tender for hot finish seamless tube (hfs) with nominal bore 20mm, heavy, plain-end black and painted with2 coats of red oxide zinc chrome primer to is:2074/92 (reaffirmed 2002) after grit blasting or mechanicalbrushing for air brake stock to specification is: 1239 / 2004, part-i, table-5 (heavy), amdt.3 of may08.