Hydrogen Sulphide effects on low alloy steels up to 36Rc

[pitrer]

This subject was partially closed in thread330-25461, but it will be good to know how long HRC 30-36 (or grater than 22) will survive in lower concentration of H2S. For North Sea wells will be 350-1000ppm (0.00035%-0.001%). This will probably make some difference on material survival to 2% of H2S from cited in the other post. Some of my clients are required to use non H2S steel (due to strength) for short operation(up to 24hours) in low H2S wells.

 

[blacksmith37]

It depends; If it is a clean Cr:Mo with low Mn and very low Ni, double water quenched and tempered , with exceptionally fine grain ( like 10 or smaller ) , It will have very good resistance to H2S. This is the type material that meets API T-95 . There may be C-100 and C-105 grades today ( I have been retired awhile). But I don't know what you do for components other than tubulars.

 

[SJones]

There are two answers to the question:

1. How long is a piece of string?

2. How lucky does your client feel?

Your client will, ultimately, be duty bound to heed the requirements of ISO 15156-2 unless they can come up with a satisfactory case to justify otherwise. Thus, you and they may like to refer to Figure B.1 of the ISO document.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[blacksmith37]

Regarding time to fail : Using the NACE smooth tensile bar method, for the materials that failed, 90% of failures occurred within 200 hours . Some did occur within 24 hours ( can't remember a percentage).

 

[pitrer]

Thanks for replays! North Sea wells are mostly on 4000m depth.

 

[SJones]

@pitrer - your only out will be to achieve grade and temperature compliance with ISO 15156-2, Table A.3. You may also wish to check your concentration conversions.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.