CN1066889A

CN1066889A - The manufacture method of tungsten carbide base carbide alloy

Info

Publication number: CN1066889A
Application number: CN 91103269
Authority: CN
Inventors: 孙景; 王洪礼
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 1991-05-16
Filing date: 1991-05-16
Publication date: 1992-12-09
Anticipated expiration: 2006-05-16
Also published as: CN1034875C

Abstract

The invention discloses a kind of manufacture method of tungsten carbide base carbide alloy.At first middle particle tungsten powder, carbon black, tricobalt tetroxide, Vanadium Pentoxide in FLAKES compound were carried out carbonization 1～1.5 hour under 950～1300 ℃ of temperature, make the carbonized stock of WC+Co+VC, add that with above-mentioned carbonized stock cobalt makes the WC-VC-Co Wimet then.Adopt this method can be very easily with in the particle tungsten powder make the Wimet of thin crystalline substance.This alloy is particularly suitable for being applied to make precise punching die.

Description

The manufacture method of tungsten carbide base carbide alloy

The present invention relates to Wimet, more particularly, the invention relates to the manufacture method of the tungsten carbide base carbide alloy that precise punching die uses.

The classical production process of tungsten carbide base carbide alloy is that elder generation adds carbon black with tungsten powder and makes wolfram varbide, adds the cobalt (3～20%) of suitable proportion then in wolfram varbide, through ball milling, oven dry, granulation, moulding and sintering, makes WC-Co series hard alloy blank.Need 1300～1900 ℃ high temperature in the tungsten powder carbonization process.High temperature cabonization not only needs to consume a large amount of energy, and is difficult to obtain the compact grained wolfram varbide.Fine grain tungsten powder can reduce carbonization temperature, produces thinner tungsten carbide powder, but the production technique of thin tungsten powder itself is very complicated, and cost is higher.

China's magazine " Wimet " has been delivered " the carbonization at low temperature legal system is got the research of WC-Co powder " literary composition on 1984 the 4th phases, this article discloses a kind of method of the WC-Co of preparation powder, with W+6.9%C+4.1%Co ₃O ₄Compound can make the WC-Co powder in 2 hours 900 ℃ of following carbonizations, total carbon about 6%, uncombined carbon is less than 0.1%.Utilize this method can make in, fine grain WC powder.In above-mentioned WC-Co powder, add a certain amount of cobalt, can make the Wimet of better performances through sintering.But the WC mean particle size of this alloy is 1.2 microns～1.6 microns, still can not satisfy the accuracy requirement of precise punching die.

When making the WC-Co alloy, grow up in order to suppress in the sintering process WC grain, often add some grain growth inhibitors, for example VC, NbC, TiC, TaC etc.Traditionally, these inhibitor all add during ball milling hybrid alloys material before sintering.

Though VC is good grain growth inhibitor, when making practical Wimet, but seldom use it.Its reason is that the adding of VC often makes the intensity of WC base cemented carbide obviously descend, and is easy to embrittlement.

The present invention adopts a kind of easy method, has but obtained beyond thought good result.

The purpose of this invention is to provide the simple and easy method that particle tungsten powder in a kind of usefulness prepares the fine-grained wc base cemented carbide.Have good hardness and bending strength with the prepared Wimet of present method, and manufacturing cost is lower.

Manufacture method of the present invention is, at first with middle particle tungsten powder, carbon black, tricobalt tetroxide, Vanadium Pentoxide in FLAKES compound, under 950～1300 ℃ of temperature, carried out carbonization 1～1.5 hour, make the carbonized stock (being weight percentage) of WC90.54～98%-Co 0～7.35%-VC0.1～3.47%, add that with above-mentioned carbonized stock cobalt makes the WC-VC-Co Wimet then.

The best proportioning of above-mentioned prepared carbonized stock is WC 92.5～96.2%-Co 3～7%-VC 0.50～3%(weight percentage); Best carbonization temperature is 1100～1170 ℃.

Characteristics of the present invention are that particle tungsten powder in the use (mean particle size 1.5-2.0 micron) just can make thin peritectic alloy.In carbonization technique,, also add Co simultaneously except that with addition of carbon black ₃O ₄And V ₂O ₅, make carbonization process under 1150 ± 20 ℃ lesser temps, carry out.This is because Co ₃O ₄After being become cobalt by hydrogen reducing, generated Co with tungsten and carbon ₃W, Co ₆W ₆C, Co ₃W ₃Intermediate products such as C play katalysis to the carbonization of tungsten powder, have promoted tungsten powder carbonization under lower temperature greatly.

Add V simultaneously at the tungsten powder carbonation stage ₂O ₅, its objective is in the tungsten powder carbonization V ₂O ₅Also be carbonized and generate VC.The benefit of doing like this is, saved the operation of independent preparation VC, the more important thing is V ₂O ₅Proportion less than VC, thereby, for the VC that adds same weight, add V ₂O ₅Volume be 2.5 times of VC, this can guarantee that material mixes more evenly.At V ₂O ₅Carbonization becomes the particle maximum in the time of can suppressing the tungsten powder carbonization in the process of VC.Prepared VC grows up to WC grain in sintering process and plays restraining effect once more, promptly plays the effect of twice inhibition.

