Laser Cladding: Innovative Localized Hard-facing/Restoration Technique
Laser cladding is a cutting-edge welding process that has the capability to modify the surface properties of a substrate with exotic and/or harder materials. In this process, the feed-stock in the form of micron-sized alloy powder is melted by a laser beam to deposit the durable overlay with a thickness of 0.020” to 0.250” on the substrate.
IBC Coatings Technologies offers laser cladding as a localized treatment for extending the operational service life of high value/performance components by increasing resistance to wear, corrosion, and erosion in a wide variety of applications and environments.
Why Laser Cladding?
Traditional cladding techniques, such as arc-based welding, often require excessive heat input, which may result in negative effects on performance of the whole component, such as distortion and reduced mechanical properties. In contrast, the heat input of the laser beam can be accurately adjusted which is critical to maintain dimensional accuracy for tight component tolerances. It has minimal side effects on the mechanical integrity of the component, either locally treating the damaged area or improving the surface properties for a specific part in the chain of manufacturing.
Laser Cladding Features:
- Highly concentrated heat input with very narrow heat affected zone
- High adhesion strength due to metallurgical bond with minimal dilution
- High deposition rate (2 – 3.5 kg/hr)
- Capability of cladding a wide variety of materials, even those with poor weldability
- Cost-effective due to few required pre/post processing treatments
- Exceptional weld quality in terms of both mechanical and surface properties due to greatly lowered defects such as porosities and cracks
- High repeatability and precisely controllable
Crushing Wheel Die Cast Plunger Tip Forging Pin High Temperature Cutting Die Repaired Centrifuge Rotor Shaft Coupling Shaft
| Arc Welding | Thermal Spray | Hard-Chrome Plating | Laser Cladding | |
|---|---|---|---|---|
| Heat Input | High | Low | N/A (chemical process) | Low |
| Dilution Rate | 10 – 40% | N/A(mechanical bonding) | No metallurgical bond | <5% |
| Hardness (HV) | Relatively Low | <1000 | 800 – 1000 | >1000 |
| Distortion | High | Low | N/A | Low |
| Heat Affected Zone | Large and wide | Low | N/A | Low |
| Quality | Less durable | Full of pores and less durable | Prone to chipping and delamination | Highly dense and Long life |
| Pre/Post Treatments | Many | Many | Many | Few |
| Automation | Difficult | Difficult | Difficult | Easy |
| Coat Thickness | >0.020” | 0.020” – 0.040” | 0.002” – 0.006” | >0.020” |
Laser Cladding Capabilities
- 4 kW IPG fiber laser
- Headstock/tailstock positioner with capacity of 4000 lbs coupled with maximum diameter of 12 in and maximum length of 11 ft
- Wide selection of cladding materials
- Research and development / feasibility studies
- Equipped with quality analysis
Laser Cladding Cell: Exterior View Laser Cladding Cell: Interior View
Laser Cladding Target Materials
| Target Material | Typical Hardness (HV) | Thermal Stability (°C) | Application |
|---|---|---|---|
| High Strength Steels (M2, H13) | 550 – 650 | 450 – 500 | Tool repair |
| Rockit™ | 900 – 1100 | – | Excellent substitution for hard chrome, high abrasion resistance at ambient temperature |
| SS309, SS316L | 250 – 300 | – | Used as root layer/build up, relatively good general corrosion resistance |
| SS420, SS431 | 550 – 600 | 500 – 550 | Reasonable wear resistance |
| Stellite-6 | 550 – 600 | 500 – 550 | Excellent galling, wear, erosion, and cavitation protection over a wide temperature range |
| Stellite-21 | 400 – 450 | 500 – 550 | Superior thermal and mechanical shock resistance, relatively high resistance to galling and cavitation |
| Inconel-625 | 250 – 300 | 900 – 1000 | Applied in extremely high corrosive environments, used as buffer layer |
| Inconel-718 | 400 – 450 | 600 – 650 | Age hardenable, high temperature stability and corrosion protection, ideal for hot forging punch |
| NiCrSiB-65%WC | 1500 – 2500 | 600 – 650 | Extremely high abrasion/erosion resistance and excellent for part-to-part sliding wear due to relatively low friction coefficient |
| Colmonoy 69 (NiCrMoCu) | 600 – 650 | 500 – 550 | Excellent resistance to aluminum liquid erosion used in high pressure die cast |
| Ni80Cr20 | 300 – 350 | 1000 – 1100 | Hot oxidation resistance |
