Knowledge base
AD 2000 Merkblatt W0: approved material manufacturer for pressure equipment
What assessment to AD 2000 W0 means for bolts on pressure equipment
Term explained
What assessment to AD 2000 W0 means for bolts on pressure equipment
The AD 2000 Code is the German set of technical rules for pressure vessels and pressure equipment, published by the Arbeitsgemeinschaft Druckbehälter. The W series deals with materials: W0 sets out the requirements a material manufacturer must meet, and W7 covers bolts and nuts made of ferritic and austenitic steels. Anyone who wants to supply bolts for pressure equipment to AD 2000 must therefore be assessed as a material manufacturer to W0 and must test and certify their parts to W7.
What assessment to W0 covers
A notified body assesses the company: quality assurance and organisation, traceability from bar stock to certificate, test equipment and its calibration, the qualification of the testing personnel, the independence of the NDT supervisor from production, and the certificates to EN 10204. RS Randack has been assessed by TÜV NORD as a material manufacturer to AD 2000 W0 and to EN 764-5; EN 764-5 is the European equivalent for material manufacturers under the Pressure Equipment Directive. The assessment also expressly serves as a basis for the UK market under the Pressure Equipment (Safety) Regulations. The certificate is available in the Downloads section.
What W7 means for your bolts
Bolts and nuts to W7 are made from materials with a material data sheet, for example 21CrMoV5-7, 40CrMoV4-6, 42CrMo4 or X22CrMoV12-1, and each lot undergoes a tensile test and is tested for hardness and impact energy; for service above 300 °C, the elevated-temperature yield strength is added. Inspection and the 3.1 or 3.2 certificate are governed by the Merkblatt and by the requirements of the pressure equipment manufacturer. RS Randack keeps raw material from approved mills in stock, tests in its own materials laboratory and carries out witnessed inspections with the inspection bodies on site.
What you should specify
The code that applies to the pressure equipment (AD 2000, Pressure Equipment Directive or both), design temperature and pressure, material and material data sheet, certificate type and inspection body. The test sequence is then already defined with the quotation.
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