CN102676740B - Nano composite molten steel purifying agent and preparation method thereof - Google Patents

Abstract

The invention discloses a nano composite molten steel purifying agent. The nano composite molten steel purifying agent comprises the following raw materials in percentage by mass: 3 to 10 percent of nano SiC, 10 to 20 percent of silico-calcium alloy powder, 4 to 15 percent of K2O powder, 5 to 16 percent of Na2O powder, 2 to 6 percent of Mg powder, 2 to 8 percent of Ti powder, 3 to 5 percent of a bonding agent and the balance of iron powder. A method for preparing the nano composite molten steel purifying agent includes: firstly mixing uniformly the nano SiC with the silico-calcium alloy powder to obtain a mixture a, then mixing uniformly the mixture a, the K2O powder and the Na2O powder to obtain a mixture b, then mixing uniformly the mixture b, the Mg powder, the Ti powder and the iron powder to obtain a mixture c, adding the bonding agent into the mixture c and stirring uniformly, finally briquetting and molding. The nano composite molten steel purifying agent can greatly improve the purification degree of molten steel, and the performance of a steel product treated by using the nano composite molten steel purifying agent is the same as that of the steel product purified by using a ladle furnace (LF), so that the nano composite molten steel purifying agent can replace the LF furnace used for refining, and the steelmaking cost can be greatly reduced.

Description

A kind of nano combined purification of molten steel agent and preparation method thereof

One, technical field

The present invention relates to a kind of purification of molten steel agent and preparation method thereof, specifically a kind of nano combined purification of molten steel agent and preparation method thereof belongs to metallurgical technology field.

Two, background technology

For improving every performance of metallic substance, mainly is to adopt AOD, VOD, several refinery practices of LF to reach the purpose of purify hot metal in the steel-making industry at present, mainly adopts at casting industry in molten steel, to add various scavenging agents and rare earth alterative is realized the final deoxidation of molten steel and purification.

Rare earth alloy, silicocalcium, silicon-aluminium-barium alloy etc. are adopted in traditional purification of molten steel agent usually, but because this class alloy production all needs to adopt pyrotic smelting, make technological process energy consumption height, seriously polluted.Particularly country is technical and to after the rare earth resources unified management for the resource of preciousness can continue to be applied to national defence and high-tech, the rare earth alloy price is rise at double in recent years, causes some meagre profit products can't adopt rare earth alloy to improve the performance of product again.Therefore must study new scavenging agent product and substitute in order to save precious resources such as rare earth alloy.

The principal reaction of steel-making is oxidizing reaction, and oxygen blast makes the Si in the iron and steel, Mn, and P, the C oxidation obtains the molten steel of different carbon contents simultaneously, also makes and has dissolved too much oxygen in the molten steel. and the oxygen in the steel comprises the free oxygen of dissolving and the oxygen in the inclusion.Deoxidation is to be dissolved in oxygen level in the steel by reduction, and oxygen is transferred in the oxide inclusion, and come-up is removed, and reaches the purpose that reduces the oxygen level in the steel, purifies iron and steel, and the performance of steel is improved.

Potassium, elements such as sodium are arranged in the periodic table of elements first row, it is most active element, so being applied to purify in the iron and steel liquation with modifying technology is the Yang Xiangshou of Shandong Polytechnic Univ professor invention in 1992, potassium has at first been studied by Shandong Polytechnic Univ, the effect of sodium in cast iron materials, find potassium, sodium is in that to improve aspect the cast iron effect obvious, to potassium, sodium adds the form in the cast iron, the mechanism of action and effect thereof have carried out preliminary research, domestic other unit has also carried out the research of this respect afterwards, demonstrates potassium, sodium has good prospects for application in Foundry Production.

In recent years, nano material has obtained paying attention to and using in many scientific domains gradually, and nano material is that its granular size generally is no more than 50nm(1nm=10 by the molecular solid material of the nanoparticle of nanometer scale ^-9M), have many special performances, high as toughness height, wear resistance, be with a wide range of applications.Nano material (TiN, SiC, TiC etc.) dispersion size is superfine, higher hardness is arranged and huge surface energy is arranged.The nanometer modifying technology has been broken some the conventional rules in the production of iron and steel high-abrasive material.Usually, improving hardness in iron and steel high-abrasive material strengthening process must follow toughness to descend, but because the high surface of Nanoalloy alterant and it are played the dispersion hardening effect simultaneously in the crystal grain thinning process, so often can reach the net effect that improves alloy rigidity and toughness simultaneously.

