Tungsten (W) and niobium (Nb) belong to the refractory metal group and are used as alloying elements in steels and superalloys for high demand products. These metals are also used in a high purity single-phase state for products within nuclear, space, military and research facilities.

In the current study, tool wear development and surface quality at different cutting conditions have been evaluated when machining high purity W 99.95% and Nb 99.7% in longitudinal turning. Cryogenic LN₂ cooling and hybrid induction-assisted machining strategies were applied in order to alter W and Nb material state with respect to the ductile-to-brittle transformation temperature, and thus to attempt controlling their machinability. These advanced machining strategies were benchmarked against the more conventional machining solutions of dry, flood and high pressure cooling.

It was found that the use of LN₂ cooling demonstrated the best result in terms of tool life when machining W followed by induction-assisted heating, dry and flood. All machining strategies provided similar surface quality which is related to strong build-up edge formation and respective surface alteration. When machining Nb, high pressure coolant results in best performance in terms of tool life and surface quality, then followed by flood and cryogenic strategies. Overall, substantial improvement of surface quality (R_a = 0.4–0.6 μm) was observed for high cutting speeds v_c ≥ 225 m/min.

钨（W）和铌（Nb）属于难熔金属类，在高需求产品的钢和超合金中用作合金元素。这些金属还以高纯度单相态用于核，太空，军事和研究设施中的产品。

在当前的研究中，在纵向车削中加工高纯度W 99.95％和Nb 99.7％时，已经评估了不同切削条件下的刀具磨损发展和表面质量。应用低温LN ₂冷却和混合感应辅助加工策略是为了相对于韧性到脆性转变温度改变W和Nb的材料状态，从而尝试控制其可加工性。这些先进的加工策略以干，水浸和高压冷却等更传统的加工解决方案为基准。

已经发现，在加工W并随后进行感应辅助加热，干燥和注水时，使用LN ₂冷却在刀具寿命方面表现出最好的结果。所有机加工策略均提供相似的表面质量，这与结实的边缘形成和相应的表面变化有关。在加工Nb时，高压冷却液在刀具寿命和表面质量方面具有最佳性能，然后是溢流和低温策略。总体而言，表面质量（的实质性改善ř_一个 = 观察到高的切削0.4-0.6微米）速度v _Ç  ≥225米/分钟。