Views: 0 Author: Site Editor Publish Time: 2026-06-18 Origin: Site
Tapered drill rods kept breaking, causing losses for the customer. In response to the customer complaint, we provided a solution and handling plan.
In November 2024, a customer purchased H22*108mm*7-degree drill rods from our company. Multiple rods broke. Faced with the customer's complaint and the urgency of the situation, we convened a meeting that same day with company leaders and technicians to address the issue.
The conclusions reached are as follows:
1. The customer's drill rods had laser engravings, which may have contributed to fatigue and breakage. We noticed that the breakages were uniformly located at the logo area.
2. The customer was using a hydraulic rock drill. The impact working pressure of such hydraulic rock drills typically reaches 15–25 MPa, generating stress wave amplitude and impact frequency far exceeding that of pneumatic rock drills. Because our material is 55SiMnMo, and its fatigue life is insufficient (55SiMnMo is a high-carbon low-alloy steel (or medium-carbon alloy steel), it typically undergoes an integral quenching and tempering heat treatment process). This process cannot create the high-pressure stress layer on the surface required to resist hydraulic shock. Under the continuous action of high-stress waves, the drill rod is prone to early fatigue fracture from the thread root or the inner hole surface.
After analysis and patient explanation from the customer, we immediately had them adjust their operating methods. We sent the customer several models of 23CrNi3Mo drill rods, ultimately resolving the problem.
Through the above case, we found that different materials have different applications. When problems arise, it is crucial to promptly and patiently resolve the current issues for customers and provide timely and professional problem analysis.
If targeting the pneumatic drill bit (pneumatic drill rod) market, 55SiMnMo is a mature and cost-effective classic choice. If you are preparing to enter the hydraulic drilling rig (trolley) drill bit market, we recommend immediately halting the R&D or production plans for 55SiMnMo and directly transitioning to purchasing low-carbon alloy hollow steel such as 23CrNi3Mo or 25CrNiMo, along with a matching carburizing heat treatment line. Otherwise, the product simply cannot pass the on-site operating condition tests of high-power hydraulic rock drills.
