Material Identification 1

[brandonb73]

Our client has a pressure vessel in which was installed an unauthorized nozzle. The State has told them the nozzle can stay persuant to an acceptable UT test and calculations showing the material thickness is adequate.

The customer has provided a spectrochemical analysis of the material. In order to run calculations however, I need tensil and yield strength data. Do I need to ask the customer to also have these test done or is there some way to obtain this based on the spectrochemical analysis?

 

[metengr]

brandonb73;
You need to go back and obtain a material certification for this nozzle material. There should have been a material test report verifying the nozzle material is an SA XXX material or some UNS designation.

If you have no material certification or test report for this nozzle, you will need to have a sample of the nozzle removed for a complete chemical analysis along with hardness testing and microstructural evaluation to properly type of the material as an ASME SA Grade. This work should be performed by a competent metallurgical lab.

 

[brandonb73]

At the end of the report submitted by the materials lab, it states that the Alloy type is 1018 carbon steel. Is't 1018 a cold finish bar spec? The nozzle if obviously made of pipe.

 

[metengr]

brandonb73;
Type 1018 is a low carbon steel designation that means it contains 0.18% carbon by mass with no other substantial alloy elements. I would check the P and S contents and compare with an ASME SA 106 material specification.

What you need to do is to have the lab perform hardness testing and have them obtain an equivalent ultimate tensile strength value to determine if the nozzle material is an SA 106 Grade A or B material. The hardness testing is critical for providing an approximate tensile strength.

 

[metengr]

brandonb73;
Just some additional advice because of my involvement with ASME B&PV Code, NBIC and the various Jurisdictions across the US. The final determination of this unauthorized nozzle installation can become a nightmare because in addition to material identification as per your original post you most likely will need to verify weld joint configuration for Code compliance and using ASME Section VIII, Div 1 calculations to verify this nozzle meets reinforcement requirements for openings in shells. The ultrasonic testing should be able to accomplish two things - verify weld quality, weld joint configuration as well as wall thickness.

 

[SnTMan]

I would add weld procedure and welder qualifications will have to be verified as well. Nightmare for sure.

Might be easier to cut it out and replace it properly.

Regards,

Mike

 

[JK01]

Can you PMI the material?

 

[metengr]

JK01;
You mean can you conduct a PMI of the nozzle versus conducting a complete chemical composition?

It depends on the AI and Jurisdiction. PMI is typically used for sorting of materials based on certain key elements versus attempting to type a material to an SA specification for use. If it was my Jurisdiction or I was the AI, my reply would be no.

 

[JK01]

metengr;

Yes, meant to state PMI on the nozzle. PMI cannot be used as a materials certificate, only for verification purposes.