Optical interferometry and metallographic analysis were used to study the structure of cutting seams obtained after 09G2S steel cutting by a PMVR-5 plasma torch. These plasma torches have many design features in the gas-dynamic stabilization system of the plasma arc. The application of a new plasma torch can obtain higher quality and lower energy costs of cutting medium-thick 09G2S steel. Metallographic analysis has shown that the qualitative composition of the cut surface structure is almost the same, so priority criteria for comparative quality analysis are surface microgeometry parameters. The parameter evaluation shows high quality of cutting almost along the entire length of a cut, since the technological feature influence of plasma arc cut into the metal affects less than 0.3 mm from the sheet edge. The use of additional methods of gas-dynamic stabilization in PMVR-5.2 plasma torch (feed symmetry with a double swirl system of plasma-forming gas) makes it possible to achieve additional advantages in terms of surface quality compared to PMVR-5.1. A number of features that affects cut quality when cutting metals of different thicknesses for welding depends on the inclination angle of a plasma torch during cutting. Estimates of the surface layer hardness indicate minimal deviations from the requirements of GAZPROM Standard 2-2.4-083 (instructions on welding technologies in the construction and repair of field and main gas pipelines), which allows further use of cutting seams obtained by studied plasma torches for welding without removing thermal influence zones. Thus, the application of new plasma torches for precision-finishing plasma cutting of metals, including production of welded joints, is possible.

中文翻译：

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等离子割炬设计对金属精密空气等离子切割过程中切割质量的影响

采用光学干涉法和金相分析方法研究了PMVR-5等离子炬切割09G2S钢后得到的切割缝结构。这些等离子炬在等离子弧的气体动态稳定系统中具有许多设计特点。新型等离子割炬的应用可以获得更高质量和更低能源成本的中厚 09G2S 钢切割。金相分析表明，切割表面结构的定性成分几乎相同，因此比较质量分析的优先标准是表面微观几何参数。参数评估表明，几乎在整个切割长度上的切割质量都很高，因为等离子弧切割金属的技术特征影响距离板材边缘不到 0.3 毫米。与 PMVR-5.1 相比，在 PMVR-5.2 等离子炬中使用额外的气体动力学稳定方法（具有等离子形成气体双涡流系统的进给对称）可以在表面质量方面获得更多优势。在切割不同厚度的金属进行焊接时，影响切割质量的许多特征取决于切割过程中等离子割炬的倾角。对表面层硬度的估计表明与 GAZPROM 标准 2-2.4-083（现场和主要天然气管道的建造和维修中的焊接技术说明）要求的偏差最小，这允许进一步使用由研究的等离子炬获得的切割接缝用于焊接而无需去除热影响区。因此，