Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old February 4th 21, 12:43 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Apr 2016
Posts: 78
Default Get -40C in my fillet weld tensile break tests

Ideas to get a controlled temperature of around -40C (also -40F) in a
test sample?

"Robustly" by physics:
100C - boiling water
0C - ice
-17C - brine-ice slurry (?)
??? -40C ???
-80C - "cardice" - solid CO2
-196C - liquid nitrogen

Reason is, found a way to tensile-test fillet welds, and so far always
seeing breaking strength come out at around 560MPa, when you do the
maths relating breaking force to the fracture area.

The 355MPa yield of the Rectangular Hollow Sections (RHS) isn't seen -
and I know they have exactly that yield stress from beam bending
measurements.

Here's the tests - "Alladin's Cave" of misdemeanours and skulduggery ?
;-)

http://www.weldsmith.co.uk/tech/struct/struct.html
"Steel Structural Performance index-page"

Various tests.

Specifically the fillet weld tensile tests

http://www.weldsmith.co.uk/tech/stru...4_fwbeamt.html
"Fillet welds tensile tested in beam test"

http://www.weldsmith.co.uk/tech/stru...t_testrig.html
"Tensile-test rig for beam-configuration fillet-weld samples"

Movie of - 10 seconds - shared on "Dropbox"
https://www.dropbox.com/s/esgwfk5jen..._fwtr.mp4?dl=0

Yup, I know that as a PhD level scientist I have to work as a welder
because everyone already ensconced in "office engineering" jobs
manicured in their white shirts sees me as a "Dennis Hopper like"
(think eg. "Blue Velvet" (1986) film) character of the science and
engineering world ;-)
If you keep the office door closed to all but your own manicured kind,
you can keep reality out. Who can blame them if no-one comes and
hurls them out into the cold hard world their scheme avoids? :-)

It would be helpful to see whether that "no yield event - straight to
local fracture at high(er) stress" is associated with a low
temperature brittleness charactistic.

I could "dam-off" the RHS close to the weld and at the far end, and
fill it with a cooling fluid.
Ice-brine looks good for -17C.

Throw a blanked over the entire sample for a while for all parts of
the sample to be at that temperature, then slide in the hydraulic
cylinder and "pump it up" and see what the temperature causes or does
not cause.

What about for -40C
???

Regards,
Rich Smith

  #2   Report Post  
Old February 4th 21, 03:38 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jun 2011
Posts: 5,825
Default Get -40C in my fillet weld tensile break tests

"Richard Smith" wrote in message ...

Ideas to get a controlled temperature of around -40C (also -40F) in a
test sample?

The lowest setting on my Alpicool C20 DC-powered freezer is -40C. Temps
below -20C are accessed with the E1 special setting.
https://www.amazon.com/Alpicool-C20-.../dp/B075R1LH8D

It works well enough but isn't as rugged or hands-off reliable as a normal
AC-powered freezer, and really should have thicker insulation.

  #3   Report Post  
Old February 4th 21, 06:33 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Oct 2007
Posts: 398
Default Get -40C in my fillet weld tensile break tests

On Thu, 04 Feb 2021 11:43:58 +0000, Richard Smith
wrote:

Ideas to get a controlled temperature of around -40C (also -40F) in a
test sample?

"Robustly" by physics:
100C - boiling water
0C - ice
-17C - brine-ice slurry (?)
??? -40C ???
-80C - "cardice" - solid CO2
-196C - liquid nitrogen

Reason is, found a way to tensile-test fillet welds, and so far always
seeing breaking strength come out at around 560MPa, when you do the
maths relating breaking force to the fracture area.

The 355MPa yield of the Rectangular Hollow Sections (RHS) isn't seen -
and I know they have exactly that yield stress from beam bending
measurements.

Here's the tests - "Alladin's Cave" of misdemeanours and skulduggery ?
;-)

http://www.weldsmith.co.uk/tech/struct/struct.html
"Steel Structural Performance index-page"

Various tests.

Specifically the fillet weld tensile tests

http://www.weldsmith.co.uk/tech/struct/201124_fwbeamt/201124_fwbeamt.html
"Fillet welds tensile tested in beam test"

http://www.weldsmith.co.uk/tech/struct/210122_fwtest_rig/210122_fwtest_testrig.html
"Tensile-test rig for beam-configuration fillet-weld samples"

Movie of - 10 seconds - shared on "Dropbox"
https://www.dropbox.com/s/esgwfk5jenhm024/210122_fwtr.mp4?dl=0

Yup, I know that as a PhD level scientist I have to work as a welder
because everyone already ensconced in "office engineering" jobs
manicured in their white shirts sees me as a "Dennis Hopper like"
(think eg. "Blue Velvet" (1986) film) character of the science and
engineering world ;-)
If you keep the office door closed to all but your own manicured kind,
you can keep reality out. Who can blame them if no-one comes and
hurls them out into the cold hard world their scheme avoids? :-)

It would be helpful to see whether that "no yield event - straight to
local fracture at high(er) stress" is associated with a low
temperature brittleness charactistic.

I could "dam-off" the RHS close to the weld and at the far end, and
fill it with a cooling fluid.
Ice-brine looks good for -17C.

