (inoculant) under the molten metal state taking out from smelting furnace.At this, this nucleating agent can be barium base nucleating agent (Fe-Si-Ba).This nucleating agent can add to 1.0% with 0.4% of molten mass quality.

This cast alloy iron can be by forming to be transformed into martensitic matrix structure via the molten metal in quenching and the cooling casting mold of tempering.At this, can implement as follows to quench: cast alloy iron is kept 0.5～1.5 hour at the temperature of 860～950 DEG C, and this cast alloy iron of oil cooling is to room temperature.Can implement as follows tempering: the cast alloy iron after quenching is kept 0.5～1.5 hour at the temperature of 180～220 DEG C, and this cast alloy iron of air cooling is to room temperature.

This cast alloy iron can further comprise the sulfuric horizon that 0.005～0.0015mm is thick.Here, sulfuric horizon can form by the cast alloy iron enforcement ion sulfurization to being transformed into martensitic matrix structure.

This cast alloy iron can further contain 0.01～0.5% niobium (Nb) by weight.

This cast alloy iron can further contain 0.1～0.5% vanadium (V) by weight.

This cast alloy iron can further contain 0.06～0.01% boron (B) by weight.

This cast alloy iron can further contain 0.2～0.4% copper (Cu) by weight.

According to a further aspect in the invention, the method of a kind of manufacture for the blade of compressor is provided, the method comprises: melting step, wherein prepare molten metal, described molten metal comprises by weight 3.2～3.8% C, 2.0～2.6% Si, 0.5～1.0% Mn, 0.2～0.6% Cr, 0.1～0.6% Mo, 0.04～0.15% Ti, be less than 0.3% P, be less than 0.1% S, iron and the tramp material of surplus; Casting step, wherein by molten metal is injected to casting mold, and cooling molten metal, obtains and comprises flake graphite and the work piece of 15～30% carbide by volume; Grinding step, is wherein ground to predetermined shape by cooled work piece; And heat treatment step, wherein the work piece after grinding are implemented to thermal treatment and make it be transformed into martensitic matrix structure.

The method may further include and breeds step, wherein takes out molten metal and nucleating agent is injected in molten metal.

Heat treatment step can comprise: quenching process, and wherein make the work piece after grinding at the temperature of 860～950 DEG C, keep 0.5～1.5 hour, and these work piece of oil cooling are to room temperature; And drawing process, wherein make the work piece after quenching at the temperature of 180～220 DEG C, keep 0.5～1.5 hour, and these work piece of air cooling are to room temperature.

The method may further include fine grinding step, wherein the work piece of grinding after processing completely by thermal treatment subtly.

The method may further include ion sulfurization step, is wherein forming sulfuric horizon through on the surface of complete heat treated work piece.Here, sulfuric horizon can thick 0.005～0.0015mm.

This cast alloy iron can further contain 0.01～0.5% niobium (Nb) by weight.

This cast alloy iron can further contain 0.1～0.5% vanadium (V) by weight.

This cast alloy iron can further contain 0.06～0.01% boron (B) by weight.

This cast alloy iron can further contain 0.2～0.4% copper (Cu) by weight.

According to another aspect of the present invention, provide the blade for compressor that adopts this cast alloy iron to manufacture.

Invention beneficial effect

According to these aspects, the present invention with this structure can provide the combination of a kind of element by means of mixing with suitable proportion and martensitic matrix structure, flake graphite structure and carbide and can improve the cast alloy iron of wear resistance and tensile strength simultaneously.This contributes to be used to the parts under high temperature and high pressure environment with low cost fabrication, such as compressor blade.

In prior art, meet the requirement of compressor blade by adding expensive rare earth element, can replace these expensive rare earth elements to manufacture the blade for compressor with the element of relative low price, thereby reduce material cost.

According to a further aspect in the invention, blade can be manufactured by the forging of casting but not use in prior art.Therefore, can reduce significantly aftertreatment, and can produce multiple blades simultaneously, cause productivity to be improved significantly.In addition, adopt relative at a low price cast alloy iron but not can reduce significantly material cost for the manufacture method of the expensive rapid steel that forges.

Brief description of the drawings

Fig. 1 schematically shows for testing according to the frontview of the sample of the tensile strength of the cast alloy iron of an exemplary embodiment of the present invention (test specimen); With

Fig. 2 to Figure 12 is by catching according to the 1st enlarged photograph obtaining to the surface tissue of the cast alloy iron of the 11st illustrative embodiments of the present invention.

