Laser-Cut Steel Parts: Mild, Hot-Rolled and Cold-Rolled

Cold-rolled 1008 sheet or hot-rolled A36 plate: what the print should say

Cold-rolled sheet is quoted for thin, formable parts and hot-rolled plate for brackets and weldment plates that need thickness. The two differ at the surface and in dimensional control: cold rolling gives a smoother surface and holds tighter dimensions, while hot-rolled steel carries mill scale and holds looser ones (source 4). Cold-rolled sheet is normally furnished with a matte, oiled surface unless the order says otherwise (source 1).

Write the grade the way the mill sells it. Cold-rolled sheet is bought to ASTM A1008, the "Standard Specification for Steel, Sheet, Cold-Rolled, Carbon, Structural..." (source 1), so "CRS per ASTM A1008 CS Type B, 0.120 in" is a complete callout. Hot-rolled sheet and strip is bought to ASTM A1011 (source 2), and structural plate to A36, which is produced as plate, structural shapes and bars (source 3). If your print says 1018, that is a different carbon steel, covered on the steel materials page; for a laser-cut plate part, name the grade and the condition on the print.

Mill scale, pickling and what they mean for powder coat and welding

Hot-rolled steel leaves the rolling mill with a flaky oxide skin called mill scale (source 6). Pickled and oiled (P&O) plate has been through an acid bath that removes the scale, and a thin film of oil is applied afterward because pickled steel rusts in humid air (source 7). Scale matters under a coating: paint applied over it comes off with the scale (source 6), and oil, oxides and scale have to be removed before powder coating (source 8). So a plate that will be powder coated is called out on the print as P&O, or with the scale removal it needs, and the quote follows the print.

For weldments the same question comes up at the joint, so a plate that will be welded is called out as P&O or the print specifies the weld prep at the joint. The cut edge is its own question. Oxygen assist gas, common on mild steel, leaves an oxidized edge that can make powder coating hard to adhere to, and fabricators clean it off before coating; nitrogen as the assist gas leaves a smooth, shiny edge with no oxidation (source 9). If an edge matters under powder coat or at a weld, mark it on the print. Laser-cut parts, welded covers weld symbols and fit-up; weld-in bungs are quoted as machined parts on their own page.

Kerf, edge and tolerance on laser-cut steel

The cut profile is quoted from your print, and where the print gives no tolerance, the quote states the tolerance used. Kerf is the width of the channel the cut removes, and it varies with the laser and the material (source 10), so draw the part at its finished size and the quote works from the print. An edge break is called out on the print when edges will be handled. A hole that has to be round and to size, such as a locating hole in thick plate, is called out as a reamed or machined feature and quoted on the same order.

The laser cut tolerances page explains what a profile tolerance covers and what it does not: it is not flatness and not hole position across a bend. Hot-rolled steel is rolled to looser dimensional tolerances than cold-rolled (source 4), so the print should say whether the stock thickness is fine or a finished thickness needs a machined face. Where a plate is a spacer or a shim stack, plates and spacers covers thickness callouts.

When steel beats aluminum

Steel wins on stiffness and weldability; aluminum wins on weight. The deflection of a loaded cantilever depends on the modulus of elasticity E and the area moment of inertia I of its section (source 13). A36 has a modulus of about 200 GPa and a density of about 7.8 g/cm³ (source 3); 6061 aluminum has about 69 GPa and 2.70 g/cm³ (source 11). So a steel bracket of the same thickness deflects far less than the aluminum one, which is why a mount that has to hold a sensor or a stop rigidly lands here. A36 is readily welded by all welding processes (source 3), while 6061 near a weld has the properties of 6061-T4, a loss of strength of around 40% (source 11); that is why weldment plates, gussets and frames land here too.

Choose aluminum when the part is carried or moved often, lives near saltwater, or will be anodized rather than painted. Iron rusts when it meets oxygen and moisture, and faster in salt (source 14), where 5052 aluminum is noted for its resistance to seawater and salt spray (source 12). A bare steel part therefore gets a finish, or the print accepts an unfinished surface on a part that will be welded and painted as an assembly. The laser-cut aluminum parts page covers 5052 and 6061 the same way this one covers steel; custom CNC brackets compares the two on the most common part.

Finishes and typical parts

Powder coating is quoted on laser-cut steel. A finish called out on the print is quoted with the part. Bare steel is not a finish: if no finish is wanted, say so on the print, for example "no finish", and the quote follows the print. Finishing for laser-cut parts and the powder coating page cover the callouts.

Typical parts: L and Z brackets in cold-rolled sheet with two bends and a slot; weldment base plates and gussets in A36 plate; machine mounts and feet; guards and shields; adapter and spacer plates; tabs and weld-on brackets. Quantities run from one piece to production runs of 10,000, and one order covers cut, bends, tapped holes, hardware, weld prep and finish. The laser-cut parts hub lays out how one order works; the quote form takes the files first.

