German standard

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The internal pressures are calculated by using the following formula:

Temperature < 120°C

Temperature > 120°C

OD/ID <= 1.67:

1.67 < OD/ID <= 2.0:

Where:

P	Internal pressure (MPa) (*10 => bar)
t_min	Minimum wall thickness (mm)
S	Allowable stress (S = R_p0.2/1.5^*) (MPa)
OD	Nominal outside diameter (mm)
ID	Inside diameter (ID = OD-2×t_min) (mm)

^*Safety factor 1.5 require delivery with certificate according to DIN / EN 10204.

For austenitic steels when R_p0.2/R_m <= 0.5 at 20°C the allowable stress can be calculated using R_p1.0 instead of R_p0.2.

For steels with less ductility than 25% (A) higher safety factors are required.

The allowable stress has been calculated according to following:

S =	R_p1.0/1.5 for austenitic steels (3R12, 3R60, 6R35, 8R40, 5R75, 2RK65and Sanicro 28)
S =	R_p0.2/1.5 for 3RE60 and SAF 2304
S =	R_p0.2/1.56 for SAF 2205
S =	R_p0.2/1.6 for SAF 2507

Attention: The pressures on these pages are given only as guidance. Dimensioning of piping systems also depend on other factors like external forces, thermal stresses, dead weight etc. Furthermore the design must be made according to regulations from local authorities and approved accordingly. For tubes in pressure vessels and boilers it is important to consider AD Merkblätter and TRD (Technische Regeln Für Dampfkessel).

Allowed wall thickness and outer diameter:
2RK65™	t <= 20.0 mm	OD <= 220 mm
Sanicro^® 28	1.0 <= t <= 20.0 mm	OD <= 250 mm
3RE60™	1.0 <= t <= 7.0 mm	10 <= OD <= 76 mm
SAF 2304^®	1.0 <= t <= 24.0 mm	5 <= OD <= 260 mm
SAF 2205™	t <= 24.0 mm	OD <= 260 mm
SAF 2507^®	1.0 <= t <= 10.0 mm	OD <= 220 mm^*

^*Cold finish only!

Proof strength R_p1.0 (MPa)

Sandvik	W-Nr	20°C	100°C	150°C	200°C	250°C	300°C	350°C	400°C
3R12^*1)	1.4306	215	181	162	147	137	127	121	116
3R60™^*2)	1.4435	225	199	181	167	157	145	139	135
6R35 CF^*3)	1.4541 CF	235	208	195	185	175	167	161	156
6R35 HF^*4)	1.4541 HF	215	181	162	147	137	127	121	116
8R40^*5)	1.4550	240	211	196	186	177	167	161	156
5R75 CF^*6)	1.4571 CF	245	218	206	196	186	175	169	164
5R75 HF^*7)	1.4571 HF	225	199	181	167	157	145	139	135
2RK65^*8)	1.4539	250	205	195	185	175	165	160	155
Sanicro^® 28^*9)	1.4563	250	220	205	190	185	180	175	165

(1 MPa = 10 bar)
*1) DIN 17458, Juli 1985
*2) DIN 17458, Juli 1985
*3) DIN 17458, Juli 1985, cold finish
*4) DIN 17458, Juli 1985, hot finish
*5) DIN 17458, Juli 1985
*6) DIN 17458, Juli 1985, cold finish
*7) DIN 17458, Juli 1985, hot finish
*8) Vd-TÜV-Blatt 421, 06.2005. OD<=200mm, t<=20mm.
*9) Vd-TÜV-Blatt 483, 06.96. OD<=250mm, 1.0<=t<=20.0mm

**PROOF STRENGTH R_p0.2 (MPa)**
Sandvik	W-Nr	20°C	100°C	150°C	200°C	250°C	300°C
3RE60™^*10)	1.4417	450	370	(350)	330	(325)	320
SAF 2304^®^*11)	1.4362	400	330	310	290	280
SAF 2205™^*12)	1.4462	450	360	335	310	295
SAF 2507^®^*13)	(1.4410)	550	480	445	420	405

(1 MPa = 10 bar)
*10) Vd-TÜV-Blatt 385, 06.88. 10<=OD<=76mm, 1<=t<=7mm. Tmax 300°C (1<=t<=4mm allows Rp0.2 20°C 480 MPa) Values at 150°C and 250°C are interpolated.
*11) Vd-TÜV-Blatt 496, 09.2001. Tmax 280°C Beiblatt 12.2001 5<=OD<=273mm, 1.0<=t<=24.0mm.
*12) Vd-TÜV-Blatt 418, 06.2004. OD<=260mm,t<=24.0mm. Tmax 280°C
*13) Vd-TÜV-Blatt 508, 09.2001. OD<=220mm, 1<=t<=10mm; cold finish only! Tmax 250°C