Embodiment

Now in connection with accompanying drawing detailed description exemplary embodiment.For the object of brief description by reference to the accompanying drawings, parts identical or that be equal to, by being endowed same label, no longer repeat the description to it.

Conventionally, cast iron has the performance such as the high-wearing feature of bringing because of its high rigidity and good machinability (machinability).But cast iron has low tensile strength and high fragility, therefore, it is not too suitable as the parts that are exposed to high-pressure atmosphere.Particularly, need to there is the wear resistance higher than prior art for the blade of compressor, because it is not only exposed to high-pressure atmosphere but also is closely being connected in adjacent component to prevent the situation lower slip of the leakage of refrigerant of compressing.The invention provides a kind of cast alloy iron, its by contained various elements in the content hybrid alloys cast iron with suitable so that tensile strength and wear resistance be elevated to and be enough to be used in various object manufactures and form.Below, will be described each element.Here, if not otherwise specified, each content is all based on weight ratio.

(1) carbon (C): 3.2～3.8%

Carbon in cast iron is that the carbide form representing with graphite or with Fe3C exists.Therefore, in the time that carbon content is low, most carbon exists with the form of carbide, so, can not observe well flake graphite structure.Or rather, in the time that C content is 1.7～2.0%, graphite is net distribution, in the time that C content is 2.0～2.6%, show as crystalline graphite, in the time that C content is 2.6%～3.5%, be usually expressed as thin graphite flake, and when C content is higher than 3.5% time, show as coarse thick graphite flake.In the time that the carbon content in cast alloy iron is limited at 2.7～3.8% scope, carbon exists with flake graphite structure conventionally.For high-carbon cast iron, its metal construction contains ferrite (ferrite) and coarse thick graphite flake, and has relatively high physical strength and hardness, if but carbon content is too high, and its mechanical property can reduce.

Therefore, the addition of carbon exceedes 3.2% and may obtain uniformly flake graphite structure of entirety.Meanwhile, high carbon content has reduced zero pour.This contributes to improve castability (castability).But the amount of aquadag thing exceedingly increases, thereby increase fragility and the detrimentally affect to tensile strength.,, in the time that carbon saturation (Cs) is about 0.8 to 0.9, can obtain the highest tensile strength.Therefore, the threshold limit value of carbon content is decided to be to 3.8% and can obtains satisfied tensile strength.

(2) silicon (Si): 2.0～2.6%

Silicon as graphitizer (graphitizer) for decomposing carbide to obtain aquadag thing., the interpolation of silicon can provide the effect increasing such as carbon content.In addition, silicon is for making the graphite microtexture that is present in cast iron be grown to serve as flake graphite structure.Conventionally,, in the time that Si-C content is low, obtain relatively high physical strength and hardness, but mobility is relatively low.On the contrary, in the time that Si-C content is high, mobility is high but physical strength and hardness are low.

But, in the time adding a large amount of silicon, also can play the effect that increases tensile strength by strengthening the basal body structure of (strengthening) cast iron.,, owing to using high silicon content to have the effect that strengthens basal body structure, the Si/C of increase can reduce the amount of graphite and improve tensile strength.This can be observed significantly in the time implementing the breeding of molten metal.From this angle, silicone content is decided to be in 2.0～2.6% scope.

(3) manganese (Mn): 0.5～1.0%

Manganese is the element that promotes the formation of graphited spoken parts in traditional operas ((carbidic) of the carbide) cast iron that disturbs carbon, and for stable bond carbon (, cementite).And manganese disturbs ferritic precipitation refinement (refine) perlite, to play a role in the time that the basal body structure of cast iron is transformed into perlite.Particularly, manganese is combined and is formed manganese sulfide by the sulphur in cast iron.Manganese sulfide floats to the surface of molten metal to be removed as slag, or solidifies and be retained in cast iron to prevent the formation of iron sulphide as non-metallic inclusion afterwards., manganese also can be used as removing the element of the toxicity (detoxifies) of sulphur.

As mentioned above, manganese is stablized and refine pearlite.Here, along with the increase of manganese content, the intensity of cast iron and hardness increase and plasticity-and toughness drop.In addition, manganese can significantly reduce martensitic transformation starting point (Ms).But in the time adding a large amount of manganese, it forms carbide, therefore increase fragility and affect the mechanical property of cast alloy iron.

