CN105586501A

CN105586501A - Preparation method for iron-titanium-cobalt alloy

Info

Publication number: CN105586501A
Application number: CN201410570027.4A
Authority: CN
Inventors: 李科
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-10-23
Filing date: 2014-10-23
Publication date: 2016-05-18

Abstract

The invention discloses a preparation method for an iron-titanium-cobalt alloy. The preparation method comprises the following steps: step 101 of proportioning according to a weight ratio of WC:FeNiCo = 2.5-3:1 and ball-milling; a step 102 of drying and pelletizing pressed materials after ball-milling; and step 103 of pressing an alloy and sintering the alloy in vacuum. An iron-titanium alloy prepared by the preparation method for the iron-titanium-cobalt alloy can be adopted to obtain a structure with high strength and good impact resistance under a common vacuum sintering condition, and the structure is an ideal material for replacing YG20C. In a sintering process, binder metal has good wettability on WC, and is relatively strong in liquid-phase filling capacity; and equipment used in a manufacturing process is almost the same as that used for preparing a conventional hard alloy, so that the cost of updating a production line can be saved better.

Description

Teleoseal preparation method

Technical field

The invention belongs to metallurgical manufacture field, relate to a kind of teleoseal preparation method.

Background technology

Kovar alloy, English: KOVAR['k: v ɑ :]; Translation: can cut down (also claiming to be equivalent to GB4J29, ASTMF15, UNSK94610 by teleoseal); KOVAR is nickeliferous 29%, the Bohemian glass iron-based sealing alloy of cobalt 17%. This alloy has the linear expansion coefficient close with Bohemian glass and corresponding Bohemian glass within the scope of 20 ~ 450 DEG C can carry out effective sealing-in and mate, higher curie point and good low temperature structure stability, the oxide-film densification of alloy, easily welding and welding, have good plasticity, machinable, be widely used in and make electrovacuum element, transmitting tube, kinescope, switching tube, transistor and sealing plug and relay1 case etc.

Research to cold pier cold-punching mould at present, its main damage form has two kinds, one is wear-out failure, mainly to sweep away in continuous upsetting repeatedly, the friction of workpiece and mould and cause the wearing and tearing of grinding tool, the destruction that dimension overproof causes, another kind is cracking destruction, main cause is under repeated stock, makes mould fatigue cracking.. Numerous in the situation that, cracking is the main damage form of mould. The fatigue performance of strengthening mould and shock resistance become the main path in service life. For carbide alloy, on the left branch line of alloy, strengthen exactly the length of free path, to improve intensity, alloy rigidity declines to some extent simultaneously. The hardness of alloy is the guarantee that mould has excellent abrasive resistance. High hardness and mould fragility is strengthened, impact resistance just reduces, and has caused mould easy to crack, and low hardness can not meet instructions for use. Should keep high hardness number to meet again the bending strength of alloy mold enough high, be very important in selection. In the selection of alloy, high cobalt alloy YG20 or YG20C just become the preferred material of cold pier cold-punching mold, extensive use in industry, and the destruction that facts have proved YG20 and YG20C material is seldom the problem of size wearing and tearing, and be often the destruction-cracking destruction of the second form, so want to improve the service life of mould, be just summed up as the bending strength and the shock resistance that improve material.

The bending strength of high-cobalt hart metal and shock resistance will be good than low cobalt alloy many, but also strengthened the cost of alloy. Although selecting high-cobalt hart metal YG20 and YG20C is the first-selection of cold pier cold-punching mold material, its combination property is also good than other alloy, and practice has also proved this point. Its common failure mode of the cold pier cold-punching mold of widely used YG20 and YG20C remains cracking destruction, meanwhile, expensive due to cobalt, its application is also restricted.

Summary of the invention

For overcoming traditional high-cobalt hart metal bending strength and shock resistance deficiency, the technological deficiency of cost costliness, the invention provides a kind of teleoseal preparation method simultaneously.

