“Do metal structural components need RoHS certification too?” The answer is yes: metal structural components used in electrical and electronic products exported to the EU, as well as components of electrical and electronic products regulated under China’s new RoHS standards, must comply with RoHS limits for hazardous substances. Many companies mistakenly believe that RoHS applies only to plastics and electronic components, only to face compliance issues regarding hexavalent chromium in plating layers or lead content in steel.
This article outlines the key RoHS requirements for metal structural components.
1.
What RoHS restricts: 10 substances and their limit values
The EU RoHS 2.0 Directive (2011/65/EU) restricts 10 hazardous substances. The maximum concentration limits, calculated based on homogeneous materials, are as follows: Lead, mercury, hexavalent chromium, polybrominated biphenyls (PBB), and polybrominated diphenyl ethers (PBDE) are all limited to 0.1% (1,000 ppm); cadmium is limited to 0.01% (100 ppm); and four types of phthalates (DEHP, BBP, DBP, DIBP) are each limited to 0.1%. China’s new mandatory RoHS standard also regulates these same 10 substances, with limit values aligned with those of the EU.
“Homogeneous material” refers to a material of uniform composition that cannot be mechanically separated;
plating layers and base materials are assessed separately rather than being calculated as a mixture of the entire component.
II. High-Risk Areas for Hardware Structural Components: Platings and Alloys
RoHS compliance risks for hardware components center on two areas: first, surface platings—hexavalent chromium in anti-corrosion coatings (such as zinc or chrome plating) is the most common substance to exceed limits; testing for hexavalent chromium, lead, mercury, and cadmium in metal platings and coatings must be conducted separately. Second, alloy materials—exemptions apply when lead is present as an alloying element in steel (limit of 0.35% for machining steel), hot-dip galvanized steel (0.2%), and copper alloys (up to 4%); however, the validity of these exemptions must be verified (some expire in 2027).
Stainless steel and aluminum components generally pose lower risks, but material certificates and composition traceability records must still be maintained.
III.
Testing and Determination: Ensuring Effectiveness
RoHS compliance is typically demonstrated through test reports from third-party laboratories: heavy metals like lead and cadmium are tested using ICP-OES or ICP-MS, while hexavalent chromium is tested via UV-Vis spectrophotometry (with a limit of 0.1 µg/cm² for metal anti-corrosion coatings). Laboratories must hold CNAS/CMA accreditation, and reports must specify the test methods, sample descriptions, and compliance results.
Enterprises exporting to the EU must also sign a Declaration of Conformity (DoC) and, as required, affix the appropriate mark to the product or provide a table detailing the content of hazardous substances.
Note: There is no such thing as a “single certificate valid globally” for RoHS; markets such as the EU, China, and the UK have their own distinct regulations, requiring compliance with each specific standard.
IV. Common Misconceptions and Pitfalls to Avoid
- Testing only the base material, not the coating: A compliant base material does not guarantee a compliant finished product. Surface treatment processes—such as electroplating, spraying, and anodizing—are high-risk stages for exceeding limits on substances like hexavalent chromium; testing must be conducted on a layer-by-layer basis for homogeneous materials.
- Treating exemptions as a “get-out-of-jail-free card”: Exemptions apply only to specific uses and concentration limits (e.g., lead content ≤0.35% in steel); they become invalid if limits are exceeded or usage conditions are not met. Furthermore, some exemptions have expiration dates, so it is crucial to stay updated on regulatory changes.
- Expired reports or unqualified testing bodies: Test reports must clearly state their validity period and scope of coverage. Ensure the testing body’s qualifications are verifiable via CNAS or CMA directories, and beware of low-cost “fake reports.”
V.
Trend: Continuous Expansion of Controlled Substance Lists
The EU is currently evaluating additional restricted substances, and China’s mandatory RoHS standard has been implemented; the scope of hazardous substance control is shifting from the original “6 substances” to “10 substances plus additional candidate substances.”
Industry experts recommend incorporating RoHS compliance into supplier quality agreements: require suppliers to provide composition certificates and coating test reports for every batch of material, and establish a two-tiered defense system combining “incoming material spot checks” with “periodic third-party testing.” RoHS compliance for hardware components is not merely about having a single report before shipment;
it requires a comprehensive control chain spanning everything from material procurement to surface treatment.
