Tender For corrigendum : supply of seamless steel tubes of od 38 x 4.5 mm , seamless steel tubes of od 38 x 5.6 mm , seamless steel tubes of od 38 x 6.3 mm , seamless steel tubes of od 38 x 7.1 mm , eamless steel tubes of od 51 x 4.5 mm , seamless steel tubes of od 51 x 5.0 mm , seamless steel tubes of od 57 x 6.3 mm