Teleoseal preparation method, comprises the steps:

Step 101 ball milling of preparing burden: carry out ball milling according to the proportioning of part by weight WC:FeNiCo=2.5:1 to 3:1, WC is tungsten carbide;

Step 102, after ball milling completes to binder drying and granulating;

Step 103 is suppressed alloy vacuum-sintering;

Mass ratio FE:Ni=1.5-2.5:1 in described FeNiCo.

Preferably, in described step 101, adopt wet-milling mode when ball milling.

Concrete, in described step 101, the wet-milling time is no less than 20 hours.

Preferably, part by weight WC:FeNiCo=7:3 in described step 101.

Preferably, pressure when described step 103 is suppressed is 150-350 MPa.

Preferably, in described step 103, sintering temperature is 1360-1400 degree Celsius.

The iron-nickel alloy that adopts teleoseal preparation method of the present invention to make, under the condition of conventional vacuum sintering, can obtain the institutional framework that intensity is high, shock resistance is good, is the ideal material that substitutes YG20C. In sintering process, Binder metal is good to WC wetability, and liquid phase filling capacity is stronger, and the equipment using in process for making and traditional carbide alloy are roughly the same, can well save the cost that upgrades production line.

Detailed description of the invention

Below the specific embodiment of the present invention is described in further detail.

At present, Fe, Ni also often appear in Hardmetal materials as cementing phase, but still can not replace cobalt completely. Fe, Co, Ni are same gang element, with WC(tungsten carbide) phasor of composition is also quite similar, and to the wetability of WC, cobalt, nickel are the same in a vacuum, angle of wetting equals zero, and iron is poor, solubility is also different, and the molten WC of Ni is 12 ~ 20%, Co is 10 ~ 15%, and Fe minimum, cementing strength and the grain size of recrystallization speed when it must have influence on sintering, cementing and WC, thus alloy strength performance affected. Thereby improve the effective means that wetability also will become improves alloy strength.

In Fe, add the Ni of some, can improve the wetability of cementing relative WC, meanwhile, Fe and Ni form unlimited solid solution, can make Fe be strengthened. Practice shows, the alloy property of the cementing system mutually of iron nickel of Fe:Ni=3:1 is best. In this its tissue of cementing carbide alloy, be prone to η phase, in order to prevent the appearance of η phase, can in compound, add a small amount of carbon black, simultaneously also can reinforced iron-base tissue. For the bonding strength of the cementing phase of alloying and raising and WC adds a certain amount of Co powder, microhardness result at Co-WC and Ni-WC solid solution shows, it is larger that cobalt is compared nickel phase strengthening effect, and Co and Fe, Ni all can form unlimited solid solution, make cementing wetting further improvement and strengthening mutually, by the optimization of this institutional framework of alloy, alloy is greatly enhanced service life.

According to above-mentioned analysis, for the common failure mode of cold pier cold-punching mould, improve taking Fe-Ni-Co as main binding mutual-assistance alloy microstructure, reinforced alloys performance, development high-strength iron nickel is for the strength materials of cobalt.

Embodiment

(1) batching ball milling: WC70%-FeNiCo30%, granularity-200 order. Ratio of grinding media to material 3:1, wet-milling 20h, vacuum drying, mixes glue and granulates. WC is tungsten carbide.

(2) compacting and sintering: compacting A standard specimen (5 × 5 × 30mm) and nail clip mould.

Wherein determine suitable pressing pressure (150-350Mpa) and constriction coefficient (1.18-1.25), vacuum-sintering temperature (1360-1400 DEG C).

