Key points for cutting S355K2G2W weathering steel plates

Cutting S355K2G2W is straightforward, but each method has its nuances. Here’s how to get clean, reliable cuts.

Plasma cutting. Fast and widely used. For plates over 15mm, the cut edge develops a thin hardened layer (1–2mm). If you plan to weld that edge, grind back 2–3mm to remove surface hardness and prevent cracking. Use standard plasma parameters for structural steel.

Oxy-fuel cutting. Common for heavy plates (20–100mm). Avoid excessive preheat—too much widens the heat-affected zone and alters the microstructure. Use the lowest preheat that gives a stable, consistent cut.

Laser cutting. Best for plates under 12mm and complex shapes. Produces narrow kerf and minimal heat input—heat-affected zone often under 0.5mm. Ideal for precision parts like architectural panels.

Shearing. Suitable only for thin plates (under 6mm) and straight cuts. No heat, no metallurgical changes. Deburr sharp corners after cutting.

After cutting. Remove loose scale and slag from the cut edge with a light grind or wire brush. Don't grind aggressively—the patina needs a slightly rough surface to form properly. Never apply paint, oil, or sealant to fresh cut edges unless the design requires it.

One common mistake. Using high-speed plasma without adjusting for S355K2G2W's copper content. Copper can cause hot shortness if parameters are too aggressive. Stick to the recommended cutting speeds for the plate thickness.

Practical tip. Test your cutting parameters on a scrap piece before production. Adjust speed, gas pressure, and amperage on the test piece—not the actual plate.