Great demonstration of how welds can be affected by temperature. As an industrial example, I worked at a nuclear power plant for many years. Needless to say there are literally thousands upon thousands of welds many of which are on high pressure systems (2300psi) which included the reactor vessel, pressurizer and lower pressure systems (1100psi) steam generators. After construction (all the welding was done to code) there were very strict Temperature controls, mostly during shutdown for refueling outages. If ambient temperatures got down to 70°F or less, we had very strict pressure limits e.g. closer to hundreds of pounds to prevent stressing the pressure vessels and creating microscopic stress cracks. And it’s not just meeting Temperature or Pressure restrictions however gradual the change, but we also had very strict Heatup and cooldown rates not to exceed 100°F/Hr to allow the metals crystalline structure to adapt to their new temperatures without inducing stress. It was extremely rare and hard to exceed heatup rates, it super easy to exceed Cooldown rates which was really the big concern. Most these stresses were not of a catastrophic nature, but they were more a very subtle long term effect. Once a defect was introduced into the metal, the stress of repeated heat up and cooldown cycles showed cracks were developing that started to show up in all the NDT testing during outages. I’m sure many other industries with similar pressure vessels have the same concerns with not just absolute metal temperatures but maybe more so “Rate of Change” thermal limits. And Yes, we did have these thermal and rate of change events, and Yes there were many repairs made e.g. replacing large sections of feedwater piping etc. but more importantly there was a very strict limit to the number of Thermal Cycles that the plant’s design can tolerate, and they were all carefully tracked and once the design limit of any component is reached, it’s game over for that component, and they shortened the (designed) life of the plant. In fact, we once had a major outage to replace our 4 Steam Generators in both plants due to leaks due to cracks. The moral of the story is, just because it doesn’t fail catastrophically immediately doesn’t mean you’re good to keep stressing the equipment thinking everything is just as strong as the day it was built. Granted most of us will never have to deal with such things, but I’m sure there are some of your viewers who will eventually go on to work on things that have some liability like Oil Pipelines, Refineries and Power Plants or Structures that support people. It’s an important lesson to understand how temperatures affect welds, and that’s why this demonstration is of great value and a lesson to be learned. Thanks Greg, and please keep the lessons coming, it maters today and perhaps well into the future.
Wow I could imagine the level of welding at those nuclear plants I've always been interested in that kind of work but I realized it's a lot of traveling.
Nuclear power was on a slow decline as many owner operators found keeping up with regulatory inspections that required very expensive modifications or replacements. The industry trend was to extend run times and shortening outages. So between plant closures, longer runs between outages and shorter outages, traveling maintenance people found it was not worth the expense of moving around. My plant was one of the more remote plant relative to others ( west coast plants are few and far between compared to east coast), so those who came to our plant usually were motivated by mild winters and the coastal beauty, so they came despite the long distance. We had seismic restraints that were the size of 1 ton pickup trucks and a few that were bigger, with unbelievably huge welds to match! I was lucky to be there before it became operational, and I watched much of the final construction especially of the seismic restraints I mentioned. It was fascinating, and although it was like a rough 1800’s western frontier town with 3,000 construction workers, it was a very friendly brotherhood that you just don’t see these days. Most of the worker loved to tell their story and answer your questions. Greg would have fit right in and he was typical of the good folks you would meet. I miss those days.
Another entertaining video. Your results didn't surprise me. I've heard mechanical engineers and metallurgists talking about "nil ductility temperature" (NDT)ratings for metal and also something called RTNDT. It came up in discussions about the handling fixtures for a steam generator that was going to be transported by truck and huge trailer. Actually there were two trucks on the front of the trailer and one on the back pushing - the thing was huge. The specification for the fixture called for an RTNDT temperature of something like -40°C (which is the same temperature as -40°F). The plate (Probably some variation of A36?) the fixtures were made of was about 4 inches thick. Early metal bridges (mostly riveted together) had an abysmal failure rate, especially in cold weather. I'm not sure what is done to modify the behavior of steel at low temperatures. But there is a part of metallurgy science that deals with it. I confess I wasn't really paying attention at the time because my issues were with other parts of the system.
My grandpa spent some time welding on the blast doors of Atlas missile bases in the 50s. He talked about having to weld laying on his back in 0 degree weather and failing xray and having to blow out 2ft thick welds. He blamed the cold.
Under the worst situations is always when something fails inspection and needs to be repaired lol. No doubt that’s cold enough that on thick steel the weld could have cracked while cooling. Worst sound in the world is a “ping” sound right after you finished welding lol.
