Pre-sintered Brazing Preforms (PSPs)
Reducing Cycle Times, Improving Performance
In order to deliver a lean manufacturing process while offering improved metallurgical bonds strength, Aimtek, Inc. offers the Pre-sintered Preforms (PSP) series of products. PSPs are used to dimensionally restore and repair cracks in critical components such as vanes and blades in gas turbine engines through a diffusion braze process. PSPs provide a repair method, proven over 30 years of deployment on turbines, that enables quicker turn-around times, lower costs, and proven reliability.
What are PSPs?
Pre-sintered Preforms (PSPs) are a sintered powder metallurgy product composed of a homogeneous mixture of a superalloy base material and braze alloy powders. Typical superalloy content ranges from 40 to 70% and plate thickness ranges from 0.3mm (.010”) to 5mm (.200”). Custom preforms can be cut from a sintered plate, tack welded to a component and vacuum brazed.
PSP Design Considerations
- Enables repair of alloys that cannot be welded
- Is a reproducible, well-defined process
- Allows for multiple components at a time, making it a quicker process than a weld repair
- Lowers labor cost via use of less direct labor and less skilled labor
- Reduces or eliminates post processing due to better dimensional control
- Eliminates post-weld heat treatment, shrinkage, and HAZ issues associated with welding (like hot cracking)
- Matches the base alloy more closely for higher joint strength (parent metal welding is difficult or impossible)
- Has less distortion (from uniform heating), low porosity, better dimensional control, no shelf-life, and no messy components to handle
- Minimizes re-braze cycles and post braze
PSP Application on Curved Surfaces
For brazing to concave surfaces, curved PSP’s are recommended.
Unlike flat preforms, curved PSPs eliminate the need for a second braze cycle on both convex and concave surfaces reducing processing time.
With Aimtek’s PSP versatility, greater alloy matching is made possible
The porosity of custom preforms is less than 2%, so little to no shrinkage occurs; this is a major advantage of Aimtek’s pre-sintered preforms over traditional brazing pastes and green tapes. Those braze methods present several problems, primarily with uncontrollable shrinkage and multiple rebrazing cycles. Unlike pastes and green tapes, PSP components require minimal post-braze grinding or machining to restore a part to its original dimensions. PSP’s are available in all of the above forms, which are used to restore worn holes or bores.
Working In Partnership to Implement a Lean Process
Aimtek engineers utilize their extensive metallurgy background and industry leading best practice knowledge stemming from experience to assist customers in understanding the processes involved. Our engineers can then custom design a repair procedure and an alloy to give the best possible results, leading to significant savings for customers, reduced turnaround and labor time, and the ability to salvage parts that would previously have been scrapped.
- Flat Plates
- Laser Cut Preforms
- Curved Geometry Preforms
- Flexible Tape
- Braze Paste
- PSP Paint