BS6323 Part 4 CFS 3 tubes
Seamless and welded steel tubes for automobile mechanical and general engineering purposes
Part 4: Specific requirements for cold finished seamless steel tubes
Method of manufacture
The tubes shall be manufactured by a seamless process and shall be cold finished.
It is permissible for cold finished tubes to have on internal or external surfaces an adherent layer of
residual lubricant originating from the drawing process. If phosphate or other residues are
detrimental to subsequent processing, then their removal shall be the subject of an agreement
between the manufacturer and the purchaser.
Delivery condition
The tubes shall be supplied in one of the following delivery conditions (see Table 3 in BS 6323-1:1982).
a) Cold finished/hard (cold finished as drawn): BK;
b) Cold finished/soft (lightly cold worked): BKW
c) Annealed: GBK
d) Annealed (including de-scaling): GZF;
e) Normalized: NBK
f) Normalized (including de-scaling): NZF.