CN103834766A - Dip pipe for RH vacuum refining device - Google Patents

Abstract

The invention discloses a dip pipe for an RH vacuum refining device. The dip pipe comprises an ascension pipe and a descending pipe and is divided into the arc-shaped ascension pipe and the arc-shaped descending pipe by a middle partition wall, wherein a lifting gas blowing-in guide pipe is arranged at the lower part of the ascension pipe, a lifting gas outlet is formed in the lifting gas blowing-in guide pipe, and the dip pipe formed by the ascension pipe and the descending pipe is fixed at the lower end of a vacuum chamber through a flange welded on the dip pipe. As the dip pipe with the structure fully utilizes the space of the bottom of the vacuum chamber, a gap between the ascension pipe and the descending pipe of a conventional dip pipe, which is generated due to a refractory material, is omitted, the flow area of dip pipe molten steel is enlarged, and therefore, the circular flow of a vacuum circulating gas stripping unit RH can be obviously increased.

Description

The soaking tub that RH equipment for vacuum refining is used

Technical field

The present invention relates to molten steel furnace external refining field, particularly a kind of RH equipment for vacuum refining soaking tub used.

Background technology

In external refining field, vacuum refining of liquid steel equipment mainly contains the device such as RH, VD.RH refers to monoblock type or split type vacuum chamber, in the time processing molten steel, all metallurgical reactions are all to carry out in vacuum chamber, the bottom of RH is two circular soaking tubs, be respectively upcast and downtake, top connects hot-bending pipe, and hot-bending pipe is connected with pumped vacuum systems, and each several part is combined into a set of equipment for vacuum refining.

The whole metallurgical reaction process of RH is all carried out in block has the vacuum chamber of firebrick lining.After soaking tub is inserted in molten steel, start its vacuum chamber to vacuumize, now under the effect of barometric point, molten steel liquid level rises in vacuum chamber, simultaneously, be blown into the hydrogen using as lift gas at the lower position of upcast, the molten steel under lift gas rises drive in upcast accelerates to rise, along with the reduction of pressure and separating out of vacuum indoor gas, molten steel is fountain shape and enters vacuum chamber, and molten steel atomization is tiny drop.Because the gas being mixed under vacuum in molten steel is sucked away, molten steel flow back into ladle from downtake again because of the effect of gravity, has so just realized the lasting circulation of molten steel turnover vacuum chamber.

The restricted link of RH refining is circulating of molten steel and mixes, and no matter molten steel component and equalizing temperature, or speed and the effect of the purifying reaction such as degassed, decarburization, desulfurization are all relevant with it.So circular flow Q is one of index of reflection RH device processing efficiency, can be expressed by following experimental formula:

Kuwabara formula:

$Q=114\&times;{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000476161810000011.png"\; state="\{\{state\}\}">G</figure-callout>}}^{\frac{1}{3}}\&times;{\mathrm{<figure-callout\; id="4"\; label="d"\; filenames="HDA0000476161810000011.png"\; state="\{\{state\}\}">d</figure-callout>}}^{\frac{4}{3}}\&times;{\left[\mathrm{Ln}\frac{P_0}{P}\right]}^{\frac{1}{3}}$

Wherein: G is gas supply flow (unit: Nm3/min)

D is soaking tub diameter (unit: m)

Po is barometric point (unit: pa)

P is vacuum chamber residual pressure (unit: pa)

The clear male formula in little open country:

Q=3.8×10 ^-4Du ^0.3·Dd ^1.1·G ^0.31·Hg ^0.5

Wherein: Du is upcast diameter (unit: cm)

Dd is downtake diameter (unit: cm)

G is gas supply flow (unit: Nm ³/ min)

Hg is that pore is to upcast distance suitable for reading (unit: cm)

Dynamical device is the target that technical development is pursued, and the maximum molten steel cycling rate of RH is brought up to more than 70% by early stage 30%～50%, even reaches 100%.Can be drawn by experimental formula, for the ladle of determining capacity, the approach that improves RH circulation usefulness has the soaking tub of increase internal diameter, increases lifting airshed and reduces several forms such as the interior gaseous tension of vacuum chamber, but be subject to the restriction of following factor, the further raising of circulation usefulness has suitable difficulty, and these factors comprise:

(1) vacuum tightness of RH treatment unit has reached below 100Pa, generally can reach 50Pa, can meet degassed requirement, and continuing to reduce vacuum tightness needs to consume more multiple-energy-source, loses more than gain;

(2) after producing and experiment showed, that lift gas flow increases to a certain degree, molten steel circular flow does not increase counter falling; And increasing lifting airshed needs vacuum pump to have larger exhaust capacity could meet vacuum tightness requirement;

(3) when soaking tub is worked, need insert in ladle, increase soaking tub scantlings of the structure is subject to the serious restriction of ladle size.

Summary of the invention

In view of this, the two arc soaking tubs of integral type that the object of the present invention is to provide a kind of RH equipment for vacuum refining to use, this kind of soaking tub can increase circular flow under the condition that does not change existing RH equipment for vacuum refining size, thereby effectively improves the usefulness of RH equipment for vacuum refining.

