Oxygen cutting is one of the most widely used methods for cutting thick steel plate, delivering both economical and high-quality results when applied correctly. As thickness increases, however, so does the number of variables affecting edge quality. In this article, we look at the key factors that determine edge quality in oxygen cutting of thick plate.
How Does Oxygen Cutting Work?
Oxygen cutting relies on an exothermic reaction in which steel burns in the presence of oxygen, and the molten material is removed from the cut line by a high-pressure oxygen jet. This method offers a more economical alternative to laser and plasma cutting, particularly for thicknesses of 10 mm and above. However, the reaction proceeding in a controlled manner depends on selecting the right parameters.
Key Factors That Determine Edge Quality
Cutting Speed
Choosing the right cutting speed is critical for thick plate. If speed is too high, the flame doesn't have enough time to fully melt and remove the material, resulting in irregular lines on the cut surface. If speed is too low, the kerf widens, the heat-affected zone (HAZ) grows, and excessive melting marks appear on the edge surface.
Nozzle Selection and Condition
The nozzle directly determines the shape and intensity of the oxygen flow. Using a worn nozzle or one unsuited to the thickness distorts the flame shape and causes irregularities on the cut surface. For thick material, nozzles designed specifically for that thickness should be used.
Oxygen Pressure and Purity
Oxygen pressure must be kept at a level appropriate for the thickness; low pressure fails to fully remove molten material, while high pressure causes the kerf to widen excessively. The purity of the oxygen used also directly affects cut quality; lower-purity oxygen slows cutting speed and increases edge roughness.
Nozzle Standoff Distance
The distance between the nozzle and the material surface determines how the flame affects the material. Failing to keep this distance constant causes quality fluctuations along the cut, and this risk increases especially on deformed or uneven sheet surfaces.
Common Quality Issues in Thick Plate
- Vertical drag lines and irregularity on the cut surface
- Excessive slag buildup on the bottom edge
- Hardening and brittleness in the heat-affected zone
- Kerf width variations along the cut
Most of these issues stem from speed, pressure, and nozzle selection not being properly optimized for material thickness.
Ways to Improve Quality Control
To achieve consistent quality in thick plate cutting, it's recommended to develop separate parameter sets for each thickness range and to perform test cuts regularly. Regularly checking nozzle wear and replacing it when necessary also helps keep cut quality consistent.
DMK Makina's Approach to Oxygen Cutting
DMK Makina uses thickness-specific combinations of speed, pressure, and nozzle selection in oxygen cutting of thick steel plate, producing high edge quality with low tolerance deviation. For large-scale, thick parts frequently required in heavy industry and steel construction projects, an experienced operator team and regular equipment maintenance deliver consistent results.
Serving industrial businesses across the Thrace and Marmara regions, DMK Makina offers oxygen cutting that delivers reliable edge quality on thick material, evaluating each project's thickness and tolerance requirements together with its technical team.