CN108570618A - A kind of strontium nitrate toughening high hard alloy and its casting and heat treatment method - Google Patents

A kind of strontium nitrate toughening high hard alloy and its casting and heat treatment method Download PDF

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CN108570618A
CN108570618A CN201810589778.9A CN201810589778A CN108570618A CN 108570618 A CN108570618 A CN 108570618A CN 201810589778 A CN201810589778 A CN 201810589778A CN 108570618 A CN108570618 A CN 108570618A
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casting
strontium nitrate
powder
temperature
alloy
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罗丰华
夏光明
严淑群
贺立
杨昊
李益民
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Central South University
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/002—Heat treatment of ferrous alloys containing Cr
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • C22C33/06—Making ferrous alloys by melting using master alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
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  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
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  • Crystallography & Structural Chemistry (AREA)
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Abstract

The mass percentage of a kind of strontium nitrate toughening high hard alloy and its casting and heat treatment method, alloy each element is Cr：9.0~13.0, B：2.6~2.9, C：0.7~0.9, Nb：0.4~0.8, V：The content of 0.4~0.8, Mn are less than 0.3, Sr：0.04~1.0, S, P：≤ 0.01, surplus Fe.Wherein C, B summation：3.3~3.6；C/Cr content ratios：0.06~0.08；The summation of Nb, V are 0.5~1.0.It gets out Fe strontium nitrate briquettings first, is handled by cast alloys after alloying ingredient, melting and Metamorphism treatment, then using Q-tempering.Ingot casting integral hardness of the present invention reaches HRC66.5~70.0, and impact flexibility reaches 13.8~18.0J/cm2, bending strength reaches 1336~1664MPa.

Description

A kind of strontium nitrate toughening high hard alloy and its casting and heat treatment method
Technical field
The invention belongs to high-hardness and wear-resistant cast-iron fields, and it is solid to be related to a kind of fine hard phase and supersaturation that strontium nitrate is rotten Solution, martensitic matrix phase wear and corrosion resistant cast iron alloy and its component preparation method, can be widely used for electric power, metallurgy, machine Mechanical wearing piece manufacture in the industries such as tool, chemical industry.
Technical background
Fe-Cr-B-C abrasion resistant casting alloys are mainly with Fe2B or M2B is hard phase, has good toughness and high rigidity, height Corrosion resistance, melting-casting manufacturability is good, has very wide application prospect.
Metamorphism treatment is to improve one of Fe-Cr-B-C alloy structures and mechanical property effective ways.Alterant is according to effect The elements such as strong carbon, nitrogen, sulfide formation element, such as Ti, V, and strong constitutional supercooling element, such as surface active element can be divided into Rare earth (RE), Mg etc..
Rare earth element is gathered on the solid growth interface of liquid, and limitation crystal grain is grown up, to improve the hardness of alloy, intensity and resistance to Mill property；And thinning microstructure, so that boride suspension shape and graininess distribution is occurred, improves impact flexibility.Research shows that：In Fe-Cr- The cerium (Ce) of addition 0.6% can make impact flexibility improve 86.4% in B-C alloys.Add the mixing alterant of 1.0% (Ce+La) Into Fe-Cr-B alloys, the hardness of alloy increases to 70.2HRC by 52HRC, and impact flexibility is by 3.36J/cm2It is increased to 6.38J/cm2。
RE Modified can rare earth alloy or rare-earth wires single Modification Manners, can also take compound modification treatment, i.e., with N, The mixture of the elements such as Ti, V, Mg, Si and rare earth is as alterant.Silicon Mg mixed rare-earth alterant (RE-Si-Mg) is most common Be composite inoculating method, some researches show that：Fe-Cr-B-C alloys after RE-Si-Mg is rotten impact toughness than before rotten Improve 72.2%；After RE-Ti goes bad and is heat-treated, impact flexibility improves 1.8 times；It is carried through the RE-Mg impact flexibility that goes bad It is high by 34.6%；Desmachyme all disappears after RE-Ti-N is rotten, and toughness improves 133.3%；Through the rotten places RE-Mg-V-Ti After reason, impact flexibility reaches 15.6J/cm2；After RE-Ti-Si-V Metamorphism treatments, impact flexibility reaches 12J/cm2More than.
These using the method for RE Modified all there are one common difficulty, i.e. the pure rare earth, rare earth alloy of high activity or multiple Close rare earth material.Due to the high activity of rare earth so that the tissue of alloy, performance are difficult to control after alterant itself or Metamorphism treatment System, modification effect are difficult to ensure.
