Any tube with a very fine diameter is called a capillary tube.
Usually refers to the inner diameter is equal to or less than 1 mm of the tube, because the diameter of some fine as hair so called capillary.
It’s currently used in medicine, in building materials.
Descriptions of Carbon Steel Seamless Steel Pipe
Cold Rolled SAE 1045 carbon steel seamless pipe
ASTM A106, ASTM A53, API 5L Gr.B, DIN17175,DIN1629
Control with in the standard, OD:+-1%, WT:+-10%
10#,20#, 45#,16Mn,A106(B,C),A53(A,B),API J55,API K55,Q235,Q345,ST35.8,ST37,ST42,ST45,ST52
Waterproof paper, and steel strip packed. Standard Export Seaworthy Package.Suit forall kinds of transport,or as required
1000 metric tons/month
1 ton,sample order accepted
Within 7-10 workdays after receiving deposit or L/C