energpart
Mechanical
- May 19, 2021
- 3
Hello,
Our company supply valves for the OnG industry. One job in particular has us supplying Duplex SS ball valves.
We submitted Mill Cert for end user review. They rejected and commented to have each heat be micrographically examined at 400x minimum to check for absence of grain boundary carbides, sigma, chi and laves phase. I checked and they did have this requirement in their project specification.
Problem is, the valves has already been delivered and there is no more test sample at material lab to do this micrography. The comment(s) came much later.
I tried to counter by asking them to refer to the micrograph from ferrite count which was done according to ASTM E562 19e1 to look for these phases. Also, that mechanical and corrosion test found acceptable to supplement no defect to microstructure. But, still not acceptable.
I attach one of the micrograph for ferrite count here for you guys to help clarify if you can't indeed check for the phases as per comment. I am not a material science expert and neither is the end user's engineer.
As my initial respond is rejected, do you guys have any suggestion on how to best respond to this comment so that they will accept the material(s) ?
Our manufacturer is on another continent and can't support much. They have no expertise on material science and there is no more heat lot to sample.
Thanks.
Our company supply valves for the OnG industry. One job in particular has us supplying Duplex SS ball valves.
We submitted Mill Cert for end user review. They rejected and commented to have each heat be micrographically examined at 400x minimum to check for absence of grain boundary carbides, sigma, chi and laves phase. I checked and they did have this requirement in their project specification.
Problem is, the valves has already been delivered and there is no more test sample at material lab to do this micrography. The comment(s) came much later.
I tried to counter by asking them to refer to the micrograph from ferrite count which was done according to ASTM E562 19e1 to look for these phases. Also, that mechanical and corrosion test found acceptable to supplement no defect to microstructure. But, still not acceptable.
I attach one of the micrograph for ferrite count here for you guys to help clarify if you can't indeed check for the phases as per comment. I am not a material science expert and neither is the end user's engineer.
As my initial respond is rejected, do you guys have any suggestion on how to best respond to this comment so that they will accept the material(s) ?
Our manufacturer is on another continent and can't support much. They have no expertise on material science and there is no more heat lot to sample.
Thanks.
