These contact stresses are high enough to plastically yield the pipe surface under the multiple sealing lands, forming a 360-degree circumferential, permanent, metal-to-metal seal between the pipe and fitting body. Finally, the installation process causes the Lokring driver to grow slightly in diameter — an "elastic strain" — so that it exerts an elastic, radial preload on the metallic seals.
The high contact stresses cause plastic deformation of the pipe surface under multiple sealing lands, resulting in a 360-degree circumferential, permanent metal-to-metal seal. The installation process leads to slight expansion of the Lokring driver — an "elastic strain" — which applies an elastic, radial preload on the metallic seals.