Abstract The development of wear resistant materials for drill-bit inserts are of primary importance for efficient percussive drilling in hard abrasive rock. To speed up the development of enhanced wear resistance materials, the laboratory tests are fundamental to evaluate the material performance before proceeding to the in-field drilling test which is labor-intensive and costly in time and resources. The current work aims to perform a comparative study of the wear resistances of drill-bit inserts intended for rotary-percussive drilling. Three laboratory testing methods were adapted to evaluate the abrasive sliding wear and abrasive impact wear which are the main wear components in rotary-percussive drilling. The standard abrasion value (AV) test and the standard LCPC (Laboratoire Central des Ponts et Chaussees) test which were originally developed to study the rock abrasivity, are adapted to study, respectively, the abrasive sliding wear and abrasive impact wear of drill-bit inserts. The disintegrator abrasive impact wear test was adapted to study the effect of impact velocity on impact abrasive wear. The testing setups were modified to enable testing drill-bit inserts as specimens. The drill-bit insert materials were selected to represent various cemented carbide microstructures including five WC-Co grades which differ by the volume fraction of Co and the grain size of WC, and one diamond enhanced insert. All drill-bit inserts were tested in dry condition against Kuru grey granite which is a homogenous rock and well suited as a reference in connection with hard rock testing. The wear measurements were evaluated with respect to the effects of drill-bit insert material and microstructure. The abrasive sliding wear test and abrasive impact wear tests exhibit similar behavior related to the effects of average grain size of WC and volume fraction of Co on the wear measurements for the investigated WC-Co inserts. In all performed tests, the weight losses of WC-Co inserts increased with the volume fraction of Co and average grain size of WC. The abrasive impact wear tests performed on diamond enhanced insert showed a significant improvement of the impact wear resistance by adding diamond particles. Though the removal of the composite matrix between diamond particles was observed, the diamonds particles were providing an additional protection for the composite matrix which explain the lower mass losses of diamond enhanced insert compared to WC-Co inserts. However, an initial stage of decohesion at the diamond/WC-metallic binder interface were observed indicating possibilities of diamond removal at more higher impact energy.

中文翻译：

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对用于硬岩旋转冲击钻孔的钻头刀片耐磨性评估的实验室试验的改编

摘要 开发用于钻头刀片的耐磨材料对于在硬质磨蚀性岩石中进行高效冲击钻进具有重要意义。为了加快开发增强耐磨材料，实验室测试是评估材料性能的基础，然后再进行现场钻孔测试，这是一项劳动密集型且时间和资源成本高的工作。目前的工作旨在对用于旋转冲击钻孔的钻头刀片的耐磨性进行比较研究。采用三种实验室测试方法来评估磨料滑动磨损和磨料冲击磨损，它们是旋转冲击钻井中的主要磨损成分。标准磨损值（AV）试验和标准LCPC（Laboratoire Central des Ponts et Chaussees）试验最初是为研究岩石磨蚀性而开发的，分别适用于研究钻头的磨粒滑动磨损和磨粒冲击磨损插入。粉碎机磨料冲击磨损试验适用于研究冲击速度对冲击磨料磨损的影响。对测试设置进行了修改，以便能够将钻头刀片作为样本进行测试。选择钻头刀片材料来代表各种硬质合金微观结构，包括五种 WC-Co 等级，其不同在于 Co 的体积分数和 WC 的晶粒尺寸，以及一种金刚石增强型刀片。所有钻头刀片均在干燥条件下针对 Kuru 灰色花岗岩进行了测试，Kuru 灰色花岗岩是一种均质岩石，非常适合作为硬岩测试的参考。磨损测量是根据钻头刀片材料和微观结构的影响进行评估的。磨料滑动磨损试验和磨料冲击磨损试验表现出与 WC 平均粒度和 Co 体积分数对所研究的 WC-Co 刀片磨损测量的影响相关的类似行为。在所有进行的测试中，WC-Co 刀片的重量损失随着 Co 的体积分数和 WC 的平均晶粒尺寸而增加。在金刚石增强型刀片上进行的磨料冲击磨损试验表明，通过添加金刚石颗粒，其抗冲击磨损性能得到显着提高。尽管观察到金刚石颗粒之间的复合基体被去除，但金刚石颗粒为复合基体提供了额外的保护，这解释了与 WC-Co 刀片相比，金刚石增强型刀片的质量损失较低。然而，观察到金刚石/WC-金属粘合剂界面处的脱聚的初始阶段表明在更高的冲击能量下金刚石去除的可能性。