Royce Onsite Machining provides controlled crankshaft annealing and heat treatment of crankshafts to address excessive hardness and bending caused by overheating, bearing failure or mechanical stress.
When a crankshaft is exposed to high temperatures and then cools rapidly, crankpins can develop increased surface hardness and distortion. In many cases, hardness levels exceed OEM tolerance limits, inducing internal stress and making precision machining difficult.
Our heat treatment process is designed to reduce crankpin hardness, assist in correcting runout and return the component to a condition suitable for final machining.
When Is Crankshaft Annealing Required?
Crankshaft annealing is typically required where inspection identifies:
- Excessive crankpin hardness
- Runout beyond OEM tolerances
- Thermal stress following failure
- Hardness levels that prevent accurate machining
By reducing hardness before final machining, the crankshaft can be restored to compliant operating condition and its service life significantly extended. Our annealing process can reduce crankpin hardness by up to 300 HB, eliminating harmful excess hardness and supporting full restoration to OEM standards.
Integrated Crankshaft Restoration
Crankshaft annealing is often carried out prior to precision machining to ensure correct tolerances and surface finish can be achieved. Where required, this service is delivered in conjunction with our Crankshaft Grinding Machining to restore dimensional accuracy.
If crankpin damage is present alongside excessive hardness, annealing may also form part of a wider repair programme including our Onsite Crankpin Machining & Crankpin Repair services.
Why Royce Onsite Machining?
Royce Onsite Machining is built on over 50 years of combined hands-on experience in heavy industrial and marine environments.
We understand the operational impact of crankshaft failure and focus on delivering controlled heat treatment of crankshafts that integrates directly with precision machining to restore performance and reliability.
We regularly support operations across Oil & Gas, Power Generation, Marine, Petrochemical, Mining and Heavy Industry, and Infrastructure sectors, where unplanned downtime can have significant operational and financial consequences.
Frequently Asked Questions
What is crankshaft annealing?
Crankshaft annealing is a controlled heat treatment process used to reduce excessive hardness in crankpins following overheating or failure. It restores the material to a machinable condition and supports compliance with OEM tolerance limits.
Why is heat treatment of crankshafts necessary after failure?
After bearing seizure or overheating, crankpins can harden beyond acceptable limits and develop increased runout. Heat treatment of crankshafts reduces this hardness and internal stress, allowing precision machining to be carried out accurately and safely.
How much hardness can be reduced during crankpin annealing?
Our annealing process can reduce crankpin hardness by up to 300 HB, depending on the extent of thermal damage. This helps eliminate harmful excess hardness and prepares the crankshaft for final machining.
Is crankshaft annealing carried out alongside machining?
Yes. Crankshaft annealing is commonly performed prior to precision machining. Where required, it is integrated with our Crankshaft Grinding Machining or Onsite Crankpin Machining & Crankpin Repair services to complete the restoration process.
