CN1261608C - In-situ synthesize (TiW) C granule reinforced Fe base composition and its preparation metod - Google Patents

Abstract

The present invention relates to in-situ synthesized (TiW)C granule reinforcing Fe-based composite materials and a preparation method thereof, and belongs to the implement field of wear-resistant steel materials. Ti atoms in titanium carbide are partially replaced with W atoms to form (TiW)C granule reinforcing composite materials. The composite materials are prepared from 0.566 to 2.397 wt% of C, 2.264 to 4.758 wt% of Ti and 4.383 to 18.267 wt% of W. The materials can be formed by a powder profiling arc melting technology, and preferably formed by a block raw material melting technology in a vacuum induction electric furnace. Since the specific gravity of made (TiW)C granules is approximate to that of iron-based bodies, the mutual solubility of boundary surfaces is good, and the bonding force is strong, the segregation extent of (TiW)C in fusants is reduced, and the problem that granules are difficult to add at high temperature is solved, which is convenient for preparation. The abrasion resistance of abrasive-resistant materials is increased.

Description

Synthetic (TiW) C particle of original position strengthens Fe based composites and preparation method thereof

Technical field

The invention belongs to the study on the modification of wear resisting steel iron material, relate to design and preparation technology that the in-situ authigenic wild phase prepares steel-based composite material.

Background technology

Over past ten years, people's attention is being paid close attention to the technology of preparing of in-situ composite always, its remarkable advantage is, eliminated the interface uncompatibility between matrix and strengthening phase, because can be formed on the thermodynamics more stable second mutually in melt by forming core and growth process.Although initial original position synthetic composite material grows up in Al base alloy, be applied to the research of Fe base in-situ composite very soon, mainly be to the TiC-Fe composite study.Though the synthetic TiC particle of original position strengthens the Fe based composites and prepares successfully, but density that it should be noted that TiC and liquid metal differs bigger, earlier the TiC particle that forms is in floating or state of aggregation in process of setting, causes the come-up in the castingprocesses or the appearance of segregation phenomena.

From report both domestic and external, the TiC/Fe matrix material that most volume fractions are bigger all is to adopt the powder metallurgy preparation, but the toughness of material of powder metallurgic method preparation is low, and shock-resistant ability is relatively poor, the production cost costliness, and this has limited its development and has used.Adopt the in-situ authigenic castmethod then to restrain 0 and obeyed this shortcoming, but the volume fraction of the material of general preparation is all less than 15%, reason is in preparation process, and the formation of TiC in melt is violent (Δ G=-186606+13.22T J/mol), reacts restive.

At above-mentioned shortcoming, the present invention proposes synthetic (TiW) C particle of original position and strengthens Fe based composites and preparation technology thereof.

Summary of the invention

The synthetic in position TiC particle of the present invention strengthens on the basis of Fe based composites, utilizes W can substitute among the TiC at least 50% Ti atom, forms (TiW) C particulate reinforced composite, and its density is at 6.67-9.07g/cm ³Change in the scope, and the density of TiC and Fe is respectively 4.25g/cm ³And 7.8g/cm ³, this shows that the density of (TiW) C more approaches the density of matrix Fe, (TiW) C particulate reinforced composite that easy acquisition is evenly distributed has significantly reduced the segregation degree of TiC at melt, and the wear resistance of material and impact property are improved.By synthetic (TiW) C particle of original position, it is good to have an interface compatibility, and bonding force is strong, has solved that particle adds difficult problem under the high temperature, is convenient to preparation.This practical application to this matrix material is significant.Substitute Ti preparation (TiW) C/Fe matrix material with a part of W and then can make in wear resisting steel iron material, the volume fraction of this matrix material can reach 30%.

(TiW) C percent by volume is 10-30% in the matrix material.Matrix can be ferrite matrix, pearlite matrix or martensitic matrix, decides according to performance requriements.Reach as high as 30% for ferrite matrix (TiW) C particulate percent by volume, reach as high as 20% for perlite or martensitic matrix (TiW) C particulate percent by volume.Starting material can be powder body materials, also can be by the block alloy material by required (TiW) C percent by volume and formulated to the requirement of matrix.

(TiW) the C/Fe matrix material by iron matrix (or steel) with second mutually (TiW) C form.The preparation of material can have following two kinds of schemes: 1. be starting material with technically pure iron, Ti, W, C powder, adopt arc melting.Each composition partition ratio is as shown in table 1; 2. be that starting material adopt the vacuum induction furnace melting with master alloy, cast iron (4.0%C), steel scrap (0.2%C), ferrotianium and ferrotungsten, chemical ingredients is as shown in table 2.