Utilize the prepared WC-VC-Co powder of method of the present invention, according to firing condition, method adds an amount of carbon black and cobalt powder traditionally, through ball milling, oven dry, granulation, moulding, sintering, can make the Wimet blank.Existing Wimet producing apparatus and manufacturing process all are applicable to the manufacturing of Wimet of the present invention.

Below in conjunction with embodiment manufacture method of the present invention is further described.

Example 1～example 6 all adopts commercially available industrial pure material.Example 1 is the embodiment of the scope of the invention to example 5, and example 6 is a comparison example.Raw material powder in each example weighs up by the proportioning shown in the table 1.

Table 1

The example sequence number	W powder degree (micron)	Batching (Wt%)				Carbonized stock composition (wt%)
									W	Co ₃O ₄	V ₂O ₅	C	Co	Vc	wc
		1	2.0	87.26	5.44	0.7	6.6	4.1								0.5	Surplus
2	1.66								87.31	5.33	0.7	6.66	4.02	0.55	Surplus
		3	1.40	88.13	4.49	0.7	6.67	3.3								0.5	Surplus
4	1.66								81.27	9.18	0.69	6.36	7	0.5	Surplus
		5	1.66	83.92	3.88	4.11	8.09	3								3	Surplus
6	2.0								93.31	0	0	6.69	0	0	100

Before the carbonization, analyze the oxygen level of tungsten powder earlier, carbon black, V ₂O, Co ₃O ₄Baking oven inner drying 4 hours.Raw material powder mixes in the Stainless Steel Ball mill tube then, and the ratio of ball material is 2: 1, does and mixes 6 hours.The material that mixes is placed graphite boat, build, at F _e-C _rIn-Al the resistance furnace, in hydrogen atmosphere in 1100～1170 ℃ of following carbonizations 1～1.5 hour.After fragmentation, sieving, sampling analysis contains cobalt amount, total carbon content and free content.Relevant carbonization technique condition and carbonization result's situation, as shown in table 2.

Introduce the alloy of trial-production CV8 and two trades mark of CV15 below, its composition is respectively 8%Co+0.5%VC+WC and 15%Co+0.5%VC+WC.The compound WC-Co-VC that the weighing carbonization is good is equipped with an amount of carbon black according to sintering condition and after mixed 24 hours, adds an amount of cobalt powder according to required alloy designations again and continued ball milling 46 hours in the ball milling bucket, adds 3% section again

Table 2

The example sequence number	Carbonization technique		The carbonization result
					Temperature (℃)	Time (hour)	Total carbon (%)	Uncombined carbon (%)
	1	1170	1.5	5.86					＜0.05
2					1150	1.5	5.79	＜0.03
	3	1100	1.5	5.80					Vestige
4					1150	1.5	5.65	0.03
	5	1150	1.5	6.12					0.03
6					1150	1.5	Not carbonization

Paraffin mixes discharging after 2 hours.The ratio of ball material is 3～4: 1, and grinding medium is a gasoline.Slip is crossed 320 mesh sieves, is dried to suitable degree and granulates, and sieves vacuum-drying.With the alloy powder compression molding, de-waxing in hydrogen atmosphere in 1420～1460 ℃ of following sintering 1 hour, promptly makes alloy blank.The performance of the performance of these two kinds of trade mark alloys and YG8, YG15 sees Table 3.

Table 3

Alloy designations	Alloying constituent	Hardness	Bending strength (N/ mm ²)	Porosity (%)	WC grain degree (micron)
						CV8	WC+8%Co+0.5%VC	91	2000	＜0.2	0.8
CV15	WC+15%Co+0.5%VC	89.2	2230	＜0.2	0.8
						YG8	WC+8%Co	89.5	1700	＜0.2	1.8
YG15	WC+15%Co	88	2060	＜0.2	2.0

As can be seen from Table 3, the alloy CV8 for preparing with method of the present invention compares with YG15 with domestic existing YG8 with CV15, and tangible positively effect is arranged, and its hardness value and intensity level all are greatly improved, and the WC grain mean sizes is significantly less than YG class alloy.Since with in the particle tungsten powder made fine-grained alloy, greatly reduce the manufacturing cost of fine-grained alloy.

The alloy material that utilizes the present invention to make has been made the accurate drawing die of picture tube electron gun element and has been cut off mould, but a sharpening life-span processing parts has satisfied the requirement of producing more than 350,000, has obtained beyond thought good result.

Claims

1, a kind of manufacture method of tungsten carbide base carbide alloy, its technical characterictic is, at first with middle particle tungsten powder, carbon black, tricobalt tetroxide, Vanadium Pentoxide in FLAKES compound, under 950～1300 ℃ of temperature, carried out carbonization 1～1.5 hour, make the carbonized stock (being weight percentage) of WC90.54～98%-Co0～7.35%-VC0.1～3.47%, add that with above-mentioned carbonized stock cobalt makes the WC-VC-Co Wimet then.

2, the manufacture method of Wimet as claimed in claim 1, its technical characterictic are that the proportioning of prepared carbonized stock is that WC92.5～96.2%-Co3～7%-VC0.50～3%(is weight percentage).

3, the manufacture method of Wimet as claimed in claim 1 or 2, its technical characterictic are that described carbonization temperature is 1100～1170 ℃.