Further, in the time that manganese content is suitable, manganese does not have large impact to the structure of cast iron.Therefore,, for promoting pearlitic formation and desulfurization, manganese content is decided to be in 0.5～1.0% scope.

(4) chromium (Cr): 0.2～0.6%

Chromium is to promote carbide to form and disturb the graphited element of carbon.In the time that chromium is added in a large number, it forms white cast iron and has exceedingly increased hardness, causes machinability to reduce.On the contrary, chromium stable carbide and contribute to increase thermotolerance.Chromium is also prevent the distance between ferrite formation in cast iron, shortening perlite lamella and promote the element that perlite forms.Chromium also improves the amount with stabilizing pearlite, and refine pearlite structure.But, in the time of chromium too high levels, can form too much cementite, this may cause the formation of chill (chilled) structure.

Therefore, can add 0.2～0.6% chromium, more preferably 0.1～0.3% chromium improves mechanical property and thermotolerance.

(5) molybdenum (Mo): 0.1～0.6%

When its content is lower than 0.6% time, molybdenum stable carbide refine pearlite and graphite.In the time adding molybdenum, the amount of phosphorus (P) should be lowered.Otherwise can form P-Mo quaternary eutectic (P～Mo quaternary eutectic) and fragility increases.Meanwhile, molybdenum improves the homogeneity of section structure, improves the performance such as intensity, hardness, shock strength, fatigue strength and high temperature (lower than 550 DEG C), reduces shrinkability, and improves heat treatment performance and quenching performance.According to these performances, molybdenum content is decided to be in 0.1～0.6% scope, more preferably in 0.4～0.6% scope.

(6) vanadium (V): 0.1～0.5%

Vanadium is also for refine pearlite structure and graphite, and easily in cast iron, forms carbide and nitride, and allow carbide and nitride dispersed widely with particle form.This makes whole cast iron obtain uniform performance.In addition, vanadium can not reduce the machinability of cast iron, even also improves hardness and the tensile strength of cast iron.Particularly, vanadium has good impact to wear resistance, if but containing excessive vanadium, cast iron is chill.Therefore, the content of vanadium is decided to be between 0.1～0.5% vanadium, preferably in 0.2～0.4% scope.

(7) boron (B): 0.06%～0.01%

Boron refinement graphite but for reducing the amount of graphite and promoting the formation of carbide.Particularly, in the time adding a small amount of boron, boron is with the state precipitation of norbide.Norbide increases hardness and the wear resistance of cast iron significantly.Particularly, norbide forms netted.In the time adding a small amount of boron, norbide forms discontinuous net, but in the time adding excessive boron, forms continuous net, and this causes mechanical property to reduce.

In the time that boron is added in cast iron, need to consider the relation between Si and B.In general,, if Si/B<80, norbide can precipitate in cast iron; If 80<Si/B<130, a small amount of norbide can precipitate; If Si/B>130, does not have norbide to precipitate.Observe in one embodiment of the invention in the time of Si/B=36.6, have relatively a large amount of norbides, and in this case, cast iron shows very strong wear resistance.

In the time that the cast alloy iron of boracic is corroded, the norbide with high rigidity forms the first sliding surface with load-supporting, and perlite with relative soft etc. is corroded with dished the second sliding surface of shape.Groove between the first sliding surface and the second sliding surface is used for oil in reserve therein.This can make lubricating oil be continuously fed to norbide, reduces thus the degree of corrosion and improves the wear resistance of boron cast iron.Meanwhile, in the time that boron content increases, norbide also increases.This has correspondingly improved the support operation of norbide to reduce the pressure on the first sliding surface that puts on per unit area, reduces thus the degree of wear and therefore improves wear resistance.

But in the time that boron content is too high, the diameter of norbide increases, and therefore weaken and the bonding force (coupling force) of basal body structure.Correspondingly, in the time applying frictional force, norbide is easy to separated.Separated norbide, as the hard abrasive grains on friction surface, has aggravated the wearing and tearing of cast iron.And under these circumstances, the hardness of cast iron excessively increases, and causes machinability to be lowered.Consider these performances, the content of boron is decided to be in 0.02～0.1% scope.

