"WEBVTTKind: captionsLanguage: enhi I'm Michael feifer principal consultant and trainer at industrial metallurgists this brief video is about steel hydrogen and brement if you're involved in the exciting world of product design and Manufacturing then understanding metal Metallurgy and metals engineering will be a great help to you with helping with material selections for for new designs for new components helping to develop capable sustainable manufacturing processes identifying good suppliers capable suppliers and solving problems when they occur quality problems and product failures and Metallurgy and metals engineering can often be a key part of of of engineering and solving problems and hopefully this video will help you out with with that so this video is about steel hydrogen embrittlement hydrogen embrittlement is a real problem that occurs and most most commonly we're we're concerned with hydrogen and Britt Fasteners we don't want Fasteners to fail during use because that can lead to problems with structures or when they're used in in products well components coming coming apart because the Fastener is holding them together uh fracture during use and cracking and fracturing during use is not what we want so we want to understand what causes hydrogen and brement and how to prevent it from occurring so hydrogen and Brittan occurs when a when a metal is exposed to hydrogen atoms and those atoms are able to diffuse into the metal and then diffuse to the grain boundaries and then finally form bubbles of the grain boundaries those bubbles exert stresses on the grain boundaries that result in a weakening of the grain boundaries and that weakening can lead to cracking and fracturing of the metal the result of the embrittlement is loss of ductility and cracking and failure when the metal is exposed to stresses that are below the Metal's yield strength so we don't see any deformation of the metal when the cracking occurs because the the the cracking occurs at stresses below the metals yield strength these are two examples of Fasteners that failed during use due to hydrogen and Brittan when when when Fasteners fail due to hydrogen and Britt they fail due to they fail the the the fracture mode is called intergranular cracking because the crack goes along the grain boundaries of the of the metal so this shows the crack going along the grain boundaries in the metal the the image on the right is a scanning electron microscope image of a steel Fastener that fractured due to hydrogen embrittlement and what we see individual grains along the grain boundaries I mean individual grains along the fracture surface and that's because the crack moved along the grain boundaries as as as it progressed through the metal there are three requirements for failure due to hydrogen and Britt you have to have a susceptible material have to have exposure to an environment that contains hydrogen and the material has to be exposed to have have tensil stresses on it it could either be residual stresses or applied stresses or a combination of the two there are a number of different materials that are susceptible to hydrogen embrittlement I'm going to focus on steel for this short video so with high strength we're concern with with Steels we're concerned about high strength Steels these are Steels that have been properly heat treated and they would have tensil strengths greater than about 1,000 megapascals or have a tensil strength greater than 145 KSI and this shows a Fastener that's been installed and we and when when when a Fastener is installed there are tensil stresses on on the Fastener that can lead to cracking if the material has been Britt due to hydrogen ement with steel fasteners quite often they are coated with a metal for Corrosion Protection um some common metals that are used for Corrosion Protection include zinc nickel and chromium during the electroplating process hydrogen atoms are present will form at the surface of the metal and those hydrogen atoms can diffuse into the metal um and this shows a plating bath and on the right so zinc um so as I mentioned the these Coatings are are um the common Coatings are zinc nickel and chromium hydrogen brittman can be prevented for parts for high strength steel fasteners that are electroplated by baking the Fasteners within a few hours after the coating has been deposited on the metal during the bakeout process hydrogen diffuses out of the metal like is shown here and when the hydrogen diffuses out of and the hydrogen diffuses out of the metal before it's able to get to the grain boundaries and form the bubbles so it's very important that the bakeout occur a few hours after electr plating so that the hydrogen does not have enough time to get to the grain boundaries because if too much time elapses between electr plating and the bakeout then the hydrogen will get to the grain boundaries and the bakeout will not will not work also the bake temperature and time have to also be sufficient to enable the hydrogen to diffuse out of the steel and remember the steel is coated with a coating either zinc or nickel or chromium or whatever other coating might be used and that coating is is a barrier to the hydrogen moving out and so the temperature and the time have to be temperature has to be high enough the time long enough to make sure that the hydrogen is able to diffuse through out of the steel and through the coating there are a number of ASM specifications that discuss the baking temperatures and times based on steel strength and or hardness and you can consult these these documents for for direction about the temperatures and times to use with electroplated high strength steel parts there's also this this standard as well um other uh other metals can