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Our low temperature blog articles have been read and accessed from all over the world. I thought I would expand on the theme – performance of steel and equipment in cold temperatures, by sharing some good pieces written by other people. Please take a second and browse these links and let me know if you enjoyed them. If you have any questions, please don’t hesitate to send me an email or leave a comment.

Related Content: Did you know this article is the third in a series on Low Temperature and Equipment? Have a look at: Performance of Steel and Equipment Part 1 and Part 2

Pipe and cold temperatures:

In Alberta, cold temperature-rated pipe is an integral part of moving our resources around the world. From an educational point of view, piping is an interesting industry to look at from a metallurgic lens because of the amount of data available, and the knowledge that has been gathered to try and improve a pipe line’s integrity. Cold temperatures in the Canadian oil and gas industry are a given and with piping we have to take extra precautions because of a phenomenon called hydrogen embrittlement. Hydrogen embrittlement is important in Alberta because pipe caring H2S, and even the welding process itself, can cause hydrogen molecules to diffuse into the materials and change the metallurgic properties of the steel. Although hydrogen embrittlement is not the same as cold temperature failures, they are both brittle failures and the properties of toughness and ductility are adjusted to avoid both cases of material failure. You can read more material selection for pipe in low temperatures here:

http://www.pipelineandgasjournal.com/selection-pipe-material-low-temperature-service-0?page=show

How it all started:

Professors love to tell the story about how the world learned about cold brittle failures. As the legend goes, we learned about cold temperature brittle failures while manufacturing “Liberty Ships” during World War II while the USA was producing a lot of Liberty ships across several shipyards up and down the coast. On this project, there was some advancements in manufacturing technology primarily through the use of submerged arc welding, but each of the ships were designed and built the same way. Some of these ships traveled through warm southern shipping lanes and some identical ships traveled north through frigid cold temperatures. The result was a significant number of brittle fractures in the hull on only the ships traveling north. The failure analysis showed a metallurgic problem as the ships headed north reached temperatures cold enough to cause a ductile to brittle transition in the steel because of the low temperatures. You can read a great snapshot of the Liberty ship build at: http://en.wikipedia.org/wiki/Liberty_ship

Failure mechanism:

If you have ever had the chance to see a fracture firsthand, it can be an enlightening experience. Failure analysis is one aspect of engineering that is becoming less and less as we become better engineers. However, failure analysis of steel structures is still an important part of the profession and necessary to determine the failure mechanism. In these articles, we mentioned that the failure mechanism for low temperature brittle failure is in fact brittle, but what does that mean? And what does that look like? This slide show goes into more detail about the possible different mechanical failures and what each one looks like. This presentation provides an excellent review in case you ever get asked to determine how or why something failed/broke:

http://goo.gl/56LP5H (save powerpoint file)

Hydrogen embrittlement:

I mentioned hydrogen embrittlement above, and although I don’t want to go into any detail on the subject, I find the phenomenon very interesting and very applicable to pipe design. If you want to learn more, you can start your research with these links:

Do you have any other resources on hydrogen embrittlement or designing steel structures for cold temperatures? Send me an email at jason@spartaengineering.com