(8) titanium (Ti): 0.04～0.15%

Titanium refinement graphite, accelerates pearlitic formation, and improves pearlitic high-temperature stability.In the time that the content of titanium is relatively low, its promotes greying and improves the distribution of graphite and the shape of cast iron.But along with the increase of content, titanium is deposited near crystal interface with the form of the compound such as TiN, TiC etc., become the core of solidifying of austenite matrix.This causes hardness of cast to increase, and reduces the machinability of cast iron simultaneously.For relatively low content, titanium (Ti) promotes greying, and the ferritic amount that increases grey cast iron structure is to reduce hardness.On the contrary, for high-content, titanium refinement cast iron crystal, and strengthening (enhancing) alloy structure.Meanwhile, due to the precipitation of TiC2 on crystal interface, the hardness of grey cast iron further increases.

Ti is a kind of alloying element for the manufacture of D-type Graphite Iron Cast.D-type Graphite Iron Cast, compared with those A-type Graphite Iron Cast, has higher hardness and wear resistance.When the content of Ti is lower than 0.1% time, Ti is partly melted in ferrite, and mainly with the form precipitation of TiC2 or TiN.Correspondingly, Ti makes the abundant deoxidation of molten metal and denitrogenation.Meanwhile, in the time that TiC2 or TiN are crossed deepfreeze (undercooled), A-type graphite attenuates and D-type graphite occurs.And, due to relatively high content of graphite and ferrite content, form the structure that A and D mix, reduced intensity and the hardness of grey cast iron simultaneously.

When Ti content is higher than 0.1% time, Ti can increase the intensity of D-type graphite and make the amount of D-type graphite exceed 95%.Meanwhile, relatively low content of graphite and ferrite content increase are melted in the amount of the Ti in ferrite, thereby and ferrite be reinforced and increase intensity and the hardness of grey cast iron.Therefore,, in order to obtain D-type content of graphite and to improve machinability, titanium content is decided to be in 0.04～0.15% scope.

(9) niobium (Nb): 0.01～0.5%

The further fining metal crystal of niobium and make even structure.Particularly, when Nb content is lower than 0.5% time, niobium forms the banded phase that is rich in Nb, so that further refinement graphite increases the thermal structure stability of alloy, and increases P eutectic hardness.Here, in the time that content of niobium exceedes 0.5%, thereby it forms the cube shaped phase reduction mechanical property that is rich in Nb.Therefore, content of niobium is decided to be in 0.01～0.5% scope.

(10) copper (Cu): 0.2～0.4%

Copper makes the shape of graphite become thick and short, and copper is to reduce D-type and E-type supercooled graphite and promote the element that A-type flake graphite forms.And copper has the good function of improving graphite shape, and in eutectic process, prevent greying and chill (chilling) that reduce cast iron.In addition, copper improves the distribution of carbide, forms perlite and refined structure.

Further, copper carrys out refine pearlite by the distance that promotes perlite to form and to shorten between perlite.Copper also improves castability by the mobility that increases molten metal, thereby reduces residual stress (residual stress).

In addition, copper makes structure refinement and slightly improves tensile strength, the hardness etc. of cast iron.In the time that carbon content is about 0.3%, obviously shows these effects, and in the time adding 0.3～0.5% chromium, be expected to show better effect.Therefore,, as above-mentioned, copper content is decided to be in 0.2～0.4% scope.

(11) phosphorus (P): lower than 0.3%

Phosphorus forms iron phosphide (Fe3P) thereby compound exists with ternary eutectic steadite (ternary eutectic steadite) together with cementite with ferrite.Iron phosphide is easily crossed deepfreeze and in the time of casting, is easily caused segregation (segregation).Therefore,, along with the increase of phosphorus content, fragility increases and tensile strength reduces sharp.Therefore, phosphorus content is decided to be lower than 0.3%.

(12) sulphur (S): lower than 0.1%

In the time adding a large amount of sulphur, the mobility of molten metal reduces, and the shrinkability of cast alloy iron increases, and likely can cause the formation in cavity or crack.Therefore, sulphur content is preferably the least possible.Here, when sulphur content is lower than 0.1% time, these bad impacts that sulphur brings can be not clearly, therefore needs to control within sulphur content remains on this content.

The element that cast alloy iron of the present invention can have these performances by mixing is produced, for manufacturing the blade of compressor.Hereinafter, will technique that manufacture the blade that is used for compressor be described, described blade is to be made up of this cast alloy iron.

(1) melting (Smelting)

Aforementioned elements is mixed to prepare starting material with suitable proportion.Starting material are inserted in a medium-frequency induction furnace, and heating is until then fusing completely, is smelted into molten metal.The temperature of taking out molten metal here, from stove is about in the scope of 1500 DEG C to 1550 DEG C.

