Spring Steel Strip

In accordance with GB/T 13304 standard, spring steel is divided into non-alloy spring steel (carbon spring steel) and alloy spring steel based on chemical composition.
The carbon content of carbon spring steel generally ranges from 0.62% to 0.90%. It can be classified into regular manganese grade (0.50%–0.80% Mn) and high manganese grade (0.90%–1.20% Mn) by manganese content, with 65Mn as a typical example.
Alloy spring steel takes carbon steel as the base matrix. By appropriately adding one or more alloying elements, its mechanical properties, hardenability and other performances can be improved to meet the manufacturing requirements of various springs.
In addition, certain grades of high-quality carbon structural steel, carbon tool steel, high-speed tool steel, stainless steel, etc., can also be used for spring production.

Standard: GB/T 13304
Main grades: 65Mn, 50CrVA, 60Si2Mn
Carbon spring steel C: 0.62%–0.90%; Mn 0.50%–0.80% (regular) / 0.90%–1.20% (high-Mn, e.g. 65Mn)
Thickness: 0.08–4.5 mm
Width: 7–650 mm
Applications: Springs for automotive components, clutch parts, diaphragm springs and other related products

Spheroidization rate ≥95%
Thickness tolerance ±0.005mm
Custom packaging available (wooden crates / fumigation-free pallets / plywood pallets)
Anti-rust warranty ≥6 months

Q1: What are the primary applications of your company's spring steel materials?
A1: Compressor valve plates / shock absorber valve plates, textile machine needles/pointers, printing ink doctor blades, stone processing gang saw blades, wood sawing tools, medical devices, automotive parts, hardware tools, footwear materials, coil springs / clockwork springs.

Q2: Which grades are best suited for automotive parts, and can heat-treatment hardness be customized per drawing?
A2: 65Mn is our highest-volume domestic spring steel grade, used for seat clips, wire harness spring plates, snap fasteners and small clutch shims - balanced toughness that resists cracking under stamping. 60Si2Mn suits chassis heavy-duty springs and stabilizer bars. 51CrVA (EU-equivalent 51CrV4) is preferred for clutch diaphragm springs, valve springs and other high-fatigue precision springs. Heat-treatment hardness can be customized according to customer drawings.

Q3: What is the maximum thickness available for stamping-grade spring steel strip?
A3: Standard cold-rolled spring/tool steel strip (SK5, 65Mn, T10A) is available in 0.08-4.5mm; below 0.08mm we can supply ultra-precision ultra-thin strip (0.01-0.1mm) for micro precision stamping such as battery contacts and micro spring plates.

Q4: What hardness levels can you provide?
A4: Hardness is customized to customer requirements, up to a maximum of 60 HRC (Rockwell).

Q5: Do you provide chemical composition test reports, and what is the sample delivery lead time?
A5: Every batch is supplied with an MTC (Material Test Certificate) report. Standard order delivery time is approximately 35 days.

Q6: What tolerance precision can you control to?
A6: We operate two Sendzimir 20-high rolling mills from the US, achieving thickness tolerance as tight as ±0.003mm.