төмрийн хүдэр олборлох арга
төмрийн хүдэр олборлох арга 4018. ISOISO 4018 1988Hexagon head screws Product . ISO 4018 1988 Stage 95 99 00 Preliminary 10 Proposal 20 Preparatory 20 00 New project registered in TC/SC work programme 30 Committee 30 00 Committee draft CD registered 30 99 CD approved for registration as DIS.