-- The Home Page of the Finishing Industry
23+ years of serious education, promoting Aloha,
& the most fun you can have in metal finishing smiley
    no popups, no spam
on this site
current topics
topic 10557

Scale problem on the interior and exterior of the parts


WE have a process where it calls for our extruded basics to be annealed before machining. This causes a flaky, scale problem on the interior and exterior of the parts. Whatever is not machined retains this scale. We have to plate them zinc/chromate and have an impossible time removing the scale. Has anyone ever removed a scale like this. Possible origin from oil heated or baked onto the parts during the anneal process.

James D. Browning
HPE - Batesville, Mississippi, USA


I suspect you know the right answer and just want to hear someone confirm it :-)

Clean the oil off before heat treating the parts! An alkaline descaler may be the most powerful process approach to removing the baked on scale.

Ted Mooney, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey


Dear James,

If youre the guy doing the plating then you have as tough time. If youre the component mfr. then do your plater a favour by hot phosphating the parts prior to the annealing.

The hot phosphate ensures that the parts are oil free, and the phosphate coating will prevent any scale formation.

good luck !

Khozem Vahaanwala
Khozem Vahaanwala
Saify Ind supporting advertiser
Bangalore, Karnataka, India

saify logo

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Comment to THIS thread START a NEW threadView CURRENT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.