Laser Marking Application Case: Standard Marking on Carbon Steel

Equipment Configuration: Chuangxin MFP Series 20W / 30W / 50W Fiber Laser

Carbon steel (commonly referred to as “iron”) is the most fundamental metal material in industry, widely used in tools, molds, structural components, and more. Carbon steel has a higher absorption rate for fiber lasers than stainless steel, resulting in more pronounced color contrast during marking—making it one of the easiest materials for laser marking.

I. Material Characteristics

The main components of carbon steel are iron and carbon, with a relatively high absorption rate for 1064nm fiber lasers. When heated by the laser, the surface rapidly oxidizes to form a mixed layer of Fe₃O₄ and FeO, producing marks ranging from deep black to brownish-black.

Types of carbon steel:

• Low-carbon steel (carbon content <0.25%): Softer, easy to mark, clear black marks
• Medium-carbon steel (carbon content 0.25-0.60%): Moderate hardness, stable marking results
• High-carbon steel (carbon content >0.60%): Harder, requires slightly higher energy
• Cast iron: High carbon content (>2%), may exhibit graphite precipitation during marking, marks tend toward gray

II. Equipment Configuration

III. Parameter Reference

20W Model

30W Model

50W Model

Comparison with stainless steel: Carbon steel marking typically requires 10-15% lower power percentage than stainless steel, because carbon steel has a higher absorption rate and forms black marks more easily.

IV. Effect Characteristics

• Color: Deep black to brownish-black, good contrast
• Clarity: Clear marks, sharp edges
• Feel: Slight tactile sensation
• Wear Resistance: Good, oxide layer firmly bonded to the substrate
• Comparison with stainless steel: Black marks on carbon steel are easier to achieve than on stainless steel, and the color is deeper

V. Precautions

1. Rust issues: If the carbon steel surface has rust, it must be ground or derusted before marking, otherwise the marks will be uneven
2. Surface oil: Carbon steel often has anti-rust oil; thoroughly clean with alcohol before marking
3. Coated carbon steel: If the carbon steel has a coating (galvanized, chrome-plated, etc.), the laser must first remove the coating before marking; parameters need to be appropriately increased
4. Cast iron caution: Cast iron surfaces are porous and loose; marks may not be clear enough. It is recommended to increase power or use denser hatch spacing
5. Anti-rust treatment: Laser marking damages the surface oxide layer of carbon steel, making the marked area more susceptible to rust. If the product requires rust prevention, anti-rust treatment is recommended after marking

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VI. Application Scenarios

• Tool / cutter brand identification
• Mechanical component numbering
• Mold coding
• Hardware product logos
• Carbon steel pipe / valve identification
• Construction hardware marking

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Summary: Carbon steel is one of the most “friendly” materials for laser marking—high absorption rate, easy to achieve black marks, and a wide parameter window. The 20W model can handle most requirements, while the 30W/50W models offer higher efficiency for large batch production.

*Actual results may vary slightly depending on carbon steel grade and surface condition. It is recommended to create samples before batch production.*