Some pictures I've taken of some samples

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Discussion Overview

The discussion revolves around the examination of fracture surfaces of different materials, specifically 1095 steel, ductile cast iron, and cast iron, as observed through photographs taken by a participant. The focus is on understanding the relationship between brittleness, surface appearance, and energy required to break these materials, with references to Charpy tests and material properties.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that 1095 steel has a finer surface than ductile cast iron and cast iron, despite being less brittle.
  • Another participant questions the magnification of the pictures and the representation of the left and right sides of the specimens.
  • A participant clarifies that the specimens are from a Charpy test with a cross section of 1x1 cm, and mentions issues with focus in the images.
  • There is a query about the state of the 1095 steel, whether it is as-forged or annealed, and a note on the significance of heat treatment in determining mechanical properties.
  • One participant suggests that the fracture surface of 1095 steel may not differ significantly from that of cast iron with minimal carbon content.
  • Another participant expresses curiosity about the possibility of obtaining microscope images for better analysis.
  • A participant raises a question about why the surface of 1095 appears smoother than that of cast irons, despite requiring more energy to break, and whether a material can be more brittle yet require more energy to fracture.

Areas of Agreement / Disagreement

Participants express various viewpoints regarding the relationship between brittleness, surface appearance, and energy required for fracture, indicating that the discussion remains unresolved with multiple competing views.

Contextual Notes

There are limitations regarding the clarity of the images and the specific conditions of the materials tested, which may affect interpretations of the fracture surfaces.

snowJT
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I've included some pictures I've taken of some samples I've broken.. and 1095 steel has a more finer surface than ductile cast iron, and cast iron, however, it is not as brittle..

I would of thought that the more brittle the material was the more cleaner the break... but... anyone have an explanation of this?

Pictures

1095 - impact 2ft lbs

http://i21.photobucket.com/albums/b300/DrGame/1095steel.jpg

ductile cast iron - impact 2 ft lbs

http://i21.photobucket.com/albums/b300/DrGame/ductilecastiron.jpg

cast iron - impact 1 ft lbs

http://i21.photobucket.com/albums/b300/DrGame/castiron.jpg
 
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What is the magnification on those pics? And what do the left and right represent?
 
oh sorry, well the actual specimen is from a charpy test, the material has a cross section of 1x1 cm, and the left and right side is both halves of the specimen, they're just small samples I put on my scanner.
 
snowJT said:
oh sorry, well the actual specimen is from a charpy test, the material has a cross section of 1x1 cm, and the left and right side is both halves of the specimen, they're just small samples I put on my scanner.
Unfortunately, some of the surface is out of focus, and from the magnfication, it is difficult to see a difference.

What was the state of the 1095? As-forged or annealed?

Also remember 1095 steel is considered high carbon, so it's fracture surface may not be too dissimilar from a cast iron with the min amount of carbon. Heat treatment is important in the mechanical properties of carbon steel - really any steel or alloy.

Classification of Cast Iron

Would it be possible to obtain images from a microscope?

It would be worthwhile to do the same test for 1020, 1040, 1060, 1080 (all with the nomimal same thermo-mechanical treatment) and a low carbon cast iron and compare the fracture surfaces.
 
I do have additional samples of 1020, and 1040

But, what I'm wondering is why the sufrace of the 1095 appears to have a smoother surface than the cast irons, yet it was tested to need more energry to break it

Is it possible for something to need more energy to break if its even more brittle than the cast irons?
 

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