CN1038149C

CN1038149C - Ferro-tungsten fluxing agent and its producing process

Info

Publication number: CN1038149C
Application number: CN94104554A
Authority: CN
Inventors: 方少垣
Original assignee: Central Iron and Steel Research Institute
Current assignee: Advanced Technology and Materials Co Ltd
Priority date: 1994-05-03
Filing date: 1994-05-03
Publication date: 1998-04-22
Anticipated expiration: 2014-05-03
Also published as: CN1122373A

Abstract

The present invention belongs to the flux field, which provides a ferrotungsten flux and a preparation method. The flux comprises chemical compositions (wt%) of 5 to 90% of iron (industrial iron powder) and tungsten (powder) as the rest. The preparation method comprises: mixing the chemical compositions, reduction treatment of the mixture at 700 to 1100 DEG C in the hydrogen protection atmosphere, cold isostatic compaction at the pressure of 150 to 250MPa, crushing and sieving the compacted mixture, high-temperature sintering granules at 1000 to 15000 DEG C in the hydrogen protection atmosphere to obtain the finished product. The flux of the present invention is mainly used in content analysis of carbon and sulphur in high-silicon, high-chromium, high-vandium, high-mangnese and other high-melting point alloy samples.

Description

The manufacture method of ferro-tungsten fluxing agent

The invention belongs to the fusing assistant field.Mainly be applicable to required fusing assistant and manufacture method thereof in the analysis of carbon and sulfur of the high-meltiing alloy sample that constituent contents such as silicon, chromium, vanadium, manganese are higher.

When the carbon in metallurgical analysis combustion method mensuration metal and the nonmetal sample, sulphur content, extensively adopting high frequency furnace is the burning sample thermal source, after making the contained carbon of sample, the abundant oxidation of sulphur composition, volatilize, be detected, outside the Pass having with sample copy stature matter, also need add some auxiliary fusing assistants, promptly common described special-purpose fusing assistant is used to flux.

In the prior art, fusing assistant commonly used has pure tungsten grain, pure iron bits, fine copper bits, pure tin grain, pure zinc granule etc., and what use in a large number is the fusing assistant of base as the pure tungsten type and with tungsten.These fusing assistants have solved carbon, the analysis of sulfur content problem of some material samples to a certain extent, but still the part that comes with some shortcomings, mainly be slow to burn-off rates such as some high-melting-point high melting point alloy and inorganic materials, fusion is complete inadequately, causes errors of analytical results big.

Chinese patent ZL92103284.3 provides a kind of tungsten stannum fluxing agent and manufacture method thereof.The tungsten stannum fluxing agent that this method is produced mainly is applicable to the carbon of samples such as non-ferrous metal, iron alloy, various steel alloy and refractory materials, glass, pottery, slag, ore, the analysis of sulphur content, and analyse for carbon, the sulphur content of high-melting-point alloy samples such as Gao Ge, high silicon, high vanadium, Gao Meng, still there is following weak point in this fusing assistant:

1.. the wetting property between the elements such as this tungsten stannum fluxing agent and chromium, silicon, vanadium, manganese is poor, and fusion is bad, and carbon sulphur can not fully volatilize.

2.. because fusing point, the boiling point of tin itself is low, evaporate easily, cause the pollution that quartz etc. is fused pipe, make troubles to cleaning.

The object of the present invention is to provide a kind of manufacture method, produce novel ferro-tungsten fluxing agent, to satisfy the requirement of the higher high-meltiing alloy sample analysis of carbon and sulfur of constituent contents such as some silicon, chromium, vanadium, manganese with ferro-tungsten fluxing agent of the effect of well fluxing.

Based on above-mentioned purpose, the manufacture method of ferro-tungsten fluxing agent of the present invention adopts powder metallurgy process to produce, and its concrete manufacturing process is:

Batching-batch mixing, reduction-moulding, screening-high temperature sintering restore.

Now that each operation division is as follows:

1.. batching

According to requirement to raw material tungsten powder and iron powder carbon, sulphur content and granularity, select raw material tungsten powder and iron powder, and (weight %) proportioning of preparing burden according to chemical composition, be equipped with tungsten powder and iron powder.

(weight %) is as follows for the chemical ingredients of this ferro-tungsten fluxing agent:

Iron 5-90%, all the other are tungsten.

Its design of chemical composition is mainly based on following starting point: utilize the wetting property of ferro element and other alloying element good, and industrial iron powder is cheap and decarbonization, desulfuration is effective, and the big characteristics of pure tungsten thermal value; Simultaneously ferrotungsten in conjunction with after, can eliminate single industrial iron powder at high temperature during sintering, be prone to burn-off phenomenon, cause conglomeration, generate lump, pulverize the shortcoming of difficulty.Tungsten powder and iron powder compound reduce under high-temperature hydrogen, and not only decarbonization, desulfuration is effective, and are easy to pulverize, and technology is simple.

Used raw material is: tungsten adopts tungsten powder; Iron adopts general industrial iron powder on the market.

Requirement to tungsten powder:

Granularity≤0.09mm;

Carbon content (weight %) is 0.001-0.005%;

Sulphur content (weight %) is 0.0005-0.001%.

