TPT January 2019

AR T I C L E

QFX Simulations Ltd

Simulation

Parameter

Billet ø 250mm

Billet ø 190mm

Nominal dimensions of the pipe to be produced

ø 270 х 44.7

ø 200 x 31.8

Minimal distance between rolls, mm

228 273

173 200 1.16

Minimal distance between guide shoes, mm

Ovalisation ratio

1.2 8.8 6.4

Reduction at the point of roll neck, % Reduction in front of the plug nose, %

8.9 6.1

Plug front distance, mm

50

45

Plug diameter, mm

168

126

Rolls rotational speed, rpm

40

Feed/rolling angle, °

12/7

Friction coefficient: between the workpiece and the rolls

0.4

Friction coefficient: between the workpiece and the guide shoes, the plug, etc

0.25 150

Initial temperature of the tools, °С Initial temperature of the billet, °С Workpiece – tool heat transfer model

1,180

simplified

Table 1: Configuration parameters of the model for rolling experimental pipes

Industrial experiment * * The JSC VMZ staff members D.A. Orlov and D.E. Klyuchnikov participated in this investigation

Two billets of 190mm diameter and four billets of 250mm diameter on the TPA 70-270 (figure 4) were pierced according to the setup parameters presented in table 1. In order to adjust these parameters, the outside diameter (figure 4d) and the wall thickness (table 2) of the hot shell were measured every time after piercing the next billet on the run-out table of the stand. The measurements were made by a vernier caliper on the head part of the shell at about 500mm from the butt.

Figure 4a: Piercing of the rough tube ø200 x 31.8mm at the TPA 70-270

Figure 4b: Adjustment of the deformation zone

Figure 4c: Pipe on the examination table before the measurement of wall thickness

Figure 4d: Pipe measuring in a hot condition after the piercing mill

Diameter of pipe the “tail”, mm

Diameter of pipe the “head”, mm

Wall thickness the “head”, mm

Wall thickness the “tail”, mm

Length, mm

Pipe diameter the “mean”, mm

No. of pipe

1

198.5/198.65

198.33/198.65

199.6/199.2

35.0/36.5

35.0/35.2

4,670

2

199.7/199.95

198.9/199.0

198.7/199.35

29.0/29.5

33.5/34

4,840

3

271.35/270.93

-

271.07/271.4

48.0/50.2

49.2/50.0

4,050

4

271.4/271.72

-

270.82/270.37

47.2/49.0

47.8/50.2

4,170

5

271.2/271.63

-

269.93/270.35

44.8/47.5

47.5/48.0

4,360

6 4,260 Note: Tools for measuring of geometrical parameters: vernier calliper with division value of 0.1mm, micrometer with division value of 0.05mm, and pipe wall thickness gauge with division value of 0.05mm (max. distance of measuring points from pipe end is 250mm) 270.95/270.08 - 269.58/269.83 46.7/45.3 45.8/46

Table 2: Measurements of the geometrical parameters of experimental pipes after cooling

80

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JANUARY 2019