AWS Structual Code: No welding shall be done on steel less than 40 deg. F. Preheat to 100 deg F. Do a fillet weld on 1" plate that cold[-40deg F] and the weld will crack down the center while cooling.
Greg i really like your channel. Not being afraid to show mistakes and to be honest pretty common mistakes i have seen alot of people make (of course not me) and the effects these mistakes actually have on the weld. Running a good bead and understanding what your doing are two different things .
Thanks for the kind words 😀. Just wait until you see some of the videos I am editing where I talk about stupid mistakes I have made as a welder/fabricator 😅. Welding stuff on backwards, welding stuff and not having it fit when done, and setting things on fire 😅.
I expected taht the welds would break, but the way they broke, especially the second one was unexpected. I also expect things going worse an higher strength steel. Great work, Greg. As the elder said: never weld on deeply frozen steel😂.
I have some ar500 I might try to weld cold and see what happens lol. Taking something that’s somewhat brittle,cooling it, and then putting a lot of stress on it is a recipe for disaster lol.
The last few winters I had to preheat and continuously heat with induction heat bc preheating alone was not enough. I had joints crack just from them cooling down and drawing in moisture as it cooled down. I’ve even had a root pass that I put in before lunch and didn’t post heat it enough. I always enjoy the content Greg
I bet that sucked. When it gets cold out and the steel is thick you can put a ton of heat into it and it still won’t even get warm. Makes you wish for 70 and sunny lol.
Well it is 53 here but I took your advice and had a frosty cold mug of Guinness Extra Stout!! A good suggestion is a good suggestion! We did hit a sweltering 71 today so I deserved it (it's my story and I will tell it any way I like!).
ooh...can you get one of those induction heaters...and test what "tempering" a weld would do...weld a bead...then heat the bead/base metal red and let cool with the induction heater to see if it strengthens or weakens it...
So I can tell you that it would likely have an effect, it’s hard to say what would happen. Most mild steel can’t be hardened via heat treatment but stress relieved and such it can. I need to do some reading more on the metallurgy end of things to get a better idea of what temps and an idea of ways to accurately test it.
@@makingmistakeswithgreg If I'm remembering random trivia correctly, Mild steel has low hardenability and low maximum hardness. So it needs to be water quenched to harden it, and the max hardness isn't that high. It still should become somewhat harder and more brittle though. An neat test there would be to water quench a weld and see how tempering it by re-heating it and letting it air cool. That's an extreme example, but helps to empirically examine if the failure is something caused when quenched or if it's just the stress in the metal itself.
Here's a thought about the wet 7018 tests you ran. I wonder if the real issue is water vapor in the air. Hear me out, water vapor has more energy, therefore it may force itself deeper into the flux than just leaving a rod in a puddle. Another way to think of this is, I have read about people making canvas boats and using house paint to make them waterproof. Yes house paint can resist liquid water, but it will still allow water vapor through, when applied to a house, which is why you need a vapor barrier. Not sure of any other way to test it other than leaving rods in an unconditioned shop and perhaps test them at different intervals (3, 6, 9 and 12 months?). Again, just a thought, although in your experience you may have already run into this and can rule this out, but I think testing it for a video a year from now might be worth a try.
The failure of the first specimen occurred in the Heat affected zone of the weld. Due to the cold temperature when welding, there was a very high cooling rate of the weld area and this resulted in an excessively hard HAZ. What you are seeing in the second test specimen is the result of a loss of fracture toughness at the lower temperature. All steels exhibit this phenomenon. This is a ductile to brittle transition. The fracture surface that you see on the second specimen is merely a brittle fracture.
European standards for electrode classification include a number that denotes the temperature at which the weld metal becomes brittle. It's decided that, if the charpy v-notch sample has impact energy absorption less than 47 joules, the metal is considered brittle. The number corresponds directly to degrees celsius x 10, so 4 would mean that the weld metal has impact toughness lower than 47 joules at a temperature of -40 celsius. It's really useful when you have to decide what electrodes are to be used in the climate the structure will reside in. For some context, typical 7018 equivalent rods become brittle at -40, the 7018-1 equivalent is brittle at -50, 6013 equivalent is brittle at 0 celsius.
Excellent info. The -1 classification helps to somewhat ID that here in the USA but most (if not all) store bought rods aren’t -1. Most people also don’t realize what that even means, which is actually important to know, for the exact reasons you mentioned.
@@makingmistakeswithgreg If I recall correctly, the -1 denotes better impact toughness at low temperature, and it means that you can weld a restrained structure with a much lower chance of weld cracking. It probably has higher ductility.