Document 1：LM cathodes research-emission principle and present Research [D] Beijing University of Technology, 2001： pp44-50.Carbon Change La2O3The chemical balance of-Mo alloys：
3Mo2C(s)+La2O3(s)=2La (s, l)+3CO (g)+6Mo
Due to Mo2The effect of C, the reduction reaction free enthalpy variation for generating simple substance La is small very much, to reaction product La With the also high 10 several orders of magnitude of the equilibrium partial pressure of CO.When temperature is higher than 1673K, i.e., 1400 DEG C, CO partial pressures are less than E-9atm When, reaction equation can carry out to the right automatically, i.e. reduction generates simple substance La.
Patent document 2：The antifriction alloy hardness of 105695884 B of Authorization Notice No. CN, preparation are HRC66~70, punching Hit 4~9J/cm of toughness2.The hardness of such alloy is higher, but impact flexibility is insufficient, and intensity index is relatively low, and bending strength is relatively low, In 346~477MPa ranges, the occasion that the Alloyapplication is big in some external loads, impact resistance is needed to act on is limited.
Document 3：The rapid cooling organization and performance of eutectic Fe-Cr-B-C alloys, casting, 2017,66 (10):1053~1056. The rapid cooling tissue of as cast condition Fe-Cr-B-C alloys by martensite+retained austenite matrix and along the continuous net-shaped distribution of crystal boundary (Fe, Cr)2(B,C)+(Fe,Cr)23(B,C)6Hard phase composition.The microhardness of rapid cooling tissue matrix phase is 800~880HV, hard Phase microhardness is 1150~1400HV, macrohardness HRC68, and impact flexibility reaches 13.6J/cm2；And it is moved back through 960 DEG C of@2h After fire, matrix is changed into ferrite and nodular cementite, hard phase (Fe, Cr)2(B, C) and (Fe, Cr)23(B,C)6On a small quantity There is suspension, cenotype (Fe, Cr) occur in dissolving, regional area3(B, C), matrix phase microhardness is 330~400HV after annealing, Hard phase is 850~1250HV, and macrohardness is reduced to HRC46, and impact flexibility is reduced to 3.4J/cm2.3 acquired results of document Reflect that the hardness of matrix phase plays significant role to the hardness and impact flexibility of such material；Using high temperature solid solution quenching-low temperature Temper, is improved the solid solubility of matrix phase and the possibility of hardness, referenced patent document 2, such alloy after Overheating Treatment, There is the possibility promoted in aspect of performance such as impact flexibility.
Invention content
The object of the present invention is to provide a kind of strontium nitrate toughening high hard alloy and its casting and heat treatment methods.This method is adopted It is alterant with strontium nitrate, the carbide, boride in high temperature melting state Fe-Cr-B-C alloys, which have, promotes high activity Sr The thermodynamic condition that element is formed, and form compound containing Sr in C, B so that casting alloy structure refinement, carbon boride occur Suspension shape and presentation graininess distribution；After heat treatment, matrix is that the polynary supersaturated solid solution of high rigidity, martensite etc. are non-flat Weigh phase so that alloy has good toughness, high rigidity and higher intensity index.
Since strontium nitrate powder density is very low, being added directly into melt can float with clinker and cause Sr loss of elements, from And lose modification effect, therefore the present invention using strontium nitrate powder and iron powder after mixing, be molded into powder compact, then with Fe-Cr-B-C casting alloys melt together.The weight ratio of strontium nitrate powder and iron powder substantially 1:3~10, that is, form Fe-3.80 The mixing briquetting of~10.46wt.%Sr.The too high levels of the too low then Fe of Sr amounts, can influence burdening calculation；And Sr content mistakes High then green compact forming difficulty.Wherein strontium nitrate is white amorphous powder, and nitric acid content of strontium is more than 99.0%, therefore pure to its Degree and granularity are not strict with.Since strontium nitrate is hydrated compound, dry, dehydration is done before dispensing.Fe Powder is reduction Fe powder or water atomization Fe powder, can contain the member in the alloying element or impurity ranges in modified cast iron in Fe powder Element, such as Ni, V, Cr, being subject to does not influence briquette forming and influence burdening calculation.
The high-wearing feature for the patent document 2 that the present invention selects, high corrosion-resistant Fe-Cr-B-C alloys are basic alloy, then are added Add 0.04~1.0%Sr elements rotten.The multi-element eutectic alloy containing elements such as Fe, Cr, B, C, Nb, V, Sr is formed, each element Mass percentage is Cr：9.0~13.0, B：2.6~2.9, C：0.7~0.9, Nb：0.4~0.8, V：0.4~0.8, Mn's Content is less than 0.3, Sr：0.04~1.0, S, P：≤ 0.01, surplus Fe.Wherein C, B summation：3.3~3.6；C/Cr content ratios： 0.06~0.08；The summation of Nb, V are 0.5~1.0.
With reference to patent document 2, it is specific prepare alloy when, can be used ferrochrome (high-carbon, middle carbon, micro- carbon), ferro-boron, ferro-niobium, Vanadium iron, pure iron, etc. according to component requirements dispensing.Raw material and its composition are listed in table 1.
