Quality
Waterjet Newsletter – 9/13/2005
Hard-Coating Removal with an
Abrasive Waterjet Coating removal with high-pressure
waterjets has been reviewed in previous newsletters. This short article will
review a hard-coating removal method with an abrasive waterjet, which was
described by Ruusuvuori et al.* in their award-winning paper on the 2005 WJTA
conference. Hard-coatings are increasingly
being used to enhance the wear resistance of critical and expensive
components, especially in the aviation industry. Thermal spraying methods,
such as HVOF (High-Velocity-Oxygen-Fuel), are used to apply hard metal
coatings, such as WC-Co and Cr3C2-NiCr, onto these
components. These coatings are very dense and have very high adhesion. As
good as they are in protecting the components, they are difficult to remove
when the components need repair and recoating. Traditionally, these coatings
are removed with electro-chemical baths or mechanical grinding. These methods
are environmentally unfriendly and time consuming. Abrasive waterjet can effectively
remove these coatings with an erosion process. The impact of process
parameters to coating removal speed follows trends similar to those in
cutting processes. Higher water pressure and abrasive flow rate, as well as
slower traverse speed, will result in higher removal speed. Abrasive size
should be optimized for a specific coating. In their tests, aluminum oxide
abrasive (instead of garnet, which is popular in cutting applications) was
used because the aviation industry generally does not use iron-containing
abrasives like garnet. Unfortunately, selected values of other process
parameters were not disclosed in the paper. However, using abrasive waterjet
for hard coating removal has a risk of cutting into the softer base material once
the coating has been penetrated. The authors have conducted an in-depth
research study of different methods for accurately measuring the thickness of
the coating as a way of controlled removal. With low carbon steel as the
substrate material, an ordinary eddy-current-low-frequency coating-thickness
gauge was found to give the best results. This new hard coating stripping
technique has gained acceptance or attention from some large corporations in
the aviation industry, like KLM and HT Lasertekniikka. * Ruusuvuori, K, Lahhenpera, K, Oksa, M., Turunen,
E., Kauppila, J., Wonderen, M.
van, “Controlled HVOF Hard Coatings Removal Method,” Proceedings of the 2005
WJTA American Waterjet Conference, Houston, Texas, August 21-23, 2005, Paper
5B-2. Durable, Compact 40K/50K PSI Pumps · Long operation
lifetime: seal set lasts three times than Husky pumps · Compact: weight less
than half of most compatible pumps · Custom power end and
private labeling upon request · Custom UHP pump design
available · Contact info@qualjet.com
for details |
|
QualJet
LLC
Quality Waterjet Spare Parts Specialist · Quality
Waterjet Spare Parts o Meets/exceeds
OEM standards o 30%
longer operation life time than competing products · Extensive
Parts Coverage for: o Flow
style, IR Style o 40K/55K
pumps o Intensifiers
o On/off
valves o Cutting
head o Swivels · OEM
Expert o 20+
year waterjet OEM experience (via OH Precision) o Accept
small OEM order QualJet LLC
1-866-QUALJET (782-5538) Fax: 425-378-7776 Email: info@qualjet.com Website: www.qualjet.com To unsubscribe the
newsletter: unsubscribe@qualjet.com For newsletter archive: www.qualjet.com/Newsletter.htm
Waterjets or parts for sale: Industry
jobs: qualjet.com/IndustryJobs.htm Copyright ©2005, QualJet LLC |
|
|