Thank you Sir , we are using dockweiler pipes consistently in pharmaceutical industry and this small video has helped me to resolve my problem of black spots during welding.
We are seeing point-like as well as grain boundary delta ferrite in 316L sintered at 1400 C. Is this (point-like) common or might be an error in EBSD phase map?
So when you suggest using nickel alloys, are you suggesting stainless alloys with a higher nickle content like 317, or nickle alloys like inconel? Im speaking In general, not specifically..
Hello Dr. I 've heard that austenite micro structe should not be solidifeied to pure austenite to prevent hot cracks in welding and the last microstructure should be supported with some ferrite.
Great explanation. Thanks. I am a Master Trainer Welding Technology from Mumbai India. I am working as a freelance Professional Trainer and industry consultant.
Hello Sir. Your video is very informative and I am interested to know that, whether the type of delta ferrite (like vermicular ferrite, Lacy ferrite, acicular ferrite, etc.) influences the mechanical properties or not? I hope for an early reply.
Thank you for your comment. According to the understanding of Dr. Torsten Köcher, the type of delta ferrite would not influence the mechanical properties of the tube structure significantly. For sure you have different kinds of delta ferrite. The crystallization orientation differs as we are considering a “competition” between fcc (austenite) and bcc (ferrite) structures. Unfortunately we have no information, if the type of ferrite has a different impact. However, in case of 316L we are considering a general delta ferrite content of 5-8% which is not harmful for the mechanical integrity of the system. It might be even supportive for the mechanical stability. At Dockweiler, we are more concerned about the corrosion properties of the material and 8% will be critical here already. We hope this comment answers your question.
Dear Kundan, the parent pipe either sheet metal welded or seamless hollow from origin. Both pre-materials have undergone a slow cooling down phase in which the delta ferrite phase is dissolved in the material. Cool down time is app. 10 days. The weld seam cool down time is way too fast to dissolve the delta ferrite. Cool down time is some seconds Dissolve is certainly the wrong wording here. We are considering an equilibrium here depending on the temperature. The transition during or after welding is kinetically blocked as the metal is crystalized very fast and the atoms cannot move anymore. I hope that explains it. Best Regards
Can we eliminate delta ferrite by heat treatment.. What is effect of delta ferrite on making Hollow pipes from solid bar by piercing process ? Final product is SS tubes for heat exchanger & pressure vessel application
Dear Narayan Rathod, Thanks for your interest in our videos and for your question. With regard to the upper mentioned process you will not create delta ferrrite. Even though you may find a value in the ferritoscopic testing, this result is caused by deformation Martensit which giving a result here as it’s ferromagnetic. If you need more information, feel free to contact us again.
@@deepakmandowara9833 Dear Deepak, as the measurement instrument is just detecting the potential for magnetization, there is no option to distinguish here. The only option is to be aware about the manufacturing process that were executed. However, a seamless tube which has not been annealed will have deformation martensit and will give a result on the instrument and a welded tube not annealed will give a signal as well whereas here you need to consider delta ferrite. Best Regards, Torsten
Thanks a lot for your lovely comment. If you or classmates have other topics, please let us know. You can contact us by e-mail at marketing@dockweiler.com or by phone at 038757-580.
Dear Gudimallam Jothi Vinodkumar, Thanks for your question. 1.4435 indicates the steel grade. It’s a particular 316L with a higher Molybdenum content. Pretty famous among pharmaceutical manufacturers in Europe. BN2 means „Baseler Norm“: this Standard has been developed by the chemical industry in Switzerland and its specifying the alloy composition very well. Due to that also delta ferrite will be reduced during welding. We hope this answers your question. If you have any further questions, please feel free to contact us again.
Thank you Sir , we are using dockweiler pipes consistently in pharmaceutical industry and this small video has helped me to resolve my problem of black spots during welding.
Hello abhi patane, thank you for your feedback. We are very happy that we could help you with our video.
We are seeing point-like as well as grain boundary delta ferrite in 316L sintered at 1400 C. Is this (point-like) common or might be an error in EBSD phase map?
Dear Amir Mostafaei, thank you for your question. To me that seems to be an error as well the melting point of 316L is 1398°C. Best Regards, Torsten
So when you suggest using nickel alloys, are you suggesting stainless alloys with a higher nickle content like 317, or nickle alloys like inconel? Im speaking In general, not specifically..