Love your videos as i learn more with each one i watch!! Would it make any difference in your welds if your rod is kept in a freezing cold garage in the winter? Thank you again for all the help you give people
If the rods are super cold they will require more amperage at the start. What you would likely see is the beginning 3/8th of an inch is more “humped up” than usual. Within a second or two the rod would be above room temp but that initial start could be rough. I have welded at -16 outside with rods in a pouch. The rods likely dropped to atleast 18 degrees, and I didn’t notice a huge difference. I preheated the steel I was welding to 250 degrees though which helped the weld wet out. Welding on super cold steel (especially thicker steel) is a big mistake, cold rods likely less so.
Great idea, I will definitely do that. I will do some Texas tig (stick welding with a filler rod like tig), and some open gaps with poor fitups. I can tell you that getting full strength out of those situations will be tough. Strength would come down to how good you are.
Dude. Are you from the U.P. of Michigan? Respect to the accent regardless. I'm starting my welding certification course at 45 and this channel helps so much!! Thanks!!
No problem, glad to hear you’re investing in your skills 👍. I am from southern Wisconsin. I have a bunch of friends from the U.P. and they crack me up because their accent is just like mine but even stronger lol.
Excellent tests! Hey.....teaser..... What's up with the 6010/7018 welds & bend tests, on the table, that aren't mentioned or discussed?? LoL Thanks for another excellent video!
So I think what happened is the steel became brittle and had a brittle failure due to the cold. If I had cooled it down and given it time to warm up it likely would have been fine. Bending it while it was -40 was enough to reduce the steel’s flexibility and thus is broke much like an iron casting.
![[UNCUT] "เสรีพิศุทธ์" แฉยับ! งัดหลักฐานใหม่ชั้น 14 ได้นอนคุกสมใจแน่!! I คนดังนั่งเคลียร์ I 2 ก.ย.67](http://i.ytimg.com/vi/O1SSg4p9Izs/mqdefault.jpg)
Great demonstration of how welds can be affected by temperature. As an industrial example, I worked at a nuclear power plant for many years. Needless to say there are literally thousands upon thousands of welds many of which are on high pressure systems (2300psi) which included the reactor vessel, pressurizer and lower pressure systems (1100psi) steam generators. After construction (all the welding was done to code) there were very strict Temperature controls, mostly during shutdown for refueling outages. If ambient temperatures got down to 70°F or less, we had very strict pressure limits e.g. closer to hundreds of pounds to prevent stressing the pressure vessels and creating microscopic stress cracks.
And it’s not just meeting Temperature or Pressure restrictions however gradual the change, but we also had very strict Heatup and cooldown rates not to exceed 100°F/Hr to allow the metals crystalline structure to adapt to their new temperatures without inducing stress. It was extremely rare and hard to exceed heatup rates, it super easy to exceed Cooldown rates which was really the big concern. Most these stresses were not of a catastrophic nature, but they were more a very subtle long term effect. Once a defect was introduced into the metal, the stress of repeated heat up and cooldown cycles showed cracks were developing that started to show up in all the NDT testing during outages.
I’m sure many other industries with similar pressure vessels have the same concerns with not just absolute metal temperatures but maybe more so “Rate of Change” thermal limits.
And Yes, we did have these thermal and rate of change events, and Yes there were many repairs made e.g. replacing large sections of feedwater piping etc. but more importantly there was a very strict limit to the number of Thermal Cycles that the plant’s design can tolerate, and they were all carefully tracked and once the design limit of any component is reached, it’s game over for that component, and they shortened the (designed) life of the plant. In fact, we once had a major outage to replace our 4 Steam Generators in both plants due to leaks due to cracks. The moral of the story is, just because it doesn’t fail catastrophically immediately doesn’t mean you’re good to keep stressing the equipment thinking everything is just as strong as the day it was built. Granted most of us will never have to deal with such things, but I’m sure there are some of your viewers who will eventually go on to work on things that have some liability like Oil Pipelines, Refineries and Power Plants or Structures that support people.
It’s an important lesson to understand how temperatures affect welds, and that’s why this demonstration is of great value and a lesson to be learned. Thanks Greg, and please keep the lessons coming, it maters today and perhaps well into the future.
Wow I could imagine the level of welding at those nuclear plants I've always been interested in that kind of work but I realized it's a lot of traveling.
