Carbon steel / iron cutting
Short answer
Carbon steel — informally called iron (რკინა) in Georgian — is technically mild steel, and we cut it in-house on a fiber laser CNC up to 10mm thick at ±0.1mm tolerance; plate thicker than 10mm is beyond our laser. Oxygen-assisted cutting leaves a dark oxidized edge, a normal physical result rather than a defect. Minimum order is 1 piece, quotes arrive within 24 hours, production takes 1–3 working days.
Colloquial "iron cutting" and the technical "carbon steel cutting" written on a drawing refer to the same material: mild steel, which contains no chromium and, unlike stainless, has no built-in corrosion resistance. At Craftarea we cut carbon steel in-house on our own fiber laser CNC, from raw sheet to finished part, driven by your DXF or DWG file. This page sets out the real thickness ceiling of our machine, the smallest hole diameter that comes out clean, why a dark oxidized edge appears after cutting, and when we route a job to a partner workshop instead. We regularly cut carbon steel nameplates, mounting brackets, decorative panels and mangals; the material is affordable and strong, provided the surface gets a protective coating afterward.
Key facts
- Max thickness
- 10mm (fiber laser CNC)
- Tolerance
- ±0.1mm positional
- Min hole diameter
- ≈1.5 × sheet thickness
- Minimum order
- 1 piece
- Quote turnaround
- Within 24 hours of file receipt
- Production time
- 1–3 working days
- Accepted files
- DXF, DWG, AI, PDF (vector)
- Edge finish
- Dark, oxidized (oxygen-assisted cut)
Carbon steel, iron, or mild steel — what's the difference?
In everyday Georgian, "რკინა" (iron), "ფოლადი" (steel) and "შავი ლითონი" (black metal) are used almost interchangeably, but none of them names a separate material. Technically, carbon steel is an alloy of iron (Fe) and carbon that, unlike stainless, contains no chromium and has no corrosion resistance. The "black" name refers to the dark mill-scale layer left on the sheet after hot rolling, clearly visible even on raw, uncut stock. So "iron cutting" and "steel cutting" describe the same job. If the part is destined for a damp environment and you do not plan to paint it, carbon steel is the wrong choice — that calls for stainless (inox).
- Iron / iron cutting — everyday term
- Steel — general technical term
- Carbon steel / mild steel — the precise material name
- Stainless / inox / nerzhaveika — a different, chromium-bearing metal
What thickness of carbon steel (iron) do we cut?
Our fiber laser CNC cuts carbon steel up to 10mm thick at ±0.1mm positional tolerance. Sheet from 0.5–3mm cuts fast and economically — the most common range for nameplates, signage and decorative parts. From 4–10mm, cutting time and therefore cost rise, because the laser needs more power and a slower pass. 10mm is the real ceiling for our machine; anything thicker requires a different process. Minimum hole diameter runs at roughly 1.5× the sheet thickness — in 3mm steel, a hole under 4.5mm no longer comes out clean. Minimum order is 1 piece.
Why does the cut edge go dark — the physics of oxygen-assisted cutting
When cutting carbon steel we add oxygen as the assist gas alongside the laser beam: it reacts exothermically with the heated metal and helps the laser cut quickly even through thick sheet. That same reaction coats the cut edge in a thin layer of iron oxide, giving it a dark, sometimes brownish-blue tint. This is a normal physical result, not a defect, and it does not affect the strength of the part. We cut stainless and aluminum with nitrogen instead, so their edges come out noticeably cleaner and lighter — one of the main practical differences between the materials. Where the edge will be visible, light grinding removes the oxide layer easily.
What do we make from carbon steel?
Carbon steel is chosen where price and strength matter more than the raw surface appearance — the aesthetics are handled afterward with paint or powder coating. We regularly cut carbon steel for door and office nameplates, mounting and support brackets, ornamental mangals (BBQ grills), decorative panels and partitions, and structural parts. If the piece will stand outdoors or in a damp space, uncoated carbon steel will rust over time, so we recommend a zinc or paint layer.
When is plasma cutting or a partner workshop the better answer?
Our laser CNC cuts carbon steel cleanly and accurately up to 10mm, but on heavier structural plate a laser stops being the rational tool and plasma cutting becomes more efficient. We do not own plasma equipment: those jobs we either run through a vetted partner workshop or point you directly to the right shop. We also have no guillotine, press brake, lathe or milling machine — we cannot produce bent or turned parts, though we will advise which stage to give to whom. In practice, almost every nameplate, sign, decorative or bracket job falls within the 10mm range.
Carbon steel thickness, minimum hole size and typical use
| Thickness (mm) | Typical use | Min hole diameter | Edge quality | Note |
|---|---|---|---|---|
| 0.5–1 | Thin letters, signage, decor | ≈1.5mm | Clean, minimal oxidation | Deforms easily, needs careful handling |
| 1.5–2 | Nameplates, mounting plates | ≈3mm | Light, even oxidation | The most common order thickness |
| 3 | Brackets, structural parts | ≈4.5mm | Visible dark edge | Standard structural thickness |
| 4–5 | Industrial parts, mounting plates | ≈7mm | Dark; grinding needed on visible surfaces | Cutting time increases noticeably |
| 6–8 | Heavy structural parts | ≈11mm | Thick oxide layer | Production time extends |
| 9–10 | Maximum-thickness parts | ≈15mm | Thick, rough oxidized edge | The hard ceiling for our laser |
Frequently asked questions
Are carbon steel, iron and mild steel the same thing?
In practice, yes. The technical name is carbon (mild) steel; colloquially the same material is called iron or simply steel. There is no separate "iron" product — the genuinely different material is stainless, which contains chromium.
What's the maximum thickness you can laser-cut in carbon steel?
Our fiber laser CNC cuts carbon steel up to 10mm thick at ±0.1mm tolerance. Thicker plate needs plasma cutting, and we run those jobs through a vetted partner workshop.
Why does the cut edge come out dark or discolored?
The oxygen used as assist gas reacts with the hot metal and leaves a thin iron-oxide layer on the edge. This is a normal physical effect and does not weaken the part. On visible edges it grinds off easily.
What hole diameter can you cut in carbon steel?
Minimum hole diameter is roughly 1.5× the sheet thickness: about 3mm in 2mm steel, 4.5mm in 3mm, and 9mm in 6mm. Anything smaller loses edge quality.
Does a cut part need any further processing?
For visually prominent or outdoor parts, we recommend grinding plus a paint or zinc coating to prevent rust. For functional, hidden parts this is optional.
What file do I need to prepare for carbon steel cutting?
A vector DXF or DWG file with closed contours, drawn at real size. We also accept AI and vector PDF. Full requirements are covered on our file-preparation page.
How much does carbon steel cutting cost?
Price is calculated from total cut length, sheet thickness and quantity — a linear metre costs more in thicker sheet, while larger runs lower the per-unit price. We send an exact quote within 24 hours of receiving your file.
Can you cut plate thicker than 10mm?
Not on our own laser — that thickness needs plasma or another process. In that case we manage the project together with a vetted partner workshop.