Table 1 can be applied to prepare the raw material and composition of invention alloy
The material composition of table 1 is not unique, and specific ingredient raw material obtained by reality determine.Wherein ferrochrome, Crome metal, ferro-boron, ferro-niobium and vanadium iron provide the content of Cr, B, Nb and V of invention alloy, and high carbon ferro-chrome is used for balancing C content.It is pure Iron can be electrical pure iron, electromagnetic pure iron or ingot iron.
The method specifically comprises the following steps：
(1) Fe- strontium nitrates powder compact prepares
After mixing using iron powder and strontium nitrate powder, it is molded into powder compact.The weight ratio of strontium nitrate powder and iron powder is big It causes to be 1:3~10, that is, form the Fe- strontium nitrate mixing briquettings of Fe-3.80~10.46%Sr.The load to go bad as rare earth Sr Body.
(2) alloying ingredient, melting and Metamorphism treatment
After weighing good corresponding raw material according to the component requirements proportioning of Fe-Cr-B-C alloys, then add 0.04~1.0% Sr elements are rotten.Fe- strontium nitrate powder compacts are positioned over furnace bottom first, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium Iron and pure iron.Induction furnace, vaccum sensitive stove etc. can be used carry out melting and prepares alloy.Fusion temperature is higher than 1480~1580 DEG C；So After reduce furnace power, after melt temperature is down to 1300~1360 DEG C, with the fine aluminium deoxidation of dispensing total amount 0.1~0.15%； Continue heat preservation and stands about 5~10 minutes.
(3) it casts
Ranging from 1250~1300 DEG C of cast temperature.Designed alloy has deep eutectic ingredient, is molded in normal sands Non-equilibrium matrix can be formed under the conditions of making, such as amorphous, nanocrystalline or martensitic structure.Since designed alloy is total Brilliant ingredient, melt have good mobility fine, can casting and forming by various methods, such as normal sands Mold casting or The special casting method such as model casting, lost foam casting, permanent mold casting, ceramic mold casting, die casting, centrifugal casting.In order to keep away Exempt from that thermal stress-cracking occurs, die sinking temperature will be less than 200 DEG C after having cast, and naturally cool to environment temperature.
(4) it is heat-treated
Casting is put into box stove heat, heating temperature is 950~1060 DEG C, and soaking time is 1~4h.Heat temperature raising Speed is no more than 10 DEG C/min.
After heat preservation, casting is quickly entered to 5~15% brine or buck quenching cooling.It should constantly be stirred in cooling procedure It mixes, quenches cooling time >=30min.
Then in 200~250 DEG C of 2~4h of temper, environment temperature is naturally cooled to.
Step (1) described iron powder is purity >=98.5%, the reduced iron powder or purity >=99.0% of -100 mesh of granularity, grain Spend the water-atomized iron powder of -100 mesh, or quite granularity contains a small amount of alloy iron powder for not influencing casting alloy ingredient.Also may be used To select the powder of smaller particle size, the compact strength with follow-up dispensing and furnace charge preparation is not influenced can be pressed by being subject to.
Step (1) is described to be uniformly mixed into mixed cartridge type batch mixing, V-type batch mixing or stir mixing, substantial uniform to realize .
Step (1) described green compact is die forming, and pressing pressure is 100~600MPa, and green compact size is unlimited.It can also adopt Take isostatic cool pressing method.
The purpose that Fe- strontium nitrate powder compacts are positioned over furnace bottom is by step (2)：The substances such as ferrochrome, ferro-boron have than The low fusion temperature of pure iron, therefore can preferentially melt and be impregnated into the Fe- strontium nitrate powder compacts of bottom so that straight iron powder is gradually Fusing；Strontium nitrate resolves into tiny SrO and oxynitrides under by heat effect simultaneously.Wherein oxynitrides gas molecule Floating-upward process contribute to solution to remove the gred；And the density of the fine particle SrO released is relatively low, about 4.70g/cm3, can be by Gradually upper emersion melt.In the process that SrO powder floats, by Fe3C、Cr3C2Equal carbide restore to form active Sr elements, and with C, B Reaction forms and is similar to Sr (B, C)6Compound.By the metamorphism of Sr, the reticular structure of distribution along crystal boundary and needle-shaped boron Compound disappears, and alloy is made of primary crystal matrix phase and eutectic structure, and this eutectic structure is worn by tiny matrix phase with hard phase It inserts and forms so that the intensity and impact flexibility of alloy are improved.The SrO particles that strontium nitrate is pyrolyzed are more tiny, anti- Speed is answered to accelerate, the tiny dispersion of reaction product, modification effect is reinforced.
The CO gases formed in SrO powder floating, reaction process also have the effect of degasification, slagging-off, to which further purification is molten Body.