(2) breed (Inoculation)

Nucleating agent is injected in the molten metal of melting in melting step.Breed and produce many graphite nucleis to promote greying, and contribute to being uniformly distributed and the increase of intensity of graphite.Here, ferrous alloy containing barium and silicon (FeSi72Ba2) is used as nucleating agent and its content can be 0.4～1.0% of molten metal mass.

(3) casting (Casting)

To there is the cavity of desired shape to form in being injected into a prefabricated casting mold breeding the molten metal breeding in step.Here, casting is to adopt to have used the shell mold process of coated sand (resin-coated sand) or investment casting process (investment mold process) to implement.Cooling work piece blade contains flake graphite and carbide, and the content of this carbide can account for 15%～30% of blade cumulative volume.Here, this carbide shows that the component increasing is incorporated on carbon.An example of carbide can comprise Fe3C (so-called iron carbide) etc.

(4) grinding (Grinding)

The work piece blade grinding obtaining from casting step is become to required shape.

(5) thermal treatment (Heat treating)

Thermal treatment can comprise quenching process and drawing process.

-quenching (Quenching): the work piece blade after grinding is heated to 860～950 DEG C by the resistance furnace that employing can be controlled air themperature, and remain on this state and assign 0.5～1.5 hour.Work piece blade after heating is put in the oil of temperature within the scope of 10～30 DEG C rapidly with cool to room temperature.Quenching can make pearlite matrix structural transformation become martensitic matrix structure, thereby improves hardness.,, after quenching completes, obtain the blade that contains martensitic matrix structure, carbide and flake graphite.

-tempering (Tempering): the blade of the martensitic cast iron that contains carbide and flake graphite obtaining by quenching is heated to 180～220 DEG C by the resistance furnace that employing can be controlled air themperature, and remain on this state and assign 0.5～1.5 hour.Blade air cooling after heating, to room temperature, slightly to reduce the intensity and the hardness that increase by quenching, and is increased to ductility.This causes reducing fragility.

(6) fine grinding (Fine Grinding) and polishing (Polishing)

The cast iron vanes that the contains carbide fine grinding obtaining with tempering by heat treated quenching is become to have final shape and required surface quality with polishing.

(7) ion sulfurization (Ion-Sulfurizing) (sulfuration (sulphurizing))

To carrying out ion sulfurization through the carbide cast iron blade of fine grinding and polishing acquisition, to form the sulfuric horizon of thick 0.005～0.015mm on the surface of blade.This sulfuric horizon can work together with the flake graphite existing in blade, and further improves oilness and wear resistance that blade self has.

Embodiment 1

Manufacture embodiment 1 by following method.

Prepare starting material, described starting material comprise following element by weight, the i.e. iron of C:3.4%, Si:2.2%, Mn:0.7%, Cr:0.4%, Mo:0.4%, V:0.3%, B:0.06%, Ti:0.1%, Nb:0.25%, Cu:0.25%, P<0.3%, S<0.1% and surplus.The starting material of preparation are put into a medium-frequency induction furnace, and its temperature of raising is until starting material are fully melted that cast alloy iron is smelted into molten metal.At the temperature of 1525 DEG C, from stove, take out the molten metal of cast alloy iron.

The molten metal of the cast alloy iron taking out from stove after melting is bred by injecting nucleating agent.Here, nucleating agent is ferrous alloy containing barium and silicon, i.e. FeSi72Ba2, and its content is 0.7% of molten metal mass.

Be cast in the molten metal of the cast alloy iron breeding in previous step by shell mold process or investment casting process, obtain the blade of the pearlitic cast iron that contains flake graphite and carbide.Here, carbide content is 25% of blade cumulative volume.

The blade grinding of acquisition is become to required shape.

Then, blade is heated to 910 DEG C and under same temperature, keep 0.7 hour.Blade after heating is put into the oil of 20 DEG C, and then cool to room temperature, is transformed into martensitic structure by basal body structure thus.The blade obtaining by quenching is heated to 210 DEG C, keeps 0.7 hour, then air cooling is to room temperature.

Therefore and obtain work piece vanes cross fine grinding and polishing, carry out subsequently ion sulfurization, thereby on the surface of blade, form the sulfuric horizon of thick 0.008mm.

