不透性石墨 meaning in Chinese

impermeable graphite
impervious graphite

Test method for impact of impermeable graphite materials
不透性石墨材料冲击试验方法
Technical regulations for imperious graphite tube
不透性石墨管技术条件
Test method for flexure strength of impermeable graphite materials
不透性石墨材料抗弯强度试验方法
Test method for compressive strength of impermeable graphite materials
不透性石墨材料抗压强度试验方法
Test method of mechanical properties of impermeable graphite materials - general
不透性石墨材料力学性能试验方法总则