Kumgangatho we-ASTM, imathiriyeli eyahlukeneyo enemigangatho eyahlukeneyo yentsimbi, ngaphandle koko, iipropathi zabo zoomatshini kunye nokwakheka kweekhemikhali, iipropathi zetsimbi zahlukile. Kukho uluhlu lwemigangatho ye-astm enemigangatho eyahlukeneyo yentsimbi. Inkcazo esemgangathweni ye-ASTM A53 / A53M yoMbhobho, intsimbi, iBla...
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