Embodiment 2

By the following element comprising by weight,, the starting material of the iron of C:3.2%, Si:2.0%, Mn:0.5%, Cr:0.2%, Mo:0.1%, Ti:0.04%, P<0.3%, S<0.1% and surplus are fused into molten metal.Then at the temperature of 1500 DEG C, take out this molten metal.0.4% the amount using FeSi72Ba2 as nucleating agent with molten metal mass is added in molten metal.Then, the molten metal after breeding by the casting of shell mold process or investment casting process, obtains thus and wherein contains the work piece blade that volume ratio is 15% carbide.

After this work piece blade of grinding, the work piece blade of grinding is heated to 860 DEG C, keep at the same temperature 0.5 hour, put into the oil of 10 DEG C to be cooled to room temperature, be transformed into thus martensitic structure.The work piece blade with martensitic structure is heated to 180 DEG C, keeps 0.5 hour at identical temperature, then air cooling is to room temperature.Blade after air cooling is processed by fine grinding, polishing and ion sulfurization successively, to form the sulfuric horizon that a 0.005mm is thick on the surface of blade.

Embodiment 3

By the following element comprising by weight,, the starting material of the iron of C:3.8%, Si:2.6%, Mn:1.0%, Cr:0.6%, Mo:0.6%, V:0.5%, B:0.1%, Ti:0.15%, Nb:0.5%, Cu:0.5%, P<0.3%, S<0.1% and surplus are fused into molten metal.Then at the temperature of 1550 DEG C, take out this molten metal.Using 0.1% FeSi72Ba2 adding as nucleating agent of molten metal mass.Then, the molten metal after breeding is cast by shell mold process or investment casting process, be equivalent to 30% carbide of work piece blade to contain volume ratio, thereby be ground to required shape.

Blade after grinding is heated to 950 DEG C, and keeps 1.5 hours.Blade after heating is put into the oil of 30 DEG C with cool to room temperature, obtain thus the blade that contains martensitic matrix structure, carbide and flake graphite.The blade of acquisition is heated to 220 DEG C, keeps 1.5 hours, then air cooling, to room temperature, reduces fragility thus.After this, implement fine grinding and polishing to obtain the net shape of blade, and implement ion sulfurization to form the sulfuric horizon of thick 0.015mm on the surface of blade.

Embodiment 4

According to embodiment 4, the starting material of the iron that comprises C:3.3%, Si:2.1%, Mn:0.6%, Cr:0.3%, Mo:0.2%, V:0.2%, B:0.02%, Ti:0.05%, P<0.3%, S<0.1% and surplus are by weight fused into molten metal.At the temperature of 1515 DEG C, take out this molten metal.Identical with embodiment 1 of other steps.

Embodiment 5

According to embodiment 5, the starting material of the iron that comprises C:3.3%, Si:2.2%, Mn:0.7%, Cr:0.4%, Mo:0.3%, V:0.2%, Ti:0.04～0.15%, Nb:0.1%, P<0.3%, S<0.1% and surplus are by weight fused into molten metal.At the temperature of 1510 DEG C, take out this molten metal.Identical with embodiment 1 of other steps.

Embodiment 6

According to embodiment 6, the starting material of the iron that comprises C:3.4%, Si:2.3%, Mn:0.8%, Cr:0.4%, Mo:0.3%, V:0.3%, Ti:0.06%, Cu:0.2%, P<0.3%, S<0.1% and surplus are by weight fused into molten metal.At the temperature of 1520 DEG C, take out this molten metal.Identical with embodiment 1 of other steps.

Embodiment 7

According to embodiment 7, the starting material of the iron that comprises C:3.6%, Si:2.4%, Mn:0.9%, Cr:0.5%, Mo:0.5%, B:0.05%, Ti:0.12%, Cu:0.3%, P<0.3%, S<0.1% and surplus are by weight fused into molten metal.At the temperature of 1530 DEG C, take out this molten metal.Identical with embodiment 1 of other steps.

Embodiment 8

According to embodiment 8, the starting material of the iron that comprises C:3.3%, Si:2.2%, Mn:0.7%, Cr:0.4%, Mo:0.3%, Ti:0.04～0.15%, Nb:0.1%, P<0.3%, S<0.1% and surplus are by weight fused into molten metal.At the temperature of 1510 DEG C, take out this molten metal.Identical with embodiment 2 of other steps.

