Experimental research on the surface strengthening technology of roller cone bit bearing based on the failure analysis

Abstract

The roller cone bit is one of the most important rock breaking tools used in the oil–gas drilling industry. Its performance directly influences the drilling quality, efficiency and cost. As the world’s oil–gas resource exploration continuously developed, the drilling speed accelerated, accelerating the failure speed of the bearing. The roller cone bit’s service life was almost directly dependent on that of the bearing. In this paper, a bearing failure analysis, and an experimental research on the surface strengthening technology of the bearing with field applications etc. were carried out. The results showed that the bearing’s main failure modes included fracture, plastic deformation and wear. The main reasons were overload and uneven distribution of the load; elevated temperature due to friction caused property and structure change in material; wear increased the fit clearance between the bearing and the cone, increasing dynamic impact load etc. The bearing surface strengthening technology, employing plasma-arc surfacing DH-60 wear resistance alloy, could prolong the service life of the bearing. Experimental research and field tests showed that the wear and impact resistance of the enhanced bearing increased by 30% with an increased service life of 12% on average.