What Is Cold Root Rolling

Cold Root Rolling is the process of burnishing the root radius of a previously cut thread, in a Rotary Shouldered Connection.

A hardened roll, similar in profile to the thread being manufactured, is placed in contact with the root radius of the tapered thread, and pressure is applied to force the roller to penetrate into the cut surface of the root radius, displacing and cold-forming the thread material.

This deformation cold-works the material, imparting an improved surface finish and compacts and displaces the grains of the root material.

Industry experience with the cold root rolling process has suggested an increase in fatigue life of 3 to 5 times over similar un-treated connections under the same working environment.

Learn about CJWinter's cold root rolling tools in our introductory video.

Some studies have noted laboratory results of up to 27 times better life attributable directly to cold root rolling process.

For almost 60 years, CJWinter has been an industry leader in supplying thread rolls and thread rolling tools globally.

CJWinter has used that experience to design tools specifically for Rotary Shouldered Connections in the Petroleum Industry.

We believe this is the only self-contained, commercially available tool that will cold root roll threads compliant with ANSI/API Specification 7.2:2008 and ISO 10424-2:2007, in accordance with NS-1 cold root rolling procedures, and DS-1 Third Edition, Volume 3.33.6.

Our in-house engineering staff is always available to assist with any technical manufacturing situation. Contact us today to request a compliance consultation with our engineering staff.

See cold root rolling in action — watch the video clip below.

What is Cold Root Rolling?