Ali 5L X65 pipe FAILEDNACE Hic test

[goodbadgood]

Hi i have 2 samples from different Api 5l X65 pipes which failed NACE hic test. I am looking for a root cause analysis. Based on your experiences can you please guide me what to check specifically in microstructure analysis? Inclusion content in unetched conditions will be useful? Any other guidance will be helpful. Thanks

 

[blacksmith37]

I would include the HIC test requirement on the purchase order.

 

[SJones]

Before you get to microstructure, start with confirming the melting and rolling practice and chemical composition, i.e. was the steel specifically manufactured to be capable of passing the standard HIC test with acceptance criteria as per ISO 15156-2. This will guide you in what to look for when you get it under the microscope.

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.

 

[pradipgoswami]

Hi Googbadgood,

Failures in HIC testing are lot attributed to the manufacturing and the cleanliness of the steel.Welding comes next.
APL-5L-Annex H specifies many quality requirements some of which are as follows:=


H.3.2 Steel making:-The steel shall be made to a clean steel practice, by either the basic oxygen steel-making process or the electric furnace process & shall be killed.
--Vacuum degassing or alternative processes to be used to reduce the gas content.
--The molten steel shall be treated for inclusion shape control.
--A procedure (e.g. metallographic examination) may be agreed between the purchaser and the manufacturer to assess the effectiveness of inclusion shape control.
--For S levels ≤ 0.001%, inclusion shape control may be waived by agreement.

H.4.3 HIC/SWC test to be met.

Were all these requirements met at the first place.

What were the requirements of the P.O.

Appreciate your response.

Thanks.


Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299
All provided answer are personal opinions or personal judgements only. It's not connected with any employers by any means.

 

[goodbadgood]

HI Blacksmith37
Hic test was included in the PO

Hi Sjones
Chemical analysis is under progress and i am waiting for results let see what will be the values

Hi Pradipgoswami

This was already considered by the manufacturer.
However i have checked the micro-structure and crack morphology and found inclusion at crack tip and in between crack openings. It looks like MnS inclusions which makes the area susceptable to HIC.
EDS / SEM will confirm the composition of the inclusions