Steel pull test result coupler pulling through lack ofTensile test, according to the Central Institute or pull test, and if I get the missing steel themselves, it shows that the Coupler ok with strength.
The test by drawing the coupler pulling the pull test Tensile test or the central institutions. And if I pull the iron deficiency was shown that ok Coupler is strong.
Test pull pull steel coupler until lack test pulling or Tensile test according to Institute of various central and if enough ดึงขาด the steel will show. OK Coupler strength.