Table 1 10vol%TiC and (TiW) chemical ingredients of C-Fe, wt%

Sample	C	Ti	W	Fe
					10vol％TiC/Fe	1.132	4.528	0.000	94.340
10vol％(Ti 0.9W 0.1)C/Fe	1.132	4.075	1.738	93.055
					10vol％(Ti 0.8W 0.2)C/Fe	1.132	3.622	3.477	90.573

10vol％(Ti 0.7W 0.3)C/Fe	1.132	3.170	5.125	90.573
					10vol％(Ti 0.5W 0.5)C/Fe	1.132	2.264	8.692	87.912
10vol％(Ti 0.6W 0.4)C/Fe	1.132	1.811	10.429	86.628
					20vol％TiC/Fe	2.397	9.516	0.000	88.105
20vol％(Ti 0.9W 0.1)C/Fe	2.397	8.564	3.653	85.404
					20vol％(Ti 0.8W 0.2)C/Fe	2.397	7.613	7.307	82.701
20vol％(Ti 0.7W 0.3)C/Fe	2.397	6.661	10.960	80.000
					20vol％(Ti 0.5W 0.5)C/Fe	2.397	4.758	18.267	74.596
30vol％TiC/Fe	3.765	15.029	-	81.201
					30vol％(Ti 0.5W 0.5)C/Fe	3.765	7.515	28.850	59.870

Table 2TiC/Fe and (TiW) chemical ingredients of C/Fe, wt%

Material	Cast iron	Steel scrap	Ferrotungsten	Ferrotianium
					10vol％TiC/Fe	25.367	59.644	-	14.969
10vol％(Ti 0.7W 0.3)C/Fe	25.518	56.642	7.362	10.478
					10vol％(Ti 0.5W 0.5)C/Fe	25.619	54.627	12.270	7.484
10vol％(Ti 0.6W 0.4)C/Fe	25.669	53.619	14.724	5.988
					15vol％TiC/Fe	41.816	35.176	-	23.008
15vol％(Ti 0.5W 0.5)C/Fe	42.203	27.433	18.860	11.504
					20vol％TiC/Fe	59.102	9.443	-	31.455
20vol％(Ti 0.5W 0.5)C/Fe	59.575	-	25.784	13.554

Utilize W can substitute among the TiC at least 50% Ti atom, wherein 50% refers to molar fraction, and promptly 0.5 mole Ti is substituted by the W atom among the TiC, has formed (Ti _0.5W _0.5) C; The volume that 10vol%, 20vol% refer to (TiW) C phase among (TiW) C/Fe respectively accounts for the 10vol% and the 20vol% of material cumulative volume, the chemical component weight percentage range is: C:0.566-2.397%, Ti:2.264-4.758%, W:4.383-18.267%

In-situ composite of the present invention has proved that through measured data it has following advantage: 1 has eliminated in the material second segregation phenomena that causes owing to density difference with matrix.The performance of 2 materials is obviously improved.Be in particular in: 1) (TiW) matrix of C/Fe material, whole hardness apparently higher than TiC/Fe matrix material (as shown in table 3).2) (TiW) contrast of the wear resistance of C/Fe matrix material is with the TiC/Fe matrix material under the volume integral number, and wear resistance has improved 2-3 times nearly.

Table 3TiC/Fe and (TiW) hardness ratio (HV) of C/Fe

Sample	Matrix	Whole	The second phase contribution rate %
				10vol％TiC/Fe	258.92	322.76	63.84
10vol％(Ti 0.5W 0.5)C/Fe	354.16	436.38	82.22
				15vol％TiC/Fe	332.74	406.61	73.87
15vol％(Ti 0.5W 0.5)C/Fe	425.34	514.27	88.93
				20vol％TiC/Fe	411.27	486.85	75.58
20vol％(Ti 0.5W 0.5)C/Fe	451.48	551.54	100.06

In addition, hardness test has been carried out in vertical section to material, promptly along the top of material vertical section to the bottom hardness every certain range finding material, the result shows obviously has the ununiformity of hardness in the TiC/Fe matrix material, be greater than the lower middle portion of material in the vertical hardness near material, structure observation is found, the quantity of second phase on material top is more, and the closer to the bottom, the quantity of second phase is few more.And in (TiW) C/Fe, tissue distribution is comparatively even, Hardness Distribution along the vertical section is consistent substantially, this explanation is synthesized (TiW) C phase with part Ti original position in material that W substitutes among the TiC, because its density approaches iron, second is evenly distributed mutually, has overcome the poly-phenomenon of second skew, improve the TiC/Fe performance of composites, further specified the improvement that adds after the W material structure and performance.

Alloy can adopt arc melting also can adopt vacuum induction melting.

Arc melting technology: adopt commercial with titanium valve, carbon dust, tungsten powder, iron powder.By after the composition proportion, stir with stirrer, under 270MPa pressure, make prefabricated section with double-column hand-operated hydraulic press, put into the non-consumable tungsten electrode arc furnace melting 10 minutes of argon shield then, the positive and negative melting of sample is respectively once.

The melting technology of vacuum induction furnace: starting material comprise: cast iron (4.0%C), steel scrap (0.2%C), ferrotungsten, ferrotianium, at first cast iron is purified, promptly the remelting in electric furnace of bulk cast iron is purified, and be metered into aluminium by 2% and carry out slag making, deoxygenation, decon, adding a spot of silicon increases mobile, when temperature reaches 1600 ℃, in sand mold, make cast iron bar.Eliminated rust in the steel scrap surface, ferrotianium and ferrotungsten are put into electric furnace be heated to about 400 ℃ oven dry half an hour with Ex-all moisture content and gas.