Sir, I love metallurgy. After watching your videos my interest towards metallurgy increased further.
Thank you! 😊
Hello Dr. I 've heard that austenite micro structe should not be solidifeied to pure austenite to prevent hot cracks in welding and the last microstructure should be supported with some ferrite.
Great explanation. Thanks. I am a Master Trainer Welding Technology from Mumbai India. I am working as a freelance Professional Trainer and industry consultant.
Hello Sir. Your video is very informative and I am interested to know that, whether the type of delta ferrite (like vermicular ferrite, Lacy ferrite, acicular ferrite, etc.) influences the mechanical properties or not? I hope for an early reply.
Thank you for your comment. According to the understanding of Dr. Torsten Köcher, the type of delta ferrite would not influence the mechanical properties of the tube structure significantly. For sure you have different kinds of delta ferrite. The crystallization orientation differs as we are considering a “competition” between fcc (austenite) and bcc (ferrite) structures. Unfortunately we have no information, if the type of ferrite has a different impact.
However, in case of 316L we are considering a general delta ferrite content of 5-8% which is not harmful for the mechanical integrity of the system. It might be even supportive for the mechanical stability. At Dockweiler, we are more concerned about the corrosion properties of the material and 8% will be critical here already.
We hope this comment answers your question.
@@DockweilerAG Thanks a bunch.
IN ASME Sec 3, Desirable qty in weldments in SS304 and SS316 is 5-12FN. Why?
Thank you for your questions. We need to consult a specialist internally. As soon as we have an answer, we will get back to you. 🙂
We asked our specialist and he needs further details. Would you please be so kind to describe the request in further detail?
Sir,why only weld shows Ferrite content but not parent metal (pipe) in SS
Dear Kundan,
the parent pipe either sheet metal welded or seamless hollow from origin. Both pre-materials have undergone a slow cooling down phase in which the delta ferrite phase is dissolved in the material. Cool down time is app. 10 days.
The weld seam cool down time is way too fast to dissolve the delta ferrite. Cool down time is some seconds
Dissolve is certainly the wrong wording here. We are considering an equilibrium here depending on the temperature. The transition during or after welding is kinetically blocked as the metal is crystalized very fast and the atoms cannot move anymore.
I hope that explains it.
Best Regards
Can we eliminate delta ferrite by heat treatment..
What is effect of delta ferrite on making Hollow pipes from solid bar by piercing process ?
Final product is SS tubes for heat exchanger & pressure vessel application
Dear Narayan Rathod,
Thanks for your interest in our videos and for your question.
With regard to the upper mentioned process you will not create delta ferrrite. Even though you may find a value in the ferritoscopic testing, this result is caused by deformation Martensit which giving a result here as it’s ferromagnetic.
If you need more information, feel free to contact us again.
is there any method to diffrentiate between deformation martensite and delta ferrite?
@@deepakmandowara9833
Dear Deepak,
as the measurement instrument is just detecting the potential for magnetization, there is no option to distinguish here.
The only option is to be aware about the manufacturing process that were executed.
However, a seamless tube which has not been annealed will have deformation martensit and will give a result on the instrument and a welded tube not annealed will give a signal as well whereas here you need to consider delta ferrite.
Best Regards,
Torsten
Loving your videos. Very Informative, since I am a student of RWTH Aachen doing Metallurgical Engineering
Thanks a lot for your lovely comment. If you or classmates have other topics, please let us know.
You can contact us by e-mail at marketing@dockweiler.com or by phone at 038757-580.
Sir, 1.4435 BN2 indicates?
Dear Gudimallam Jothi Vinodkumar,
Thanks for your question.
1.4435 indicates the steel grade. It’s a particular 316L with a higher Molybdenum content. Pretty famous among pharmaceutical manufacturers in Europe.
BN2 means „Baseler Norm“: this Standard has been developed by the chemical industry in Switzerland and its specifying the alloy composition very well.
Due to that also delta ferrite will be reduced during welding.
We hope this answers your question. If you have any further questions, please feel free to contact us again.
Hi Sir, thanks for sharing...
More knowledge in short video 👍
Thank you for your comment. 🙂 If you have other topics for our video FAQs, feel free to email them to us: marketing@dockweiler.com.