Carbon-steel self-tapping threaded inserts with blue-white zinc plating are popular in Europe for the following reasons:
1. **Environmental compliance**
The trivalent-chromate blue-white finish is free of hexavalent chromium, so it satisfies REACH, RoHS and WEEE. Import and end-user approval risks are minimal.
2. **High salt-spray performance**
The coating normally passes 240 h white-rust and 500 h red-rust in neutral salt-spray tests, meeting the service-life corrosion requirements of European construction, appliance and automotive sectors.
3. **Cost-performance balance**
10B21/1022 carbon steel is cheap; after carburising it gives a good hardness gradient. Blue-white plating costs only one-third to one-half of stainless steel, yet delivers comparable or better indoor/semi-outdoor corrosion resistance, giving distributors a healthy margin.
4. **Fast assembly and reparability**
The insert cuts its own thread in aluminium, magnesium or engineering plastics in a single operation, cutting labour time. It can be unscrewed and replaced, matching Europe's "easy-maintenance" design philosophy.
5. **Standards compatibility**
Common sizes (M2.5-M12, 1D-3D length) match ISO, DIN and EN threads, so they drop straight into existing designs without drawing changes.
6. **Mature supply chain**
China, Turkey and others export hundreds of thousands of tonnes annually; prices are transparent and lead times short. Major European hardware and automotive chains (e.g. Würth, Bauhaus) list them as standard SKUs, giving strong channel push.
Taken together-regulatory compliance, performance-to-price ratio, installation advantages and ready availability-carbon-steel blue-white zinc self-tapping inserts have become the "compliant, high-value" default in Europe, creating a self-reinforcing demand loop.