For achieving the above object, the invention provides following technical scheme:

A kind of RH equipment for vacuum refining soaking tub used, comprise upcast, downtake, when vacuum refinement, soaking tub inserts in the molten steel of ladle, this kind of soaking tub is straight tube shape integral structure, by midfeather, soaking tub is divided into the upcast of arc and the downtake of arc, wherein, upcast is made up of the part arc inner wall of soaking tub and a side wall surface of midfeather, downtake is made up of another part arc inner wall of soaking tub and the opposite side wall of midfeather, the bottom of upcast is provided with lifting air-blowing and enters conduit, lifting air-blowing enters conduit and is provided with the outlet of lifting gas, upcast, the Area Ratio of downtake can be arranged to different ratios by mobile midfeather, by upcast, the soaking tub that downtake forms is fixed on vacuum chamber lower end by the flange of welding on it, in order to match with the two arc soaking tubs of integral type of the present invention, the bottom surface of vacuum chamber has the endoporus of two arcs identical with downtake shape with upcast, the arcwall of endoporus is made up of vacuum chamber outer wall, the straight wall of endoporus and the straight wall of upcast and downtake are overlapping in vertical direction, form and upcast with this, the space that downtake communicates.

Further, the outer diameter D of soaking tub ₁length be the ladle inner diameter D suitable for reading of 0.75～0.98 times ₀, the wall thickness L of soaking tub ₁for 150mm～750mm.

Further, the thickness L of the midfeather in the middle of the upcast of soaking tub and downtake ₂be 1.0～1.5L ₁, the side-play amount L of the distance between center line soaking tub medullary ray of midfeather ₄span is: 0～0.3D ₁.

Further, the immersion depth L of soaking tub ₃for 100mm～800mm.

Further, promote the lifting gas outlet that air-blowing enters conduit and be arranged on the bottom of upcast, and promote gas outlet and be axially set to 1～3 layer, every interlamellar spacing 150mm～300mm, and every one deck is at least provided with 1 air outlet along upcast from low to high.

RH equipment for vacuum refining of the present invention is due to the gap of having cancelled the upcast of existing soaking tub and downtake and refractory materials and separating, make full use of vacuum chamber bottom space, and then increase the circulation area of soaking tub molten steel, increase the area equivalent diameter of soaking tub, therefore can significantly increase the molten steel circular flow in vacuum circulating degasser RH, and then obtain following effect:

(1) the two arc soaking tubs of RH equipment for vacuum refining of the present invention integral type used are compared with existing split type soaking tub, and circular flow is improved significantly in the situation that not increasing lifting airshed.

(2) the two arc soaking tubs of RH equipment for vacuum refining of the present invention integral type used make owing to being stained with the maintenance that upcast that slag causes and downtake circulation area reduce to cause and the cycle stretch-out of finally scrapping in working process by strengthening the circulation area of upcast and downtake, and therefore the two arc soaking tubs of the integral type of RH equipment for vacuum refining of the present invention are extended than typical split type circular soaking tub work-ing life.

(3), because the circulation area of upcast and downtake increases, allowing to promote airshed can effectively increase, and further strengthens circular flow.

(4) the two arc soaking tubs of RH equipment for vacuum refining of the present invention integral type used are by increasing after the circulation area of upcast and downtake, the top speed of upcast exit molten steel reduces, be conducive to reduce molten steel and splash highly, reduce the cold steel adhesion amount in vacuum chamber and in hot-bending pipe.

(5), for same molten steel circular flow requirement, the two arc soaking tubs of RH equipment for vacuum refining of the present invention integral type used can reduce to promote airshed than existing split type soaking tub, and further reduce vacuum pump rate of air sucked in required.

Brief description of the drawings

Fig. 1 is the two arc soaking tub structural representations of RH equipment for vacuum refining of the present invention integral type used;

Fig. 2 is the A-A sectional view of Fig. 1;

Fig. 3 is that the lifting air-blowing of the I part of Fig. 2 enters conduit and puff port structural representation.

In figure: 1 is vacuum chamber, 2 is upcast, and 3 is downtake, and 4 is ladle, and 5 is partition wall, and 6 is mounting flange, and 7 enter conduit for promoting air-blowing, and 8 is puff port.

