Originally Posted By: BHopkins
Originally Posted By: aquariuscsm
Seeing this thread made me wonder,when did real metal bumpers go away being replaced by plastic "bumper covers"? And why?
It all started with the 1973 model year. NHTSA and congress implemented regulations that required a 5 mph safety bumper.
Interesting side fact with regards to this...
A bunch of power stations that were built in the 1980s started suffering a phenomenon called "flow accelerated corrosion" in the 1990s. Pleasant Prarie was one of the ones that awoke the industry, when two workers walked out of a lift and were scalded to death...
http://journaltimes.com/news/corroded-pi...6bfffcd1be.html
https://en.wikipedia.org/wiki/Pleasant_Prairie_Power_Plant
The accelerated corrosion process is a surface oxide is formed, and is washed off, reforms, is washed off, and never forms a stable passive layer.
Turns out that power station metals historically included a lot of scrap...that scrap had bumper bars from the hay day of the automotive industry and doped the steel with a tiny amount of Chrome.
Steel made in the 80s wasn't doped...no-one realised that the issue was an issue, as steel ALWAYS behaved the way that it used to...that lead to feedwater failures all over the world.
We HAD it at Wallerawang, but it was limited to thermocouple pockets...we found that if we sampled the metal and had a tiny little bit of chrome, the process was stable...no chrome, we cut them out.
Originally Posted By: aquariuscsm
Seeing this thread made me wonder,when did real metal bumpers go away being replaced by plastic "bumper covers"? And why?
It all started with the 1973 model year. NHTSA and congress implemented regulations that required a 5 mph safety bumper.
Interesting side fact with regards to this...
A bunch of power stations that were built in the 1980s started suffering a phenomenon called "flow accelerated corrosion" in the 1990s. Pleasant Prarie was one of the ones that awoke the industry, when two workers walked out of a lift and were scalded to death...
http://journaltimes.com/news/corroded-pi...6bfffcd1be.html
https://en.wikipedia.org/wiki/Pleasant_Prairie_Power_Plant
The accelerated corrosion process is a surface oxide is formed, and is washed off, reforms, is washed off, and never forms a stable passive layer.
Turns out that power station metals historically included a lot of scrap...that scrap had bumper bars from the hay day of the automotive industry and doped the steel with a tiny amount of Chrome.
Steel made in the 80s wasn't doped...no-one realised that the issue was an issue, as steel ALWAYS behaved the way that it used to...that lead to feedwater failures all over the world.
We HAD it at Wallerawang, but it was limited to thermocouple pockets...we found that if we sampled the metal and had a tiny little bit of chrome, the process was stable...no chrome, we cut them out.