Nuclear power was on a slow decline as many owner operators found keeping up with regulatory inspections that required very expensive modifications or replacements. The industry trend was to extend run times and shortening outages. So between plant closures, longer runs between outages and shorter outages, traveling maintenance people found it was not worth the expense of moving around. My plant was one of the more remote plant relative to others ( west coast plants are few and far between compared to east coast), so those who came to our plant usually were motivated by mild winters and the coastal beauty, so they came despite the long distance. We had seismic restraints that were the size of 1 ton pickup trucks and a few that were bigger, with unbelievably huge welds to match! I was lucky to be there before it became operational, and I watched much of the final construction especially of the seismic restraints I mentioned. It was fascinating, and although it was like a rough 1800’s western frontier town with 3,000 construction workers, it was a very friendly brotherhood that you just don’t see these days. Most of the worker loved to tell their story and answer your questions. Greg would have fit right in and he was typical of the good folks you would meet. I miss those days.
A fly putting out a weld on a pre-cooled plate is freaking awesome :)
You just never know what we're going to talk about but it's interesting.
Another entertaining video. Your results didn't surprise me. I've heard mechanical engineers and metallurgists talking about "nil ductility temperature" (NDT)ratings for metal and also something called RTNDT. It came up in discussions about the handling fixtures for a steam generator that was going to be transported by truck and huge trailer. Actually there were two trucks on the front of the trailer and one on the back pushing - the thing was huge. The specification for the fixture called for an RTNDT temperature of something like -40°C (which is the same temperature as -40°F). The plate (Probably some variation of A36?) the fixtures were made of was about 4 inches thick.
Early metal bridges (mostly riveted together) had an abysmal failure rate, especially in cold weather. I'm not sure what is done to modify the behavior of steel at low temperatures. But there is a part of metallurgy science that deals with it. I confess I wasn't really paying attention at the time because my issues were with other parts of the system.
My grandpa spent some time welding on the blast doors of Atlas missile bases in the 50s. He talked about having to weld laying on his back in 0 degree weather and failing xray and having to blow out 2ft thick welds. He blamed the cold.
Under the worst situations is always when something fails inspection and needs to be repaired lol. No doubt that’s cold enough that on thick steel the weld could have cracked while cooling. Worst sound in the world is a “ping” sound right after you finished welding lol.
AWS Structual Code: No welding shall be done on steel less than 40 deg. F. Preheat to 100 deg F. Do a fillet weld on 1" plate that cold[-40deg F] and the weld will crack down the center while cooling.
I can’t imagine how bad a 1in plate would break welding it at -40 lol. Great info 👍
Greg i really like your channel. Not being afraid to show mistakes and to be honest pretty common mistakes i have seen alot of people make (of course not me) and the effects these mistakes actually have on the weld. Running a good bead and understanding what your doing are two different things .
Thanks for the kind words 😀. Just wait until you see some of the videos I am editing where I talk about stupid mistakes I have made as a welder/fabricator 😅. Welding stuff on backwards, welding stuff and not having it fit when done, and setting things on fire 😅.
I expected taht the welds would break, but the way they broke, especially the second one was unexpected. I also expect things going worse an higher strength steel. Great work, Greg.
As the elder said: never weld on deeply frozen steel😂.
I have some ar500 I might try to weld cold and see what happens lol. Taking something that’s somewhat brittle,cooling it, and then putting a lot of stress on it is a recipe for disaster lol.
Thinking of c45. Should crack instantaneously, perhaps while welding.
The last few winters I had to preheat and continuously heat with induction heat bc preheating alone was not enough. I had joints crack just from them cooling down and drawing in moisture as it cooled down. I’ve even had a root pass that I put in before lunch and didn’t post heat it enough. I always enjoy the content Greg
I bet that sucked. When it gets cold out and the steel is thick you can put a ton of heat into it and it still won’t even get warm. Makes you wish for 70 and sunny lol.
Never know when you need to know. Great review.
Well done Greg.
On a side note yes code boiler welding needs to preheat area,as building heat was shut off during the night even in the winter , crazy out there..
Well it is 53 here but I took your advice and had a frosty cold mug of Guinness Extra Stout!! A good suggestion is a good suggestion! We did hit a sweltering 71 today so I deserved it (it's my story and I will tell it any way I like!).
It was 71 at 2am here 😅. I was in the tin shed for 8 hours and it never dropped below 90, 71 sounds like heaven lol.
ooh...can you get one of those induction heaters...and test what "tempering" a weld would do...weld a bead...then heat the bead/base metal red and let cool with the induction heater to see if it strengthens or weakens it...
So I can tell you that it would likely have an effect, it’s hard to say what would happen. Most mild steel can’t be hardened via heat treatment but stress relieved and such it can. I need to do some reading more on the metallurgy end of things to get a better idea of what temps and an idea of ways to accurately test it.
@@makingmistakeswithgreg If I'm remembering random trivia correctly, Mild steel has low hardenability and low maximum hardness. So it needs to be water quenched to harden it, and the max hardness isn't that high. It still should become somewhat harder and more brittle though.