If strontium nitrate powder is not previously prepared to be positioned over furnace bottom at briquetting, it is easy to float to bath surface, melt rapidly Surface oxygen content is high, and the SrO for being pyrolyzed generation is not easy to be reduced to form active Sr, and modification effect weakens.
The Fe3C、Cr3C2Equal carbide are formed by C and Fe element reactions when high carbon ferro-chrome and fusing, due to Fe3C、 Cr3C2The stability of equal carbide at high temperature is not so good as Mo2C, and the temperature melted is more than 1400 DEG C of reactions described in document 1 Temperature, the partial pressure of CO gases is also extremely low in melt；And the property of Sr and La is much like, thus it is similar to document 1, it generates The reduction reaction of active Sr can carry out.EDS energy spectrum analysis, which also indicates that, contains Sr elements in casting alloy object phase.
Step (4) is when hardening heat is 950~1060 DEG C, as hardening heat increases, some dissolving of hard phase Into matrix phase so that matrix phase volume fraction increases, while alloying element content also improves in matrix phase, can be formed after quenching The martensitic structure of more high rigidity.Hereby it is ensured that whole hardness and comprehensive performance.
The tissue of Fe-Cr-B-C alloys is cast mainly by hard phase (Fe2B or M2B etc.) and matrix phase (α or martensitic phase) Composition.The hardness of alloy depends primarily on the volume ratio of hard phase, i.e. hard phase is higher, and the hardness of material is bigger.But due to hard Matter is mutually excessive, and matrix phase intensity is relatively low, integral hardness can be caused to decline, toughness is insufficient.Therefore, in addition to hard phase and matrix phase Ratio is outside determinant, and the characteristic of matrix phase is also critically important.When hardening heat is less than 950 DEG C, hard phase can be analysed from matrix Go out so that material hardness declines, the reductions such as impact flexibility.Continue raising hardening heat and reach 1100 DEG C, office in casting can be caused Portion's burning so that alloy ductility declines.
The Fe-Cr-B-C alloys that are not limited to of Sr Modification Manners of the present invention, can also be applied to other cast irons and C contents compared with High smelting iron and steel is rotten, micronization processes.
The present invention be mainly characterized by directly strontium nitrate powder use to be mixed with iron powder, formation powder compact, as Sr elements change Matter carrier.When high temperature melting, strontium nitrate is pyrolyzed into SrO, utilizes Fe in Fe-Cr-B-C alloy high-temp melts3C、Cr3C2Deng carbonization The reduction of object forms activity Sr elements, and is reacted with C, B, is formed and is similar to Sr (B, C)6Compound, avoid the occurrence of boron Compound is netted and acicular texture, promotes tiny eutectic structure to be formed, plays the rotten toughening effect of thinning microstructure.Again by quenching Fire-temper so that volume fraction, solid solubility and the hardness of matrix phase increase, so as to improve matrix phase and boron, carbon compound Between rapport.Ingot casting integral hardness reaches HRC66.5~70.0, and impact flexibility reaches 13.8~18.0J/cm2, bending resistance Intensity reaches 1336~1664MPa.
Description of the drawings
1 cast sturcture of Fig. 1 present examples schemes；
1 casting alloy X-ray diffracting spectrum of Fig. 2 present examples；
The EDS collection of illustrative plates and ingredient of 1 casting matrix phase of Fig. 3 present examples.
Specific implementation mode
The various method of smelting of the present invention, casting method are not limited by following examples, and any right in the present invention is wanted The improvement in range and variation for asking book claimed are all within protection scope of the present invention.
Select high carbon ferro-chrome, chromic carbide iron, crome metal, ferro-boron, ferro-niobium, vanadium iron, ingot iron, straight iron powder, strontium nitrate powder, Fine aluminium etc. is raw material, and alloy is configured in the composition range that invention requires.
Embodiment 1. uses iron powder after mixing, to be molded into powder compact with strontium nitrate powder.Strontium nitrate powder and iron powder Weight ratio substantially 1:3, that is, the Fe- strontium nitrate mixing briquettings of Fe-10.46wt.%Sr are formed, the load to go bad as rare earth Sr Body.
Select high carbon ferro-chrome, chromic carbide iron, ferro-boron, ferro-niobium, vanadium iron, ingot iron and above-mentioned Fe- strontium nitrates mixing briquetting For raw material, composition range is as follows：Cr:10.0wt.%；B:2.9wt.%；C:0.7wt.%；Nb:0.4wt.%；V: 0.2wt.%；Sr:1.0wt.%；Impurity element control is shown in Table 2.The impurity such as a small amount of Al, Mn, N will not cause alloy property basic Property variation, therefore it is unlisted in table 2.