What to send, and how the parts are inspected

A DXF or STEP plus a PDF print is ideal; any file type is accepted. The print carries: grade and condition (1008 cold-rolled, or A36 hot-rolled, P&O or mill finish); thickness as a decimal; quantity; finish by name and color, or "no finish"; which holes are tapped, countersunk or reamed, with size; bends with angle, inside radius and flange lengths; weld symbols and weld prep for an assembly; and which faces and edges are cosmetic. The inside radius is quoted as drawn, with a note if it won’t form. With no drawing, a dimensioned sketch, a new sample part or photos are enough to start; the CAD work is then quoted as its own line, and the quote lists anything missing. A fully dimensioned 2D PDF is quoted without a CAD line.

Every part inspected against your print before it ships: the cut profile, hole sizes and positions, thickness, bend angles and tapped holes, each against its callout, and coated parts against the finish and color on the print. If a part doesn’t match the print, it’s remade or credited. Anything that cannot be cut or inspected as drawn is flagged in the quote. No C of C or material certifications ship with parts by default. If your PO needs them, say so before the quote. Inspection reports on critical dimensions aren’t included by default. If you need one, ask when you place the order.

Sources

All accessed 4 October 2026. Where a figure here differs from your print, the print governs.

1. ASTM International, "ASTM A1008/A1008M-26, Standard Specification for Steel, Sheet, Cold-Rolled, Carbon, Structural, High-Strength Low-Alloy, High-Strength Low-Alloy with Improved Formability, Required Hardness, Solution Hardened, and Bake Hardenable": store.astm.org (commercial steel CS Type B among the designations; "Unless otherwise indicated, sheet surfaces shall have a matte finish and shall be oiled").

2. ASTM International, "ASTM A1011/A1011M-25, Standard Specification for Steel, Sheet and Strip, Hot-Rolled, Carbon, Structural, High-Strength Low-Alloy, High-Strength Low-Alloy with Improved Formability, and Ultra-High-Strength": store.astm.org (hot-rolled sheet and strip in coils and cut lengths).

3. Wikipedia, "A36 steel": en.wikipedia.org/wiki/A36_steel (produced as plates, structural shapes and bars; readily welded by all welding processes; Young’s modulus 200 GPa; density 7.8 g/cm³).

4. Wikipedia, "Rolling (metalworking)": en.wikipedia.org/wiki/Rolling_(metalworking) (hot-rolled surface covered in mill scale and looser dimensional tolerances; cold rolling improves surface finish and holds tighter tolerances; cold-rolled sheet comes in conditions from full hard to skin-rolled and is annealed to induce ductility).

5. Wikipedia, "Cold working": en.wikipedia.org/wiki/Cold_working (the metal is less ductile; annealing relieves the loss of plasticity; better surface finish and dimensional control).

6. Wikipedia, "Mill scale": en.wikipedia.org/wiki/Mill_scale (flaky surface of hot-rolled steel, mixed iron oxides; removed by flame cleaning, pickling or abrasive blasting; paint over it comes off with the scale).

7. Wikipedia, "Pickling (metal)": en.wikipedia.org/wiki/Pickling_(metal) (pickle liquor removes scale; pickled sheet steel rusts in humid air, so a thin film of oil is applied).

8. Wikipedia, "Powder coating": en.wikipedia.org/wiki/Powder_coating (removal of oil, dirt, greases, metal oxides and welding scale is essential before powder coating).

9. Dan Davis, "Taking the (Oxide) Edge Off", Products Finishing, 1 March 2013: pfonline.com (oxygen assist gas on mild steel creates an oxidized edge that makes powder coating difficult to adhere; oxide removal before coating; nitrogen gives smooth, shiny edges with no oxidation).

10. Wikipedia, "Saw" (section "Kerf"): en.wikipedia.org/wiki/Saw#Kerf (kerf is the narrow channel left by the cut and the measure of its width; a laser’s kerf changes with the laser’s power and the material).

11. Wikipedia, "6061 aluminium alloy": en.wikipedia.org/wiki/6061_aluminium_alloy (after welding, properties near the weld are those of 6061-T4, a loss of strength of around 40%; Young’s modulus 69 GPa; density 2.70 g/cm³).

12. Wikipedia, "5052 aluminium alloy": en.wikipedia.org/wiki/5052_aluminium_alloy (resistance to seawater and salt spray).

13. Wikipedia, "Deflection (engineering)": en.wikipedia.org/wiki/Deflection_(engineering) (end-loaded cantilever deflection FL³/3EI, E the modulus of elasticity and I the area moment of inertia).

14. Wikipedia, "Rust": en.wikipedia.org/wiki/Rust (iron rusts in contact with water and oxygen, faster with salt; coatings such as paint, lacquer or wax isolate the iron; a thin layer of oil can be applied).