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RPM Innovations, Inc. Rapid City, SD

Laser Repair Technology (LRT)

Sub-links: Repair (LRT) | Cladding (LCT) | Freeform Manufacturing (LFMT)

Laser Repair Technology Repairs Titanium Turbine Blade When operating any type of mechanical equipment with moving parts, repairing or rebuilding worn metal components is part of everyday life.

Repairing worn components typically saves dollars over purchasing new ones.

When a worn part is rebuilt, the potential also exists to repair that component in such a manner that it will have a longer wear life than a new part.

Repair Parts That Were Previously Un-repairable

The concept of repairing parts versus replacing them is not new; however, the use of the Laser Repair Technology (LRT) to repair components previously considered un-repairable is. Laser Deposition Technology (LDT) has a number of key benefits over other repair techniques that make it possible to repair some parts that were previously un-repairable. Using other techniques, either the part could not physically be repaired, or it was not economically feasible to perform the repair.

Some of the benefits of LDT over other repair techniques are:

  • Metallurgical Bond versus Mechanical Bond
    The LDT process creates a metallurgical bond which is much stronger than the mechanical bond created using spray welding or plating techniques.
  • Low, Controlled Heat Input
    The LDT process creates very low and controllable heat input with minimal dilution and heat effect zones.
  • Minimal Stress and Distortion Created by Deposits
  • Rapid Cooling Rates
  • Cost Effective for Repairs and Manufacturing

The key benefits of LDT over other techniques are that it 1) creates a stonger bond and 2) inputs less heat to the part being repaired. The benefits of the stronger bond are obvious. The lower heat input means less distortion of the part during the repair process. These two benefits make the LDT process unique.

Following are a number of specific case studies where the benefits of Laser Repair Technology (LRT) made it possible to repair parts that were previously unrepairable.

Contact Us about the details of your project.

Case Study: Titanium Bearing Housing

An application employing a low-wattage repair is shown in figures below. This is a Ti-6Al-4V bearing housing from a gas turbine engine. The bearing seating area was worn to an out-of-tolerance condition, and the housing was considered scrap. The process was utilized to build up the worn area, which was followed by final machining to print tolerances. This housing was successfully repaired, with no measurable distortion, and has completed an evaluation run in a test engine. The repair costs are about 50% of new pricing plus it saves all of the materials that would be required to manufacture a new housing. Delivery for the repaired housing is a few days compared to several weeks for a new housing.

Titanium Bearing Housing Before Repair
Bearing Housing Before Repair
Titanium Bearing Housing After Deposition
Bearing Housing After Deposition
Titanium Bearing Housing After Deposition
After Deposition

Case Study: Inconel 718® Compressor Seal

The figures below illustrate a very finesse repair of a gas turbine Inconel® 718 compressor seal. When the labyrinth seal diameter wears 0.008 in., the engine loses power and the seal is considered scrap. This test seal was repaired using Inconel® 718.

Gas turbine Inconel 718 compressor seal repair before repair
Compressor Seal Before Repair
Gas turbine Inconel 718 compressor seal repair after laser deposition
Compressor Seal After Laser Deposition
Gas turbine Inconel 718 compressor seal repair after final machining
Compressor Seal After Final Machining

Case Study: Low-wattage Repair of Titanium Components

Low-wattage repair of titanium components has many potential aerospace, Department of Defense, and commercial applications. The figures below show a typical low-wattage repair of a simulated defect in this Ti-6Al-4V plate. Multiple layers were applied to achieve the full depth of deposit required for this repair. Note the typical columnar grain growth in the deposit and the very small HAZ in the surrounding base material. Minimal distortion was experienced with this type of repair, which may be used on several aircraft structural components such as wing spars or bulk heads. Several gas turbine engine components as well as land-based turbine blades are potential candidates for this low-wattage repair. Repairs of this type typically involve critical components and require substantial qualifications of the repair process before the process can be implemented. The potential savings in time, materials, and dollars is great.

