6. Technical Requirements

Products shall meet the requirements of this standard and be manufactured in accordance with the product drawings and technical documents confirmed by both the supplier and the demander. The materials and coatings used in product manufacturing shall comply with the safety and environmental protection regulations of the application area.

6.1 Dimensions and Appearance Quality

• 6.1.1 The ratio  shall not be less than [a certain value]. The piston rod diameter and stroke of the gas spring shall be selected according to [relevant standards]. Special requirements shall be agreed upon by the supplier and the demander.
• 6.1.2 The dimensional tolerance of the extended length of the gas spring shall comply with the IT16 – level accuracy regulations in GB/T 1800.1.
• 6.1.3 The coating on the piston rod of the gas spring shall be uniform, and the surface shall be smooth and free from defects such as scars, blisters, peeling, pitting, pinholes, and nodules.
• 6.1.4 The coatings on other exposed parts except the piston rod shall be uniform and free from defects such as red rust, peeling, blisters, roughness, and uncoated areas (except for process holes and holes smaller than 1mm).
• 6.1.5 The quality of the paint coating on the gas spring cylinder barrel shall comply with the regulations of QC/T 484. The paint coating shall be uniform, free from exposed bases, obvious pitting, and severe sagging, and may have a slight “orange peel” effect.

6.2 Force Characteristics

• For gas springs with a specified force greater than 100N, the force value shall be determined in integer multiples of 50N. There shall be no jamming during the compression and extension processes of the gas spring.
• 6.2.1 The specified force value  and friction force : The limit deviation of the specified force value and the dynamic friction force shall comply with the regulations in Table 2. Special requirements can be agreed upon by the supplier and the demander.
• 6.2.2 Unlocking force : The unlocking force of the gas spring shall be agreed upon by the supplier and the demander according to customer requirements.
• 6.2.3 Start – up force : The start – up force of the gas spring shall be less than .
• 6.2.4 Force ratio : The force ratio of the gas spring shall be agreed upon by the supplier and the demander according to the usage conditions.
• 6.2.5 Locking force : For rigid – locking gas springs, when the displacement of the piston rod is not more than 2mm, the compression locking force shall be greater than . The locking force of elastic – locking gas springs, the tensile locking force of rigid – locking gas springs, and special requirements shall be agreed upon by the supplier and the demander.

6.3 Extension Speed 

The extension speed  of the gas spring shall be between 40mm/s and 200mm/s. Special requirements shall be agreed upon by the supplier and the demander.

6.4 Sealing Performance

When the gas spring is locked at any position and stored at room temperature for 24 hours, its stroke shall not change.

6.5 High and Low Temperature Resistance Performance

After the gas spring is stored at high and low temperatures, the attenuation of its nominal force  and locking force  shall not be more than 5%.

6.6 Cycle Life

After the gas spring has undergone the high and low temperature performance test, it shall be subjected to [a certain number of] cycle life tests ( shall be tested according to the actual stroke; when , it shall be tested according to [the specified stroke]). After the test, the total attenuation of its nominal force  and locking force  shall not be more than [the specified value]. The dynamic friction force shall comply with the regulations in Table 2, and the amount of oil leakage shall be less than 0.5g. The change in the piston rod stroke shall be agreed upon by the supplier and the demander.

6.7 Tensile Resistance Performance

The tensile resistance performance of gas spring products shall comply with the regulations in Table 3.

6.8 Corrosion Resistance Performance

• 6.8.1 After 72 – hour neutral salt spray testing, the gas spring shall be free from blisters, peeling, and corrosion defects; the threads at the rod ends and pipe ends, as well as the hole openings, shall not have blisters or peeling.
• 6.8.2 After 48 – hour neutral salt spray testing, the hard – chromium – plated piston rod shall be free from blisters, peeling, and corrosion defects on its rod body; the rod – end threads and hole openings shall not have blisters or peeling.
• 6.8.3 The corrosion resistance performance of other exposed parts shall comply with the regulations of the corresponding coatings in QC/T 625.
• Special requirements shall be agreed upon by the supplier and the demander.

Technical Specification for Lockable Gas Springs (English version of national strandard, initiated by LeiYan Gas Springs), proposed and prepared by SAC/TC 235 (National Technical Committee 235 on Spring of Standardization Administration of China).