Hot dip galvanising Vs thermal zinc spray

[Qamlr]

Dear Team members

 

Could you please explain basic difference between hot dip galvanizing and thermal zinc spray. We have requirement of both on certain component. Can I adopt thermal zinc spray process in lieu of hot dip galvansing.

 

Please clarify.

 

Regards

 

Prashanth Hegde

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[Vino Varghese]

Dear Prashanth,

 

Hot Dip Galvinising does provide a metallurgical bonding Vs mechanical Bonding with Zinc Spray.

HDG is prefered in corrosion Environment as the zinc layer deposit is more firm due to chemical bonding.

 

Regards

VPV

 

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[Arun Das]

 

Dear Mr.Hegde,

 

Thermal spray coatings are a melted, or softened ceramic, metallic, or polymer materials are transported by a gas stream to a properly prepared substrate

 

Hot-dip galvanizing is essentially a brazing process. Steel is cleaned (mechanically and chemically) and then heated to >850°F in a molten zinc bath. The molten zinc reacts with the surface of the steel and forms a coating of various layers of zinc and iron alloys, depositing a layer of material that is approximately 40% pure zinc.

 

Arun S Das

Inspection Engineer

Velosi Certification LLC

Qatar

Mob: +97433240549

+919847051202 ( India )

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From: Qamlr <qa...@cicb-chemicon.com>
To: "material...@googlegroups.com" <material...@googlegroups.com>
Sent: Thu, 9 December, 2010 2:24:58 PM
Subject: [MW:8627] Hot dip galvanising Vs thermal zinc spray

[rmsengineering]

Hi hot deep galvanizing & zink spray though both give same cathodic
protection and are metallurgical bonds basic difference is in case of
zink spray there is a possibility of porosity which is not in case of
HDG the porosity level could be 6 yo 7 % in case of flame spray and 2
to 3% in case of arc spray

[Weldbro]

Dear Mr. Hegde,

Zinc is sprayed on base metals by the help of arc spray process hence
ideally if you have to compare hot dip galvanizing vs thermal zinc
spray we will have to compare arc spray as a process vis-a-vis hot dip
galvanizing

Hot dip galvanizing is a process where steel or even aluminium is
passed thru a molten bath of zinc at a temperature of 460 degree
celsius.In this process coated zinc reacts with oxygen forming zinc
oxide which further reacts with CO2 to form Zinc carbonate which
increases the corrosion resistance of parts coated.

Arc spray is a process wherein two wires melt with a arc and the
molten pool is sprayed on the substrate by the help of compressed
air.

Now both the above processes come with their own advantages and
disadvantages. Arc spray can be done quickly and is a viable option
for smaller parts while Hot dip galvanizing is good for bigger
parts . Arc spray coatings will have inherent porosity while hot dip
coatings will be smoother. Arc spray coatings have thickness advantage
and can be done for higher thickness of coating while hot dip doesnt
qualify in such cases.

Weldbro
Weldbro blogs regularly at www.weldblog.com which is the first and
most vibrant dedicated blog of welding community and invites all to
participate. You can even apply to be a author with full control on
your articles.

Best Regards

On Dec 9, 8:44 pm, Arun Das <indhua...@yahoo.co.in> wrote:
>  
> Dear Mr.Hegde,
>  
> Thermal spray coatings are a melted, or softened ceramic, metallic, or polymer
> materials are transported by a gas stream to a properly prepared substrate
>  
> Hot-dip galvanizing is essentially a brazing process. Steel is cleaned
> (mechanically and chemically) and then heated to >850°F in a molten zinc bath.
> The molten zinc reacts with the surface of the steel and forms a coating of
> various layers of zinc and iron alloys, depositing a layer of material that is
> approximately 40% pure zinc.
>  
> Arun S Das
> Inspection Engineer
> Velosi Certification LLC
> Qatar

> Mob:              +97433240549        +97433240549              +919847051202        +919847051202( India )

> For more options, visit this group's bolg athttp://materials-welding.blogspot.com/