Welding Quality
Industrial Welding
Welding Compliance
29 Oct 2026
How to Control Subcontracted Welding Work: Quality Responsibilities, Inspection Records and Certification Readiness
By Editorial Team
Table Of Contents
- Introduction
- Why you need to control your welding work
- What is being subcontracted?
- Evaluate & approve your welding subcontractor
- Control welding processes & welder qualifications
- Control material marking & traceability
- Define inspection requirements
- Control non-conformances
- Keep records of your subcontracting
- Common mistakes manufacturers make
- Frequently Asked Question
- Conclusion
Related Blogs
OCT
05
OCT
01
SEP
30
Introduction
Manufacturing companies often subcontract elements of their product including welding, machining and surface preparation. This can help control production capacity and utilise specialist knowledge to deliver projects on time. However, you will still want to control your welding.
Whenever you are outsourcing welding of components to an external workshop, you will need to know how they will control the welding based on your requirements. If the responsibilities aren’t clear you could end up with incorrect material, welding processes, incomplete inspection records and issues when customers or certifying bodies come to inspect. Controlling your welding when working with structural steel & rail components & industrial equipment is an important element of ensuring consistency of your product.
There are many standards that can be relevant depending on the product. EN ISO 3834 will give you the requirements for quality of fusion welding of metallic materials. EN 1090 and EN 15085 can be relevant to your structural steel/aluminium components & rail vehicles/components respectively. It will depend on what product you are manufacturing, what contract you have, what standard you are working to and what certification you are working to.
This article will explain how you can implement a practical method to control your welding work & keep records of your work.
Why you need to control your welding work
There will be extra interfaces whenever you are subcontracting welding.
If these are not clearly defined you could encounter issues such as:
- Unapproved or incorrect welding process being used
- Incorrect welder qualifications
- No marking on material after cutting
- No inspection reports or incomplete production records
- Unapproved repairs
- Component doesn’t match approved drawing
- Customer delays due to lack of supporting documentation
- You should implement controls before starting any subcontracting.
To ensure the work is being done to your requirements & there is enough evidence to prove how, who & what was done.
What is being subcontracted?
First thing to know is what work you are going to be subcontracting.
This could include:
- Preparation of welded components.
- Subassembly welding.
- Fabrication of structural steel/aluminium components.
- Rail components.
- NDT.
- Heat treatment or other post weld treatments.
- Surface preparation & coating.
Each element should be considered to know what technical requirement, inspection & records are needed.
For example if you are subcontracting structural steel beam welding then you would want to control:
Approved drawings
- Correct grade of material
- Welding processes
- Qualified welders
- Inspection requirements
- Component marking.
If you are subcontracting rail component welding then you may have additional controls to consider due to the EN 15085 requirements.
Practical tip – Create a subcontracting register to show what supplier you are using, what work is being done, what technical requirements apply, if it is approved, what inspections are required & who is responsible.
Evaluate & approve your welding subcontractor
Before ordering any work from a subcontractor you should know that they can consistently deliver to your requirements. The evaluation should be proportionate to the risk and complexity of the work.
Some important things to consider when evaluating your welding subcontractor are:
Technical capability
Do they have the correct welding equipment, qualified welders, correct production facilities & experience of the materials & components?
Welding quality
How do they control their welding processes, production instructions, consumables, equipment & non-conformance?
If applicable, check that they have the correct welding quality documentation & qualifications in place.
Welder qualifications
Are the welders assigned to the work qualified for the process, material, product & within the qualification range?
Inspection capability
Can they carry out the required visual, dimensional & NDT? With competent personnel & equipment?
Performance
Are they reliable with deliveries? Do they have a history of defects? Are they good at implementing corrective actions?
Make sure you have approval & where applicable regularly review. Just because they have been approved previously doesn’t mean they will deliver every job correctly.
Control welding processes & welder qualifications
Ensure the subcontractor has clear & controlled technical instructions.
- Approved drawings.
- Applicable standards.
- Welding procedure specifications (WPS).
- Inspection requirements.
Welding Procedure Specification
This provides instructions on how to weld within the parameters & within the qualification range. You should know what approved WPS applies to your work & how you will verify that it is being used.
Welding Procedure Qualification Record
If you require procedure qualification then you will need the supporting WPQR to provide evidence of the testing & what variable range they have been qualified for. You should verify that they have the correct procedure qualified for your production work.
Welder qualifications
Ensure they have the correct qualifications for the work. Where applicable verify they have valid/continuity requirements for the correct process, material, product & qualification range.
Revision control
Ensure they are not using outdated drawings, WPS & production instructions. Define how you will communicate the changes & ensure they are removing the old documents.
EN ISO 3834 can provide a relevant framework for your welding quality systems. The exact requirements will depend on what quality level you are working to & what product standard/contract you are working to.
Control material marking & traceability
It is very important to control material traceability if you are sending steel plates, pipes, sections, aluminium & partially fabricated components to a subcontractor.
Define what controls you have in place to ensure the material can be identified.
Depending on your contract & requirements you may need to have records of:
- Material grade & product.
- Supplier documentation & inspection certificates.
- Heat numbers/batch.
- Incoming inspection.
- Material issue.
- Marking transferred after cutting.
- Component/assembly identification.
- Linking materials to products.