Embodiment

The two arc soaking tubs of RH equipment for vacuum refining integral type used that the present invention completes practice on the RH of 180t equipment for vacuum refining, concrete structure as shown in Figure 1, Figure 2 and Figure 3.This soaking tub is straight tube shape integral structure, be divided into the upcast 2 of arc and the downtake 3 of arc by midfeather 5, upcast 2 is made up of the part arc inner wall of soaking tub and a side wall surface of midfeather 5, downtake 3 is made up of another part arc inner wall of soaking tub and the opposite side wall of midfeather 5, the bottom of upcast 2 is provided with lifting air-blowing and enters conduit 7, enter on conduit 7 to be provided with and to promote gas outlet in lifting air-blowing, lifting is blown into conduit 7 and is communicated with puff port 8.Upcast, downtake upper end arrange the flange 6 being welded and fixed, with fixing with vacuum chamber 1.In order to match with the two arc soaking tubs of the present embodiment, vacuum chamber bottom surface has the endoporus of two arcs identical with downtake 3 shapes of arc with the upcast 2 of arc, the arcwall of endoporus is made up of vacuum chamber outer wall, the straight wall of the downtake 3 of the straight wall of endoporus and the upcast 2 of arc and arc in the vertical direction (or vertical direction) is upper overlapping, forms with this space communicating with the downtake of the upcast of arc, arc.Wherein each correlation parameter of the two arc soaking tubs of integral type is: soaking tub inner diameter D ₁get the ladle back cut diameter D of 0.9 times ₀, i.e. 2711mm; Ring pipe outer wall thickness L ₁for 325mm; Partition wall thickness L ₂be 1.2 times of L ₁, i.e. 390mm; Air outlet apart from vacuum chamber apart from 1000mm; Air-blowing quantity is 2.00Nm ³/ min; Vacuum indoor pressure is 500Pa, and partition wall is apart from the side-play amount L at soaking tub center ₄constantly change, make final circular flow that wide variation also occur, particular case is as listed in table 1:

The two arc soaking tub circular flow change list tables 1 of integral type

Note: in form, departure distance negative value represents that partition wall medullary ray moves in the soaking tub half section that comprises upcast.

Correlation parameter and the circular flow of the RH equipment for vacuum refining typical soaking tub used of corresponding 180t are as shown in table 2 with it.

Circular flow and the correlation parameter table 2 of typical case's soaking tub

As shown in table 2, the internal diameter of the RH equipment for vacuum refining typical tubular soaking tub used of 180t is 1860mm, distance between the center of rising pipe center and decline pipe is 1360mm, be provided with one deck air outlet, air outlet apart from vacuum chamber apart from 1000mm, soaking tub internal diameter is 550mm, and gas supply flow is 2.0Nm ³/ min, vacuum chamber pressure is 500Pa, the circular flow of realizing is only 113t/min.

From table 1, be all 2.00Nm at air-blowing quantity ³/ min, vacuum indoor pressure is in the situation of 500Pa, is set to arc by upcast and downtake, and appropriateness changes the side-play amount L of partition wall apart from soaking tub center ₄the circular flow of RH equipment for vacuum refining changes in the interval of 406.25t/min at 218.20t/min, and compared with typical soaking tub, the circular flow of its molten steel has improved 92.92%～259.29%, the circular flow that has greatly improved RH equipment for vacuum refining, has shortened smelting cycle.

Finally explanation is, above preferred embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is described in detail by above preferred embodiment, but those skilled in the art are to be understood that, can make various changes to it in the form and details, and not depart from the claims in the present invention book limited range.

Claims (5)

1. the soaking tub that RH equipment for vacuum refining is used, comprise upcast, downtake, when vacuum refinement, soaking tub inserts in the molten steel of ladle, it is characterized in that, described soaking tub is straight tube shape integral structure, by midfeather, soaking tub is divided into the upcast of arc and the downtake of arc, wherein, upcast is made up of the part arc inner wall of soaking tub and a side wall surface of midfeather, downtake is made up of another part arc inner wall of soaking tub and the opposite side wall of midfeather, the bottom of upcast is provided with lifting air-blowing and enters conduit, enter on conduit to be provided with and to promote gas outlet in lifting air-blowing, by upcast, the soaking tub that downtake forms is fixed on vacuum chamber lower end by the flange of welding on it, vacuum chamber bottom surface has the endoporus of two arcs identical with the shape of upcast and downtake, the arcwall of endoporus is made up of the outer wall of vacuum chamber, the straight wall of endoporus and the straight wall of upcast and downtake are overlapping in vertical direction, form and upcast with this, the space that downtake communicates.

2. RH equipment for vacuum refining according to claim 1 soaking tub used, is characterized in that the outer diameter D of soaking tub ₁length be the ladle inner diameter D suitable for reading of 0.75～0.98 times ₀, the wall thickness L of soaking tub ₁for 150mm～750mm.

3. RH equipment for vacuum refining according to claim 1 soaking tub used, is characterized in that, the thickness L of the midfeather in the middle of the upcast of soaking tub and downtake ₂be 1.0～1.5L ₁, the side-play amount L of the distance between center line soaking tub medullary ray of midfeather ₄span is: 0～0.3D ₁.

4. RH equipment for vacuum refining according to claim 1 soaking tub used, is characterized in that, the immersion depth L of soaking tub ₃for 100mm～800mm.

5. RH equipment for vacuum refining according to claim 1 soaking tub used, it is characterized in that, the lifting gas that lifting air-blowing enters conduit exports the bottom that is arranged on upcast, and promoting gas exports and is axially set to 1～3 layer along upcast from low to high, every interlamellar spacing is 150mm～300mm, and every one deck is at least provided with 1 air outlet.

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