Since nano material have high rigidity, high temperature resistant, granularity is little (less than 50nm), surface energy is big, the low (characteristics such as 18.0mv) of good dispersity and surperficial ZETA current potential, has better bonding force with metal, have crystal grain thinning and the dispersion-strengthened action stronger than general alterant, can obviously change weave constructions such as metallic matrix and carbide.Therefore, this alterant and this technology can significantly improve hardness, intensity and ductility and the toughness of iron and steel and non-ferrous alloy material, thereby improve the quality of original ferrous materials greatly and reduce rare and content noble element, or reduce, original thermal treatment process that conforms to the principle of simplicity, reduce production costs greatly.

Because the distinctive character of nano material, how nanoparticle being joined in the ferrous materials liquid is a very difficult problem all the time, and the application of nano material is subjected to certain restriction always.

Three, summary of the invention

The present invention aims to provide a kind of nano combined purification of molten steel agent and preparation method thereof, and technical problem to be solved is to select a kind of purification of molten steel agent to make its decontamination effect improving that can reach the LF stove, thereby reaches the purpose that reduces steel-making cost, reduces production process.

The nano combined purification of molten steel agent of the present invention is based on potassium, sodium element, add other raw materials such as nano-powder simultaneously, nano-powder is because light specific gravity, particle is tiny, as easy as rolling off a log polymerization simultaneously, nano-powder being uniformly dispersed in scavenging agent and also can being uniformly dispersed after scavenging agent adds molten steel is the primary technical problem that solves of the present invention.

The raw material of the nano combined purification of molten steel agent of the present invention constitutes by mass percentage:

Nano SiC 3-10%, silicocalcium powder 10-20%, K ₂O powder 4-15%, Na ₂O powder 5-16%, Mg powder 2-6%, Ti powder 2-8%, binding agent 3-5%, surplus is iron powder.The massfraction 55-60wt% of silicon in the silicocalcium powder, the massfraction 25-35wt% of calcium.

Described binding agent is bath of glass and wilkinite, and wherein bentonitic quality is 1% of binding agent quality, and surplus is bath of glass.

The particle diameter of described nano SiC is less than 50nm.

The preparation method of the nano combined purification of molten steel agent of the present invention operates according to the following steps:

A, nano SiC and silicocalcium powder mixed obtain compound a;

B, with described compound a, K ₂O powder and Na ₂The O powder mixes and obtains compound b, and described compound b is particulate state;

C, described compound b, Mg powder, Ti powder and iron powder mixed obtain compound c, add binding agent in the described compound c to stir, last compound stalk forming gets final product.

The molten steel of melting is carried out deoxidation, purifying treatment according to common process in ladle, adds the nano combined purification of molten steel agent of the present invention preparation then, from the ladle bottom to ladle blowing argon gas 4-10 minute (flow 0.5-1Pa), cast molding then.The add-on of nano combined purification of molten steel agent is the 0.2-0.5% of steel quality.

Compared with the prior art, beneficial effect of the present invention is embodied in:

1, the nano combined purification of molten steel agent of the present invention can increase substantially the degree of purification of molten steel, steel performance after the nano combined purification of molten steel agent of the present invention purifying treatment is identical with LF stove decontamination effect improving, the LF stove for refining be can substitute, thereby steel-making cost, saving facility investment, minimizing production process, the molten steel energy consumption of reduction unit reduced greatly.

2, sylvite and sodium salt are adopted in purification of molten steel agent in the past more, but get damp because salt very easily absorbs airborne moisture content, and product is difficult for preserving.The nano combined purification of molten steel agent of the present invention is added other reducing material again based on potassium, sodium element, preferably resolves the problem that the product suction is got damp.

3, the raw material that particle diameter is less at first mixes among the preparation method of the present invention, progressively mixes with the raw material of big particle diameter again, and nano-powder can be uniformly dispersed, and avoids the generation of agglomeration.

Four, description of drawings

Fig. 1 and Fig. 2 are the photos of the nano combined purification of molten steel agent of the present invention.

Five, embodiment

Embodiment 1:

The raw material of nano combined purification of molten steel agent and being constructed as follows in the present embodiment:

10 parts of nano SiCs, 15 parts in silicocalcium powder (silicon 57.02% calcium 30.03%), K ₂10 parts in O powder, Na ₂10 parts in O powder, 5 parts in Mg powder, 5 parts in Ti powder, 5 parts of binding agents (bath of glass 99%, wilkinite 1wt%), 40 parts of iron powders; Wherein the particle diameter of nano SiC is less than 50nm.

The preparation method:

A, nano SiC and silicocalcium powder mixed obtain compound a;

B, with described compound a, K ₂O powder and Na ₂The O powder mixes and obtains compound b, and described compound b is particulate state;

C, described compound b, Mg powder, Ti powder and iron powder mixed obtain compound c, add binding agent in the described compound c to stir, last compound stalk forming gets final product.

