High- & Low-Carbon Wire｜Strong, Tough, Easy to Form – Ideal for Springs and Mechanical Components

Key Industry ChallengesIn the production of springs, screws, bolts, and mechanical parts, common issues include inconsistent wire quality across batches, cracking or deformation during forming, and final products that fail to return to their intended shape. These problems typically stem from the use of improperly annealed wire or wire with an unsuitable carbon content, which results in excessive brittleness or softness. This leads to increased production costs from material waste and rework.

Root Cause of the Problem

Standard carbon wire often has a coarse microstructure and contains impurities that result in inconsistent strength, residual stress, and a higher risk of cracking during drawing or coiling. In particular, wire that hasn't undergone vacuum degassing or precise carbon content control may end up being too hard or too soft, which directly affects its formability and durability under real-world operating conditions.

Solution: Carbon Wire from Yamaichi

Yamaichi Special Steel (Thailand) offers Japanese-quality high and low carbon wire manufactured to JIS G3505, JIS G3506, JIS G3507, and JIS G4051 standards. Each wire undergoes multiple stages of annealing and cold drawing, with strict mechanical property inspections. Customers can select grades that best match their application—whether requiring high strength, good ductility and recovery, or ease of forming.

Specifications of YAMAICHI Carbon Wire

1. SW-A (Equivalent to SW40C) – Low Carbon Wire

• Carbon content: 0.35–0.45%
• Tensile strength: 700–900 MPa
• Easy to form – ideal for screws, bolts, binding wire, and general mechanical parts
• High ductility – easy to bend and further draw

2. SW-B (Equivalent to SW60C) – Medium Carbon Wire

• Carbon content: 0.55–0.65%
• Tensile strength: 900–1100 MPa
• Balanced strength and toughness
• Suitable for light springs and medium mechanical parts
• Annealed to relieve stress prior to forming

3. SW-C (Equivalent to SW80C) – High Carbon Wire

• Carbon content: 0.75–0.85%
• Tensile strength: 1100–1350 MPa
• Excellent recovery – suitable for springs and punching dies
• High fatigue resistance and long service life

4. SWRM6–12 – Hot Rolled Wire Rod for Forming

• Low to medium carbon steel (C ~0.10–0.25%)
• Suitable for cold heading and wire drawing in screw and bolt production
• Annealed for smooth surface and formability

5. SWRCH10K–15K – Cold Heading Quality Wire for Screws and Bolts

• Low carbon steel (C ~0.10–0.15%)
• Spheroidized annealing for fine, round grains
• Excellent cold formability
• Ideal for screws, bolts, and precision cold-formed parts

6. SWM – Wire for Machining Applications

• Medium to high carbon steel
• Cold drawn and precision annealed
• Smooth surface and consistent hardness to reduce tool wear
• Ideal for machining, drilling, and high-precision components

Key Advantages of Yamaichi Wire

• Produced to Japanese standards under ISO 9001:2015 quality control
• Precise control of carbon content and tensile strength in every batch
• Smooth, uniform surface free from nicks or roughness
• Cut-to-length or coil format available with custom packaging
• Ready for delivery within Thailand – supporting automotive, machinery, and mold industries

※ For more information, please contact us or download the brochure.

Glossary

• Tensile Strength: Maximum stress a material can withstand while being stretched before breaking
• Annealing: A heat treatment process that relieves stress and increases ductility
• Vacuum Degassing: A process to remove gases and impurities from steel to improve purity
• Cold Heading: A cold forming process used to manufacture bolts and screws

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