(1) densification process of this alloy sintering

The necessary factor that affects densification process is exactly the angle of wetting between liquid-solid phase, and the capillary pressure of liquid improves along with the reduction of the angle of wetting to WC particle, thereby the ability of liquid phase filling aperture is improved along with the reduction of the angle of wetting to solid phase. Secondly be the quantity of liquid phase, in the time that amount of liquid phase is no more than 50%, capillary pressure improves along with the increase of amount of liquid phase. Meanwhile, the flow resistance of WC particle reduces with its increase. With regard to this material, its cementing phase composition is 30% left and right, and the molten WC ability of Ni, Co is larger, therefore, the enhanced dissolution rate of WC, has increased the liquid phase of sintering, common amount of liquid phase remains on 15 ~ 36% and is advisable, and thus, is enough to ensure that densification process has enough liquid phases. Ensure the coated current downflow of WC particle in liquid phase, completed dissolving, separate out, solid-phase sintering three processes, made it completely densified, finally reached the object of sintering. In experiment, have the alloy of microscopic defect to make up completely, macrostructure observe and carrying out flaw detection without any defect, illustrating that this material is wetting improves, and stowage capacity is strengthened.

(2) impact of sintering temperature alloy performance

The amount of liquid phase of sintered body increases with the raising of sintering temperature, with regard to this material, because Fe-Co-Ni forms unlimited solid solution, effectively crystallization range is narrower, and when sintering temperature slightly changes, the concentration tonsure of liquid phase will change larger, experimental result shows, within the scope of 1360-1380 DEG C, performance is more stable, in the time reaching 1400 DEG C, more than bending strength decline 500Mpa, and sample edges of the periphery rust, illustrate that wandering tendency exists, temperature is higher again, may produce lower seat. Illustrate that thus this material sintering temperature interval is narrower, larger to temperature sensitivity, should strictly control aborning.

(3) effect of each element in alloy

Carbon is mainly the appearance of the crisp hard phase that suppresses very easily to produce in the cementing alloy of Fe-Ni, and strengthens cementing phase, and the height of its quantity also affects the height of sintering temperature. Co, Ni improve the wetability of Fe to WC, and Co solid solution has been played " pinning " effect in mutually in cementing, stops dislocation motion, strengthening matrix, and optimizing tissue structure, makes cementing strengthening mutually, ensures that densification process is complete.

(4) strength characteristics

Bending strength is to weigh an important indicator of carbide alloy, and it is a mark of alloy toughness. Bending strength is high, and its good toughness is described, shock resistance is good. This material sintered state intensity A scale monodrome reaches 3370Mpa, average out to 2880Mpa.

More than comprehensive, the iron-nickel alloy that adopts teleoseal preparation method of the present invention to make, under the condition of conventional vacuum sintering, can obtain the institutional framework that intensity is high, shock resistance is good, is the ideal material that substitutes YG20C. In sintering process, Binder metal is good to WC wetability, and liquid phase filling capacity is stronger, and the equipment using in process for making and traditional carbide alloy are roughly the same, can well save the cost that upgrades production line.

Above-described is only the preferred embodiments of the present invention, and described embodiment is not in order to limit scope of patent protection of the present invention, and the equivalent structure that therefore every utilization description of the present invention is done changes, and in like manner all should be included in protection scope of the present invention.

Claims

1. teleoseal preparation method, comprises the steps:

Step 102, after ball milling completes to binder drying and granulating;

Step 103 is suppressed alloy vacuum-sintering;

Mass ratio FE:Ni=1.5-2.5:1 in described FeNiCo.

2. a teleoseal preparation method as claimed in claim 1, is characterized in that, adopts wet-milling mode in described step 101 when ball milling.

3. a teleoseal preparation method as claimed in claim 2, is characterized in that, in described step 101, the wet-milling time is no less than 20 hours.

4. a teleoseal preparation method as claimed in claim 1, is characterized in that part by weight WC:FeNiCo=7:3 in described step 101.

5. a teleoseal preparation method as claimed in claim 1, is characterized in that, pressure when described step 103 is suppressed is 150-350 MPa.

6. a teleoseal preparation method as claimed in claim 1, is characterized in that, in described step 103, sintering temperature is 1360-1400 degree Celsius.