① The average grain of the soft annealed (O60) pipes should be 0.025~0.06mm, light annealed (O50) pipes≤ 0.035 mm.
* Light-drawn (H55) and hard-drawn (H80 )tempers are available in round tube only.
※ Rockwell hardness values shall apply only to tubes having a wall thickness of 0.3 mm or over and to round tubes having an inside diameter of 8 mm or over and to rectangular including square tubes having an inside major distance between parallel surfaces of 5 mm or over. For all other tube no Rockwell hardness values shall apply. Rockwell hardness tests shall be made on the inside surface of the tube. When suitable equipment is not available for determining the specified Rockwell hardness, other Rockwell scales and values shall be specified subject to agreement between the manufacturer and the purchaser.
