Children's tricycles need to comply with a series of safety standards when undergoing EU EN71 testing to ensure that the toy vehicles will not cause harm to children during use. The following are the main steps of the detection process:

1. Choose a certification agency: First, choose an authoritative and professional certification agency to apply. This agency will test and evaluate the product to ensure that it meets the EN71 standard.

2. Submit application and samples: Submit an application to the selected certification body, including filling in relevant forms, providing product samples and necessary technical documents. Ensure that all information submitted is true, accurate and complete.

3. Product testing: The certification agency will test the submitted children's tricycle samples. The testing content may include testing of physical and mechanical properties, flammability, chemical substance content, etc.

4. Evaluation and review: Conduct evaluation and review based on test results and submitted technical documents. If the product meets the EN71 standard, the certification body will issue the corresponding certification certificate.

5. Issuing a certificate: After the children's tricycle sample passes all tests and evaluations, the certification agency will issue an EN71 certification, allowing the product to be sold in the EU market.

6. Continuous supervision: After obtaining EN71 certification, manufacturers need to accept continuous supervision by the certification body to ensure the continued compliance of the product, including regular product sampling and factory inspections.

The testing process covers from physical performance testing of samples to chemical performance testing, and final certification and supervision. Manufacturers should ensure that every aspect of product design, production and testing meets EU safety standards to protect children's health and safety.