After weighing good corresponding raw material according to component requirements proportioning, using induction melting and sand mold die cast.Specific steps For：
Fe- strontium nitrate powder compacts are positioned over furnace bottom, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure Iron.Fusion temperature is 1580 DEG C；Until completely melted, furnace power is reduced, it is total with dispensing after melt temperature is down to 1360 DEG C The fine aluminium deoxidation of amount 0.15%；Continue heat preservation and stands about 10 minutes.Ranging from 1300 DEG C of cast temperature.Temperature is molded after having cast Less than 200 DEG C, environment temperature is naturally cooled to.
Then casting is put into box stove heat, heating temperature is 950 DEG C, soaking time 4h.Heat temperature raising speed No more than 10 DEG C/min.After heat preservation, casting is quickly entered to 5% brine hardening cooling.It should be stirred continuously in cooling procedure, Quench cooling time >=30min.Then in 200 DEG C of temper 4h, environment temperature is naturally cooled to.
Fig. 1 is casting alloy tissue, and based on Fe primary phases and eutectic phase, wherein eutectic phase is Fe phases and boron, carbon compound The eutectic structure of object；Fig. 2 be casting alloy X-ray diffracting spectrum, display alloy substrate be α-Fe phases, diffraction maximum compared with Width, and it is wider nearby at 65 °, therefore be the martensitic phase for having a large amount of Cr solid solutions, carbon, boron compound Fe2B、Fe3C and Cr23C6 Based on complex chemical compound, and show Sr (B, C)6Compound exists；Fig. 3 be casting alloy matrix phase EDS collection of illustrative plates and As a result analysis result, EDS can only show in alloy there are Sr elements in the qualitative analysis of ingredient, illustrate that SrO is produced with melt Effect makes Sr elements that alloying occur, plays melt metamorphism.
Gained ingot casting integral hardness reaches HRC67.7, and impact flexibility reaches 13.8J/cm2, bending strength reaches 1434MPa。
Embodiment 2. uses iron powder after mixing, to be molded into powder compact with strontium nitrate powder.Strontium nitrate powder and iron powder Weight ratio substantially 1:10, that is, the Fe- strontium nitrate mixing briquettings of Fe-3.80wt.%Sr are formed, the load to go bad as rare earth Sr Body.
It is raw material, ingredient to select high carbon ferro-chrome, crome metal, ferro-boron, ferro-niobium, ingot iron and above-mentioned Fe-SrO mixing briquetting Range is as follows：Cr:10.0wt.%；B:2.7wt.%；C:0.7wt.%；Nb:0.5wt.%；Sr:0.04wt.%；Impurity member Element control is shown in Table 2.The impurity such as a small amount of Al, Mn, N will not cause alloy property essence to change, therefore unlisted in table 2.
After weighing good corresponding raw material according to component requirements proportioning, vacuum induction melting and the casting of water cooling swage can be used It makes.The specific steps are：
Fe- strontium nitrate powder compacts are positioned over furnace bottom, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium and pure iron.It is molten It is 1480 DEG C to change temperature；Until completely melted, furnace power is reduced, after melt temperature is down to 1300 DEG C, with dispensing total amount 0.1% fine aluminium deoxidation；Continue heat preservation and stands about 5 minutes.Ranging from 1250 DEG C of cast temperature.Die sinking temperature is wanted after having cast Less than 200 DEG C, environment temperature is naturally cooled to.
Then casting is put into box stove heat, heating temperature is 1050 DEG C, soaking time 1h.Heat temperature raising speed No more than 10 DEG C/min.After heat preservation, casting is quickly entered to 15% brine hardening cooling.It should constantly be stirred in cooling procedure It mixes, quenches cooling time >=30min.Then in 250 DEG C of temper 2h, environment temperature is naturally cooled to.
Gained ingot casting integral hardness reaches HRC68.1, and impact flexibility reaches 17.0J/cm2, bending strength reaches 1336MPa。
Embodiment 3. uses iron powder after mixing, to be molded into powder compact with strontium nitrate powder.Strontium nitrate powder and iron powder Weight ratio substantially 1:8, that is, the Fe- strontium nitrate mixing briquettings of Fe-4.65wt.%Sr are formed, the load to go bad as rare earth Sr Body.
It is raw material to select high carbon ferro-chrome, chromic carbide iron, ferro-boron, ferro-niobium, ingot iron and above-mentioned Fe-SrO mixing briquetting, at Divide range as follows：Cr：10.0wt.%；B：2.7wt.%；C:0.8wt.%；Nb:0.6wt.%； Sr:0.8wt.%；Impurity member Element control is shown in Table 2.The impurity such as a small amount of Al, Mn, N will not cause alloy property essence to change, therefore unlisted in table 2.
After good corresponding raw material being weighed according to component requirements proportioning, using induction melting and model casting, the specific steps are：
Fe- strontium nitrate powder compacts are positioned over furnace bottom, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure Iron.Fusion temperature is 1560 DEG C；Until completely melted, furnace power is reduced, it is total with dispensing after melt temperature is down to 1320 DEG C The fine aluminium deoxidation of amount 0.12%；Continue heat preservation and stands about 8 minutes.Ranging from 1280 DEG C of cast temperature.Temperature is molded after having cast To be less than 200 DEG C, naturally cool to environment temperature.
