JPS60145248A - Production of blank material for forging by horizontal and continuous casting - Google Patents

Abstract

PURPOSE:To improve yield with the decrease in loss by mending and to produce a blank material for forging having good quality by specifying the step between a connecting ring and a casting mold and performing casting. CONSTITUTION:A billet is drawn after the length (l) of the stroke for intermittent drawing of the billet is set at the length of the blank material for forging to be obtd. within a 50-500mm. range. The step (d) between a connecting ceramic ring 4A and a casting mold 2A is further increased to d>3.4 (60/N)<1/2> (where N: the drawing cycle of a time/minute unit) in order to grow deeply a cold shut 7 in the direction perpendicular to the surface of a billet 6A. The billet is cut in the position of the cold shut 7A which is the discontinuous solidified part of the billet surface after the billet 6A is drawn in the above-mentioned way. The cut billet is used as a blank material for forging.

Description

Detailed Description of the Invention In horizontal continuous casting, the structure of the O mold, in which the slab is intermittently drawn while solidifying within the mold, was developed, for example, by Japanese Patent Publication No. 52-88.
046 is referred to, and the intermittent one-shot omission is, for example, JP-A-F1B47.
-15882.

No.! The figure shows the state of implementation of conventional horizontal continuous casting. A mold (2) with a cooling channel (1) is connected to a tweed nozzle (3) on the tundish side along the horizontal axis via a ceramic ring (4) for connection. The slab (6) which has been connected and formed a solidified shell (5) in the mold (2) t, i is intermittently pulled out from the end of the mold. After the solidification part leaves the connection 11yg due to drawing, molten steel flows in and solidification continues, so a discontinuous part of solidification, that is, a cold shunt (7), occurs on the surface of the cast H.◎ During casting, the number of intermittent drawing cycles is about 20-150 cycles/min, and the drawing stroke is 10-39 cycles/min.
Approximately mm, cold shut depth Fi usually 8~
It is about 7 mm. It is generally known that as the number of intermittent pulling cycles increases, the cold shut becomes shallower and the i-shape surface properties become better. However, increasing the number of drawing cycles to make the cold shut shallower will make the casting unstable, so realistically it is difficult to increase the number of cycles to more than 150 cycles/minute.Also, mechanical constraints on the equipment configuration become serious. @ Thus, it is difficult to roll and forge horizontal continuous slabs with cold shut with care. In other words, if the material is used without maintenance, the cold shaft part will break during rolling and forging.Moreover, it takes time and effort to properly care for the grain surface before rolling and forging, which increases losses and makes it unprofitable. It disappears.

The purpose of the present invention is to manufacture high-quality forging materials by horizontal continuous casting.◇For this purpose, 1. The conventional horizontal continuous casting method has two materials for #Ili forging materials! In order to reduce the influence of surface flaws on the slab, the direction of improvement is to reduce the depth of cold shuts, even if the number of cold shuts is large.

In contrast, the present invention has been made with a new and original intention to extremely reduce the number of cold shunts, increase the mutual spacing between them, and increase the depth of the cold shunts. In the present invention, in the horizontal continuous casting method, the stroke length of the intermittent drawing of the slab 2) is 50 to 500 mm.
Slab drawing is carried out as a long-term measure for the casting and operation material that is to be obtained within the am IIi range. As a result of pulling out the slab σ1 with one long drawing stroke (1) in this way, the stigz
As shown in the figure, slab (6A) K is σl removal length (1)
A cold shutoff (TA) occurs at an interval corresponding to K.

The length of one g1 removal stroke (2) is smaller than the length of the mold (2 mm) to prevent the 9-leak act.◎In principle, if the length of the mold (2A) is made longer, the length of the g1 stroke length (2) will be that much longer. You will be able to obtain a cast H that does not meet the cold shut, but if the stroke is too long, the cast HcP will be affected by the solidification process.
Internal quality deteriorates, such as cracks and cracks. There are some problems such as the relationship between the solidification speed and fabrication speed in the rough mold (2A), the functional relationship of the drawing device to the resistance of slab removal, and profitability issues, and there are restrictions on the RK for drawing. The length of the mold cannot be very long, and is limited to about 700 to 800 mm at most.

