Re: [MW:11291] Re: Pickling Passivation of Hastalloy

Dear Prasad,

 

Please note the following point regarding the passivation of Nickel based alloys, like, Inconel, Hastelloy etc.

• The nickel-based alloys aren't chemically passivated like stainless steels (passivation solutions are also nickel stripping solutions). However, these alloys must be cleaned of any zinc, lead, tin, bismuth, sulfur & phosphorus contamination before heat treatment or high temperature use in service. The main purpose is to improve the surface clealiness so that in service, the corrosion/oxidation resistance remains unaffected. Particularly, the a.m. impurities are detrimental to the high temp. application of these alloys.
• Normally, A combination of alkaline cleaning and flash pickling is used. Similarly, embedded iron particles are removed by pickling for the minimum time possible. Iron contamination can be detected by either a 12-24 hour soak in 1% NaCl (rust appears) or the ferroxyl test (blue stain appears). Generally, the Formulas for pickling solutions are given by the alloymanufacturers Haynes Intl. for Hastelloy.  

In my opinion, you may ask the alloy supplier what standard they follow for pickling/passivation of the surface for special applications.

 

I hoe this clarifies,

 

With bes regards,

 

Prasad Joshi

Linde

On Sat, May 28, 2011 at 9:42 AM, Prasad <prsgne@gmail.com> wrote:

I have already downloaded info. from suggested site but to have more
authentic reference
I need to know ASTM standard for this.

Please help me out.

Best regards,

Prasad

On May 27, 11:28 am, jignesh.r...@Linde-LE.com wrote:
> Dear Mr. Prasad,
>
> Referwww.haynesintl.com.

>
>  It suggest some recommendations for pickling and passivation for
> hastalloy.
>
> After PWHT, the oxide film is more adherent than normal 18/8 grade
> stainless steel.  Molten caustic  bath followed by acid pickling found to
> be most suitable method.
>
> With Best Regards,
>
> Jignesh R Rana
> Manager - Materials Technology, QA/QC & Standards
>
> Linde AG
> Linde Engineering Division
> Dr.-Carl-von-Linde-Str. 6 - 14
> 82049 Pullach / Germany
> phone:    +49 89 7445 - 2360
> fax:           +49 89 7445 - 4952

> e-mail:    jignesh.r...@linde-le.com

> web:        http://www.linde.com
>
> This e-mail is confidential. If you are not the intended recipient, please
> notify us immediately. You should not disclose its contents to any other
> person nor use it for any purposes.
>

> Prasad <prs...@gmail.com>

> Sent by: materials-welding@googlegroups.com
> 27.05.11 05:50
> Please respond to
> materials-welding@googlegroups.com
>
> To
> "Materials & Welding" <materials-welding@googlegroups.com>
> cc
>
> Subject
> [MW:11160] Pickling Passivation of Hastalloy
>
> Dear experts,
>
> We are fabricating a pressure vessel with Hastalloy claded plates.
> Vessel is to undergo PWHT. I would like to know which is the ASTM
> standard covers
> pickling of Hastalloy material, like A380 is for SS materials.
> Code of construction is ASME Sec. VIII Div. 1 2007.
>
> THanking you in advance.
>
> Prasad
>
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