Global Maritime Directory

The maritime industry, company by company

Goltens Repair & Overhaul

Crankshaft Annealing and In-Situ Annealing

Class-approved in-place annealing that removes excessive hardness from crankpin and journal surfaces after bearing failures, salvaging otherwise condemned crankshafts.

Description

Bearing failures often leave areas of extreme hardness in the crankpin (600 to 700+ HB versus a factory-tempered 250-350 HB). Goltens' in-place annealing process, approved by Germanischer Lloyd, heats the shaft in a tightly controlled manner above its critical temperature, holds it for a period related to shaft diameter and damage, then cools it in a controlled way so hardness returns to within maker tolerances. The journal is then machined to finish diameter and polished, generally to 0.03 Ra or better.

Key features

  • Removes far less material than machining below the hardened layer, extending shaft life
  • Restores the engine in weeks rather than months
  • Hundreds of crankshafts salvaged in over 60 countries, in situ or in Goltens workshops
  • Covers engine preparation, inspection, pre-machining, hardness removal, finish machining and reassembly
  • Portable annealing equipment deployed globally

Applications

Marine main and auxiliary engines after bearing casualties; case studies include a US Navy vessel main engine and a Wartsila 6L46C.

Specifications

Class approvalGermanischer Lloyd
Unhardened crankshaft hardness250-350 HB
Post-casualty hardness600 to 700+ HB
Finish0.03 Ra or better

More from Goltens

All services of Goltens →

Similar services