JPS6349323A - Manufacture of welding titanium pipe - Google Patents

Abstract

PURPOSE:To easily manufacture the titled welding pipe in good shaped with less residual stress, the eliminate the correction stage thereafter and to improve the productivity and cost reduction by providing a heating device just before the sizing stage of the conventional process performing the pipe making of a titanium steel strip. CONSTITUTION:The titanium steel strip S coming out of an uncoiler 1 was made a welding titanium pipe S' via a sizing mill 8, straightener 9 and cutter 10 via a forming mill 4, squeezing mill 5, welder 6 and belter 7, but attained to no good shaped pipe due to much residual stress and a heat treatment, lubrication treatment, drawing, degreasing, bright heat treatment, etc., of correction process was necessary, thereafter. Now, therefore, the heating stage 11 to improve the workability by removing the residual stress just before the sizing stage 8 is provided, the blank pipe S' is made at the fixed temp. of 50-650 deg.C of less than a recrystallizing temp. and worked in the good shape of less residual stress in the succeeding stages 8, 9, 10. Consequently the correction process thereafter is eliminated, the productivity of the titled welding pipe is improved and the can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method of manufacturing a welded titanium steel pipe.

(b) Prior art Because welded titanium tubes have excellent corrosion resistance, their fields of use have been expanding more and more in recent years. This welded titanium tube is the second
It is manufactured on a welded pipe production line as shown in the figure. The titanium steel strip S unwound by the uncoiler 1 is first flattened by the leveler 2, the irregular part at the tip is cut by the shear 3, and then curved into a tubular shape by the forming mill 4.
Thereafter, both sides are squeezed with squeeze rolls 5 to secure the tube shape, and the abutted edges are welded with a welder 6 to form a blank tube. Furthermore, the bead of the welded part is scraped off with a belt tough, the bead is drawn into a standard size shape with a sizing mill 8, the oil is removed with a straightener 9, and the bead is cut into a predetermined size with a cutter 10. Make it.

In the sizing process of this conventional line, when raw pipes are drawn to standard dimensions, there is no problem for pipes with relatively loose outside diameter tolerances, but there are sufficient demands for pipes with somewhat strict standards. There were some inconveniences that were not satisfied.

Table 1> If the outer diameter tolerance of the titanium tube is, for example, 60.5φ, the first
As shown in the table. In this case, J-engineering SH463Q, J-engineering SH4631, ASTMB, which have relatively loose tolerances,
337 can be handled only by the production line shown in FIG. However, we cannot deal with ASTM B538 or those that require strict dimensional accuracy from users.
The product will be out of tolerance.

For this reason, in the past, products that had gone through the sizing process mentioned above,
Furthermore, it was sent to the drawing process of the secondary processing line for processing. This drawing process includes heat treatment, lubrication treatment,
Since it passes through the drawing, degreasing, and bright heat treatment processes, the manufacturing process is unavoidably complicated, which causes lower productivity and yield, resulting in increased energy consumption and increased product costs. It became.

e'l Problems to be Solved by the Invention The problems to be solved by the present invention are to eliminate the drawing step of the secondary processing line that was required in the conventional method;
The object of the present invention is to provide a manufacturing method that can consistently process the dimensional correction of titanium tubes that requires a high degree of strength on a welded tube manufacturing line.

B) Means for Solving the Problems The method for manufacturing a welded titanium tube of the present invention involves processing a titanium steel strip discharged from an uncoiler through a tubular forming process, a butt edge welding process, a sizing process, a bending process, and a cutting process. In a manufacturing method for obtaining a welded titanium tube by sequentially passing the welded titanium tube, a raw tube heating device is provided at a position immediately before the entry side of the sizing process, and the raw tube is heated at a constant temperature within the range of 50 to 650 ° C, and then sizing is performed. This solves the above problems.

(E) Example In the method of the present invention, sizing processing is performed using the physical properties of titanium. As is clear from Figure 3,
Titanium has the property of softening when heated.

Therefore, in the method of the present invention, this property is utilized to perform the sizing process, which was conventionally performed in the cold process, in the warm process.

As shown in Figure 1, the main process is Formink Mill 4.
, a squeeze roll 5, a welder 6, an Iltuff, a sizing mill 8, a straightener 9, and a cutter 10 in a welded titanium tube manufacturing line. The raw pipe S' just before entering the pipe is heated to a predetermined temperature.

As the heating device 11 provided in the line, an electric heating device such as a high frequency induction heating device or a low frequency induction heating device,
Any combustion type heating device using a ring burner or the like may be used.

The temperature condition for heating is a constant temperature in the range of 50° C. to around 650° C. Specifically, the temperature value is selected in consideration of the presence or absence of post-treatment. In other words, for products that are annealed after sizing, the temperature is 650°C, which is below the annealing temperature.
Set before and after. For products that are not annealed after sizing, the temperature is set at around 500°C, which is below the recrystallization temperature. If heated above the set temperature above, the mechanical properties of the product will be impaired. Further, although the lower limit of the heating temperature does not need to be set strictly, if it is set to 50° C. or less, the softening effect will be small, and therefore accurate sizing cannot be expected.

(f) Specific Example In the welded pipe manufacturing line shown in Figure 1, sizing and
A high-frequency induction heating device was installed in front of the mill 8, and the thickness was 1.6 rtrm and the outer diameter was 61.
A 2 m long welded titanium blank tube was drawn to an outer diameter of 60.5 mIn using a sizing mill consisting of 5 stands. At this time, the raw pipe is sized without heating,
By the method of the present invention, four types of products were obtained by heating at a constant temperature in the temperature range of ios to 247°C and then sizing, and when these were compared, the results shown in FIG. 4 were obtained.

One that was heated to 108℃ and then sized, and one that
℃, 192℃, and 247℃.
The roundness of each of these was measured after sizing. As shown in Fig. 4, the measurement positions are the outer diameter dimensions at each position divided into 18 equal parts in the circumferential direction, and the measurement results for the above four types are ASTM B538.
It remained within the tolerance of ±0178.

(G) Effects By implementing warm sizing using the method of the present invention, it has become possible to relatively easily obtain products with sizing processing accuracy that could not be obtained using conventional production lines alone, resulting in products with tight tolerances. Also, it does not require complicated processing steps and can be manufactured economically. Furthermore, since additions and improvements can be made without major changes to the conventional production line, it is advantageous in terms of equipment costs.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a welded titanium tube production line equipped with a warm sizing process according to the method of the present invention. FIG. 2 is a schematic explanatory diagram of a conventional welded titanium tube production line. FIG. 3 is a diagram showing the physical properties of titanium due to temperature changes. FIG. 4 is a diagram comparing the roundness measurement results of four types of products that were subjected to the warm sizing process of the present invention and products that were processed using the conventional method (no heating). 8: Sizing mill ll: Heating device S': Titanium raw tube σ 100 200 300 460 5m 60
0 76 degrees in December (・Cn

Claims (1)

[Claims] In a manufacturing method for obtaining a welded titanium tube by sequentially passing a titanium steel strip discharged from an uncoiler through a tubular forming process, a butt edge welding process, a sizing process, a bending process, and a cutting process, immediately before the entry side of the sizing process. A method for producing a welded titanium tube, comprising: installing a tube heating device at a position, heating the tube at a constant temperature within a range of 50 to 650° C., and then sizing the tube.