Cast iron after remelting purified and steel scrap are put into the magnesia crucible of vacuum induction furnace by composition proportion, and load weighted ferrotianium and ferrotungsten are put into the secondary charging case of induction furnace, are evacuated down to 10 ^-2After the Pa; when feeding argon shield (0.05MPa) temperature reaches 1550 ℃; pour ferrotianium in the secondary charging case and ferrotungsten into wherein melting, smelting temperature remains on 1650-1700 ℃ (infrared thermometer mensuration), is incubated to pour into sand mo(u)ld after 15 minutes or swage is cast workpiece.

Two kinds of technologies are compared, and from being beneficial to industrial production, say on the angle that reduces production costs, and the molten white silk of vacuum induction furnace technology is better, has more superiority.

The present invention can be applicable on high mangaenese steel, low-chromium cast-iron and the plain cast iron, improves their wear resisting property and reduces starting material and the consumption of the energy, raises labour productivity.

Description of drawings

Accompanying drawing is the wear resisting property comparison diagram of 10vol% (TiW) C/Fe and 10vol%TiC/Fe matrix material.

Embodiment

Make cylinder iron that (4.0%) steel scrap (0.2%C), ferrotungsten, ferrotianium are raw material, by the chemical ingredients wt% of (TiW) C/Fe, cast iron: 25.619%, steel scrap 54.627%, ferrotungsten 12.270%, ferrotianium 7.484% is prepared burden.At first cast iron is purified, the remelting in electric furnace of bulk cast iron is purified, and calculate adding aluminium by 2% and carry out slag making, deoxygenation, decon, adding a spot of silicon increases flowability, when temperature reaches 1600 ℃, casts iron staff in sand mold.Eliminated rust in the steel scrap surface, ferrotianium and ferrotungsten are put into electric furnace be heated to about 400 ℃ and dry half an hour, remove the gas of moisture content and absorption.The preparatory process that above operation is just smelted.

In the vacuum induction furnace of magnesia furnace lining crucible, carry out melting by cast iron after the alloy ratio adding purification and the steel scrap after the rust cleaning, load weighted ferrotianium and ferrotungsten are in proportion put into the secondary charging case of vacuum induction furnace, open vacuum pump, furnace chamber is evacuated to 10 ^-2After the Pa vacuum; Feed argon shield; the furnace chamber internal pressure is 0.05Mpa, when temperature reaches 1550 ℃, pours into to melt in the stove and practices being contained in ferrotianium in the secondary charging case and ferrotungsten; insulation adopted sand mo(u)ld or swage to cast foundry goods after 15 minutes when molten white silk temperature remains on 1650-1700 ℃.

Foundry goods is analyzed the chemical ingredients wt% of (TiW) C/Fe

10vol％(Ti _0.5W _0.5)C/Fe C：1.132％，Ti：2.264％，W：8.692％，Fe：87.912％。

The hardness ratio of table 410vol% (TiW) C/Fe and 10vol%TiC/Fe matrix and integral body is (HV)

Sample	Matrix	Whole	Second contribution rate %
				10Vol％TiC/Fe	258.92	322.76	63.84
10Vol％(Ti 0.5W 0.5)C/Fe	354.16	436.38	82.22

Claims (5)

1, synthetic (TiW) C particle of a kind of original position strengthens the Fe based composites, it is characterized in that the part titanium atom that adopts tungsten atom to substitute in the titanium carbide forms synthetic (TiW) C particle enhancing of original position Fe based composites, the shared percent by volume of (TiW) C is 10～30 in the matrix material; Chemical ingredients percentage ratio is by weight calculated then C:0.566-2.397, Ti:2.264-4.758, W:4.383-18.267; Fe: surplus.

2, by the described Fe based composites of claim 1, it is characterized in that the shared percent by volume of (TiW) C in the said material, be up to 30 for the ferrite iron; Be up to 20 for perlite or martensite iron.

3, a kind of technology of making claim 1 or 2 described matrix materials is characterized in that adopting arc melting after starting material prepare, or adopts the vacuum induction furnace melting.

4, by the technology of the described manufacturing matrix material of claim 3, it is characterized in that described melting technology is to carry out in vacuum induction furnace, cast iron of earlier remelting being purified during melting and steel scrap add in the crucible by composition proportion, vacuumize stove internal gas pressure to 10 ^-2Feed argon gas 0.05MPa during Pa, add master alloy ferrotianium and ferrotungsten when being warming up to 1550 ℃ again, smelting temperature is 1650～1700 ℃, soaking time 15 minutes.

5,, it is characterized in that the starting material that prepare are the prefabricated sections that are pressed into the powder body material of titanium, carbon, tungsten and ferro element with the commerce that mixes by the technology of the described manufacturing matrix material of claim 3; Or cast iron, steel scrap and the ferrotianium of making master alloy and the ferrotungsten material of purifying through remelting, raw-material composition is prepared by required (TiW) C percent by volume with to the requirement of matrix.

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