CERTIFICATION OF COMPANIES IN WELDED FABRICATION, TODAY AND IN THE FUTURE

Transcription

1 Article CERTIFICATION OF COMPANIES IN WELDED FABRICATION, TODAY AND IN THE FUTURE Özlem KARAMAN GSI SLV-TR Özgür AKÇAM** GSI SLV-TR ABSTRACT Welding is a process which has a big part in our daily lives. Welding plays an important role in the bridges we cross over; railways; automobiles we drive; buses; factory buildings; industrial facilities and in the construction of the buildings where we live our lives. Being placed so tight in our daily lives, welding requires considerable care in planning, application and control to minimize risks of failures and their effects on our lives. That is why there are some international certification systems to assure quality in welded design and construction. Turkish companies that design and fabricate/construct welded structures need to prove their competence in international market. The way to achieve this is to create healthy quality systems and have these systems certified through internationally accredited and respected bodies. Keywords: Welding, quality assurance, international certification ** Contact writer. *This article has been presented as a bulletin at the VII. National Congress and Exhibition of Welding Technology organized in Ankara by the Chamber of Mechanical Engineers on November 13-14, Volume: 50, Issue:

2 INTRODUCTION Welding is a process that needs to be accurately planned every phase due to several difficulties inherent in its application and control. Thus, there are certain aspects that need to be paid due care in every step and these are summarized below. At the Design Phase Both the production and the control phases have to be accurately planned. For this aim, the following should be considered: Selection of Materials: Weldability criterion in addition to strength and other design requirements, Determination of application standard(s): Identification of the standard(s) necessary and the preparation of specification(s) to ensure that the correct material is used by suitable personnel, with suitable instructions during application, Determination of control phases, methods and scope: Identification of the control methods to be applied before, during and after production / fabrication, At the Application (Production) Phase, The welded production should be performed under supervision at every phase and in the framework of the criteria defined at the design phase. Use of Correct Materials: Using the materials at suitable place without intermixing, Employing suitable personnel: The welders and other production personnel should bear the criteria identified during the design phase. At the Control Phase: The control of the welded joints on the finished or semifinished product is an issue that requires know how, technology and experience. Therefore, the persons working at the control of welded works need to possess the technical knowledge, equipment and experience. In this scope, training and certification standards are utilized in several control methods. The qualification of the persons for each application is again identified during the design phase. Here, an important issue that the control made after the welding process is over cannot provide a complete result regarding the robustness of the weld seam. Consequently, it will not be correct to complete the production by relying only on the controls to be made (undestructive tests) at the end of production. The correct action would be to employ continual control and supervision at every phase (before, during and after production). The quality systems designed for the certification of manufacturers of welded productions generally cover the above-mentioned topics. ISO 9001 system, being a general quality management system, can be applied to enterprises performing welded production. However, ISO 3834 is another quality management system that can be applied as integrated to ISO 9001 or by itself, and it has been specially designed for companies performing directly welded production. In addition, there are other quality systems that emerge as a legal obligation special fields. As an example, we can mention the certification of the manufacturer compliance in steel/aluminum structures (DIN DIN / EN 1090) and the certification system of the manufacturer compliance for the manufacture of the railway vehicles and their parts. QUALITY SYSTEMS AND CERTIFICATION DIN EN ISO : (replacing DIN EN : 1994) This is a quality assurance system prepared for enterprises (including subcontractors) performing welded production. The system s coverage starts from the design phase and includes all the production, control and after-sales phases. The standard is made up of five main parts: Part 1: Criteria for the selection of the proper step in terms of quality expectations Part 2: Comprehensive quality expectations Part 3: Standard quality expectations Part 4: Basic Quality expectations Part 5: The documents expected to be met in terms of requirements in order to be able to certify compliance to ISO , -3 and -4. Introductory guide to ISO/TR : ISO 3834 Use of DIN EN ISO 3834 standard series During contractual negotiations: Identification of the welding quality expectations For the manufacturer: Establishment of quality requirements for welding technique and compliance thereto during the production process Boards preparing specifications: Identification of the welding quality expectations Organizations auditing the quality implementations, such as; independent inspection centers, customers or manufacturer Selection of the proper step, part 2, 3, and 4 During the selection of the proper step in certification according to ISO 3834 standard, the following factors should be considered: Meaning and significance of critical products in terms of safety Versatility of production Field of usage for the product Applications where a possibility of the emergence of metallurgical problems exist The production nonconformities (such as radial run-out, tension or weld seam irregularities) being in the quality that can impact the end product Volume: 50, Issue:

3 Quality expectation elements according to DIN EN ISO :2005 (Appendix A) Requirement ISO ISO ISO Review of the requirements Review is necessary Records necessary Records might be necessary Records not necessary Technical review Review is necessary Records necessary Records might be necessary Records not necessary The subcontractors are evaluated in the same manner as the manufacturer for the product, Subcontractors service and/or activities to be manufactured, the final responsibility for quality belongs to the manufacturer. Welders and welding operators Qualification is Welding coordination personnel Inspection and test personnel Qualification is Production and test equipment They should be kept together with safety equipment and protective clothing where for preparation, fabrication, tests, transport and lifting Equipment maintenance Maintenance plans and Record keeping is records are requested recommended Equipment identification Listing is Required Documented plans and Production planning Plans and records are record keeping is recommended Welding procedure specifications (WPS) Welding Procedure Approvals Consumable tests If requested Storage and use of welding consumables Storage of materials Heat treatment A procedure prepared according to the manufacturer recommendations is necessary Should be protected from environmental impacts. Marking should be preserved during storage Confirmation that the product standard or specification requirements have been met Procedure, records and Procedures and records are record traceability is According to the manufacturer recommendations Checks made before, during and after welding If requested Nonconformities and corrective actions Control criteria should be applied Repair and/or corrective action procedures are Control criteria should be applied Calibration or verification / validation of measurement, If requested inspection and test equipment Marking during production If requested Traceability If requested Quality records If requested Volume: 50, Issue:

4 Welders and Operators The welders and welding operators working at welded production in ISO 3834 certification need to be tested and certified according to the related standards (EN 287-1, ISO 9606, EN 1418). Welding Inspection Personnel The enterprise should employ sufficient quality and quantity of welding inspection personnel according to the welded production. The duties and responsibilities of welding inspection personnel have been described at DIN EN ISO Examples for Areas controlled under Legal Regulations Steel and aluminum constructions covered under structure inspection field (DIN , DIN V ) Pressurized containers manufactured as per the regulations (DGRL) 97/23/EG (AD2000-HP0, DIN EN ) Steel pipelines used in gas and water transmission (DVGW Arbeitsblatt GW 350) Quality requirements for production and maintenance enterprises working in the military technology field (DIN 2303) Welding of railway vehicles and vehicle parts (dın en ) The most significant examples to these systems are DIN and EN certification systems. DIN Steel Structures Assessment of manufacturer compliance This is the certification of manufacturer compliance. This is certification performed at five classes from A to E. These classes define the production capacity of the companies and the adequacy of its infrastructure of various applications. Class E certificate is the most comprehensive one and it certifies that the certificate owner company is able to manufacture both static and dynamic structures (steel construction, bridges, cranes). DIN Section / Certificate of Compliance is obligatory in Germany for all companies. The classes have been defined according to the infrastructure and personnel status of the manufacturer (A, B, C, D, E). The classes also define the limitations of the companies as well: The types of steel they can use Material thicknesses Steel construction column distances etc. However, EN 1090 series, which is a European standard prepared based on DIN , shall replace DIN starting from the middle of EN 1090 Standard Series In relation to the Europe-wide certification of companies working in the field of construction, this is a series of standards prepared for steel and aluminum structures. The standard was published in 2008 and it is expected to enter into force as of the middle of Before the effective date of the standard, the certificates of the companies that were certified according to standards DIN and DIN shall be deemed as equivalent during the validity period of these certificates. The future equivalent of DIN and DIN V V standards: EN 1090:2008 Implementation of Carrier Steel Structures and Aluminum Structures Part 1: Determination of Compliance for Carrier Structural Components Volume: 50, Issue:

5 Part 2: Part 3: Technical Requirements Expected from Carrier Steel Structures Technical Requirements Expected from Carrier Aluminum Structures Part 1: Determination of Compliance for Carrier Structural Components 1. Field of application 2. Requirements of the standard 3. Concepts 4. Expectations 5. Assessment Activity 6. Assessment of Compliance 7. Classification and Identification 8. Marking, Labeling and Packaging Appendices and Literature Performance Criteria (pren excerpt from Table ZA.1) Permitted measurement and figure deviations Conformity to welding Fracture toughness, notch test strength Bearing ability (loadability) Fatigue strength Resistance against burning Combustion behavior Lacking cadmium and its compounds Not radiating radioactivity Continuity in performance criteria Manufacturer Approved Institution European System for Conformity Assessment Activity Fundamentals of assessment of compliance First control of the product Control of the samples received from production according to the predefined test plan Production control performed by the manufacturer First control of the product Testing of samples obtained from production, open market or worksite (audit-testing) Control of the samples received from production according to the predefined test plan Continuing surveillance. Assessment and ratification of the production Systems according to BPR Appendix III 2(i) 2(ii)-1 2(ii) Certification Declaration of manufacturer Expectations Related to Application Class (pren Excerpt from Tab. A.3) Part EXC 1 EXC 2 EXC 3 EXC EN EN EN EN General Ratification of Welding Procedure Welders and Welding Operators Welding Inspection 7.6 Acceptance Criteria No No Assessment group D See Table 12 and Table 13 Technical information according to Table 14 and Table 15 Assessment group C (in general) See Table 12 and Table 13 Technical information according to Table 14 and Table 15 Assessment group See Table 12 and Table 13 Technical information according to Table 14 and Table 15 Assessment B+ Volume: 50, Issue:

6 Foreseen Publication and Effective Dates of EN 1090 Series of Standards Related part of Publication Effective date the standard date PrEN Start of (estimated) DIN EN December (estimated) DIN EN September (estimated) EN 15085: Railway Applications Production, Revision and Maintenance of Railway Vehicles and Parts DIN EN series of standards has replaced DIN 6700 series of standards. The standard is comprised of 5 parts. The quality expectations are addressed in Part 2. Part 1: General Part 2: Certification of companies conducted welded production / Quality expectations Part 3: Construction requirements Part 4: Production requirements Part 5: Test and documentation The companies are certified under 4 classes. Depending on the classes, the production capacities and related quality levels are determined. CL1 CL2 CL3 CL4 Railway vehicle / vehicle parts containing high quality weld seams. The production of the whole vehicle is covered. All the steps from CL2 to CL4 are also covered. One less class of quality level has been defined for the production of boarding doors, roof hardware, etc. other than for the main components. Production, revision and maintenance of simple equipment parts of railway vehicles. This class is for the companies that do not conducted welded production but designs, purchases and installs or purchases and operate railway vehicles and vehicle parts. Quality classes and control criteria have been identified according to each class. CONCLUSION Welding process is an application that can contain faults. It is a very low possibility to find out the faults made at welded joints with non-destructive material tests. Therefore: Welding process has to be implemented by trained and certified personnel, The welding process has to be implemented under strict audit / inspection, For this aim, certain systems have been defined. The basic purpose of these systems is to assure quality. ISO 9001 is a general quality management system. EN ISO 3834 is a standard prepared specific for Quality Management System for Companies Conducting Welded Production. Other than the standards mentioned above, there are standards for welding technique applications in certain technical fields. These standards are legal obligations that define the quality requirements expected from enterprises conducting welded production in specific fields and the basics for the certification of the compliance of these enterprises to these requirements. REFERENCES 1. ISO 3834: Quality Requirements for the Fusion Welding of Metallic Materials 2. EN : Welding of Railway Vehicles and Components Certification of the Compliance of the Companies 3. EN 1090: Compliance Requirements for Steel and Aluminum Structures 4. DIN : Compliance Requirements for Steel Structures Volume: 50, Issue: