RE: [MW:13337] RE: 13288] To increase hardness of Heat Exchanger fin

Hi Priyanka,

Looking at the description below, the intended application looks to be for HRSG.Temperature of 450 deg C is moderately high (not really very high). The choices could be:-

• Low Alloy steels such as , 9Cr-1Mo
• Ferritc S.S, e.g 12 Cr steels.
• Austenitic stainless steels 300 series such as, 321, 347H or other grades
• Nickel based alloys -Higher end alloy, would  definitely increase the cost , however may be a good investment for a longer and sustained service life.

 

The fins and the external surfaces exposed to abrading particles could be strengthened by application of HVOF or plasma arc transfer process. Application of stellite(through one of the above processes) would definitely enhance the abrasion resistance @ the service temperature.

 

Hope this would provide more information to your problem, based on the information provided till now.

 

Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist & Consultant
Ontario,Canada.
Email-pgoswami@sympatico.ca,
pgoswami@quickclic.net

-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Priya Deshmukh
Sent: Monday, December 26, 2011 4:46 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:13312] RE: 13288] To increase hardness of Heat Exchanger fin

Dear Sir,

More hardness of the fin is required because it is used in heat recovery of exhaust gases having abrasive particles in it.

The temperature might be around 450 deg. C and particles are abrasive eroding the fin surface.

Please reply if you have some solution.

Thanks & Regards,

Priyanka Deshmukh

On 12/26/11, pgoswami <pgoswami@quickclic.net> wrote:
> Hi Priyanka,
>
> What are the design conditions for the air cooled finned exchangers,
> e.g operating media, design temperature , materials of construction?
> .Is the intended application is for refinery or other type of plants ?
>
> Generally  pure aluminum is popular as fin material, however it does
> not offer much scope for improvement of hardness as this this material 
> is not heat treatable. Improvement of hardness through surface coating
> or thermal spray may impair corrosion resistance and the heat transfer coefficient.
>
> Below are some extracts on recommended material of construction for
> fin tubes, typically for oil and gas applications from various
> appropriate specifications.
>
> Thanks
>
>
> Pradip Goswami,P.Eng.IWE
> Welding & Metallurgical Specialist & Consultant Ontario,Canada.
> Email-pgoswami@sympatico.ca,
> pgoswami@quickclic.net
>
>
> *    
> Tubes with embedded aluminum fins or hot-dip galvanized steel fins,
> applicable up to a maximum operating temperature of 360 °C, should be used.
> Hot-dip galvanised steel fins shall not be used on austenitic steel tubing.
>
>
>
> *    
>
>
> -----Original Message-----
> From: materials-welding@googlegroups.com
> [mailto:materials-welding@googlegroups.com] On Behalf Of Priya Deshmukh
> Sent: Saturday, December 24, 2011 1:24 AM
> To: materials-welding
> Subject: [MW:13288] To increase hardness of Heat Exchanger fin
>
> To,
>
> All.
>
> Please provide me the procedure to increase the hardness of fin material
> without affecting its thermal conductivity.
>
> May be some spray or liquid may be available, by spraying or dipping the
> fins into the liquid the hardness can be increased.
>
> Thanks,
>
> --
> Priyanka Deshmukh
>
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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.