JPH0225244A - Method of operating horizontal continuous casting device for metallic pipe - Google Patents

Abstract

PURPOSE:To operate the horizontal continuous casting device for the metallic pipe without generating breakout and failure in drawing by starting drawing of a cast pipe at the timing at which the detected temp. of a casting mold is satd. and repeating the cycles respectively specifying the drawing time of the cast pipe and the waiting time after the drawing. CONSTITUTION:The molten metal housed in a molten metal holding furnace 1 is solidified to a pipe shape by the casting mold 13 and the horizontal continuous casting of the cast pipe 14 is executed in the following manner: The cast pipe 14 is drawn at the timing at which the temp. of the casting mold measured by a thermometer set in the casting mold 13 is satd. The drawing of the piping 14 for 0.5-7.0 second and the stopping for 0.1-5.0 second waiting time after the drawing are repeated as one cycle simultaneously with the above mentioned drawing. The failure in drawing, etc., are averted in this way and the horizontal continuous casting of the metallic pipe is stably executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of operating a horizontal continuous casting apparatus for metal tubes.

[Prior art] Regarding the horizontal continuous casting method of metal tubes, Japanese Patent Application Laid-open No. 80-5
As described in Japanese Patent No. 4255, a molding device is disposed at the pouring port of a molten metal holding furnace, the molten metal is cooled in this molding device to form a cast tube, and this casting tube is drawn and cast by a drawing device.

By the way, in the horizontal continuous casting of metal pipes, as in the continuous casting of solid slabs, when solidified slabs are continuously pulled out, fractures occur from the weak parts of the solidified shells, resulting in breakouts at the mold exit. Become. Therefore, even in horizontal continuous casting of metal tubes, it is useful to employ intermittent drawing in which drawing and stopping are repeated as one cycle.

[Problems to be Solved by the Invention] However, when the above-mentioned intermittent drawing is "simply" adopted for horizontal continuous casting of metal tubes, Breakout may occur due to insufficient production, or the solidification shrinkage of the slab that occurs in the mold during the cooling process when drawing is stopped is large, resulting in the inability to draw.

The object of the present invention is to stably perform pultrusion casting without causing breakout or failure to pull out when performing horizontal continuous casting of a cast pipe.

[Means for Solving the Problems] The present invention as set forth in claim 1 is characterized in that a molten metal contained in a molten metal holding furnace is solidified into a tubular shape in a molding device to form a cast tube, and the cast tube is pulled out by a drawing device. In the continuous casting method of the metal tube to be drawn, (1) detect the mold temperature, start drawing the above-mentioned cast pipe at the timing when this mold temperature is saturated, @ draw the above-mentioned cast pipe for a drawing time of 0.5 to 7.0 seconds; One cycle consists of drawing out and opening and stopping for a waiting time of 0.1 to 5.0 seconds after drawing out.

The present invention according to claim JJ2 has a casting temperature ΔT of 80 to 2.
The temperature was set at 00°C.

According to a third aspect of the present invention, the drawing speed (average after drawing) is 5 to 30 mm/sec.

[Made…]

According to the present invention as set forth in claim 1, there are the following effects (1) and (2), and according to the present invention as set forth in claim 2, there is further the following effect (2), and the present invention as set forth in claim 3. According to the above, there is also the following effect.

■Drawing start timing In continuous horizontal continuous casting of metal pipes, especially continuous casting of thin-walled pipes, the casting start timing is important.If drawing starts quickly, the slab will solidify in the mold after several drawing cycles.
It becomes impossible to pull out.

The wood inventor discovered that the cause of this was the heat removed from the slab by the mold. As a solution to this problem, it has been found that the inability to pull out described in L can be avoided by setting a thermometer in the mold and starting to pull out the cast tube when the mold temperature is saturated.

(Drawing time and waiting time) If the drawing time is set to 0.5 seconds or less, the residence time of the slab in the mold becomes long and mold pro-solidification occurs.

On the other hand, if the drawing time is set to 7.0 seconds or more, the formation of a solidified shell in the mold becomes insufficient and breakout occurs.Therefore, the drawing time is preferably set to 0.5 to 7.0 seconds.

If the waiting time is less than 0.1 seconds, the generation of coagulants within the mold will be insufficient and breakout will occur. On the other hand, if the waiting time is set to 5.0 seconds or more, a large amount of heat is removed from the slab to the mold, causing anti-solidification of the mold, and the slab envelops the core, making it impossible to pull out. Therefore, the waiting time is 0,
It is preferable to set the time to 1 to 5.0 seconds.

■Pouring temperature In general, the ΔT (super heat) in normal sand casting is 70 to 80°C, but in the case of horizontal continuous casting, especially metal pipes, a large ΔT is required to prevent solidification in the mold. There is a need.