Throw a blanked over the entire sample for a while for all parts of
the sample to be at that temperature, then slide in the hydraulic
cylinder and "pump it up" and see what the temperature causes or does
not cause.

What about for -40C
???


Propane boils at -42 C at atmospheric pressure.

Joe Gwinn
  #4   Report Post  
Old February 4th 21, 07:10 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jun 2011
Posts: 5,825
Default Get -40C in my fillet weld tensile break tests

"Richard Smith" wrote in message ...

......
Yup, I know that as a PhD level scientist I have to work as a welder
because everyone already ensconced in "office engineering" jobs
manicured in their white shirts sees me as a "Dennis Hopper like"
(think eg. "Blue Velvet" (1986) film) character of the science and
engineering world ;-)
If you keep the office door closed to all but your own manicured kind,
you can keep reality out. Who can blame them if no-one comes and
hurls them out into the cold hard world their scheme avoids? :-)

Rich Smith
--------------------------------

The snobbery of "Two Cultures" exists in the US scientific community too. I
first encountered it as a Chemistry undergrad, from professors who either
worked with government and industry or shunned all but pure academic
research, and tried to convince us theirs was the only ethical path.

As a lab manager in a government research facility I worked with both
hands-on and hands-off engineers, and again the theoretical, hands-off ones
could be somewhat intolerant of people who could be both. I also saw that in
Mensa, mainly from mathematicians. It was fun to watch the confusion after
someone who had binned me as a mere craftsman found I could and solve
engineering math problems mentally faster than they could with a calculator.

Personally I've been glad to stay in the lab, designing and building
hardware, and avoid boring meetings and report writing. Another lab tech
made a bumper sticker "Techs can do what engineers only dream of".

Not all great theoreticians kept their hands clean:
https://www.fromthegrapevine.com/inn...ator-invention


  #5   Report Post  
Old February 4th 21, 07:30 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jun 2011
Posts: 5,825
Default Get -40C in my fillet weld tensile break tests

"Joe Gwinn" wrote in message
...

Propane boils at -42 C at atmospheric pressure.

Joe Gwinn

-------------------------------
I checked the weather on Spitzbergen to see if the experiment could be done
at ambient temperature there.
https://www.accuweather.com/en/sj/lo...orecast/310461

Funny, New England USA was that cold over the weekend, and we are at the
latitude of Spain.
https://brilliantmaps.com/cities-transposed-latitude/



  #6   Report Post  
Old February 4th 21, 07:59 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jun 2011
Posts: 5,825
Default Get -40C in my fillet weld tensile break tests

"Jim Wilkins" wrote in message ...

"Richard Smith" wrote in message ...

Ideas to get a controlled temperature of around -40C (also -40F) in a
test sample?

----------------------------
The lowest setting on my Alpicool C20 DC-powered freezer is -40C. Temps
below -20C are accessed with the E1 special setting.
https://www.amazon.com/Alpicool-C20-.../dp/B075R1LH8D

It works well enough but isn't as rugged or hands-off reliable as a normal
AC-powered freezer, and really should have thicker insulation.
------------------------------------------
I confirmed it could be set to -40C but didn't leave it there, as it's full
of food and would have taken a long time to settle.

My Alpi wouldn't quite cool to -20C in a hot car so I made an insulated
enclosure for it, 1" foam lined inside with a yoga mat to catch and drain
summer condensation. The exterior is thin birch plywood joined at the
corners with sheet metal angles inside and truss head screws. The lid is a
flap of Harbor Freight moving blanket, doubled.

  #7   Report Post  
Old February 5th 21, 09:02 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Apr 2016
Posts: 78
Default Get -40C in my fillet weld tensile break tests

"Jim Wilkins" writes:

"Joe Gwinn" wrote in message
...

Propane boils at -42 C at atmospheric pressure.

Joe Gwinn

-------------------------------
I checked the weather on Spitzbergen to see if the experiment could be
done at ambient temperature there.
https://www.accuweather.com/en/sj/lo...orecast/310461

Funny, New England USA was that cold over the weekend, and we are at
the latitude of Spain.
https://brilliantmaps.com/cities-transposed-latitude/


Spitzbergen idea - LOL !
  #8   Report Post  
Old February 5th 21, 09:28 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Apr 2016
Posts: 78
Default Get -40C in my fillet weld tensile break tests

Joe Gwinn writes:

On Thu, 04 Feb 2021 11:43:58 +0000, Richard Smith
wrote:

Ideas to get a controlled temperature of around -40C (also -40F) in a
test sample?

"Robustly" by physics:
100C - boiling water
0C - ice
-17C - brine-ice slurry (?)
??? -40C ???
-80C - "cardice" - solid CO2
-196C - liquid nitrogen

Reason is, found a way to tensile-test fillet welds, and so far always
seeing breaking strength come out at around 560MPa, when you do the
maths relating breaking force to the fracture area.

The 355MPa yield of the Rectangular Hollow Sections (RHS) isn't seen -
and I know they have exactly that yield stress from beam bending
measurements.

