IN-SITU ANNEALING AT MEXICAN PAPER MILL WARTSILA W18V32 CRANKSHAFT

PROJECT FACTS: Mexican Paper Mill
Engine Make: Wartsila W18V32
Engine Output: 6,746 kW at 720 RPM
Crankpin Diameter (Original): 310.00 mm
Crankpin Diameter (Finished): 307.00mm
Max Hardness pre-Annealing: 650HB

IN-SITU ANNEALING AT
MEXICAN PAPER MILL
WARTSILA W18V32 CRANKSHAFT
After suffering a bearing failure on Crankpin journal #8 of
Engine #2, technical management at a Mexican paper mill
contacted Goltens to perform and inspection of the damaged
Wartsila W18V32 engine and propose a repair.
Inspection of the damaged journal revealed hardness values
far in excess of the normal hardness for this type of
crankshaft with the hardest areas showing hardness values
of almost 650HB.
Goltens proposed to machine the crankpin down to a clean
surface that was clear of cracks and further evaluate the
options. At 308.50mm (-1.50mm), the surface was clear of
cracks but the high hardness remained and covered a
significant portion of the pin’s surface. Goltens proposed
applying its annealing process to reduce the hardness in the
crankpin to within specification and retain the largest possible
diameter on the crankshaft.
REPAIRS CONSISTED OF:
• Removed 1.50 mm from crankshaft prior to annealing
• Annealed the damaged crankpin to reduce hardness to
acceptable levels.
• Machined new fillet radii
• Removed an additional 1.5mm from crankshaft post
annealing to finished size of 307.00mm (-3.0).
• Superpolished crankpin journal to acceptable roughness
limits
RESULTS:
Goltens restored the Wartsila crankshaft with only 3.00mm
off the diameter of the crankshaft. Attempts to remove the
high hardness purely through machining, if successful, would
have dramatically reduced the remaining diameter on the
shaft and resulted in significantly more downtime and cost for
the owner.
With the annealing and finish machining completed, the
generator was rebuilt, operationally tested and restored to operation