In this way, as a result of carrying out drawing with a long stroke length <1> under the reduction of manufacturing speed and am length, the number of one drawing cycle (times/min) decreases accordingly. In the invention, in order to mainly form the cold shut (7 mm) deeply in the direction perpendicular to the surface of the cast Jt' (6A), as shown in Figs. 2 and 8, the connecting ceramic ring (4 mm) and the cast Increase the height difference d with piece (2A) so that d > 8.45f].

After the slab (6A) is drawn out in this manner, the slab is cut at a certain cold shut position (7 mm) at a solidification discontinuity on the slab surface, and this cut slab is used as a material for forging.

The present invention is compared with the conventional horizontal continuous casting process, and the numerical value of p is shown below using an actual example.

(,) Comparative example■ Manufacture billets for die forging using the conventional horizontal continuous casting process.

Carbon steel (Jzs 845G) was made under the following conditions at 8 tons/charge #0 (Casting conditions) 11Dtf4's Round bar h Diameter 11G! +1111fl
Type I is 450mm- Casting temperature & (molten steel temperature in the dish) Ift20 ~
1550 C Casting speed 1! ! ! 2. Om 1 minute Drawing stroke 25 mm Drawing cycle 80 times/min (results) Under the above conditions, the cast L7'c billet was cut into a length of 250 mm, and the crankshaft was made by die forging with the cast H outer surface left untreated. Although it was manufactured, a crack developed at the location corresponding to the cold shut.

(b) Examples of the present invention Manufacture of billets for die forging using the original qK.

9 #s were made from carbon steel (J Engineering 88450) at 8 tons/charge under the following conditions (casting conditions) Slab size Round bar, diameter 110 mm Mold length 45 (j mm) Casting temperature (molten steel temperature in tundish) 1580 -15
60 C- Casting speed 2. gm/min drawing
mm (Results) A crankshaft was manufactured by cutting a billet cast under high quality conditions to a length of KI711 at the cold shut position to a length of 250 mm and die forging with the slab surface untreated, but a good product was obtained with no IIJA. (C) Comparative Example 1 Casting was carried out under the same drawing conditions as in Example (b) of the present invention, with the step (d) between the connecting ceramic ring and the mold being stopped at 5 mm, but the surface of the slab was The lower cold shut was cut off to the nozzle side, and a portion of the cold shut remained even after casting NFl#.

Although the above embodiments are round bar billets, billets with quadrangular, octagonal, and even polygonal cross sections can be manufactured in the same manner.

As described above, horizontal continuous casting was carried out using the eA of the present invention.
If the healthy slab between the 97VrL cold shunt and the cold shunt is used as the forging material, there is almost no need for surface care, and the yield will be improved by reducing care loss. Both have the effect of omitting the maintenance process.

[Brief explanation of drawings]

Fig. 1 is a longitudinal side view showing the state of implementation of conventional horizontal continuous casting. Figure 2 is a side view of Rfr showing the state of implementation of horizontal continuous casting according to the present invention. Partial enlarged vertical WTll showing the difference in level! It is a front view. (1) --Cooling channel, (2) (2A)...m type% (3) a*y eed nozzle s (4) (4
)...Connection ring, (5)・1 If! ill and '+(6)(6A)...(eye VJt, (7)(7A) Juken cold shut s (t) @own stroke length%(
d) --&! ! O

Claims (1)

[Claims] In the horizontal continuous casting method, the stroke of intermittent drawing of the casting H is within the range of 50 to 500 mm, and the drawing of the casting H is performed as the length of the material for forging to be obtained, and the step between the connecting ring and the mold is Casting is carried out with settings such that d (mm) satisfies d > 8.4 ~ ri four beads - < where N: drawing cycle in times/minute), and the thus obtained cast H is solidified discontinuously on the surface. A method for producing a forging material by horizontal continuous casting, characterized in that the material is cut at a cold shut position.