An neat test there would be to water quench a weld and see how tempering it by re-heating it and letting it air cool. That's an extreme example, but helps to empirically examine if the failure is something caused when quenched or if it's just the stress in the metal itself.
Here's a thought about the wet 7018 tests you ran. I wonder if the real issue is water vapor in the air. Hear me out, water vapor has more energy, therefore it may force itself deeper into the flux than just leaving a rod in a puddle. Another way to think of this is, I have read about people making canvas boats and using house paint to make them waterproof. Yes house paint can resist liquid water, but it will still allow water vapor through, when applied to a house, which is why you need a vapor barrier. Not sure of any other way to test it other than leaving rods in an unconditioned shop and perhaps test them at different intervals (3, 6, 9 and 12 months?). Again, just a thought, although in your experience you may have already run into this and can rule this out, but I think testing it for a video a year from now might be worth a try.
The failure of the first specimen occurred in the Heat affected zone of the weld. Due to the cold temperature when welding, there was a very high cooling rate of the weld area and this resulted in an excessively hard HAZ. What you are seeing in the second test specimen is the result of a loss of fracture toughness at the lower temperature. All steels exhibit this phenomenon. This is a ductile to brittle transition. The fracture surface that you see on the second specimen is merely a brittle fracture.
European standards for electrode classification include a number that denotes the temperature at which the weld metal becomes brittle. It's decided that, if the charpy v-notch sample has impact energy absorption less than 47 joules, the metal is considered brittle. The number corresponds directly to degrees celsius x 10, so 4 would mean that the weld metal has impact toughness lower than 47 joules at a temperature of -40 celsius. It's really useful when you have to decide what electrodes are to be used in the climate the structure will reside in. For some context, typical 7018 equivalent rods become brittle at -40, the 7018-1 equivalent is brittle at -50, 6013 equivalent is brittle at 0 celsius.
Excellent info. The -1 classification helps to somewhat ID that here in the USA but most (if not all) store bought rods aren’t -1. Most people also don’t realize what that even means, which is actually important to know, for the exact reasons you mentioned.
@@makingmistakeswithgreg If I recall correctly, the -1 denotes better impact toughness at low temperature, and it means that you can weld a restrained structure with a much lower chance of weld cracking. It probably has higher ductility.
Love your videos as i learn more with each one i watch!! Would it make any difference in your welds if your rod is kept in a freezing cold garage in the winter? Thank you again for all the help you give people
If the rods are super cold they will require more amperage at the start. What you would likely see is the beginning 3/8th of an inch is more “humped up” than usual. Within a second or two the rod would be above room temp but that initial start could be rough. I have welded at -16 outside with rods in a pouch. The rods likely dropped to atleast 18 degrees, and I didn’t notice a huge difference. I preheated the steel I was welding to 250 degrees though which helped the weld wet out. Welding on super cold steel (especially thicker steel) is a big mistake, cold rods likely less so.
I'm being sent back to assembly so I'll get some fan time during the Hot weather,no welding for the near future but it'll be cooler...
Id love to see some destructive testing on plates with gaps you know multiple pass just to close a gap
Great idea, I will definitely do that. I will do some Texas tig (stick welding with a filler rod like tig), and some open gaps with poor fitups. I can tell you that getting full strength out of those situations will be tough. Strength would come down to how good you are.
send some cold welds to Florida, Man it's hot here......Thanks Greg...
I didn’t post a pic in the video but inside the tin shed was 98 degrees, the cold coming off the plates was heavenly lol.
Dude. Are you from the U.P. of Michigan? Respect to the accent regardless. I'm starting my welding certification course at 45 and this channel helps so much!! Thanks!!
No problem, glad to hear you’re investing in your skills 👍. I am from southern Wisconsin. I have a bunch of friends from the U.P. and they crack me up because their accent is just like mine but even stronger lol.
Excellent tests!
Hey.....teaser..... What's up with the 6010/7018 welds & bend tests, on the table, that aren't mentioned or discussed?? LoL
Thanks for another excellent video!
Those are ones I kept from a video a long time ago 😀. Here is the video. th-cam.com/video/WJ1hgfscVe8/w-d-xo.htmlsi=G3fInYk6Wu3NuRq4 .
Very interesting to see the grain structure change. If you reheat it will the grain pattern return to normal? Thanks for another very good video.
So I think what happened is the steel became brittle and had a brittle failure due to the cold. If I had cooled it down and given it time to warm up it likely would have been fine. Bending it while it was -40 was enough to reduce the steel’s flexibility and thus is broke much like an iron casting.
But my igloo is melting!!