How to determine or calculate the dimensions of the tensile specimen: calibrated width (b1), b2, and R (radius)? Note that the thickness equals 1.5mm
Please refer ASTM E8 for guidance to determine tensile specimen standard sizes of different ferrous or non ferrous materials if your application area is for pressure vessels or Boilers or Cyrogenic vessel.
I would make an assumption that you have a metallic material, a flat product of thickness a = 1.5 mm, and testing will be performed at room temperature. Then following the EN ISO 6892-1 you can have 2 types of test pieces: proportional and non-proportional.
Proportional test piece:
- The original gauge length Lo = k*sqrt(So) should be not less than 15 mm (k=5.65, So - cross-section area). Nevertheless, the Lo is better to take 20 mm or more as the measurement uncertainty is increased in case it is less than 20mm.
- The width b = 8 mm results in So 12 mm2 and Lo 19.57 mm. Lo should be rounded to 20 mm. As the difference between calc and rounded values does not exceed 10%, it is acceptable.
- The parallel length Lc shall not be less than Lo + b/2 = 20+8/2 = 24 mm
- The width of the gripped ends should be >=1.2*b. In this case more than 9.6 mm. I would suggest 12 mm, but 10 mm is also acceptable.
- Radius of the transition curves should be at least 20 mm
Non-proportional test piece:
3 test piece geometries are widely used:
1) Width bo 12.5 mm, Lo 50 mm, Lc 75 mm (min 57 mm)
2) Width bo 20 mm, Lo 80 mm, Lc 120 mm (min 90 mm)
3) Width bo 25 mm, Lo 50 mm, Lc (min 60 mm)
- The width of the gripped ends should be >=1.2*b.
- Radius of the transition curves should be at least 20 mm
If I made a mistake, please correct me.
Nataliia Chernovol
hi Nataliia Chernovol; Thank you very much for your help, it's very kind of you, if you have the EN ISO 6892-1 standard - Proportional specimen send me if possible. For the samples I have an overall width of 10mm, could it be that l0 = 8mm and the overall width is 10mm?
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