JPS5856003Y2 - Rolling equipment for perforation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rolling apparatus including a perforator, such as a Mannesmann perforator, for producing seamless pipes.

Fig. 1 shows an example of a known Mannesmann drilling machine.

FIG. 1a is a top diagram showing the principle of the Mannesmouth drilling machine, and FIG. 1a shows the inclination of each centerline when the centerline in FIG. 1a is viewed from directly above.

In FIG. 1, reference numeral 1 denotes a barrel-shaped inclined roll, which rotates in the direction of the arrow in the figure, and pushes out the round steel cable material 2 from left to right in the figure while rotating.

However, the hunting portion is a cross section. The round steel cable moves from left to right in the figure because the center axes of the upper and lower inclined rolls are 1-1 and 1-2, respectively, and the center rotation of the round steel cable is at an inclination as shown in Figure 1. This is because they have an angle θ and are in contact with each other.

Since the round steel cable in No. 2 rotates while being deformed, nests are likely to occur on the central axis of the round steel cable due to the so-called Mannesmann effect.

It is therefore easily perforated by a plug of 3 placed in place by a mandrel of 4.

Usually, the biggest problem with Mannesmann drilling machines that perforate heated round steel cables is the temperature of the round steel cables.

For example, if the temperature distribution in the circumferential direction is non-uniform, the round steel cable material (hereinafter referred to as a rough pipe) after drilling will have a non-uniform wall thickness distribution in the circumferential direction.

Further, if the temperature distribution in the longitudinal direction is uneven, in the drilling process, unreasonable twisting occurs in the longitudinal direction, and the thickness distribution in the longitudinal direction becomes uneven.

In both the former and latter cases, flaws often occur on the inner and outer surfaces of the tube.

That is, in the manufacturing of seamless pipes, the temperature non-uniformity of the round steel cable is a factor that causes flaws on the inner and outer surfaces of the rough pipe and reduces the yield the most.

In order to eliminate unevenness in the temperature distribution of the round steel cable, the temperature distribution in the circumferential direction and longitudinal direction of the round steel cable being drilled is usually sampled using a thermometer shown in 5 in Figure 1. A method of detecting the absolute value of temperature and temperature distribution and feeding it back to furnace temperature control is used to control the temperature of the round steel cable material taken out of the furnace.

However, the problem here is that conventional temperature measurements only measure the surface temperature distribution of round steel cables or rough pipes. The point was that it was completely impossible to measure the internal temperature distribution.

The purpose of this invention is to indirectly detect the internal temperature on the central axis rather than the surface temperature of the round steel cable, and to feed back the measured internal temperature and longitudinal temperature distribution of the round steel cable to the furnace temperature control. This improves the control of the heating furnace's in-furnace time, enables the perforation of round steel cables with uniform temperature distribution, reduces flaws on the inner and outer surfaces of rough tubes, and improves yield. It is.

The main points of this invention are the following three points.

(1) The pressure in the rolling direction applied to the plugs is detected by installing a pressure detector between the 3rd plug and 4th mandrel of the drilling machine shown in Figure 1a, or between the stand that fixes the 4th mandrel.

(2) From the pressure P detected by the above pressure detector (1
) Calculate the internal temperature T of the round steel cable using the formula.

T=f (P) (1) (3) A heating furnace temperature control device characterized by feeding back the internal temperature of the round steel cable material detected above to heating furnace control.

FIG. 2 shows a specific example of the present invention.

Reference numeral 1 in FIG. 2 is an inclined roll, which rotates in the direction of the arrow.

2 is a round steel cable material that is being drilled, and is rotating and moving in the direction of the arrow.

4 is the mandrel that supports the plug 3 in Figure 1.
7 is a fixing base that supports the plug and mandrel 4 so that they do not move in the same direction as the material due to the pressure during drilling.

The above-described components 1 to 4 and 7 constitute a known Mannesmann drilling machine.

6 is a pressure detector attached to the position of the present invention,
The pressure P in the traveling direction of the round steel cable material applied between the plug and the round steel cable material being drilled is detected.

As this pressure detector, a known load cell or another detector can be used.

The pressure P in the traveling direction of the round steel cable applied between the plug and the round steel cable being drilled is input to the internal temperature calculation device 8 that calculates the internal temperature TM of the round steel cable.