| Aluminum-Bronze | 200 – 300 | 350 – 400 | Excellent galling resistance for cold forming tolls, good general corrosion resistance |
Attackable Failure Modes by Laser Cladding
- General Wear
- Abrasive Erosion
- Hot Gas Oxidation
- High Temperature Corrosion-Erosion-Wear
- Galling
- Cavitation
Target Industries
- Oil and Gas
- Marine
- Pulp/Paper
- Glass
- Power Generation
- Mining/Heavy Equipment
- Agriculture
- Food Processing
- Aerospace
- Steel Manufacturing
Laser Cladding Common Applications
- Flanges
- Seats
- Wear Sleeves
- Pumps
- Glass Molds
- Seal/Bearing Journals
- Impellers
- Rotor Shafts
- Pump Shafts
- Compressor Wheels
- Gearbox Housing
- Propeller Shafts
- Exhaust Valves
- Rolls
- Crank Shafts
- Engine Components
- Mandrels
Proven Solution for Hot Mill Rolls used in Steel Making Industry
Rolling steel is a process that stretches the performance limits of the components used in the rolling equipment. Abrasion wear, thermal shock, and galling can cause failures of rollers and other components creating downtime and quality issues. Being exposed to the wide range of temperature dictates the need for a high hardness, low friction solution.
IBC Coatings Technologies offers field proven solution for extending the service life of the hot mill rolls. Customer using our laser cladded carbide-based overlays have reported over 6x service life extension compared to thermal spray or arc welding resulting in lower operating cost and reduced down time.
Restoration of Hot Rolling Mill Cross-section of WC-based composite on Hot Mill Roll
Results of ball-on-flat wear test per ASTM G133 showed exceptional wear resistance of WC-based composite out of laser cladding against various surface modifications applied on steels. For all surface modification conditions, laser cladded WC-based overlay wear rate is substantially lower than the one that was deposited by thermal spray.
Laser Cladding Case Studies
Bottom Punch/Magnet Dies
When magnets are produced for motors, the magnet material is combined in a slurry and set into a die. Then, punches force the slurry into the magnet die and force all the water/contaminants out of the slurry. These punches must have non-magnetic tips, so they don’t interfere with the magnet’s polarity. In addition, the dies are subject to high metal to metal wear.
Traditionally, Stellite 6 was applied to the top surface via GTAW. However, the dilution line between the base material (W2 steel) and the substrate (Stellite 6) was choppy, and the manual process was time consuming (roughly 1 hour per punch).
IBC proposed an automated solution to improve productivity. The solution used a coaxial powder feed laser head, and custom programming was implemented to map the clad/layer paths.
IBC was able to produce a buildup of Stellite 6 that exhibited a very clean dilution line between the parent and clad material, and produced a cladding in 15-20 minutes as opposed to 1 hour. Hence, quality and productivity were improved drastically with this automated solution.
Wind Turbine Centrifuge Hubs/Shafts
Wind turbine hubs and shafts are subjected to wear due to load variation resulting from changes in wind speed/intensity. This wear can cause the gearboxes to fail prematurely, leading to high replacement costs.
IBC Coatings Technologies applied laser cladding to worn hubs, journals, and shafts, which were then machined to original design specifications. Base materials included a variety of stainless steels (410 SS, 420 SS, 440 SS). The prime cladding material was 420 stainless steel. Careful control of the preheat and process parameters ensured the clad material was free of defects and had similar/improved properties compared to the base material.
Steel Mill Rods
Steel mill rods are components which are subjected to frequent wear. Usually the wear is minor, but sufficient to make the rod no longer usable. IBC Coatings Technologies applied laser cladding to worn rods. Base material was a high strength steel (4140), and 431SS martensitic stainless steel was picked as the overlay in order to improve the wear resistance of the substrate.
Based on quality analysis after laser cladding, it was revealed that the hardness of the overlay experienced a smooth transition toward the substrate, confirming that laser cladding leads to metallurgical bonding. Additionally, there was no sign of a heat affected zone immediately after the overlay/substrate boundary.