Here's the tests - "Alladin's Cave" of misdemeanours and skulduggery ?
;-)

http://www.weldsmith.co.uk/tech/struct/struct.html
"Steel Structural Performance index-page"

Various tests.

Specifically the fillet weld tensile tests

http://www.weldsmith.co.uk/tech/struct/201124_fwbeamt/201124_fwbeamt.html
"Fillet welds tensile tested in beam test"

http://www.weldsmith.co.uk/tech/struct/210122_fwtest_rig/210122_fwtest_testrig.html
"Tensile-test rig for beam-configuration fillet-weld samples"

Movie of - 10 seconds - shared on "Dropbox"
https://www.dropbox.com/s/esgwfk5jenhm024/210122_fwtr.mp4?dl=0

Yup, I know that as a PhD level scientist I have to work as a welder
because everyone already ensconced in "office engineering" jobs
manicured in their white shirts sees me as a "Dennis Hopper like"
(think eg. "Blue Velvet" (1986) film) character of the science and
engineering world ;-)
If you keep the office door closed to all but your own manicured kind,
you can keep reality out. Who can blame them if no-one comes and
hurls them out into the cold hard world their scheme avoids? :-)

It would be helpful to see whether that "no yield event - straight to
local fracture at high(er) stress" is associated with a low
temperature brittleness charactistic.

I could "dam-off" the RHS close to the weld and at the far end, and
fill it with a cooling fluid.
Ice-brine looks good for -17C.

Throw a blanked over the entire sample for a while for all parts of
the sample to be at that temperature, then slide in the hydraulic
cylinder and "pump it up" and see what the temperature causes or does
not cause.

What about for -40C
???


Propane boils at -42 C at atmospheric pressure.

Joe Gwinn


Thanks for suggestion. Well rooted in science.
I fear that as the sample gets colder with propane evaporation, we
could get a hair-trim if the evaporated gas ignites.

The sample halves hurl around on sample weld breaking, so putting on a
"vent tube" with the propane burning at the outlet - a "flare" -
doesn't seem a viable solution.

It might be that I have to do something with "cardice" - solid CO2.
Throw-in bits until reaches -40C.

Or cool to lower temperature and pump the cylinder when weld area has is
showing -40C by thermocouple.

Thanks for suggestions.

I just looked online and find
https://en.wikipedia.org/wiki/Brine
that lowest melting point is -21.1C

Something you learn about experimenting - while you do make sure
everything holds together as it should, you don't look for the n-th
degree of accuracy of physical conditions in the proof-of-concept
tries.

To think in planning that a particular exact temperature is important
is the error of thinking that if you specify something enough, "God"
has to conform. Not going to happen. Get a pretty cold temperature
and observe what is there to observe.

Regards,
  #9   Report Post  
Old February 5th 21, 09:36 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Apr 2016
Posts: 78
Default Get -40C in my fillet weld tensile break tests

"Jim Wilkins" writes:

"Richard Smith" wrote in message ...

.....
Yup, I know that as a PhD level scientist I have to work as a welder
...
Rich Smith
--------------------------------

...
tech made a bumper sticker "Techs can do what engineers only dream
of".
...


LOL ;-)
  #10   Report Post  
Old February 5th 21, 02:23 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jun 2011
Posts: 5,825
Default Get -40C in my fillet weld tensile break tests

"Richard Smith" wrote in message ...
....
Or cool to lower temperature and pump the cylinder when weld area has is
showing -40C by thermocouple.

-------------------

That's the first method I would try, to check your assumptions and procedure
and shrapnel containment.

This suggests that impurity levels might be a significant uncontrolled
variable in your experiments:
https://www.tf.uni-kiel.de/matwis/am...tr/s9_1_1.html

Is -40C the lowest you expect in European service?
https://en.wikipedia.org/wiki/Operating_temperature

Some industrial temperature controllers have a cooling option that can
operate a solenoid valve to regulate the temperature with evaporating CO2
from a tank of room-temperature liquid.
https://www.linde-gas.com/en/process...ing/index.html
"Liquid carbon dioxide converts to solid carbon dioxide snow at –79ºC
(–109ºF)."

If the test chamber is nearly sealed the escaping gas should reduce or
prevent frost covering the sample. US regulations required an oxygen level
sensor and alarm at the test station. The body's breathing mechanism
responds to CO2 level (pH) in the blood, not oxygen level, so you may not
realize you are about to pass out from anoxia, especially with liquid
nitrogen.



Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Liberals score higher on IQ tests, Multiple choice fill in the bubble IQ tests. Some can even read their diploma.... Ed Huntress Metalworking 22 September 24th 14 03:04 AM
Fillet weld strength testing Christopher Tidy Metalworking 22 September 3rd 05 05:49 AM
The secret of a neat fillet weld? Christopher Tidy Metalworking 13 August 28th 05 07:55 PM
The secret of a neat fillet weld? Christopher Tidy Metalworking 1 August 28th 05 06:56 PM
making fillet weld with oxyacet? mongke Metalworking 2 January 12th 04 05:39 PM


All times are GMT +1. The time now is 02:23 AM.

Powered by vBulletin® Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright 2004-2021 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"

 

Copyright © 2017