Sunday, December 25, 2011

Re: [MW:13297] Surface roughness measurement instruments.

Hi Rao,
Pls. refer below

SA 2
thorough blast cleaning:Commercial finish 65% clean
The surface shall be free from visible oil, dirt and grease, from poorly adhering mill scale, rust, paint coatings and foreign matter. Any residual contamination should be firmly adhering.

 
SA 2.5
very thorough blast cleaning: Near white metal 85% clean
The surface shall be free from visible oil, dirt and grease, from poorly adhering mill scale, rust, paint coatings and foreign matter. The metal has a greyish colour. Any traces of contamination shall be visible only as slight stains in the form of spots or stripes.

 
SA 3
blast cleaning to pure metal: White metal 100% clean
The surface shall be free from visible oil, dirt and grease, from poorly adhering mill scale, rust, paint coatings and foreign matter. The blasted surface must have a uniform metallic colour.

BLASTING GRADES
Following is a table giving a clear indication of the comparative blasting grades applicable to national and international standards:
BLASTING GRADE COMMON STANDARDS COMPARISON
SSPC steel structures painting council
BS 7079 British standards
SS 05 59 00 Swedish standards
BS 4232
NACE, National Association of Corrosion Engineers


white metal (SP5) SA 3
1st quality
grade 1

near white metal (SP10) SA 2.5
2nd quality
grade 2

commercial finish (SP6) SA 2
3rd quality
grade 3
RUST GRADES
A Surface mostly covered with adherent mill scale, with little or no rust
B Mill scale has begun to flake, rust has started to form
C Mill scale has rusted away or can be scraped off easily and slight pitting has taken place
D Mill scale has rusted away and general pitting can be seen with naked eye
Thanks Regards
Sharad sharma
From: Pieper QSI <info@pieper-qsi.nl>
To: materials-welding@googlegroups.com
Sent: Saturday, 24 December 2011 2:37 PM
Subject: RE: [MW:13287] Surface roughness measurement instruments.
Dear Mr. Rao,
 
In my previous e-mail I mention that SA is roughness but that was wrong. As already mentioned by some other members SA is cleanness of surface after blasting. Unit for roughness is Ra or Rz, two different values, one measures an average roughness the other the maximum roughness, value to be used should be mentioned in the contract / coating specification. Both Ra and Rz will be measured in microns.
 
Met vriendelijke groeten / Best Regards
 
Herman Pieper
 
Pieper Quality Support & Inspection
Phone: +31 (0)521 380083
Fax:     +31 (0)84 7539225
Cell:     +31 (0)6 51691215
www.pieper-qsi.nl
 
Van: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] Namens Vasantharao
Verzonden: vrijdag 23 december 2011 13:31
Aan: materials-welding@googlegroups.com
Onderwerp: Re: [MW:13281] Surface roughness measurement instruments.
 
Dear Mr.Pieper
 
Thank you for your info.
 
Could you pl. give the units for measuring the surface roughness. As per my client spec. it is mentioned as microns only.
 
I think surface appearance after blasting should be SA 2 1/2 or SA 3 and should not be measured in microns.
 
thank you
Rao
 
From: Pieper QSI <info@pieper-qsi.nl>
To: materials-welding@googlegroups.com
Sent: Friday, 23 December 2011 2:07 PM
Subject: RE: [MW:13277] Surface roughness measurement instruments.


Dear Mr. Rao,
 
Be aware that the microns you mention is not the surface roughness but the coating layer thickness (DFT = Drie Film Thickness).
For surface roughness you will have values like SA 2,5 microns or similar and in practice mostly the comparators are used for inspection prior to first layer of coating.
After fist coating layer there is no need to measure the roughness anymore.
 
Met vriendelijke groeten / Best Regards
 
Herman Pieper
 
Pieper Quality Support & Inspection
Phone: +31 (0)521 380083
Fax:     +31 (0)84 7539225
Cell:     +31 (0)6 51691215
 
Van: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] Namens jsrisud@gmail.com
Verzonden: donderdag 22 december 2011 14:45
Aan: materials-welding@googlegroups.com
Onderwerp: Re: [MW:13259] Surface roughness measurement instruments.
 
Dear Mr. Rao,

There are portable surface roughness measuring instruments to measure as required.

UK based Rank Taylor Hobson instruments are available in India.

Srinivasan
Sent from BlackBerry® on Airtel
From: Vasantharao <vasantharao@yahoo.in>
Date: Thu, 22 Dec 2011 15:38:40 +0530 (IST)
Subject: [MW:13256] Surface roughness measurement instruments.
 
Dear Experts,
 
I work as inspection Engineer. When i go for Blasting inspection, contractor provided  me profile comparator for surface roughness measurement.
 
Contractor do  Grit blasting in the shop.
 
I need to measure surface roughness  -  75-100 microns      Painting system No#1
                                                            50-75 microns        Painting system No#2

Queries
Q 1: Comparator is enough for surface roughness measurements.
 
Q2: Is any other tools available for roughness measurement?.
 
Q3:  What is the normal industry practice.


Pl. provide your valuable suggestions as i'm new for painting activities.

Rao.
 
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The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
 
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For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.


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