Unfired pressure vessels

BS EN 13445-2:2021 pdf free.Unfired pressure vessels Part 2: Materials.
4 Requirements for materials to be used for pressure-bearing parts
4.1 General
4.1.1 Materials to be used for pressure-bearing parts shall meet the general requirements o14.1 and the special provisions of 4.2, if applicable. Materials for pressure bearing parts shall be ordered complying with the technical delivery conditions in 4.3.
Marking of materials for pressure-bearing parts shall be performed in accordance with 4.4.
Materials shall be selected to be compatible with anticipated fabrication steps and to be suitable for the internal fluid and external environment. Both normal operating conditions and transient conditions occurring during fabrication transport, testing and operation shall be taken into account when specifying the materials.
NOTE 1 The requirements of 4.1 and 4.2 should also be fulfilled when technical delivery conditions are developed for European material standards, European approval of materials or particular material appraisals.
NOTE 2 When technical delivery conditions for pressure-bearing parts are developed, the structure and requirements of EN 764-4:2014 should be met. Exceptions should be technically justified.
The materials shall be grouped in accordance with CEN ISO/CR 15608:2000 to relate manufacturing and inspection requirements to generic material types.
NOTE 3 Materials have been allocated into these groups in accordance with their chemical composition and properties in view of manufacture and heat treatment after welding.
4.1.2 Materials for pressure-bearing parts compliant with the requirements of this document shall be
accompanied by inspection documents in accordance with EN 10204:2004. Certificate of specific control
(3.1 or 3.2 certificate) shall be required for all steels if Design by Analysis — Direct Route according to
Annex B of EN 13445-3:2021 is used.
The type of Inspection document shall be in accordance with EN 764-5:2014 and Include a declaration of compliance to the material specification.
4.1.3 The materials shall be free from surface and internal defects which can impair their intended usability.
4.1.4 Steels shall have a specified minimum elongation after fracture measured on a gauge length The minimum elongation after fracture in any direction shall be≥14 %.
When measured on a gauge length other than that stated here, the minimum elongation after fracture shall be determined by converting the elongation in accordance with
一EN ISO 2566-1:1999 for carbon and low alloy steels;
— EN ISO 2566-2:1999 for austenitic steels.
4.1.5 However, lower elongation values may also be applied (e.g. for fasteners or castings), provided that appropriate measures are taken to compensate for these lower values and the specific requirements are verifiable.
NOTE Examples for compensation:
— application of higher safety factors in design;
— performance of burst tests to demonstrate ductile material behaviour.
4.1.6 Steels shall have a specified minimum impact energy measured on a Charpy-V-notch impact test specimen (EN ISO 148-1:2010) as follows:
—  27 J for ferritic and 1,5 % to 5 % Ni alloy steels;
—  40 J for steels of material group 8, 9.3 and 10
at a test temperature in accordance with Annex B, but not higher than 20 °C. The other requirements of Annex B shall also apply.
4.1.7 The chemical composition of steels intended for welding or forming shall not exceed the values in Table 4.1-1. Line 2 of the table refers to vessels or parts designed using Design by Analysis — Direct Route according to Annex B of EN 13445-3:2021, Exceptions shall be technically justified.
4.2 Special provisions
4.2.1 Special properties
Where the behaviour of a material can be affected by manufacturing processes or operating conditions, to an extent that would adversely affect the safety or service life of the pressure vessel, this shall be taken into consideration when specifying material.
Adverse effects may arise from:
— manufacturing processes: e.g. degree of cold forming and heat treatment;
— operating conditions: e.g. hydrogen embrittlement, corrosion, scaling and ageing behaviour of the material after cold forming.
4.2.2 Design temperature above 20 °C
4.2.2.1 A material shall only be used for pressure parts within the range of temperatures for which the material properties required by EN 13445-3:2021 are defined in the technical specification for the material. If the technical delivery condition does not contain the specific material values required for the allowable temperature TS the values required in EN 13445-3:202 1 for the design shall be determined by linear interpolation between the two adjacent values. Values shall not be rounded up.
For other than austenitic and austenitic-ferritic stainless steels, the specified value of ReH (Ro2) at room temperature (RT) may be used for temperatures less than or equal to 50 °C. Interpolation between 50 °C and 100 °C shall be performed with the values of RT and 100 °C and using 20 °C as the starting point for interpolation. Above 100 °C linear interpolation shall be performed between the tabulated values given in the table.
4.2.2.2 As the impact properties may be affected by long or frequent holding of the material at elevated temperatures, it is presupposed that the temperatures and periods of exposure to elevated temperatures be recorded for review during in-service Inspection. The influence of such exposure upon the lifetime expectancy shall be estimated and recorded.
For operations such as drying and cleaning of pressure vessels, steels with specified low temperature properties but without elevated temperature 0,2 % proof strength values may however be used at elevated temperatures for drying and cleaning processes provided that the values of 0,2 % proof strength used in design calculations for elevated temperatures shall be obtained by multiplying the specified minimum yield strength values at 20 °C by the factor given in Table 4.2-1.
4.2.3 Prevention of brittle fracture
The requirements in Annex B shall apply.
4.2.4 Design properties in the creep range
4.2.4.1 Creep properties of base material
For interpolation and extrapolation of creep properties given in the materials standard, see EN 13445- 3:202 1, Clause 19.
When creep properties are not available from a materials standard, they shall be determined using
EN ISO 204:2009.
4.2.4.2 Creep properties of weldments
Creep properties of weld joints subjected to stresses normal to the weld can differ significantly from those of the base material.
For the design of vessels in the creep range, this is taken into account in EN 13445-3:2021 by making use of a weld creep strength reduction factor z obtained from tests on weldments, If no data are available. a default value of z is used.
An acceptable method to determine z by cross-weld tests is given in Annex C (see also [171).
4.2.5 Specific requirements for steels for fasteners
Fasteners include bolts, studs and nuts.
Free cutting steel shall not be used. Bolting made of carbon steel or Ni alloy ferritic steel with > 3,5 % nickel shall not be used above 300 °C.
The specified minimum tensile strength of bar material of ferritic and martensitic steel for bolts shall not exceed 1 000 MPa. The minimum elongation of bar material after fracture shall be at least A5 = 14%.
Impact requirements for ferritic and martensitic steels are specified in B.2.2.4.
Bolt material with a design temperature below —160°C shall be impact tested at —196 °C.
Hydrogen embrittlement. fatigue or relaxation properties shall be taken into account where appropriate.
NOTE 1 Detailed requirements on the surface condition and internal soundness of the bar can be necessary for some applications.BS EN 13445-2 pdf free download.Unfired pressure vessels