scope:

Scope and general 

This AD 2000-Merkblatt applies to austenitic cast iron with lamellar graphite for the construction of pressure vessels (see also AD 2000-Merkblatt A 4) operating at working temperatures and at ambient temperatures from -10 °C up to the limits of temperature given in Clause 2. For temperatures below -10 °C, AD 2000-Merkblatt W 10 shall also be taken into consideration. The grades shall be selected in accordance with the planned application taking into account the mechanical, thermal and chemical stresses and the physical properties (see DIN EN 13835). See also 2.2 of AD 2000-Merkblatt W 0.

The production of austenitic cast iron with lamellar graphite presupposes an adequate level of experience on the part of the suppliers. Initial proof shall be provided to the relevant third party.

Austenitic cast iron with lamellar graphite shall be used for the construction of pressure vessels if the characterristics of the material offer operational advantages over other types of material. For pressure vessels constructed of austenitic cast iron with lamellar graphite, the following limits to the maximum allowable pressure PS apply (see DIN EN 764):

25 bar internal gauge pressure

40 bar external gauge pressure.

In the case of an internal gauge pressure of more than 6 bar and an external gauge pressure exceeding 10 bar, the following products of vessels capacity V in litres and maximum allowable pressure PS in bar shall in general not be exceeded:

Internal gauge pressure V · PS = 65000 bar litre

External gauge pressure V · PS = 100000 bar litre.

If the figures produced are higher than these values, the agreement of the relevant third party shall be obtained. 

Due account shall be taken of casting practice when designing pressure vessels made of austenitic cast iron with lamellar graphite if blowholes, cracks and peak stresses are to be avoided. The designer shall agree the types of pressure vessel with the foundry.