EP0082519A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for processing welds of pipes
Assignee: Kawasaki Heavy Industries Ltd
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Filing: 1982-12-20
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Granted: —
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Expires: 2002-12-20
Abstract
Abstract Tensile residual stress in an annular welded joint part (2) joining the ends of unit pipes (1) is mechanically removed by applying repeated hammering strokes against the inner surface of the pipes over the entire joint part thereby to cause this part to undergo locally plastic deformation. The repeated hammering strokes, which have a peening effect, are applied by several automatically operating hammering devices (21) mounted radially on a rotary head (18) secured to and unitarily moving with a shaft (6) which is driveable in rotation about its axis and in translation in its axial direction.
Inventors
- 👤 Toshio Yoshida
- 👤 Toshio Atsuta
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 11:51
CPC Classifications
B; B23; B23P; B23P9/00; B23P9/04; B24; B24B; B24B39/00; B24B39/02; B24B39/026; C; C21; C21D; C21D7/00; C21D7/02; C21D7/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
65 words
A method for mechanically removing tensile residual stress existing in an annular welded joint part joining the ends of unit pipes (1,1), which method comprises applying repeated hammering impact force to the inner surface (1') of the pipes (l,l) over the entire welded joint part thereby to cause said part to undergo locally plastic deformation and thereby to at least remove the tensile residual stress.
Claim 2
Independent Claim
65 words
A method for mechanically removing tensile residual stress existing in an annular welded joint part joining the ends of unit pipes (1,1), which method comprises applying repeated hammering impact force to the inner surface (1') of the pipes (l,l) over the entire welded joint part thereby to cause said part to undergo locally plastic deformation and thereby to at least remove the tensile residual stress.
Claim 3
Dependent Claim
26 words
A method according to claim 1 in which the repeated hammering impact force is applied by a great number of hammering strokes producing a peening effect.
Claim 4
Dependent Claim
50 words
A method according to claim 2 in which the repeated hammering impact force is applied in a manner to produce some compressive residual stress in the welded joint part (2) and simultaneously to flatten any back bead (3) protruding inward at the weld thereby to smoothen the pipe inner surface.
Claim 5
Independent Claim
128 words
An apparatus for mechanically removing tensile residual stress existing in an annular welded joint part joining the ends of unit pipes (1,1), said apparatus comprising: a shaft (6) supported for rotation; driving means (10, 11, 7, 12, 13, 8) coupled to the shaft for driving the shaft in rotation about its axis and in axial translation; a rotary head (18) secured coaxially to the shaft to be driven unitarily therewith; a plurality of hammering means (21) having respective hammering members (25) and so mounted on the rotary head that the hammering members can repeatedly strike the inner surface of the unit pipes when the rotary head is inserted relatively into the pipes; and motive power means (15) for supplying power to the hammering means to operate the same.
Claim 6
Independent Claim
128 words
An apparatus for mechanically removing tensile residual stress existing in an annular welded joint part joining the ends of unit pipes (1,1), said apparatus comprising: a shaft (6) supported for rotation; driving means (10, 11, 7, 12, 13, 8) coupled to the shaft for driving the shaft in rotation about its axis and in axial translation; a rotary head (18) secured coaxially to the shaft to be driven unitarily therewith; a plurality of hammering means (21) having respective hammering members (25) and so mounted on the rotary head that the hammering members can repeatedly strike the inner surface of the unit pipes when the rotary head is inserted relatively into the pipes; and motive power means (15) for supplying power to the hammering means to operate the same.
Claim 7
Dependent Claim
55 words
An apparatus according to claim 4 in which the shaft (6) is supported at a proximal end thereof and in which the driving means (10, 11, 7, 12, 13, 8) is coupled to the proximal end of the shaft (6) and the rotary head (18) is secured to the other distal end of the shaft.
Claim 8
Dependent Claim
66 words
An apparatus according to claim 5 in which the driving means comprises a spline (7) on the shaft, a gear (11) meshing with the spline, a motor (10) for driving the gear for rotation of the spline, a ring gear (8) on the shaft, a pinion (13) meshing with the pinion, and a motor (12) for driving the pinion for axial translation of the ring gear.
Claim 9
Dependent Claim
32 words
An apparatus according to claim 4 in which the motive power means comprises a compressed air source (15), and air passageway means (16) for supplying compressed air to the hammering means (21).
Claim 10
Dependent Claim
86 words
An apparatus according to claim 4 in which the motive power means comprises a compressed air source (15), an air passageway (16) formed axially through the.shaft (6) to supply compressed air at one end of the passageway to the hammering means (21), a swivel joint (9) connected to the shaft at the other end of the passageway (16) to supply compressed air from the compressed air source into the passageway, and piping including a valve (14) communicatively connecting the swivel joint to the compressed air source.
Claim 11
Dependent Claim
132 words
An apparatus according to claim 8 in which each of the hammering means comprises a double-acting piston (23) and air cylinder (22) mechanism, a spool valve (17) supplied with compressed air from the air passageway and being operable in changeover action to supply the air to the air cylinder alternately on two opposite sides of the piston, a first piston rod (24) fixed at one end to the piston and connected at the other end outside of the cylinder to the spool valve to operate the same and function as a control rod, and a second piston rod (25) fixed to the piston on the side thereof opposite to the first piston rod and extending out of the cylinder to function as said hammering member, whereby each hammering device is self operating.
References Cited (Backward Citations)
No citation records indexed.
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