For example, if you are supplying a steel plate with a heat number you need to know if this needs to be transferred & how. If marking is lost during subcontracting you may struggle to prove that the component was manufactured using the correct material. The level of traceability required will depend on your product requirements, customer requirements & risk assessment. Not all projects will require the same level of traceability.
Define inspection requirements
Ensure you have defined who will be carrying out the inspections. Define what inspections will be carried out by the subcontractor, what will be carried out by you & what will need customer/independent inspection.
A practical inspection plan may include:
Pre-weld
Material marking, component preparation, drawing revision, joint preparation & welding documentation.
During welding
Checking they are following the correct welding process, using the correct consumables & welding within the correct parameters. Any required inspection/monitoring.
Post-weld
Carrying out the required visual, dimensional & NDT. Checking any required repair documentation has been carried out & confirming they met the acceptance criteria.
Pre-delivery
Component identification, required inspections have been carried out, any outstanding non-conformances & required documentation has been completed.
The inspection methods & acceptance criteria should be chosen based on the applicable standard, design, contract & product requirements. There isn’t a generic checklist to follow.
Control non-conformances
You should have a process in place for dealing with defects found during subcontracting.
This could be weld indications that are not acceptable, incorrect dimensions, incorrect material, incomplete documentation & not following approved technical instructions.
This should include:
- How the non-conformance is identified & recorded.
- Who can assess & approve the disposition.
- Whether the component needs to be isolated.
- What repair instructions can be used.
- What inspections need to be carried out after repair.
- How corrective actions are recorded & verified.
Unless the subcontractor has approval to deviate from your requirements they shouldn’t accept any deviation. If repairs are being carried out that will effect the welding process requirements then you should review the instructions & basis of qualification. Any recurring defects should be analysed to find root cause. This may include improving work instructions, providing extra training to the supplier, changing inspection points or changing the approval process.
Keep records of your subcontracting
Having records is vital to prove that your work has been controlled. Define what records should be provided by your subcontractor, who will be reviewing them & where they will be stored.
Depending on your requirements you may require:
Purchase orders & technical requirements.
- Approved drawings & revision.
- Evaluation & approval of subcontractor.
- WPS & WPQR.
- Welder & welding operator qualifications.
- Material certificates & traceability.
- Inspection & NDT reports.
- Equipment calibration/verification if required.
- Non-conformance & repair records.
- Final inspection & release.
The records should be identifiable & able to be traced back to the correct order/component/batch. Having a document register can help you identify any missing records before delivery. This is much better than trying to get all your documents after the product has been completed. Define how long you will need to keep records based on the applicable standard, legal requirements, certification scheme & customer contract.
Common mistakes manufacturers make
- Assuming that because it is in your contract you don’t need to define who is responsible for proving conformance & your requirements.
- Approving a supplier without considering what they are doing. They may have the right experience for one type of welding process/product but not another.
- Sending outdated documents. Uncontrolled drawings & WPS can cause issues during production. Ensure you have a process in place for issuing documents & confirming revisions.
- Only inspecting the final component. This may not prove all the required controls have been followed during production. You may need to have some controls in place during production & records.
- Accepting incomplete documentation. Even though the component is acceptable the documentation may not be complete. Ensure you check the required documentation has been completed.
- Not reviewing the performance of your supplier. If they are having recurring defects, late deliveries or missing documentation then you should have a documented process to review their performance & approval.
Frequently Asked Questions
Does subcontracting affect my EN ISO 3834 compliance?
It can. You should have controls in place for your welding work to ensure you are following your welding quality requirements & any product/customer requirements. The exact requirements will depend on what quality level, scope & requirements you are working to.
Can I subcontract my welding?
It may be possible depending on what standard, certification scheme, contract & scope you are working to. You should have controls in place & check if there are any approval/notification requirements.
Do I need a WPS for every welding task?
It depends. The applicable welding processes, materials & requirements will determine what qualified & approved WPS you have. Ensure you are using a suitable procedure.
What documentation should I get from my welding subcontractor?
Depending on your project you may need welding procedure documentation, welder qualifications, material traceability, inspection & NDT reports, repair & final conformance. Define what is required before production.
How can I use my subcontracting records to help with my certifying body?
Having organised records will help you to prove you have control over your supplier, they have implemented the production requirements, inspection has been carried out & traceability where required. The auditor will look at the evidence to see if they meet the requirements.
Conclusion
Subcontracting welding can help you increase your production capacity & utilise specialist knowledge. To successfully subcontract your work you will need clear technical instructions, competent suppliers, controlled welding processes & inspections & complete records.
By defining who is responsible & ensuring you have the right evidence you can minimise any unnecessary quality issues & will be prepared for any customer inspections & certification.
If you are working within the EN 1090, EN 15085 or EN ISO 3834 scopes then you should ensure your subcontracting controls are in line with the standard, certification & contract.
Do you need help understanding your certification requirements?
First Welding Certification Pvt Ltd (PRVÁ ZVÁRAČSKÁ, a.s.) works in conformity assessment and certification. Get guidance on welding quality requirements, subcontractor control, inspection documentation and material traceability relevant to your manufacturing activities.
Visit our EN ISO 3834 Certification page to explore welding quality requirements, or contact our team to discuss your certification needs.