Then casting is put into box stove heat, heating temperature is 1000 DEG C, soaking time 2h.Heat temperature raising speed No more than 10 DEG C/min.After heat preservation, casting is quickly entered to 10% brine hardening cooling.It should constantly be stirred in cooling procedure It mixes, quenches cooling time >=30min.Then in 220 DEG C of temper 3h, environment temperature is naturally cooled to.
Gained ingot casting integral hardness reaches HRC69.9, and impact flexibility reaches 17.4J/cm2, bending strength reaches 1574MPa。
Embodiment 4. uses iron powder after mixing, to be molded into powder compact with strontium nitrate powder.Strontium nitrate powder and iron powder Weight ratio substantially 1:5, that is, the Fe- strontium nitrate mixing briquettings of Fe-6.97wt.%Sr are formed, the load to go bad as rare earth Sr Body.
It is original to select high carbon ferro-chrome, crome metal, ferro-boron, ferro-niobium, vanadium iron, ingot iron and above-mentioned Fe-SrO mixing briquetting Material, composition range are as follows：Cr：11.0wt.%；B：2.7wt.%；C:0.7wt.%；Nb:0.2wt.%； V:0.4wt.%； Sr:0.6wt.%；Impurity element control is shown in Table 2.The impurity such as a small amount of Al, Mn, N will not cause alloy property essence to change, because This is unlisted in table 2.
After good corresponding raw material being weighed according to component requirements proportioning, using induction melting and sand casting, the specific steps are：
Fe- strontium nitrate powder compacts are positioned over furnace bottom, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure Iron.Fusion temperature is 1560 DEG C；Until completely melted, furnace power is reduced, it is total with dispensing after melt temperature is down to 1340 DEG C The fine aluminium deoxidation of amount 0.13%；Continue heat preservation and stands about 9 minutes.Ranging from 1280 DEG C of cast temperature.Temperature is molded after having cast To be less than 200 DEG C, naturally cool to environment temperature.
Then casting is put into box stove heat, heating temperature is 1060 DEG C, soaking time 2h.Heat temperature raising speed No more than 10 DEG C/min.After heat preservation, the buck that casting is quickly entered to 5% quenches cooling.It should be stirred continuously in cooling procedure, Quench cooling time >=30min.Then in 220 DEG C of temper 2h, environment temperature is naturally cooled to.
Gained ingot casting integral hardness reaches HRC67.1, and impact flexibility reaches 14.6J/cm2, bending strength reaches 1342MPa。
Embodiment 5. uses iron powder after mixing, to be molded into powder compact with strontium nitrate powder.Strontium nitrate powder and iron powder Weight ratio substantially 1:4, that is, the Fe- strontium nitrate mixing briquettings of Fe-8.37wt.%Sr are formed, the load to go bad as rare earth Sr Body.
Select high carbon ferro-chrome, chromic carbide iron, ferro-boron, ferro-niobium, vanadium iron, ingot iron and above-mentioned Fe- strontium nitrates mixing briquetting For raw material, composition range is as follows：Cr：10.0wt.%；B：2.6wt.%；C：0.6wt.%； Nb：0.3wt.%；V： 0.1wt.%；Sr:0.4wt.%；Impurity element control is shown in Table 2.The impurity such as a small amount of Al, Mn, N will not cause alloy property basic Property variation, therefore it is unlisted in table 2.
After weighing good corresponding raw material according to component requirements proportioning, using induction melting and lost foam casting, specific steps It is as follows：
Fe- strontium nitrate powder compacts are positioned over furnace bottom, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure Iron.Fusion temperature is 1550 DEG C；Until completely melted, furnace power is reduced, it is total with dispensing after melt temperature is down to 1325 DEG C The fine aluminium deoxidation of amount 0.12%；Continue heat preservation and stands about 6 minutes.Ranging from 1285 DEG C of cast temperature.Temperature is molded after having cast To be less than 200 DEG C, naturally cool to environment temperature.
Then casting is put into box stove heat, heating temperature is 980 DEG C, soaking time 3h.Heat temperature raising speed No more than 10 DEG C/min.After heat preservation, the buck that casting is quickly entered to 15% quenches cooling.It should constantly be stirred in cooling procedure It mixes, quenches cooling time >=30min.Then in 220 DEG C of temper 3h, environment temperature is naturally cooled to.
Gained ingot casting integral hardness reaches HRC66.5 toughness and reaches 16.0J/cm2, bending strength reaches 1664MPa.
Embodiment 6. uses iron powder after mixing, to be molded into powder compact with strontium nitrate powder.Strontium nitrate powder and iron powder Weight ratio substantially 1:6, that is, the Fe- strontium nitrate mixing briquettings of Fe-5.98wt.%Sr are formed, the load to go bad as rare earth Sr Body.