The nano combined purification of molten steel agent of present embodiment preparation is added in the molten steel, the mass ratio 1:5000 of nano combined purification of molten steel agent and molten steel, from the ladle bottom to ladle blowing argon gas 4-10 minute (flow 0.5-1Pa), cast molding then.

Embodiment 2:

The raw material of nano combined purification of molten steel agent and being constructed as follows in the present embodiment:

10 parts of nano SiCs, 20 parts in silicocalcium powder (silicon 57.02% calcium 30.03%), K ₂10 parts in O powder, Na ₂10 parts in O powder, 5 parts in Mg powder, 5 parts in Ti powder, 5 parts of binding agents (bath of glass 99%, wilkinite 1wt%), 35 parts of iron powders; Wherein the particle diameter of nano SiC is less than 50nm.

The preparation method of present embodiment is with embodiment 1.

The nano combined purification of molten steel agent of present embodiment preparation is added in the molten steel, the mass ratio 1:2500 of nano combined purification of molten steel agent and molten steel, from the ladle bottom to ladle blowing argon gas 4-10 minute (flow 0.5-1Pa), cast molding then.

Embodiment 3:

The raw material of nano combined purification of molten steel agent and being constructed as follows in the present embodiment:

10 parts of nano SiCs, 15 parts in silicocalcium powder (silicon 57.02% calcium 30.03%), K ₂15 parts in O powder, Na ₂15 parts in O powder, 5 parts in Mg powder, 5 parts in Ti powder, 5 parts of binding agents (bath of glass 99%, wilkinite 1wt%), 30 parts of iron powders; Wherein the particle diameter of nano SiC is less than 50nm.

The preparation method of present embodiment is with embodiment 1.

The nano combined purification of molten steel agent of present embodiment preparation is added in the molten steel, the mass ratio 1:2000 of nano combined purification of molten steel agent and molten steel, from the ladle bottom to ladle blowing argon gas 4-10 minute (flow 0.5-1Pa), cast molding then.

The nano combined purification of molten steel agent of the present invention's preparation is used for Tianjin associating special steel Q420B steel, carries out the test of purification of molten steel, process of the test is as follows:

100 tons of molten steel amounts, nano combined purification of molten steel agent addition 200kg, the joining day of nano combined purification of molten steel agent is to add after adding VN alloy, nano combined purification of molten steel agent adds after the ladle from ladle bottom blowing argon gas 10 minutes, cast in molten steel handling scene, detected result is as follows after rolling:

1, chemical ingredients

Sequence number Heat (batch) number ??C ??Si ??Mn ??P ??S ??V ??1 ??1A?04253 ??0.18 ??0.30 ??1.52 ??0.025 ??0.009 ??0.051 ??2 ??1A?04253 ??0.18 ??0.30 ??1.54 ??0.024 ??0.009 ??0.054 ??3 ??1A?04253 ??0.18 ??0.29 ??1.52 ??0.024 ??0.008 ??0.053 ??4 ??104253 ??0.18 ??0.31 ??1.51 ??0.024 ??0.010 ??0.053

2, mechanical property

From the These parameters analysis as can be seen, add behind the scavenging agent of the present invention every index and improve morely than GB, particularly ballistic work improves 287.39% than GB.Every index and Tianjin integrated steel mill Q420B data after the refining of LF stove are close substantially, slightly improve.Illustrate that purification of molten steel agent of the present invention can substitute LF stove refinery practice, steel product quality can reach the standard-required of LF stove refinery practice.

Claims (3)

1. nano combined purification of molten steel agent is characterized in that its raw material constitutes by mass percentage:

Nano SiC 3-10%, silicocalcium powder 10-20%, K ₂O powder 4-15%, Na ₂O powder 5-16%, Mg powder 2-6%, Ti powder 2-8%, binding agent 3-5%, surplus is iron powder;

Described binding agent is bath of glass and wilkinite, and wherein bentonitic quality is 1% of binding agent quality, and surplus is bath of glass.

2. nano combined purification of molten steel agent according to claim 1, it is characterized in that: the particle diameter of described nano SiC is less than 50nm.

3. the preparation method of the described nano combined purification of molten steel agent of claim 1 is characterized in that operating according to the following steps:

A, nano SiC and silicocalcium powder mixed obtain compound a;

B, with described compound a, K ₂O powder and Na ₂The O powder mixes and obtains compound b, and described compound b is particulate state;

C, described compound b, Mg powder, Ti powder and iron powder mixed obtain compound c, add binding agent in the described compound c to stir, last compound stalk forming gets final product.