Laser Deposition
Laser Deposition
Laser Deposition Samples
Laser Deposition Samples
Metallography
Metallography

Case Study: Repair of Ti-6Al-4V Forging

RPM Innovations received a Ti-6Al-4V drive plate forging that needed repair. The forging was undersized. Material needed to be added to the part to build it up so it could be machined to the proper fit. The drive plate is for an atomizer wheel used in a Flue Gas Desulfurization system. All of the parts in the atomizer wheel rotate up to 15,000 RPM. For this system, it is important that the part be precisely machined and that the material used be resistant to wear. Titanium is used to minimize the weight of the part while maintaining the hardness and strength needed for the application.

Using Laser Repair Technology (LRT), material was added to the part. Once the material was added, the strong metallurgical bond allowed the material to be machined off to the proper fit while maintaining the required strength and hardness for the application. The low heat input of the LRT process ensured that the part did not change its shape or material properties.

Ti-6Al-4V Drive Plate repair using Laser Repair Technology
Forging As Received
  • Ti-6Al-4V atomizer drive plate.

  • Part rotates up to 15,000 rpm.

  • Forgings were undersized.

  • Used Laser Repair Technology (LRT) for building up material.

 
ti-6al-4v Drive Plate forging during deposition
Forging During Deposition
ti-6al-4v Drive Plate forging after deposit
Forging After Deposit
ti-6al-4v Drive Plate forging after final machining
Forging After Final Machining

Case Study: Pick-up Tube Repair

A "Pick-up Tube" rotates in a circular path and is used to pick up a slurry mixture. The majority of wear on this part occurs on its outer edge. The outer edge was originally manufactured using an alloy Inconel 718. Conventional methods to repair this part were tried; they all failed.

RPM Innovations developed a repair process using Laser Repair Technology (LRT), Inconel 718 as the base filler material, and Nickel-Chrome-Boron as the final surface material. The repaired Pick-up Tube has improved wear, abrasion resistance, and a longer service life.

Pick-up Tube repair using Laser Repair Technology
Pick-up Tube
  • Pick-Up Tube rotates in a circular path and picks up a slurry mixture.

  • Wear occurs on the outer edge of the part, which is made out of the alloy Inconel 718.

  • Conventional repair methods had failed.

  • Repaired using Laser Repair Technology (LRT),  Inconel 718 as the base filler material, and  Nickel–Chrome–Boron deposited as the final surface material.
     
  • Repaired part has improved wear, abrasion resistance, and a longer service life.

 
Pick-Up Tube Before Deposit with an Inconel 718 Plug in Place
Pick-Up Tube Before Deposit with an Inconel 718 Plug in Place
Pick-Up Tube After Laser Deposit
Pick-Up Tube After Laser Deposit
Pick-Up Tube Post Machining
Pick-Up Tube Post Machining

Case Study: Stator Housing Repair

A Stator Housing came into our shop for repair. Three of the ribs on the housing were worn over 0.100". Each of the three ribs were positioned on the part at a different angle, which the repair process had to take into account.

RPM Innovations developed a repair process using Laser Repair Technology (LRT) and 420 Stainless Steel. Previous attempts were made to repair this part using conventional repair methods. These previous attempts failed due to the distortion created with the introduction of high heat input.

Stator Housing repair using Laser Repair Technology
Stator Housing As Received
  • Stator Housing had three separate ribs that had worn out over 0.100”.

  • Each rib was at a different angle that had to be accounted for.

  • Parts were repaired using laser deposition with 420 Stainless Steel.

  • Part was previously repaired using conventional welding methods. These methods caused too much distortion due to the heat input.

 
Stator Housing before deposit
Before Laser Deposition
Stator Housing during deposit
During Laser Deposition
Stator Housing after deposit
After Laser Deposition

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About RPM Innovations

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Building real parts from CAD files. RPM’s two laser deposition labs can employ freeform laser manufacturing which can drastically reduce Research and Development time and expense.