It is raw material to select high carbon ferro-chrome, chromic carbide iron, ferro-boron, ferro-niobium, ingot iron and above-mentioned Fe-SrO mixing briquetting, at Divide range as follows：Cr：10.0wt.%；B：2.6wt.%；C：0.8wt.%；Nb：0.8wt.%； Sr:0.2wt.%；Impurity member Element control is shown in Table 2.The impurity such as a small amount of Al, Mn, N will not cause alloy property essence to change, therefore unlisted in table 2.
It is specific to walk using vacuum induction melting and iron mould casting after weighing good corresponding raw material according to component requirements proportioning It is rapid as follows：
Fe- strontium nitrate powder compacts are positioned over furnace bottom, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure Iron.Fusion temperature is 1560 DEG C；Until completely melted, furnace power is reduced, it is total with dispensing after melt temperature is down to 1315 DEG C The fine aluminium deoxidation of amount 0.14%；Continue heat preservation and stands about 7 minutes.Ranging from 1290 DEG C of cast temperature.Temperature is molded after having cast To be less than 200 DEG C, naturally cool to environment temperature.
Then casting is put into box stove heat, heating temperature is 1020 DEG C, soaking time 2h.Heat temperature raising speed No more than 10 DEG C/min.After heat preservation, the buck that casting is quickly entered to 10% quenches cooling.It should constantly be stirred in cooling procedure It mixes, quenches cooling time >=30min.Then in 220 DEG C of temper 3h, environment temperature is naturally cooled to.
Gained ingot casting integral hardness reaches HRC70.0, and impact flexibility reaches 16.8J/cm2, bending strength reaches 1538MPa。
Embodiment 7. uses iron powder after mixing, to be molded into powder compact with strontium nitrate powder.Strontium nitrate powder and iron powder Weight ratio substantially 1:7, that is, the Fe- strontium nitrate mixing briquettings of Fe-5.23wt.%Sr are formed, the load to go bad as rare earth Sr Body.
Select high carbon ferro-chrome, chromic carbide iron, ferro-boron, ferro-niobium, vanadium iron, ingot iron and above-mentioned Fe- strontium nitrates mixing briquetting For raw material, composition range is as follows：Cr：11.0wt.%；B：2.6wt.%；C：0.9wt.%； Nb：0.2wt.%；V： 0.2wt.%；Sr:0.10wt.%；Impurity element control is shown in Table 2.The impurity such as a small amount of Al, Mn, N will not lead to alloy property root Person's character changes, therefore unlisted in table 2.
After weighing good corresponding raw material according to component requirements proportioning, induction melting and lost foam casting can be used.Specific step It is rapid as follows：
Fe- strontium nitrate powder compacts are positioned over furnace bottom, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure Iron.Fusion temperature is 1500 DEG C；Until completely melted, furnace power is reduced, it is total with dispensing after melt temperature is down to 1300 DEG C The fine aluminium deoxidation of amount 0.13%；Continue heat preservation and stands about 8 minutes.Ranging from 1250 DEG C of cast temperature.Temperature is molded after having cast To be less than 200 DEG C, naturally cool to environment temperature.
Then casting is put into box stove heat, heating temperature is 1020 DEG C, soaking time 1h.Heat temperature raising speed No more than 10 DEG C/min.After heat preservation, the buck that casting is quickly entered to 15% quenches cooling.It should constantly be stirred in cooling procedure It mixes, quenches cooling time >=30min.Then in 200 DEG C of temper 4h, environment temperature is naturally cooled to.
Gained ingot casting integral hardness reaches HRC67.7, and impact flexibility reaches 17.2J/cm2, bending strength reaches 1398MPa。
Embodiment 8. uses iron powder after mixing, to be molded into powder compact with strontium nitrate powder.Strontium nitrate powder and iron powder Weight ratio substantially 1:8, that is, the Fe- strontium nitrate mixing briquettings of Fe-4.65wt.%Sr are formed, the load to go bad as rare earth Sr Body.
Select high carbon ferro-chrome, chromic carbide iron, ferro-boron, ferro-niobium, vanadium iron, ingot iron and above-mentioned Fe- strontium nitrates mixing briquetting For raw material, composition range is as follows：Cr：13.0wt.%；B：2.6wt.%；C：0.8wt.%； Nb：0.6wt.%；V： 0.4wt.%；Sr:0.05wt.%；Impurity element control is shown in Table 2.The impurity such as a small amount of Al, Mn, N will not lead to alloy property root Person's character changes, therefore unlisted in table 2.
