EN ISO 3834-2 is the comprehensive part of the standard for quality requirements in fusion welding. It does not grade a single weld or a finished product. It checks whether a fabricator manages the whole welding process in a controlled and documented way. For a buyer of structural steel, an EN ISO 3834-2 certificate is evidence that welding is planned, supervised and recorded, not left to chance.
What EN ISO 3834-2 covers
The standard sets requirements for the organization around the weld, not only for the welder. It applies to fusion welding, where the parent metal is melted to form the joint, which covers the arc processes used for structural steel. In practice an auditor looks at areas such as:
- The review of the contract and the technical requirements before work starts
- Welding personnel, welding coordination and inspection personnel
- Equipment, its maintenance and the planning of production
- Welding procedures and their qualification
- Storage and handling of welding consumables and parent material
- Inspection and testing before, during and after welding
- Non-conformance, corrective action and calibration of equipment
- Identification, traceability and quality records
These are the same topics a project team raises when a joint fails inspection. A certified system gives them a defined place in the fabricator's routine. Our guide to steel factory quality control shows how the same topics appear in daily shop work.
What it does not cover
The certificate is easy to over-read, so keep its limits in mind.
- It is not a product certificate. A certified fabricator can still deliver a defective weld, and your inspection plan still applies.
- It is not a welder qualification. Welder and procedure qualifications follow other standards and are checked separately.
- It is not ISO 9001. ISO 9001 is a general quality management system. EN ISO 3834-2 is specific to welding.
- It is limited to the scope on the certificate. The processes, the parent materials and the site named in the annex define what is covered.
Part 2, Part 3 and Part 4
The standard comes in levels. Part 2 is comprehensive, Part 3 is standard and Part 4 is elementary. A project specification may state which level it requires, and some execution standards, such as EN 1090-2, link the required level to the execution class of the structure. Check what your specification says before you compare bidders.
Truong Thinh's certificate
Truong Thinh Construction Investment and Trading Joint Stock Company holds EN ISO 3834-2:2021, certificate INY-CER/26/1220 Rev.00, issued by Bureau Veritas Vietnam. The initial certification date is 17 September 2026 and the certificate was issued on 28 September 2026. It is valid until 16 September 2029, subject to annual re-evaluation by Bureau Veritas auditors.
The scope is the manufacture and installation of structural steel components and accessories for civil, industrial and infrastructure works, at the operative site in Quarter 4, Vinh Tan Ward, Ho Chi Minh City. The annex lists parent material groups 1.1 and 1.2 under ISO/TR 15608 and welding processes 136 and 121 under ISO 4063. You can see the full document on our page about certified quality, and the welding scope is repeated in the technical specifications.
What it means for your project
Use the annex to test the certificate against your own job:
- Steel grade. Parent material groups 1.1 and 1.2 cover steels up to a minimum yield strength of 360 MPa. Confirm that your grade falls inside those groups.
- Welding process. Processes 121 and 136 are submerged arc and gas-shielded flux-cored welding. If the design depends on a different process, ask how it is controlled.
- Site. The certificate names the operative site where the work is done. Check that your members are made there.
- Dates. Check the expiry date and ask when the next annual review is due.
When you compare a structural steel fabricator, put these four questions to each bidder, and also read our advice on how to choose a steel structure manufacturer and on bolted and welded connections. Our company facts page keeps the certificate details current.
If your specification calls for a certified welding quality system, send the drawings, the steel grades and the delivery window, and request a fabrication quotation from our engineering team.
Frequently Asked Questions
Is EN ISO 3834-2 the same as ISO 9001?
No. ISO 9001 certifies a general quality management system. EN ISO 3834-2 certifies the quality management of welding specifically, and it names the processes and materials covered.
Does the certificate qualify individual welders?
No. Welders and welding procedures are qualified under separate standards. The certificate shows that the fabricator controls those qualifications as part of its welding system.
How long is the certificate valid?
Truong Thinh’s certificate is valid until 16 September 2029, subject to annual re-evaluation. Always read the expiry date on the document you are given.
How can a buyer verify a certificate?
Contact the issuing body. The certificate states that its validity can be checked with Bureau Veritas Vietnam on +84 28 38 122 196.
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