According to our experience with cast iron pipes, the temperature is 80°C with a wall thickness of 15m and a wall thickness of 4.5m.
■ A ΔT of 200°C was required. So, casting?
It is preferable that the degree ΔT is 80 to 200°C.

■Drawing speed When the drawing speed is slower than 5 l/sec, heat is removed from the slab to the mold. That's enough and there's a breakout. Therefore, the drawing speed is 5 to 30
■It is better to use san/second.

(Implementation @1 Fig. 1 is a Mm system diagram showing one embodiment of the great invention, Fig. 2 is a sectional view showing a molding device, and Fig. 3 is an end view showing the molding device.

The continuous casting method 10 includes a molten metal holding furnace 1 as shown in FIG.
A mold device 13 is attached to a casting hole 12 formed at the lower side of the mold. Communicating&#! The casting device 10 cools the molten metal using a molding device W13 to form a cast pipe! 4 and horizontal pultrusion casting.

The continuous casting device 2i10 includes a heating device 11 in a molten metal holding furnace 11.
A, the casting temperature can be adjusted.

The continuous casting in 9 :a 10 is equipped with a guide roller 15 that supports the casting tube 14 on the outlet side of the mold assembly W113, and also includes a drawing roller device 16 for pulling out the casting tube 14. The pulling roller device M16 consists of a pinch roller 17 and a press roller 18. The drawing roller device 16 has a hydraulic motor 16B driven by a hydraulic pump 16A, and this hydraulic motor 16B drives a pinch roller 17, and as a result, a drawing force is applied to the cast pipe 14. There is.

As shown in FIGS. 2 and 3, the mold assembly M13 includes a mold 19 made of graphite and a core 20 also made of graphite.

The mold 19 is hollow and has a core holding inner diameter part 21t at the end on the molten metal inflow side, and a tube outer surface forming inner diameter part 22 around the center axis of the mold extending substantially over the entire length excluding the core holding inner diameter part 21.

The core 20 is inserted into the mold 19, and the flange portion 2 is fitted into the core holding inner diameter portion 21 of the mold 19 at the molten metal flow side end.
3, and a tube inner surface molding outer diameter section 24 that is provided around the center axis of the mold over substantially the entire length excluding the flange portion 23 and forming a tube molding passage 25 between the tube outer surface molding inner diameter section 22 of the mold 19. The core 20 also includes molten metal injection passages 26 communicating with the tube forming passage 25 at each of a plurality of positions (four positions in this embodiment) around the center axis of the mold in the flange portion 23 . Each molten metal injection passage 26 has a cross-sectional shape of an arc. It is preferable that the thickness g of the joint portion 27 sandwiched between adjacent molten metal injection passages 26 be as small as possible to ensure strength, and that the passage area of each molten metal injection passage 26 be made larger.

That is, the mold device 113 fits and fixes the flange portion 23 of the core 20 into the core holding inner diameter portion 21 of the mold 19, and allows the molten metal injection passage 26 and the tube forming passage 25 to communicate in a straight manner. Reference numeral 28 in FIG. 2 is a fixing pin between the mold 19 and the core 20.

Specifically, the mold device 113 fits a copper water-cooling jacket 30 to the molten metal outflow side end of the mold 19 via a copper liner 29, and also fits a copper water cooling jacket body 30 to the molten metal inflow side end of the mold 19 from a brick. The insert rings 31 and 32 are fitted, and the water cooling jacket body 30 and the insert ring 3 are fitted.
1, an iron plate 33 is fitted between them. As a result, the mold device 13 serves as a cooling section for solidifying and forming the molten metal in the water-cooled jacket body 3o, and the insert ring 3
1 is a non-cooled part, and the insert ring 32 part is a part attached to the furnace wall 11B of the holding furnace 11.

Further, the continuous casting apparatus 10 of this embodiment has a mold equipment 511.
In order to prevent the molten metal flowing into the core 20 from being overcooled, a thank-you slot 20A is provided at the end of the molten metal inflow side of the core 20, and the end of the mold fitting fi 13 is made to protrude into the furnace.

Thus, the continuous casting apparatus 10 includes a control section @41, a hot water temperature measuring device 42, and a mold temperature measuring device 143.

The control device 41 controls the casting tube 14 according to ■drawing time (t e)
The pulling roller device 16 is repeatedly pulled out by a pulling length P at a constant pulling speed (Ve) for a period of time, and then opened and stopped for the waiting time (tw) after the pulling out as one cycle.
The hydraulic pump drive control section 44 is controlled. The drawing speed of the cast tube 14 is fed back to the control device 141 via a drawing speed detector 45 connected to the output shaft of the hydraulic motor 16B.

Here, the control device 141 sets the above-mentioned extraction time te to 0.
Set within the range of 5 to 7.0 seconds, and set the waiting time tw to 0.1 to 7.0 seconds.
Set within the range of 5.0 seconds, and set the pulling speed ve to 5 to 30.
Set within the range of m/sec.

The hot water temperature training device M42 measures the hot water temperature in the molten metal holding furnace 11 and transfers the measurement result to the control device 41.

The control device 41 determines that the casting temperature ΔT (super heat) is 80 to 20, based on the measurement results of the i'i temperature measurement device W42.
Heat 'A' to a predetermined value within the range of 0℃.
211A.

The mold temperature measuring device 43 measures the temperature of the mold 19 and controls the measurement result. Transfer to CFa41. Control device 41
Based on the measurement result of the mold temperature measuring device 43, the hydraulic pump drive control section 44 of the drawing roller device 16 is controlled to start drawing the E-shaped pipe 14 at the timing when the mold temperature is saturated.

Note that during horizontal continuous casting of the present invention, the molten metal holding furnace 11.
Do not apply oscillation to both the mold device 13 and the drawing roller device 16.

Next, the operation of the above embodiment will be explained.

According to the above embodiment, there are the following effects.

■Drawing start timing The timing when the temperature of M type 19 is saturated is important.
Since drawing is started at step 4, stable drawing is possible without a large amount of heat being removed from the slab to the mold at the start of drawing.

■Drawing time and waiting time Since the drawing time is set within the range of 0.5 to 7.0 seconds, the residence time of the slab in the mold becomes too long and mold solidification does not occur, and syJ! Breakout does not occur due to insufficient formation of a solidified shell within the tube.

In addition, since the waiting time was set within the range of 0.1 to 5.0 seconds, breakout due to insufficient solidification shell formation in the mold will not occur, and there will be no breakout from the slab to the mold. There is no possibility that a large amount of heat will be removed and that mold anti-solidification will occur.

(2) Since the casting temperature ΔT (super heat) is controlled to a predetermined value within the range of 80 to 200°C, solidification within the mold can be prevented.

■Drawing speed Since the drawing speed was set within the range of 5 mm to 30 mm/sec, there was no possibility of breakout due to insufficient formation of a solidified shell in the mold, and there was no possibility of breakout occurring from the slab to the mold. There is no possibility that a large amount of heat will be removed to cause mold anti-solidification.

That is, according to the above-mentioned items (1) to (2), stable pultrusion casting is possible without causing breakout or inability to pull out even during horizontal continuous casting of thin-walled tubes.

Hereinafter, specific implementation results of the present invention will be explained.

Using the horizontal continuous casting method described in Example L, a normal cast iron material with an inner diameter of 100 mm and @j15 mm was cast horizontally. Continued casting was carried out. The casting temperature is 1400℃ (ΔT″
``190℃), 10 minutes after pouring into the molten metal holding furnace,
The timing at which the mold temperature reached the saturation point of 480°C was defined as the drawing start point. Pulling time is 1 second, waiting time is 3 seconds,
The average drawing speed was 5 layers/second. As a result, 1.2 tons of cast iron pipe was cast, and approximately 105 m of sound cast iron pipe was obtained.

[Advantageous Effects of the Invention 1] As described above, according to the present invention, when performing horizontal continuous casting of a cast pipe, stable pultrusion casting can be performed without causing breakout or failure to pull out.

[Brief explanation of the drawing]

FIG. 1 is a control system diagram showing one embodiment of the present invention. FIG. 2 is a sectional view showing the mold device, and FIG. 3 is an end view showing the mold device. 10... Continuous casting device. 11... Molten metal holding furnace, 11A... Heating device, 12... Casting port, 13... Mold device. 14...Casting pipe, 16...Drawing roller equipment! (extraction device), 41...
·Control device. 42...Hot water temperature measuring device. 43... Mold temperature measuring device. 44...Hydraulic pump drive control fR section. 45... Pulling speed detector. 46... Heater control section. Agent Patent Attorney Osamu Shiokawa 1゜Figure 1Figure 2

Claims (3)

[Claims] (1) In a continuous casting method for metal tubes, in which the molten metal contained in the molten metal holding furnace is solidified into a tubular shape using a molding device to form a cast tube, and the cast tube is pulled out using a drawing device, (a) detecting the mold temperature; Then, at the timing when the mold temperature is saturated, the casting pipe is started to be pulled out, and (b) the casting pipe is pulled out for a drawing time of 0.5 to 7.0 seconds, and the waiting time after this drawing is 0.1 to 7.0 seconds. A method of operating a horizontal continuous casting apparatus for metal tubes, characterized in that one cycle is a cycle of stopping for 5.0 seconds. (2) The method for operating a horizontal continuous casting apparatus for metal tubes according to claim 1, wherein the casting temperature ΔT is 80 to 200°C. (3) The method for operating a horizontal continuous casting apparatus for metal tubes according to claim 1 or 2, wherein the drawing speed (average during drawing only) is 5 to 30 mm/sec.