After weighing good corresponding raw material according to component requirements proportioning, using induction melting and lost foam casting, specific steps It is as follows：
Fe- strontium nitrate powder compacts are positioned over furnace bottom, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure Iron.Fusion temperature is 1550 DEG C；Until completely melted, furnace power is reduced, it is total with dispensing after melt temperature is down to 1330 DEG C The fine aluminium deoxidation of amount 0.12%；Continue heat preservation and stands about 6 minutes.Ranging from 1260 DEG C of cast temperature.Temperature is molded after having cast To be less than 200 DEG C, naturally cool to environment temperature.
Then casting is put into box stove heat, heating temperature is 980 DEG C, soaking time 2h.Heat temperature raising speed No more than 10 DEG C/min.After heat preservation, the buck that casting is quickly entered to 10% quenches cooling.It should constantly be stirred in cooling procedure It mixes, quenches cooling time >=30min.Then in 200 DEG C of temper 2h, environment temperature is naturally cooled to.
Gained ingot casting integral hardness reaches HRC68.7, and impact flexibility reaches 18.0J/cm2, bending strength reaches 1646MPa。
Casting alloy performance detection prepared by each embodiment is as described below：
1. pair example casting metal carries out hardness test using HR-150A Rockwell hardness machines, load 150Kg makes a call to five It is averaged after point, is listed in table 2.
2. pair example casting metal carries out impact flexibility test using JBS-300B shock machines, range 150J is beaten It is averaged after five samples, is listed in table 2.
3. pair example casting metal material electronics universal testing machine carries out three-point bending resistance experiment, sample size is 2 × 5 × The rectangular specimen of 50mm, span 30mm take the bending strength average value of three same treatment samples to be listed in table 2.
The ingredient of 2 embodiment of table and hardness, impact flexibility and bending strength

Claims (4)

1. a kind of strontium nitrate toughening high hard alloy, it is characterised in that：The mass percentage of each element is Cr：9.0~13.0, B： 2.6~2.9, C：0.7~0.9, Nb：0.4~0.8, V：The content of 0.4~0.8, Mn are less than 0.3, Sr：0.04~1.0, S, P： ≤ 0.01, surplus Fe；The gross mass percentage composition of wherein C, B is：3.3~3.6；C/Cr mass ratioes：0.06~0.08；Nb、V Gross mass percentage composition be：0.5~1.0.
2. casting and the heat treatment method of strontium nitrate toughening high hard alloy as described in claim 1, it is characterised in that including with Lower step：
(1) Fe- strontium nitrates powder compact prepares
After mixing using iron powder and strontium nitrate powder, it is molded into powder compact, the weight ratio of strontium nitrate powder and iron powder is 1:3~ 10, the Fe- strontium nitrate mixing briquettings of Fe-3.80~10.46%Sr are formed, the carrier to go bad as rare earth Sr；
(2) alloying ingredient, melting and Metamorphism treatment
After weighing good corresponding raw material according to the component requirements proportioning of Fe-Cr-B-C alloys, then add 0.04~1.0%Sr elements It is rotten：Fe- strontium nitrate powder compacts are positioned over furnace bottom first, are then placed in ferrochrome, crome metal, ferro-boron, ferro-niobium, vanadium iron and pure Iron prepares alloy using induction furnace melting, and fusion temperature is 1480~1580 DEG C；Then furnace power is reduced, by melt temperature After being down to 1300~1360 DEG C, with the fine aluminium deoxidation of dispensing total amount 0.1~0.15%；Continue heat preservation and stands 5~10 minutes；
(3) it casts
Ranging from 1250~1300 DEG C of cast temperature, designed alloy has deep eutectic ingredient, in common sand casting item Non-equilibrium matrix can be formed under part, by various methods casting and forming, in order to avoid thermal stress-cracking occurs, cast Die sinking temperature will be less than 200 DEG C afterwards, naturally cool to environment temperature；
(4) it is heat-treated
Casting is put into box stove heat, is heated to 950~1060 DEG C, is kept the temperature as 1~4h；Heat temperature raising speed is no more than 10 DEG C/min, after heat preservation, casting is added to 5~15% brine or buck quenching cooling, is stirred continuously, quenches in cooling procedure Fiery cooling time >=30min；Then in 200~250 DEG C of 2~4h of temper, environment temperature is naturally cooled to.
3. casting and the heat treatment method of strontium nitrate toughening high hard alloy as claimed in claim 2, it is characterised in that：Step (1) iron powder is purity >=98.5%, the reduced iron powder or purity >=99.0% of -100 mesh of granularity, the water of -100 mesh of granularity The alloy iron powder of -100 mesh of atomized iron powder or granularity.
4. casting and the heat treatment method of strontium nitrate toughening high hard alloy as claimed in claim 2, it is characterised in that：Step (1) green compact is die forming, and pressing pressure is 100~600MPa, or takes isostatic cool pressing method.
CN201810589778.9A 2018-06-08 2018-06-08 A kind of strontium nitrate toughening high hard alloy and its casting and heat treatment method Withdrawn CN108570618A (en)

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