Each day, oil fields experience connection failures. Oil and gas companies depend on complex assemblies with an increasing number of connections. Strong connections make for successful drill strings and productive, more cost-effective work—a necessity when performing modern oil industry applications.
Engineered specifically to complement diverse oil field tools, CJWinter’s line of Cold Root Rolling (CRR) tools aims to make those connections perform at their utmost capacity. In many cases, this tooling will improve connection life by three to five times.
Cold root rolling burnishes the root radius of previously cut threads in rotary shouldered connections. A hardened roll applies force to the root radius of a tapered thread, penetrating into the surface. The thread material is displaced and cold-formed, improving the surface finish as well as the strength of the root substance.
The Benefits of Cold Root Rolling
- The residual compressive stress of cold root rolling offsets the tensile stress of service in the critical stress region of a thread root. Utilizing this process results in better balance and less stress overall.
- Cold root rolling provides a flatter, more uniform finished surface with fewer scratches; this is ideal for reducing stress concentration factors and creating fewer opportunities for cracking and fatigue failures.
- Chemical erosion strikes at scratch points, which provide prime access to the material with their jagged, porous surfaces. Cold root rolling smoothes away these scratches, reducing the potential for chemical attack.
- Cold root rolling creates a work-hardening effect on the material surface. The surface will be more resistant to further deformation, as well as less susceptible to shallow cracking that can lead to sudden structural joint failure.
The CRR Tool for Rotary Tapered Connections
Cold root rolling increases fatigue life and strengthens connections, and it is now an industry requirement; the standard DS-1 sec. 3.3.66 and NS-1 sub-spec 143 require cold root rolling for all new and re-cut BHA and HWDP connections with API thread forms.
The main advantage of cold root rolling is the efficiency of operation, which is provided with significantly less cost. In addition to increasing the resiliency of rotary shouldered connections in a drill string, cold root rolling also reduces the need for repairs—this equates to lower service costs as product demand continues to grow.
We invite you to learn more about our CRR Tool by downloading a free Informational Guide today.
Also, be sure to contact CJWinter with any questions about the cold root rolling.
