Laser-Cut Stainless Steel Parts: 304 and 316

Thickness and grade for laser-cut 304 and 316

Laser-cut stainless runs from thin sheet to plate, and the print gives the grade and the thickness. Stainless plate, sheet and strip are specified under ASTM A240/A240M, which covers chromium and chromium-nickel stainless plate, sheet and strip (source 1), so a print often names 304, 304L, 316 or 316L with that spec.

Build-to-print work is not tied to a menu. The print names the grade and thickness, and the quote covers getting that sheet. Which grade to write is its own question, answered on 304 vs 316 for laser-cut parts: 316 contains molybdenum, which is there to raise resistance to pitting and crevice corrosion (source 2), and that is the reason it is the grade named where chlorides live (source 3). The grade pages for 303 and 304 and 316 cover the same alloys as machined bar. This page is the sheet and plate side: what the cut edge looks like, how the mill finish and the final finish are written, and what comes back on the part.

Sheet finish: 2B, #4 brushed, and the grain arrow

Stainless sheet arrives with a mill finish, and the print should say which one. 2B is a bright cold-rolled finish: the annealed and descaled sheet gets a final cold-roll pass on polished rolls (source 4). #4 is a general-purpose brushed finish put on with an abrasive (sources 4 and 5). No. 1 is the hot-rolled finish, a comparatively rough, dull surface that is annealed and descaled (source 4), which is fine for a hidden bracket and wrong for a visible panel.

A brushed finish has a direction, so the print carries a grain arrow, drawn relative to the part’s long edge or a datum. Grain direction decides how the flat pattern can sit on the sheet, so the quote works from the arrow. Without it, grain is not controlled, and two panels side by side can read differently in the light. For laser-cut panels and faceplates in #4, the grain arrow, the film-on callout and the 2B or #4 callout are three lines that save a remake. A face that must stay 2B is marked that way on the print, with an edge break only.

The cut edge: tint, kerf and tolerance

An assist gas that keeps oxygen out of the cut reduces oxidation at the edge (source 6), and cutting with an oxygen-bearing gas leaves oxides on the cut surface (source 7). A thin oxide layer on stainless can show as color (source 8), so a laser-cut stainless edge may show discoloration. That is cosmetic on most brackets and unwanted on food and washdown parts. The print says what the edge has to be: write the no-discoloration requirement, a deburr, or passivation after the cut on the faces and edges that matter, and the quote answers each one.

The laser removes a kerf of material (source 6), so the part is drawn at finished size. The cut profile is quoted from your print; thickness is the sheet’s own, so the print names the thickness and any tolerance it accepts on it. A hole that needs a press fit or a thread is called out on the print as a reamed or tapped hole and quoted as a second operation, which is how laser-cut, tapped and machined parts are ordered as one order. Kerf, the heat-affected zone and the tolerance class are on laser-cut tolerances.

Passivation and other finishes on the print

Passivation changes nothing you can see on a stainless part. ASTM A967/A967M (store.astm.org/a0967_a0967m-25.html) covers "several different types of chemical passivation treatments for stainless steel parts," names immersion in nitric acid, immersion in citric acid and electrochemical treatment, and requires that passivated parts "show no etching, pitting, or frosting." Passivation removes exogenous iron from the surface and restores the passive oxide layer (source 10). Name passivation per ASTM A967 on the print; name citric or nitric only if your spec requires one. It is quoted with the part. The passivation page covers the callout in more detail.

A finish called out on the print is quoted with the part; finishing for laser-cut parts covers finishes across the rest of the sheet family.

When stainless is the right buy, and the parts it becomes

Stainless forms its own thin chromium oxide film, which blocks further corrosion and repairs itself when scratched (source 5), which is why it suits a part that sees water, cleaning chemicals, food contact or salt, or that must stay bright without a coating. A dry indoor bracket may fit laser-cut aluminum in 5052 or 6061 instead. Typical parts: machine guards and kick plates in 304, washdown panels and splash guards in 316, brackets and mounting tabs, drip trays, sanitary hangers, and marine hardware in 316. Quantities run from a single guard to production runs of 10,000. Ask for more than one quantity, such as 1, 25 and 100, and the quote shows each. A blanket order is quoted too. Price, release schedule and lead time per release are set in the quote.