Embodiment 9

According to embodiment 9, the starting material of the iron that comprises C:3.4%, Si:2.3%, Mn:0.8%, Cr:0.4%, Mo:0.3%, Ti:0.06%, Cu:0.2%, P<0.3%, S<0.1% and surplus are by weight fused into molten metal.At the temperature of 1520 DEG C, take out this molten metal.Identical with embodiment 2 of other steps.

Embodiment 10

According to embodiment 10, the starting material of the iron that comprises C:3.4%, Si:2.2%, Mn:0.7%, Cr:0.4%, Mo:0.4%, V:0.3%, B:0.06%, Ti:0.1%, Cu:0.25%, P<0.3%, S<0.1% and surplus are by weight fused into molten metal.At the temperature of 1535 DEG C, take out this molten metal.Identical with embodiment 3 of other steps.

Embodiment 11

According to embodiment 11, the starting material of the iron that comprises C:3.8%, Si:2.6%, Mn:1.0%, Cr:0.6%, Mo:0.6%, B:0.1%, Ti:0.15%, Nb:0.5%, Cu:0.5%, P<0.3%, S<0.1% and surplus are by weight fused into molten metal.At the temperature of 1545 DEG C, take out this molten metal.Identical with embodiment 3 of other steps.

The data of above-described embodiment are listed in table 1.

Table 1

[table 1]

?	C	Si	Mn	Cr	Mo	V	B	Ti	Nb	Cu	P	S
													1	3.4	2.2	0.7	0.4	0.4	0.3	0.06	0.1	0.25	0.25	<0.3	<0.1
2	3.2	2.0	0.5	0.2	0.1	?	?	0.04	?	?	<0.3	<0.1
													3	3.8	2.6	1.0	0.6	0.6	0.5	0.1	0.15	0.5	0.5	<0.3	<0.1
4	3.3	2.1	0.6	0.3	0.2	0.2	0.02	0.05	?	?	<0.3	<0.1
													5	3.3	2.2	0.7	0.4	0.3	0.2	?	0.04	0.1	?	<0.3	<0.1
6	3.4	2.3	0.8	0.4	0.3	0.3	?	0.06	?	0.2	<0.3	<0.1
													7	3.6	2.4	0.9	0.5	0.5	?	0.05	0.12	?	0.3	<0.3	<0.1
8	3.3	2.2	0.7	0.4	0.3	?	?	0.04	0.1	?	<0.3	<0.1
													9	3.4	2.3	0.8	0.4	0.3	?	?	0.06	?	0.2	<0.3	<0.1
10	3.4	2.2	0.7	0.4	0.4	0.3	0.06	0.1	?	0.25	<0.3	<0.1
													11	3.8	2.6	1.0	0.6	0.6	?	0.1	0.15	0.5	0.5	<0.3	<0.1

In addition,, for complete heat treated sample, also implemented the hardness test of use HR～150A type Rockwell hardometer (Rockwell hardometer).Determine using two points up and down of the filling orifice of contiguous casting liquid, away from two points up and down of the filling orifice of casting liquid and a point between them after test position, these five points are carried out to hardness test.

Each test sample with shape shown in Fig. 1 is by adopting the raw material identical with each embodiment to make, and measures their tensile strength.Test result is shown in following table 2.

Table 2

[table 2]

And following table 3 shows the machinability of these embodiment and the test result of abradability (abradability).

Table 3

[table 3]

And, for Grindability (grinding workability), the grinding load of this cast alloy iron can be equivalent to 75% of rapid steel, and grinding stone of every finishing (dressing) (grinding stone) can 800 blades of grinding.Therefore be appreciated that it is compared with rapid steel, grinding performance significantly improves.

And, adopt the blade of rapid steel, forge instead of casting because using, there is poor efficiency, thereby and blade of the present invention can have relatively good machinability by casting manufacture, even also there is the wear resistance similar to rapid steel.Therefore, the productivity of blade of the present invention and manufacturing cost can reduce significantly.

Above-mentioned embodiment and advantage are only exemplary, and should not be interpreted as limitation of the present invention.Instruction of the present invention can easily be applied to the device of other types.This specification sheets is illustrative, and does not limit the scope of claim.Many alternative, amendment and distortion, it will be apparent to those skilled in the art that.Thereby the feature of illustrative embodiments described herein, structure, method and other characteristics can be in many ways in conjunction with that obtain other and/or alternative illustrative embodiments.

