The range of qualification for types of welded joints shall only be the same used in the welding procedure tests. A welding procedure test shall cover only that material combination of the composite tube it represents.
A.2.2.2 Additional tests required
A.2.2.2.1 Depth of penetration of clad weld
In a macroscopic examination, the depth of penetration of the clad weld to the ferritic pressure retaining inner core material or weld shall be defined. The penetration shall not penetrate essentially below the surface of the ferritic pressure retaining inner core material Unpenetrated minimum thickness shall always be maintained.
The clad welding may penetrate to the calculated minimum wall thickness of the ferritic pressure retaining core material with the following conditions:
filler and weld metal strength and toughness properties are fulfilling the ferritic pressure retaining inner core material properties;
qualification of welding procedures shall correspond completely the requirements of EN ISO 15614-1 and EN 12952 special requirements;
maximum cladding weld penetration to the calculated minimum thickness area of the ferritic inner core material is 1,5 mm;
in prior to production a production test shall be carried out. In manual welding the test shall be done by every welder. In mechanical welding the test shall be done per each welding procedure;
non-destructive testing shall be carried out after cladding welding with the extent of standard EN 12952 requirements.
A.2.2.2.2 Hardness test
Hardness tests shall be done from the outer surface of ferritic pressure retaining inner core material and from the surface of cladding. The requirements of 6.2.2.5 shall be met. The hardness values of the clad weld shall correspond to those given by the manufacturer of filler materials.
A.2.2.2.3 Bend test
Bend tests shall be carried out on clad tubes.
A.2.2.2.4 Transverse tensile test
Transverse tensile tests shall be carried out when the cladding is peeled off.
A.2.2.2.5 Microscopic examination
The test specimen shall be prepared and etched in accordance with EN 1321 on one side to clearly reveal the fusion line, the HAZ and the build up of layers.
A photograph of the parent material, transition to the parent material and the cladding shall be taken. Generally, micro-cracks in the heat affected zone (HAZ) and in the weld metal shall not be permitted
A.3 Special requirements for welder’s qualification for fusion welding of composite tubes
A.3.1 General
The general requirements of this European Standard, mainly Clause 7, shall be supplemented by the application of the specific requirements in A.3.2.
A.3.2 Application of EN 287-1 to composite tubes
A.3.2.1 Range of qualification
Only a welder’s qualification obtained with composite tubes shall be applied for welding of composite tubes. Test specimen thickness / is the total nominal thickness of the composite tube. Diameter D is the nominal diameter of the composite tube. A welder qualification shall cover only that material combination of the composite tube it represents.
A.3.2.2 Additional tests required
A.3.2.2.1 Macroscopic examination
Macroscopic examination shall be carried out when the cladding is made by TIG-welding. The depth of penetration of a clad weld in the ferritic pressure retaining inner core material or weld shall be defined. The penetration shall not be below the outer surface of the ferritic pressure retaining inner core material.
A.4 Special requirements for non-destructive testing (NDT) of welds
A.4.1 General
The general requirements of this European Standard, mainly Clause 9, shall be supplemented by the application of the specific requirements in A.4.2.
A.4.2 Special requirements for NDT of welds in a chemical recovery boiler
A.4.2.1 Volumetric testing
All the welds that are in a position in which a leak could result in a water/smelt explosion shall be subjected to 100 % volumetric testing.
A.4.2.2 Methods of testing
If it is possible, the volumetric testing shall be carried out by radiographic testing in accordance with EN 1435, class B. When choosing the radiographic technique for the tube panels, it shall be ensured that the area located next to the fins on the inside of the chemical recovery boiler furnace will be reliably inspected. If only one X-ray exposure per weld has been carried out, then a possible complementary test method and technique shall be used, in accordance with written procedures and by agreement as part of the design qualification process. A volumetric testing shall be performed on finished welds. An exception is composite tubes, where the testing can be carried out after the pressure bearing weld of parent material is ready before welding the cladding.
In addition, all composite tube welds in the position where a leak can result in a water/smelt explosion shall be examined 10 % by a penetrant test method. Inspection shall be carried out inside the furnace on finished welds. This addition is not necessary if radiography has been carried out with the cladding included.
Annex В
(informative)
Significant technical changes between this European Standard and the
previous edition
|
Clause/Paragraph/Table/Figure |
Change |
|
General |
Numbering system of tables and drawings has changed. |
|
2 / Normative references |
References updated. |
|
Table 9.1.1 / NDT of drum welds |
Footnotes corrected. |
|
Table 9.1.2 / NDT of header welds |
Footnotes corrected. |
|
9.1.4 / NDT of welds - Tubes |
Requirements modified. |
|
Table 9.1-3 / NDT of tube welds |
■— Dissimilar welds between austenitic and martensitic steels with d0< 76,1 mm added as a new type of welds. — Footnotes added. |
|
9.2 / Qualification of nondestructive testing (NDT) personnel |
Requirements modified. |
|
9.3.3 / Penetrant testing |
Requirements modified. |
|
9.3.4 / Magnetic particle testing |
Requirements modified. |
|
Table 9.3.1 / Acceptance criteria for weld surface imperfections |
Limits of imperfection revised on basis of EN ISO 5817 instead of EN 25817. |
|
Table 9.4.1 / Acceptance criteria for weld internal imperfections detected by radiography |
Limits of imperfection revised on basis of EN ISO 5817 instead of EN 25817. |
|
9.4.2.2 / UT - Acceptance criteria |
Requirements modified. |
|
Annex A / Special requirements for composite tubes |
Title changed from “Chemical recovery boiler". |
|
A.2.2.2.1 / Depth of penetration of clad weld |
Requirements specified. |
|
NOTE The technical changes referred include the significant technical changes from the EN revised but is not an exhaustive list of all modifications from the previous version. |
|
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 97/23/EC
This European Standard has been prepared under a mandate given to CEN by the European Commission to provide a means of conforming to Essential Requirements of the New Approach Directive 97/23/EC.
Once this standard is cited in the Official Journal of the European Union under that Directive and has been implemented as a national standard in at least one Member State, compliance with the clauses of this standard given in table ZA.1 confers, within the limits of the scope of this standard, a presumption of conformity with the corresponding Essential Requirements of that Directive and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and Directive 97/23/EC
|
Clauses of this European Standard |
Content |
Essential Safety Requirements (ESRs) of Directive 97/23/EC, Annex I |
|
4.5 |
Inspection |
3.2.1 |
|
6 |
Qualification of weld procedures |
3.1.2 |
|
7 to 8.2 |
Qualification of welding personnel |
3.1.2 |
|
9.2 |
Non-destructive tests |
3.1.3 |
|
10.1 |
Final inspection |
3.2.1 |
|
10.2 |
Proof test |
3.2.2 |
|
12 |
Marking and labelling |
3.3 a) |
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within the scope of this standard.Bibliography
EN 10204, Metallic products— Types of inspection documents
EN ISO 9000:2005, Quality management systems — Fundamentals and vocabulary (ISO 9000:2005)
EN ISO 9001, Quality management systems — Requirements (ISO 9001:2008)
EN ISO 15614-13, Specification and qualification of welding procedures for metallic materials — Welding procedure test— Part 13: Resistance butt and flash welding (ISO 15614-13:2005)
EN ISO 23279, Non-destructive examination of welds — Ultrasonic testing — Characterization of indications in welds (ISO 23279:2010)
CEN/CR 12952-17, Water boilers and auxiliary installations— Part 17: Guideline for the involvement of an inspection body independent of the manufacturer