also um uh undergo hydrogen Brittan um and there too much to discuss in this in this particular um discussion but like titanium is another alloy that can be IM brittle due to hydrogen but I'll discuss that in another session um there are also other sources of hydrogen that can cause embrittlement of high strength Steels the pickling used during the cleaning process prior to electroplating can can cause embrittlement and so a there are steps to take to prevent embrittlement due to this process due to pickling also corrosion reactions during use and exposure to environments that contain hydrogen during use can also because hydrogen embrittlement and steps have to be taken for these for for these as well and I'll discuss that in a in a separate video um just so to wrap up hydrogen and brittant is a real thing we have to do things uh to prevent high strength Steels from from becoming emitted in fact I worked on a project last month where parts were failing in a in a product due to hydrogen embrittlement and that and and the failure of the fast was resulting in two components coming apart and that was a problem for the the reliability of the entire product so it's important to understand the mechanism of hydrogen embrittlement and then the steps to take to prevent embrittlement from occurring and also if you send Parts out if you're having Fasteners made by a third party and they're having the parts electroplated by another per party it's important to have a good specification that this that that lays out um the requirements on the on the coating and the hydrogen bakeout and to make sure that your suppliers understand the the your requirements and the bakeout so that you don't have Pro get parts put them in your products and find out a year later that you're having a problem that's that results in um in in unhappiness for a lot of people um so that's it if you enjoyed this watching this video and you learned something please subscribe to our Channel to get announcements about future future videos and also like it and share it with your friends and colleagues and finally we offer lots of metalurgy training on with with different with courses and um videos and also we have free um um a um articles that we send out each week on on different topics of metalurgy and metals engineering with respect to product design and Manufacturing and you can go to our website and and get all that information there here's the different training that we offer and the resources including our blog which has a sign up to receive notices about new articles podcasts courses and webinars so if you're interested in learning more about Metallurgy to help you be more a more productive and effective engineer sign up so you can get get all of our stuff um thanks for watching good luck with your medals and feel free to call or email if you have a question or want to discuss a project byehi I'm Michael feifer principal consultant and trainer at industrial metallurgists this brief video is about steel hydrogen and brement if you're involved in the exciting world of product design and Manufacturing then understanding metal Metallurgy and metals engineering will be a great help to you with helping with material selections for for new designs for new components helping to develop capable sustainable manufacturing processes identifying good suppliers capable suppliers and solving problems when they occur quality problems and product failures and Metallurgy and metals engineering can often be a key part of of of engineering and solving problems and hopefully this video will help you out with with that so this video is about steel hydrogen embrittlement hydrogen embrittlement is a real problem that occurs and most most commonly we're we're concerned with hydrogen and Britt Fasteners we don't want Fasteners to fail during use because that can lead to problems with structures or when they're used in in products well components coming coming apart because the Fastener is holding them together uh fracture during use and cracking and fracturing during use is not what we want so we want to understand what causes hydrogen and brement and how to prevent it from occurring so hydrogen and Brittan occurs when a when a metal is exposed to hydrogen atoms and those atoms are able to diffuse into the metal and then diffuse to the grain boundaries and then finally form bubbles of the grain boundaries those bubbles exert stresses on the grain boundaries that result in a weakening of the grain boundaries and that weakening can lead to cracking and fracturing of the metal the result of the embrittlement is loss of ductility and cracking and failure when the metal is exposed to stresses that are below the Metal's yield strength so we don't see any deformation of the metal when the cracking occurs because the the the cracking occurs at stresses below the metals yield strength these are two examples of Fasteners that failed during use due to hydrogen and Brittan when when when Fasteners fail due to hydrogen and Britt they fail due to they fail the the the fracture mode is called intergranular cracking because the crack goes along the grain boundaries of the of the metal so this shows the crack going along the grain boundaries in the metal the the image on the right is a scanning electron microscope image of a steel Fastener that fractured due to hydrogen embrittlement and what we see individual grains along the grain boundaries I mean individual grains along the fracture surface and that's because the crack moved along the grain boundaries as as as it progressed through the metal there are three requirements for failure due to hydrogen and Britt you have to have a susceptible material have to have exposure to an environment that contains