GB/T 19920-2020 in English

Compared with the 2005 version of the standard, GB/T19920-2020 has made 17 technical revisions, and the main changes are concentrated in:

• Added two new structures, CT-32.5 compression support and FT-32.5 tension-compression support
• Introduced the ZI series long support seat to expand the applicable scenarios
• Deleted 6 old structural types such as AT/AM wood wedge type
• Strengthened surface treatment requirements, and the galvanized layer thickness was increased to ≥65μm

The standard systematically stipulates the material system:

• Main structure steel: GB/T712 marine steel (AH32/DH36) is preferred
• High-strength components: 42CrMo alloy steel (GB/T3077) is recommended
• Steel castings: Yield strength ≥270N/mm², elongation ≥11%

Typical case: In the 20000TEU container ship project, Jiangnan Shipyard Group adopted the GM-105 screw-adjustable intermediate tension and compression support. The material was DH36 ship plate and 42CrMo adjusting screw, which was verified by type test.

The standard establishes a three-level strength verification mechanism:

1. Preload: 10% SWL initial load
2. Verification load: 1.5 times SWL holding load for 5 minutes
3. Breaking test: 2.0-2.5 times SWL limit test

The test tooling must comply with the requirements of Appendix B of ISO17905:2015, especially the pressure test of compression support requires the use of special molds (see Figure 22).

Based on standard application practices:

• For new shipbuilding projects, the ZI series long support seats are preferred. Their modular design can reduce installation hours by 30%.
• For ships operating in tropical waters, hot-dip galvanizing is recommended. The coating thickness should be ≥80μm to enhance corrosion resistance.
• The lubrication status of rotating parts should be checked during regular maintenance, and annual load tests should be conducted in accordance with ISO17905.