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BS6323-4 BK BKW GBK NBK GZF NZF Cold Finished Seamless Steel Tubes Grade CFS1 CFS2 CFS3 CFS4 CFS5 42CrMo4
Standard: BS6323-4 Seamless and Welded steel tubes for automobile,mechanical and
general engineering purposes
Part 4: Specific requirements for cold finished seamless steel
tubes
Applications: for Auto industry / for machinery use/mechanical and general
engineering purposes
Size range: O.D.:6-280mm W.T.:1-30mm L:max12000mm
Method of manufacture:
The tubes are manufactured by a seamless process and shall be cold finished
It is permissible for cold finished tubes to have on internal and external surfaces an adherent layer of residual to subsequent processing, then their removal shall be the subject of an agreement between the manufacturer and the purchaser.
Delivery Condition:
The tubes are supplied in one of the following condition:
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
Tests:
Flattenning tests
Leak tightness test- Eddy current test
Design | Chemical Compositions( ladle analysis) | ||||||
C | Si | Mn | Pmax. | Smax. | Cr | Mo | |
% | % | % | % | % | % | % | |
CFS 3 | 0.20 max. | 0.35 max. | 0.90max. | 0.050 | 0.050 | __ | __ |
CFS 3Aa | 0.20 max. | 0.10 to 0.35 | 0.60 to 1.00 | 0.050 | 0.050 | __ | __ |
CFS 4 | 0.25 max. | 0.35 max. | 1.20 max. | 0.050 | 0.050 | __ | __ |
CFS 5b | 0.23 max. | 0.50 max. | 1.50 max. | 0.050 | 0.050 | __ | __ |
CFS 6 | 0.30 to0.40 | 0.35 max. | 0.50 to 0.90 | 0.050 | 0.050 | __ | __ |
CFS 7 | 0.20 to 0.30 | 0.35 max. | 1.20 to1.50 | 0.050 | 0.050 | __ | __ |
CFS 8d | 0.40 to 0.55 | 0.35 max. | 0.50 to0.90 | 0.050 | 0.050 | __ | __ |
CFS 9 | 0.29max. | 0.35 max. | 1.50max. | 0.050 | 0.050 | __ | 0.15 to0.25 |
CFS 10 | 0.26max. | 0.35 max. | 0.80max. | 0.050 | 0.050 | 0.80 to1.20 | 0.15 to0.30 |
CFS 11 | 0.45max. | 0.35 max. | 1.00 max. | 0.050 | 0.050 | 0.80 to1.20 | 0.15 to0.30 |
Desig nation | BKc (cold finished/hard) | BKWc(cold finished/soft ) | GBK and GZF(annealed) | NBK and NZF(normalized) | ||||||||
Remin. | Rmmin. | Amin. | Remin. | Rmmin. | Amin. | Remin. | Rmmin | Amin. | Remin. | Rmmin. | Amin. | |
N/mm2 | N/mm2 | % | N/mm2 | N/mm2 | % | N/mm2 | N/mm2 | % | N/mm2 | N/mm2 | % | |
CFS3 | 360 | 450 | 6 | 280 | 400 | 9 | 170 | 340 | 26 | 215 | 360 | 24 |
CFS3Aa | 360 | 450 | 6 | 280 | 400 | 9 | 170 | 340 | 26 | 215 | 360 | 24 |
CFS4 | 415 | 520 | 5 | 315 | 450 | 8 | 200 | 400 | 24 | 235 | 410 | 22 |
CFS5b | 480 | 600 | 4 | 385 | 550 | 6 | __ | __ | __ | 340 | 490 | 20 |
CFS6 | 470 | 590 | 5 | 350 | 540 | 7 | 300 | 440 | 22 | 280 | 460 | 21 |
CFS7 | 560 | 700 | 4 | 460 | 650 | 7 | __ | __ | __ | __ | __ | __ |
CFS8d | 575 | 720 | 4 | 470 | 670 | 6 | 300 | 510 | 20 | 340 | 540 | 18 |
CFS9 | 575 | 720 | 4 | 470 | 670 | 6 | __ | __ | __ | __ | __ | __ |
CFS10 | 575 | 720 | 4 | 470 | 670 | 6 | __ | __ | __ | __ | __ | __ |
CFS11 | 575 | 720 | 4 | __ | 670 | 6 | __ | __ | __ | __ | __ | __ |
"NOTE Welding of tubes of grades 3,3A and 5 does not require
special techniques but care should be taken and welding carried out
in accordance with guidance given in the appropriate British
Standard for welding,e.g. BS 5135.The welding of other grades shown
may require special techniques.
aGrade 3A shall be suitable for case hardening purposes.
bGrain refining elements may be added at the option of the
manufacturer .
cIf tubes in the BK and GKW condition are subsequently
welded,brazed or heated the mechanical properties in the heat
affected zone may be reduced to those given for the delivery
condition GBK or NBK.
dSteel within the limits shown,but in accordance with the chemical
composition of BS 970-1,may be supplied if agreed ate the time of
order or enquiry."
Publications reffered to:
BS970, Specification for wrought steels for mechanical and allied engineering purposes
BS970-1, General inspection and testing procedure and specific requirements for carbon, carbon manganese, alloy and stainless steels
BS3601, Specification for steel pipes and tubes for pressure purposes: carbon and carbon manganse steel with specified elevated temperature properties.
BS 3603, Specification for steel pipes and tubes for pressure purposes: carbon and alloy steel with specified low temperature properties
BS3604, Specification for steel pipes and tubes for pressure purposes: ferritic alloy steel with specified elevated temperature properties.
BS3605, Seamless and welded austenitic stainless steel pipes and steel tubes for pressure purposes
BS4360, Specification for weldable structural steels
BS4848, Hot-rolled structural steel sections
BS4848-2, Hollow sections
BS5135, Metal-arc welding of carbon and carbon manganese steels
BS6323, Specification for seamless and welded steel tubes for automobile, mechanical and general engineering purposes
BS6323-1, General requirements
ISO 4200, Plain end steel tubes, welded and seamless - General tables of dimensions and masses per unite length