Steels_ Metallurgy and Applications, Third Edition

Engineering steels 245

Table 3.11 Welded steel gas containers to BS 5045: Part 2:1989

Chemical and

physical properties

Carbon % max. 0.2
Silicon % max. 0.3
Manganese
% min. - 0.4
% max. 0.6 1.2
Phosphorus % max. 0.05 0.04
Sulphur % max. 0.05 0.04
Grain-refining
elements % max. - -
Yield stress
(N/ram 2) rain. 215 275
Tensile strength
(N/mm 2) min. 340 400
Tensile strength
(N/mm 2) max. 430 490
Elongation % min. b
Lo = 50 mm 28 24
Lo = 5.65~/So 33 29

Type a Type B Type C TypeD Type E Type F Type G

0.18 0.2 0.2 0.15 0,18

0.25 - 0.3 0.3 0,4

0.25

0.35

0.7 - - 0.5 0.6

1.5 0.6 1.2 1.4 1.4

0.05 0.05 0.025 0.04 0.03

0.05 0.05 0.03 0,04 0.045

_ a - 0.3 a - 0.7

310 200 350 285 250

430 320 430 430 430

585 420 650 510 550

21 29 21 - 21

20 35 25 20 25

aGrain-refining elements are limited to: niobium 0,08%, titanium 0.2%, vanadium 0.2%, niobium
plus vanadium 0.2%.
bWhere any other non-proportional gauge lengths are used, conversions are in accordance with BS
3894: Part 1.
Note 1. Lo is the original gauge length.
So is the original cross-sectional area.
Note 2. Type A and type C are equivalent to grades of BS 1449:1962 (withdrawn); type E is
equivalent to grade 43135 of BS 1449: Part 1; type D is similar to Euronorm 120; type G
is equivalent to type 151 grade 430 of BS 1501: Part 1,
After BS 5045: Part 2: 1989.

Design and manufacture

The manufacture of a seamless steel cylinder is shown schematically in

Figure 3.30, which illustrates the high degree of metal forming involved in this

complex hot-working operation. The process is all the more remarkable when it is

realized that the production of seamless cylinders from thick plate or billets was

developed in the 1880s and 1890s and has changed very little to the present day.

The cylinder wall is the thinnest region of the vessel and is therefore subjected

to the highest stresses. However, under fatigue conditions, the higher stresses are

generated at the junction of the relatively thin wall and the thicker concave base.

BS 5045: Part 1 details the following formulae for the calculation of minimum

wall thickness in seamless containers:

0.3 (test pressure) x (internal diameter)

t = ....................... (1)

7 x fe -- (test pressure)

0.3 (test pressure) x (external diameter)

or t = (2)

7 x fe- 0.4 (test pressure)