When a worn-out and damaged vertical pump shaft arrived at the workshop, precision restoration becomes a mission-critical service to improve system efficiency and reliability.
What are vertical pump shafts?
Vertical pump shafts are vital to keeping large-scale water systems running. Often spinning at up to 1,800 RPM, supporting loads weighing several tons within cooling systems found in power plants and irrigation setups used for agriculture.
Its critical section is the impeller journal—a precisely machined surface that supports and centres the impeller, enabling the shaft to push water through the system. It must maintain tight tolerances and remain perfectly balanced during high-speed rotations.
Keeping everything running in sync are dowel pin joints which are essential alignment features that ensure a multi-piece shaft assembly fit together with precision. The slightest distortion or misalignment can throw an entire pump system off balance.
Why vertical pump shafts are critical
Vertical pump shafts transfer power from the motor to the impeller that moves water through the system. These shafts work in demanding environments operating continuously under corrosion, heat, stress, and temperature fluctuations.
The impeller journal—the precision-machined component that supports and aligns the impeller requires the perfect dimensions for efficient operation. When its surface wears down, it can cause high vibration throughout the pump assembly, high energy costs, faster wear on other parts, and potential system breakdown.
Critical mechanical issues
The shaft we had to reclaim presented a set of complex challenges:
- The impeller journal suffered from significant wear requiring dimensional rebuilding
- Preserve and restore the integrity of four dowel pin joints without altering their positions or dimensions
- Each dowel pin joint had to be maintained within micrometre-level tolerances, any deviation would cause significant system misalignment
Traditional repair methods often struggle to maintain these exact tolerances, and anything that disturbs these precisely positioned features would render the shaft unusable making this a job for advanced precision engineering.
Implementing a methodical solution
Paired with expert planning and execution, our surface engineering team utilised advanced laser cladding technology to restore the shaft without compromising its alignment.
- Detailed mapping: We carefully recorded the precise measurements of all dowel pin locations before any work commenced.
- Pre-machining: The shaft was carefully pre-machined in our large industrial lathe to create the optimal foundation for the laser cladding process.
- Advanced material application: 410 stainless steel alloy—corrosion resistant with superior wear—were applied using our hotwire laser cladding system.
- Rigorous quality assurance: Liquid dye penetrant and ultrasonic tests were conducted to check for flaws and integrity.
- Precision grinding: The restored surface was precision-ground to exact OEM specifications.
- Dowel pin preservation: Fully protected and reinstated dowel pin joins with critical dimensions and precision alignment through masking techniques.
Laser cladding’s crucial advantages
The complexity and demand of the precision repair highlighted the crucial advantages of laser cladding that include:
- True metallurgical bonding: This process creates a stronger, permanent fusion without any risk of separation
- Minimal heat distortion: Laser produces smaller heat-affected zone that reduces the risk of warping
- Tight dimension control: This computer-controlled process deposits material with tolerances as tight as ±0.1mm, thus maintaining the exact positioning of the dowel pin features
- Superior material performance: The surface becomes highly resistant to wear and corrosion, with nearly zero porosity
Outcome: shaft saved; performance upgraded
Through our precision engineering and advanced laser cladding expertise, the vertical pump shaft was restored, returned to service, and even improved—with the impeller journal rebuilt to exact OEM specifications using a corrosion resistant 410 stainless-steel alloy, enhancing its durability, performance, and longevity. All four dowel pin joints were also precisely preserved for critical shaft alignment, ensuring a seamless reintegration that delivered a significantly lower cost in savings than a full replacement.
When is Laser Cladding applicable?
Some of the industry applications where laser cladding is particularly well-suited for metal reclamation of heavy industrial components in environments characterised by extreme wear, corrosion, heat, and mechanical stress include power plant cooling systems, irrigation pump assemblies in agricultural settings, water treatment facilities, and mining dewatering operations.
In these industries where pump performance and uptime are crucial, our laser cladding solution remains a superior alternative to costly component replacement and operational disruptions while delivering improved performance.
Our team of highly skilled surface engineering specialists has been keeping the wheels of the industry turning—from laser cladding to the latest robotic controls.
Need to restore critical components where precision matters? We offer complete surface engineering solutions that deliver precise results and extended service life. Contact our specialists today.
