Stainless Steel Marking

The hardness and grade of stainless steel determine the most effective marking process: on austenitic grades such as 304 or 316, dot peen marking and scribe marking deliver excellent results, while on martensitic grades (420) or very hard duplex stainless steels, fiber laser engraving often becomes essential. Laser engraving avoids tool wear and maintains consistent line quality, making it ideal for long production runs or hardened stainless steel parts; by contrast, scribe marking produces a continuous, aesthetic line on 304/316, while dot peen marking creates mechanically stable indents for traceability in abrasive environments.

The geometry of the stainless steel part directly influences the choice of the marking process. Very thin sheets (< 1 mm) deform easily because their low mass dissipates energy poorly, making percussion marking on stainless steel or scribe marking risky. Conversely, thick parts (> 3 mm) absorb mechanical stress without deformation and allow the creation of deep, consistent engraved markings. Thin stainless steel parts (< 1 mm): laser engraving on stainless steel with low energy and high speed is preferred. Medium stainless steel parts (1–3 mm): a mixed choice depending on the required contrast or depth. Thick stainless steel parts (> 3 mm): dot peen marking on stainless steel parts or scribe marking to achieve long-lasting mechanical depth. The presence of ribs, nearby holes, or thinned areas requires adjustments to power, frequency, and optics.

When the primary requirement is maximum contrast for machine reading (DMC, QR), laser engraving on stainless steel is the benchmark: it delivers read rates close to 99% in industrial vision systems, thanks to sharp black/white engraving on 304/316 stainless steel. If priority is given to depth and mechanical resistance (markings exposed to friction or wear), dot peen marking or scribe marking on stainless steel create stable engraved markings that retain information even after repeated abrasion. For a premium aesthetic finish, laser marking on stainless steel enables line widths below one tenth of a millimeter and controlled gradients, while scribe marking produces a continuous line perceived as high quality on visible parts (e.g. stainless steel furniture or dashboard components). The required level of detail is assessed, expected durability is compared, and the most suitable technology is selected based on the desired balance between contrast, depth, and aesthetics.

For thin and flexible stainless steel parts, the mechanical load induced by the marking process becomes critical:

• Dot peen marking on stainless steel requires a rigid backing and uniform clamping—without this, each impact may cause irreversible deformation.
• Scribe marking on stainless steel parts, due to continuous contact, further increases the risk of local deformation on thin sections. Conversely, when rigidity is high (massive parts, thickness > 3 mm), priority shifts to depth and mechanical durability: dot peen marking and scribe marking achieve useful depths without compromising the part.
• Laser engraving on stainless steel remains essential when the objective is maximum contrast for camera-based reading; it allows adjustment of speed and number of passes to achieve controlled depth without mechanical contact, but requires higher power levels and longer cycle times to reach equivalent depths.

Laser engraving, thanks to its non-contact operation, offers a clear advantage for complex geometries: it can mark stainless steel parts in narrow access areas or on surfaces that are impossible to reach with scribe marking or dot peen marking. Robotic 6-axis systems are frequently integrated to maintain an optimal angle of incidence (accuracy < 0.5 mm), combined with modular fixturing to ensure high repeatability on complex series—a solution commonly used in aerospace for stainless steel parts with organic shapes.

Laser engraving on stainless steel parts makes it possible to achieve spot sizes of 20 to 50 μm and generate line widths below 0.1 mm. It can therefore produce very small text (1 to 2 mm in height) and logos with fine details, without contact and without tool wear. By contrast, dot peen marking on stainless steel offers a typical resolution of 1 to 4 dots/mm, with line widths generally between 0.3 and 0.6 mm: an ideal format for robust Data Matrix codes, but less suitable for the precise reproduction of a logo. Scribe marking on stainless steel delivers a continuous, very clean line—appreciated for premium finishes on 304 stainless steel/316 stainless steel—with typical line widths from 0.2 to 0.5 mm and excellent consistency on flat surfaces. However, on very hard stainless steels (420, duplex), fineness and sharpness may decrease without optimized equipment or increased power.

The visual durability of a marking depends as much on its depth as on the marking process used. Laser engraving in annealing mode alters the surface color with very little material removal (typically 1 to 10 μm): it provides excellent chemical resistance but is less effective against intense mechanical friction. By contrast, dot peen marking and scribe marking create true engraved recesses (≈ 50–300 μm for dot peen, ≈ 100–500 μm for scribe marking) that maintain readability and contrast even after abrasion, making them the preferred solutions for stainless steel parts exposed to wear or frequent handling. An engraved marking or properly controlled annealing directly determines corrosion resistance and long-term aesthetic performance.

Ambient conditions (marine environments, chlorinated atmospheres, frequent cleaning, chemical products) directly affect the durability of the marking.

Corrosion resistance:

The stainless steel grade also determines the choice of marking technology: 316 stainless steel offers better resistance in chlorinated environments than 304 stainless steel; duplex stainless steels and high-alloy stainless steels provide the highest performance, while martensitic grades (e.g. 420) are more sensitive.

On 316 stainless steel or duplex stainless steel, high-contrast laser marking remains compatible with good corrosion resistance after passivation.

Contact-based processes—dot peen marking on stainless steel or scribe marking—can retain residues, which is why passivation or bath cleaning is often required.

Adaptability to operating conditions:

Production rate, handling, and accessibility influence the selected marking technology.

Fiber laser marking enables high-speed in-line integration, while dot peen marking requires more maintenance, and scribe marking demands precise part clamping.

For automated series (DMC/QR), laser engraving on stainless steel is generally preferred for its speed and vision-system compatibility.

Typical marking depths directly impact wear resistance and corrosion risk. Evaluating maintenance requirements and post-treatments (passivation, pickling) remains essential to ensure compliance under real operating conditions.