Skip to main content

[MW:36091] Re: Request for Technical Opinion – Leakage in SS 316L Schedule 10S Line After 4 Months of Service

By Materials & Welding

The Primary Cause for failure shall be Chloride-Induced Stress Corrosion Cracking (SCC).

Contributing Factors:

  - Post-Hydrotest Preservation: Evidence suggests improper or missing preservation procedures following the hydrotest.
  - Weld Integrity: Residual stresses remaining in the welds.
  - Contamination: Likely chloride contamination during or after testing.

Required Preventive Measures:

  - Water Quality: Utilize low-chloride hydrotest water, ideally maintaining levels <50 ppm Cl⁻.
  - Post-Test Protocol: Ensure immediate draining followed by thorough drying using air blowing or nitrogen.
  - Surface Treatment: Apply a formal passivation treatment and ensure all weld heat tint is removed via pickling and passivation.
  - Material Specifications: Evaluate the use of SCC-resistant materials, such as Duplex SS, for critical service components.
  - Documentation: Maintain strict preservation records for all future assets.


Regards,

 

Sushil Bhansali – (+91) – 9082159270 / 9870846831

image003

Pioneer Steel And Engineering

Mumbai,India

Email:vishal@bhansalimetals.com

Web: www.wirestainless.com

On Friday, June 26, 2026 at 1:13:59 PM UTC+5:30 Karuppa Samy wrote:

Dear All,

We would appreciate your technical opinion regarding a leakage issue observed in stainless steel piping after several months of operation.

Background:

  • Line sizes: 2" and 6" 361L Stainless Steel (Schedule 10S)
  • NDT coverage: 10% completed as per project requirements
  • Hydrostatic test: Successfully passed without any leakage
  • Records related to line preservation after reinstatement are not available, as the system was under the control of the Pre-Commissioning and Commissioning teams
  • The line has been in service for approximately 4 months

Issue:
Leakage has recently been observed at several locations, including:

  1. Weld joints
  2. Pipe body/base material
  Considering that the line successfully passed hydrotesting and has been operating for several months before the leakage occurred ,  

 Could you please share your views on the potential reasons

Thank you in advance for your valuable inputs.

Best Regards,
Karuppasamy

--
https://materials-welding.blogspot.com/
https://www.linkedin.com/groups/122787
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/materials-welding/08317959-1c0e-41ab-a117-15edfd135c24n%40googlegroups.com.

Comments

Post a Comment

Popular posts from this blog

Re: [MW:34105] SA266 GR4N 4 Cycle SPWHT

By Materials & Welding
Hi,  You are correct, Minimum refers to the one cycle for which this part will expose until final work shop PWHT. hence mill test certificate shall include this.  Max. SPWHT, refers to additional cycles of heat treatment that are reserved for future repairs during equipment lifetime.  Again, these simulated no. Of cycles shall be specified in MTC.  The idea is we need to make sure that steel mechanical properties are not compromised upon exposure to multiple repairs (i e 4 cycles in your case).  One could say, if steel is subjected to 4 cycles and is ok, then it should by defacto be good for one cycle, yet, this is wrong assumption cause mechanical problems and microstructure of materials varies accordingly based on no. Of cycles for which material will expose. This is apparent in alloy steel and especially for impact test values as an example.  In your case, this forged CS with properties before PWHT can be understood to be " as forged" condition (i.e. Wit...
Post a Comment
Read more

Materails FAQs

By Materials & Welding
Q: What are equivalents for standard Q 235 B (and Q 235 A) for U-channels? (asked by: boris.vielhaber@vait.com) A: DIN Nr. = 2393 T.2, 2394 T.2, EN 10025 W. Nr. DIN 17007 = 1.0038 Design DIN 17006 = RSt 37-2, S235JRG2 (Fe 360 B) Q: What is St DIN 2391 BK material? (asked by: dmcandrews@automaticstamp.com) A: Precision steel tubes, cold-finished/hard. Q: What is C.D.W. Boiler Tube? (asked by: montydude123@yahoo.com) A: Cold Drawn Welded Boiler Tube. Q: WHAT IS W.Nr. 1.4301? PLS TELL US IN EASY LANGUAGUE (asked...
21 comments
Read more

Heat tint (temper) colours on stainless steel surfaces heated in air // Heat tint

By Materials & Welding
Introduction The colour formed when stainless steel is heated, either in a furnace application or in the heat affected zone of welds, is dependent on several factors that are related to the oxidation resistance of the steel. The heat tint or temper colour formed is caused by the progressive thickening of the surface oxide layer and so, as temperature is increased, the colours change.   Oxidation resistance of stainless steels However, there are several factors that affect the degree of colour change and so there is no a single table of colour and temperature that represents all cases. The colours formed can only be used as an indication of the temperature to which the steel has been heated. Factors affecting the heat tint colours formed Steel composition The chromium content is the most important single factor affecting oxidation resistance. The higher the chromium, the more heat resistant the steel and so the development of the heat tint colou...
Post a Comment
Read more