Due to feature of the present invention, in the situation that not deviating from its speciality, can embody in a variety of forms, also should be understood that, except as otherwise noted, above-mentioned embodiment is not subject to the restriction of any details above, and broadly explains in the scope that should limit at appended claims, and therefore falling into all changes in boundary and the scope of claim and the equivalent way of amendment or this boundary and scope should be contained by appended claims.

Claims

1. a cast alloy iron, by weight, it comprises: 3.2～3.8% C, 2.0～2.6% Si, 0.5～1.0% Mn, 0.2～0.6% Cr, 0.1～0.6% Mo, 0.04～0.15% Ti, be less than 0.3% P, be less than 0.1% S and Fe and the tramp material of surplus

Wherein, to comprise martensitic matrix structure, flake graphite and volume ratio be 15～30% carbide to this cast alloy iron.

2. cast alloy iron according to claim 1, wherein, described cast alloy iron is added into nucleating agent under the molten metal state taking out from smelting furnace.

3. cast alloy iron according to claim 2, wherein, the addition of described nucleating agent is 0.4～1.0% of molten mass quality.

4. cast alloy iron according to claim 1, wherein, forms described cast alloy iron as follows: via quench and the molten metal of tempering in cooling casting mold to be transformed into martensitic matrix structure.

5. cast alloy iron according to claim 4, wherein, implements described quenching: cast alloy iron is kept 0.5～1.5 hour at the temperature of 860～950 DEG C, and this cast alloy iron of oil cooling is to room temperature as follows.

6. cast alloy iron according to claim 4, wherein, implements described tempering: the cast alloy iron after quenching is kept 0.5～1.5 hour at the temperature of 180～220 DEG C, and this cast alloy iron of air cooling is to room temperature as follows.

7. cast alloy iron according to claim 4, it further comprises the sulfuric horizon that thickness is 0.005～0.0015mm, and this sulfuric horizon is to implement ion sulfurization by the cast alloy iron to being transformed into martensitic matrix structure to form.

8. cast alloy iron according to claim 1, it further comprises 0.01～0.5% niobium (Nb) by weight.

9. cast alloy iron according to claim 8, it further comprises 0.1～0.5% vanadium (V) by weight.

10. cast alloy iron according to claim 1, it further comprises 0.06～0.01% boron (B) by weight.

11. cast alloy irons according to claim 1, it further comprises 0.2～0.4% copper (Cu) by weight.

12. 1 kinds of manufactures are used for the method for the blade of compressor, and the method comprises:

Melting step, wherein preparation comprises by weight 3.2～3.8% C, 2.0～2.6% Si, 0.5～1.0% Mn, 0.2～0.6% Cr, 0.1～0.6% Mo, 0.04～0.15% Ti, is less than 0.3% P, is less than 0.1% S and the Fe of surplus and the molten metal of tramp material;

Casting step, wherein injects casting mold by this molten metal, and cooling this molten metal, obtains and comprises flake graphite and the work piece of 15～30% carbide by volume;

Grinding step, is wherein ground to predetermined shape by cooled work piece; With

Heat treatment step, wherein implements thermal treatment so that it is transformed into martensitic matrix structure to the work piece after grinding.

13. methods according to claim 12, the method further comprises and breeds step, wherein takes out molten metal and nucleating agent is injected in molten metal.

14. methods according to claim 12, wherein, described heat treatment step comprises:

Quenching process, wherein make the work piece after grinding at the temperature of 860～950 DEG C, keep 0.5～1.5 hour, and these work piece of oil cooling is to room temperature; With

Drawing process, wherein make the work piece after quenching at the temperature of 180～220 DEG C, keep 0.5～1.5 hour, and these work piece of air cooling is to room temperature.

15. methods according to claim 12, the method further comprises fine grinding step, wherein work piece after the complete thermal treatment of grinding subtly.

16. methods according to claim 12, the method further comprises ion sulfurization step, wherein on the surface of the work piece after complete thermal treatment, forms sulfuric horizon, this sulfuric horizon has the thickness of 0.005～0.0015mm.

17. methods according to claim 12, wherein, described cast alloy iron further comprises 0.01～0.5% niobium (Nb) by weight.

18. methods according to claim 17, wherein, described cast alloy iron further comprises 0.1～0.5% vanadium (V) by weight.

19. methods according to claim 12, wherein, described cast alloy iron further comprises 0.06～0.01% boron (B) by weight.

20. methods according to claim 12, wherein, described cast alloy iron further comprises 0.2～0.4% copper (Cu) by weight.