Welding rail steels using gas metal arc welding shows promise for repairing railhead
defects. Finite element analysis was performed on the rail before and during the
welding process. It was revealed that the sizes of the heat affected zone (HAZ) and
fusion zone would be approximately 15 mm and 5 mm respectively. Hardness
tests showed that the parent material is harder than both the HAZ and
the welded region. The parent steel has ultimate strength, yield strength,
and elongation to failure of 1114 MPa, 624 MPa, and 11.1% respectively.
These values are higher than those of the welded rail steel. The average
for the parent specimen was
70 MPam,
while for the welded steel it was
54 MPam.
The pearlitic steel displayed ductile fracture features immediately ahead of the crack
tip but approaching the end of the fracture surface the failure mechanism became less
ductile. The welded rail steel in contrast consists of ductile features throughout the
entire fracture surface.