Austenitic stainless work hardens as it is formed (source 2), at a higher rate than carbon steel (source 11), and greater deformation than for carbon steel may be needed to reach the angle because of spring-back (source 11). A bent stainless bracket therefore carries its inside radius and bend direction on the print, with the bend direction marked relative to the grain if the sheet is #4. Where a part is welded, the print usually names the L grade, 304L or 316L, the low-carbon grades described as not susceptible to intergranular corrosion thanks to their lower carbon content (source 2), and the part is welded to the print. The quote flags any bend or callout that cannot be made as drawn.

What to put on the print and what is inspected

A quotable stainless print carries seven items: the grade (304, 304L, 316 or 316L) with its sheet spec, ASTM A240; the thickness, with the mill tolerance accepted; the general profile tolerance; hole sizes and which holes are tapped or reamed; bend radius and direction; the sheet finish (2B as received, or #4 with a grain arrow) and any finish called out, such as passivate per A967; and any face that must stay film-protected or unmarked. A DXF or STEP of the flat profile plus a PDF print is ideal, any file type is accepted, and the quote lists anything missing rather than guessing. Vendor setup takes a day: W-9, NDA, net terms available.

Every part inspected against your print before it ships. If a part doesn’t match the print, it’s remade or credited. 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. Start at the quote form or the laser-cut parts hub; lead time quoted per job, rush available.

Sources

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

1. ASTM International, “A240/A240M-26, Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications”, last updated 17 April 2026: store.astm.org (scope: stainless plate, sheet and strip).

2. Wikipedia, “Austenitic stainless steel”: en.wikipedia.org (316 contains molybdenum to resist pitting and crevice corrosion; work hardening; 304L and 316L not susceptible to intergranular corrosion thanks to a lower carbon content).

3. Wikipedia, “Marine grade stainless”: en.wikipedia.org (chloride ions can cause pitting and crevice corrosion in susceptible stainless steels; marine alloys typically contain molybdenum; 316 is preferred for marine use).

4. worldstainless (the stainless steel programme of the World Steel Association), “Surface treatment”: worldstainless.org (No. 1, 2B and No. 4 finish descriptions).

5. Wikipedia, “Stainless steel”: en.wikipedia.org (No. 2B and No. 4 as a brushed finish; stainless steels form a thin, self-repairing chromium oxide film).

6. Wikipedia, “Laser cutting”: en.wikipedia.org (kerf; an assist gas can create an inert atmosphere that reduces oxidization at the cut).

7. Masoud Kardan, Michele Vanini, Kim Vanmeensel and Joost R. Duflou, “Laser cutting of thick stainless steel plates using mixed nitrogen-oxygen assist gas”, The International Journal of Advanced Manufacturing Technology, 26 June 2026, DOI 10.1007/s00170-026-18608-2: springerprofessional.de (chromium and manganese oxides dominate the cut surface when the assist gas contains oxygen).

8. Wikipedia, “Tempering (metallurgy)”: en.wikipedia.org (thin oxide layers on steel show as colors; stainless steel can show a broader range of colors).

9. ASTM International, “A967/A967M-25, Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts”, last updated 24 January 2025: store.astm.org (scope: nitric acid, citric acid and electrochemical treatments; passivated parts show no etching, pitting or frosting on visual inspection).

10. Wikipedia, “Passivation (chemistry)”: en.wikipedia.org (stainless passivation removes exogenous iron and restores a passive oxide layer that prevents further oxidation).

11. Aalco, “Stainless Steels Alloys: Formability, Fabrication and Finishing”, AZoM, 19 May 2005: azom.com/article.aspx?ArticleID=2871 (higher strength and work-hardening rate than carbon steel; greater deformation may be necessary because of spring-back). Cited as plain text because the article is sponsored by a metals stockist.