The pressure P applied between the plug and the round steel cable material during drilling is determined by the fact that the round steel cable material has the same rolling specifications (material, outer diameter of the material before and after drilling, material wall pressure after drilling, and inclined roll of the Mannesmann drilling machine). (diameter, roll inclination angle, etc. are the same), P is proportional to the deformation resistance of the round steel cable material, especially the deformation resistance inside the round steel material.

If we consider the deformation resistance inside the round steel cable, P=ak (2) P is expressed by equation (2).

Here, a is a constant that can be determined based on rolling specifications and is obtained through experiments.

The deformation resistance inside the round steel material has a nearly proportional relationship with the temperature inside the round steel material.

For example, see Part 3 of “Rolling Theory and Its Applications” edited by the Japan Iron and Steel Institute.
, 37 Figure 18-8Mo Figure 18-8Mo Deformation resistance of steel,
The relationship between material temperatures is shown in Figure 3.

FIG. 3 shows the relationship between material temperature and deformation resistance of steel, and material temperature T and deformation resistance can be approximated by equation (3).

k = bT + c (3)b
and C are constants that can be determined experimentally for each material.

Therefore, the internal temperature TM of the round steel cable material 1 in Figure 2 is (4)
It can be shown by the formula.

TM= (P-a-c)/(a-b)
(4) As described above, the second internal temperature calculation device of the present invention can be implemented using equation (4).

In FIG. 1, numeral 5 indicates a temperature detector that detects the surface temperature T5 of the round steel cable material.

10 is a heating furnace which heated the round steel cable material 2, and is heating the round steel cable material to be drilled after 2.

9 is the third heating furnace control device of the present invention, which takes in the internal temperature TM and external temperature T5 of the round steel cable material and determines the remaining furnace time t and fuel flow rate Q of the round steel cable material being heated at 10; Output to heating furnace.

The fuel flow rate Q and the remaining reactor time t can be determined as follows.

Fuel flow rate Q: Surface temperature T5, internal temperature TM, relative to the surface reference temperature TTo, Q=Qoo+c ('ro Ts) (
5) Remaining furnace time t: T5. Reference value ΔT of TM difference.

year T5-TM≧ΔT.

Then t=To+a (T5-TM-ΔT(,)
'(6) If Ts-TM<ΔTo, t=t.

However, Qo and jo are the fuel flow rate and furnace time when the round steel material 2 is heated, respectively.

Further, C9d is a constant.

By controlling the heating furnace as described above, it is possible to eliminate wasted fuel flow in the heating furnace and to optimally manage the in-furnace time.

With this invention, it is possible to measure the internal temperature of seamless pipe material that is perforated with a Mannesmann drilling machine, press piercing mill, etc., so it is possible to measure the difference between the internal temperature and the external temperature, or the longitudinal distribution of the internal temperature of the pipe material during drilling. By feeding this information back to the furnace temperature control or operator guide, it is now possible to control the heating furnace to obtain the optimum temperature and temperature distribution for Mannesmann drilling.

In this way, the tube material discharged from the furnace has a uniform internal temperature distribution in the Mannesmann perforator, which reduces the number of defects on the inner and outer surfaces of the rough tube due to perforation and improves the yield. It can reduce unnecessary twisting of materials during the process and improve product quality.

Furthermore, the thickness distribution in the longitudinal direction is also uniform.

[Brief explanation of drawings]

Figure 1 a is a diagram of the principle of Mannesmann drilling machine, Figure 1 is a
A view from above of the upper and lower base rolls and the central axis of the round steel cable material,
FIG. 2 is a diagram showing a specific example of the present invention. FIG. 3 is a diagram of temperature and deformation resistance. 1...
- Inclined roll, 2... Round steel material, 4...
・Mandrel, 5... Temperature detector, 6... Pressure detector, 7... Mandrel fixing stand, 8...
... Internal temperature calculation device, 9 ... Furnace temperature control device, 10 ... Heating furnace.

Claims (1)

[Scope of utility model registration request] A rolling device for perforation, which comprises a heating furnace having a temperature and furnace time control device, a perforation rolling roll supplied with material from the furnace, a perforation plug, a mandrel for supporting the plug, and a perforation machine having a stand for supporting the mandrel. A rolling mill for piercing, characterized in that a pressure detector is provided between the plug and the mandrel or between the mandrel and a table supporting the andrel, and the output of this detector is provided to the control device.