Knowledge Article
Wrong welding can be expensive: here are the basic requirements you need to know
Incorrect welding can be costly - both in money and safety. Welding stainless steel and other metal structures is a precision job that requires skills, the right equipment and proper documentation. Despite this, we see the market increasingly challenged by operators who ignore or lack knowledge of current regulations - leading to incorrect solutions, lower prices and, in the worst case, serious safety risks.
But what does ”correct” welding actually mean? And what do you risk as a customer if you do not set requirements for your supplier?
When the weld must hold: The risk of incorrect welding
Many of our customers are involved in processes where quality and safety are crucial - such as in pharmaceutical production, the food industry and other advanced manufacturing. In these environments, it's not enough for a weld to just look good or hold together mechanically. It also has to be:
- Correctly executed according to standards (e.g. SS-EN ISO 3834)
- Traceable through documentation
- Controlled via testing and inspection
- Performed by certified personnel
Example: Pressure equipment - the law requires documentation
If you buy or order a component that is classified as a pressure equipment (AFS 2016:1 or AFS 2023:5), it is covered by the PED - Pressure Equipment Directive (2014/68/EU). This means, among other things, that:
- Welding must be carried out by qualified personnel
- Manufacturing must follow an approved procedure (WPS/WPQR)
- There should be material certificates, welding documentation and inspection certificates
- A third-party inspection body may need to be involved
In practice, without this documentation, the product cannot be sold or put into service, but many people are not aware of this. Many customers rely on the supplier being in control, without knowing what to ask for.
Cheaper - but wrong: what you risk with incorrect welding
Choosing the cheapest solution can be costly in the long run. The consequences of undocumented or incorrect welding can be:
- Leakage or breakdown - resulting in downtime and costs.
- Poor hygiene or contamination - particularly critical in biotechnology and food.
- Serious safety hazards - which in the worst case can cause personal injury.
- Rejections in audits and controls - especially if you work according to GMP or other quality requirements.
- Illegal sale - you risk using or selling equipment that does not comply with the law.
What you should require from your supplier
To ensure you get a safe and properly executed solution, you should always ask for it:
- WPS (Welding Procedure Specification)
- WPQR (Welding Procedure Qualification Record)
- Welder's certificate according to SS-EN ISO 9606-1 to -5 or SS-EN ISO 14732
- Material certificate (EN 10204 3.1)
- Documentation for CE marking for pressure equipment
A serious supplier can, and should, demonstrate this.
Do you need help setting the right requirements for welding?
At Colly Flowtech we work exclusively with certified methods and welders. Our manufacturing meets the requirements of EN ISO 3834-2 and we are used to delivering documented solutions for demanding industries. This gives you peace of mind - both for inspections and in your daily operations.
Do you want to know more about how we work with quality assurance in welding? Or do you need support in setting the right requirements as a customer? Contact us - we'll help you get it right from the start.
Contact us for adviceFrequently asked questions about welding
What are the consequences of incorrect welding?
Improper welding can cause leaks, hygiene problems, production stoppages or, in the worst case, personal injury. In addition, you risk using equipment that does not meet legal requirements, which can lead to legal consequences.
What is required for a weld to comply with the PED Directive?
The PED (Pressure Equipment Directive) requires, among other things, that welding is carried out by certified personnel, that the procedure is qualified (WPS/WPQR), and that documentation and third-party controls are in place.
What is WPS and why is it important in welding?
WPS stands for Welding Procedure Specification and describes exactly how the weld should be performed. It is a requirement for certified welding and ensures that the weld meets quality and safety requirements.
How do I know if a welded component is correctly documented?
Proper documentation includes welder's certificate, WPS, WPQR, material certificate (EN 10204 3.1) and any CE markings. Always ask the supplier for these before ordering.
Why should I choose a certified supplier for welded products?
A certified supplier, working to EN ISO 3834, guarantees traceability, quality and safety - minimizing the risks of errors, downtime and legal problems.
Do you have any questions?
Jesper Ohlsson
Business Area Manager Stainless Steel
Phone:
+46 72 229 44 49
Email:
jesper.ohlsson@colly.se
