This paper presents the analytical and experimental results for transient temperature fields induced in a stainless steel plate by a low-powered arc plasma torch for plasma-assisted milling. For this purpose, we first measured arc efficiencies by using the calorimetric method for plasma power levels of (3–4) kW. The measurement results showed that low arc currents of ≤ 30 A can produce relatively low arc efficiencies of (35–36) %. Then, the heated stainless steel plate was cut to reveal the very shallow surface erosion by arc plasma heating that occurred within 1 mm depth. These experimental results indicate that the relatively low arc efficiencies resulted from the low arc currents designed to thermally soften the workpiece, rather than form a melting pool. Considering these arc heating effects confined to a shallow area near the surface, we employed a 2D surface Gaussian distributed heat source model in analytical modeling of the temperature evolution in the stainless steel plates. The unsteady temperature fields predicted by the analytical solutions show relatively good agreement with the experimental data, although the analytic results show the temperatures rising earlier and descending faster. From these comparisons, we expect that this work can contribute to the optimization of the plasma-assisted milling process.

本文介绍了用于等离子体辅助铣削的低功率电弧等离子体炬在不锈钢板中引起的瞬态温度场的分析和实验结果。为此，我们首先通过对 (3–4) kW 的等离子体功率水平使用量热法来测量电弧效率。测量结果表明，≤ 30 A 的低电弧电流可以产生 (35–36) % 的相对较低的电弧效率。然后，切割加热的不锈钢板，以显示 1 毫米深度内发生的电弧等离子体加热引起的非常浅的表面腐蚀。这些实验结果表明，相对较低的电弧效率是由设计用于热软化工件而不是形成熔池的低电弧电流造成的。考虑到这些电弧加热效应仅限于表面附近的浅区域，我们在不锈钢板温度演变的分析建模中采用了二维表面高斯分布热源模型。解析解预测的非定常温度场与实验数据吻合较好，但解析结果显示温度上升较早，下降较快。通过这些比较，我们希望这项工作有助于优化等离子体辅助铣削工艺。