Requirement to iron powder:

Granularity≤0.07mm;

Carbon content (weight %) is 0.003-0.008%;

Sulphur content (weight %) is 0.001-0.008%.

The requirement of final ferro-tungsten fluxing agent product carbon, sulphur content and the granularity of being produced is:

Carbon content (weight %) is≤0.0015%;

Sulphur content (weight %) is≤0.0008%.

Granularity: 0.28-2.0mm.

2.. batch mixing, reduction

Tungsten powder that proportioning according to chemical composition is equipped with and iron powder are packed into and are carried out mechanism in the mixer and mix.After mixing compound is being reduced processing, treatment time 1-4 hour under the hydrogen shield in 700-1100 ℃ of temperature range.Its carbon, sulphur content obviously reduce.Compound after the reduction requires size range to be after die mould, fragmentation: 0.45-0.9mm.

3.. moulding, screening

Will be through compound moulding in cold isostatic press of reduction screening, its pressure is 150-250Mpa.Will be after the moulding mix the Yu material, broken once more, jig, get granularity earlier and be the particulate material of 0.28-2.0mm and carry out subsequent processing.

4.. high temperature sintering restores

The particulate material that the back granularity of the also broken screening of moulding is 0.28-2.0mm is being carried out high temperature sintering under the hydrogen shield in 1000-1500 ℃ of temperature range, sintering time 1-4 hour, decarbonization, desulfuration obtained required fusing assistant once more.

Adopt the prepared ferro-tungsten fluxing agent of manufacture method of the present invention can satisfy the higher high-meltiing alloy sample carbon of silicon, chromium, vanadium, manganese element content, the requirement of analysis of sulfur content fully, and analytical results is accurate.

In ferro-tungsten fluxing agent manufacture method of the present invention, be not only the ferro-tungsten fluxing agent of making certain particle size with tungsten powder and iron powder, the more important thing is by preparation technology, reduce the carbon and sulphur contents in the raw material powder, the carbon of the finished product, sulphur content are reduced to below the scope that is allowed.In preparation technology parameter, reduction temperature is most important.The industry iron powder is reducing under the temperature more than 850 ℃, though can significantly reduce carbon and sulphur contents, occurs " burning " phenomenon easily, causes caking, is difficult to crushing screening; If after iron powder and tungsten powder mix by a certain percentage, reduce under 700-1100 ℃ of temperature, carbon, sulphur content can obviously reduce; Simultaneously, the material after the reduction is easy to crushing screening, reaches the requirement of final ferro-tungsten fluxing agent.

Compare with fusing assistant with existing chemical analysis, the present invention has following advantage:

1. the ferro-tungsten fluxing agent of being produced is cheap, can replace the pure iron fusing assistant.And guarantee that analytical results is accurate.

2. the highly versatile of manufacture method equipment used, general powder metallurgy factory all can produce.

3. the ferro-tungsten fluxing agent thermal value height of being produced, it is little to splash, and is specially adapted to the carbon and sulphur contents analysis of high-melting-point alloy samples such as high silicon, Gao Ge, Gao Meng, Gao Fan.

Embodiment

Produced six batches of ferro-tungsten fluxing agents according to the manufacture method of ferro-tungsten fluxing agent of the present invention, the concrete chemical ingredients of its batching is as shown in table 1, and the processing parameter that manufacture method is selected for use is as shown in table 2.As shown in table 3 before and after the compound reduction with the carbon and sulphur contents of final fusing assistant goods.Its sulphur carbon content all meets design requirement.

After six batches of test portions are according to chemical composition prepared burden, mixed, enter and coldly wait moulding in the press, and broken once more, sieve, then, with the particulate material of certain particle size sintering at high temperature, promptly obtain the ferro-tungsten fluxing agent product.

The chemical ingredients (weight %) of table 1 embodiment ferro-tungsten fluxing agent

The processing parameter of table 2 embodiment manufacture method

Carbon and sulphur contents (weight %) before and after table 3 embodiment reduces in compound and the finished product (behind the high temperature sintering)

Claims

1. the manufacture method of a tungsten fusing assistant comprises batching, batch mixing, quiet moulding, fragmentation such as cold, sieves and high temperature sintering, it is characterized in that:

1.. prepare burden by following chemical ingredients, its chemical ingredients (weight %) is: iron 5-90%, all the other are tungsten;

2.. during batch mixing, after tungsten powder and iron powder mixed, its compound reduced processing in 700-1100 ℃ of temperature range under hydrogen shield, treatment time 1-4 hour;

3.. through compound moulding in cold isostatic press of reduction screening, forming pressure is 150-250MPa, and the compound after the moulding is crushing and screening once more;

4.. the particulate material after moulding and the fragmentation is carried out high temperature sintering under the hydrogen shield in 1100-1500 ℃ of temperature range, sintering time 1-4 hour, promptly getting required fusing assistant behind the sintering.

2. manufacture method according to claim 1 is characterized in that raw material tungsten adopts tungsten powder, and iron adopts industrial iron powder.

3. manufacture method according to claim 1 is characterized in that the requirement to tungsten: carbon content (weight %) 0.001-0.005%; Sulphur content (weight %) 0.0005-0.001; Requirement to iron powder: carbon content (weight %) 0.003-0.008%; Sulphur content (weight %) 0.001-0.008%.