hydrogen and the material has to be exposed to have have tensil stresses on it it could either be residual stresses or applied stresses or a combination of the two there are a number of different materials that are susceptible to hydrogen embrittlement I'm going to focus on steel for this short video so with high strength we're concern with with Steels we're concerned about high strength Steels these are Steels that have been properly heat treated and they would have tensil strengths greater than about 1,000 megapascals or have a tensil strength greater than 145 KSI and this shows a Fastener that's been installed and we and when when when a Fastener is installed there are tensil stresses on on the Fastener that can lead to cracking if the material has been Britt due to hydrogen ement with steel fasteners quite often they are coated with a metal for Corrosion Protection um some common metals that are used for Corrosion Protection include zinc nickel and chromium during the electroplating process hydrogen atoms are present will form at the surface of the metal and those hydrogen atoms can diffuse into the metal um and this shows a plating bath and on the right so zinc um so as I mentioned the these Coatings are are um the common Coatings are zinc nickel and chromium hydrogen brittman can be prevented for parts for high strength steel fasteners that are electroplated by baking the Fasteners within a few hours after the coating has been deposited on the metal during the bakeout process hydrogen diffuses out of the metal like is shown here and when the hydrogen diffuses out of and the hydrogen diffuses out of the metal before it's able to get to the grain boundaries and form the bubbles so it's very important that the bakeout occur a few hours after electr plating so that the hydrogen does not have enough time to get to the grain boundaries because if too much time elapses between electr plating and the bakeout then the hydrogen will get to the grain boundaries and the bakeout will not will not work also the bake temperature and time have to also be sufficient to enable the hydrogen to diffuse out of the steel and remember the steel is coated with a coating either zinc or nickel or chromium or whatever other coating might be used and that coating is is a barrier to the hydrogen moving out and so the temperature and the time have to be temperature has to be high enough the time long enough to make sure that the hydrogen is able to diffuse through out of the steel and through the coating there are a number of ASM specifications that discuss the baking temperatures and times based on steel strength and or hardness and you can consult these these documents for for direction about the temperatures and times to use with electroplated high strength steel parts there's also this this standard as well um other uh other metals can also um uh undergo hydrogen Brittan um and there too much to discuss in this in this particular um discussion but like titanium is another alloy that can be IM brittle due to hydrogen but I'll discuss that in another session um there are also other sources of hydrogen that can cause embrittlement of high strength Steels the pickling used during the cleaning process prior to electroplating can can cause embrittlement and so a there are steps to take to prevent embrittlement due to this process due to pickling also corrosion reactions during use and exposure to environments that contain hydrogen during use can also because hydrogen embrittlement and steps have to be taken for these for for these as well and I'll discuss that in a in a separate video um just so to wrap up hydrogen and brittant is a real thing we have to do things uh to prevent high strength Steels from from becoming emitted in fact I worked on a project last month where parts were failing in a in a product due to hydrogen embrittlement and that and and the failure of the fast was resulting in two components coming apart and that was a problem for the the reliability of the entire product so it's important to understand the mechanism of hydrogen embrittlement and then the steps to take to prevent embrittlement from occurring and also if you send Parts out if you're having Fasteners made by a third party and they're having the parts electroplated by another per party it's important to have a good specification that this that that lays out um the requirements on the on the coating and the hydrogen bakeout and to make sure that your suppliers understand the the your requirements and the bakeout so that you don't have Pro get parts put them in your products and find out a year later that you're having a problem that's that results in um in in unhappiness for a lot of people um so that's it if you enjoyed this watching this video and you learned something please subscribe to our Channel to get announcements about future future videos and also like it and share it with your friends and colleagues and finally we offer lots of metalurgy training on with with different with courses and um videos and also we have free um um a um articles that we send out each week on on different topics of metalurgy and metals engineering with respect to product design and Manufacturing and you can go to our website and and get all that information there here's the different training that we offer and the resources including our blog which has a sign up to receive notices about new articles podcasts courses and webinars so if you're interested in learning more about Metallurgy to help you be more a more productive and effective engineer sign up so you can get get all of our stuff um thanks for watching good luck with your medals and feel free to call or email if you have a question or want to discuss a project bye\n"