Abstract In porthole-die extrusion, the metal flowing through the die has to split up around the webs and then rejoin creating longitudinal welds that extend along the whole profile. The formation and quality of these welds depend on the metal flow around the webs and a number of process parameters such as the thermal and mechanical history stored in the material in the welding area and the temperature and pressure in the welding chamber. The paper presents a new laboratory test principle based on physical-simulation experiments on real materials that proves to be particularly suitable for investigating and modelling longitudinal welds in hot extrusion. In the test, the conditions governing the formation of longitudinal welds in the real industrial process are accurately reproduced and the process parameters affecting the quality of the welds can be individually controlled as well. The results achieved in applications of the test to aluminum alloy AA 6060 are presented with a focus on the operating conditions in the welding chamber that determine the transition from partial to complete longitudinal welding.
[1]
Henry Valberg,et al.
Extrusion welding in aluminium extrusion
,
2002
.
[2]
T. Wanheim,et al.
Influence of hydrostatic Pressure in Cold-Pressure Welding
,
1992
.
[3]
H. Takahashi,et al.
Experimental simulation of metal flow in porthole-die extrusion
,
1995
.
[4]
Antonie Oosterkamp,et al.
Kissing Bond Phenomena in Solid-State Welds of Aluminum Alloys
,
2004
.
[5]
L. De Chiffre,et al.
Experimental Analysis of Cut Welding in Aluminium
,
1993
.
[6]
Niels Bay,et al.
A Numerical Model for Cold Welding of Metals
,
1996
.
[7]
Lorenzo Donati,et al.
The effect of die design on the production and seam weld quality of extruded aluminum profiles
,
2005
.
[8]
Dong-Yol Yang,et al.
Investigation into the improvement of welding strength in three dimensional extrusion of tubes using porthole dies
,
2002
.