Product Overview
Spring Steel Flat Bars are engineered for applications requiring high yield strength, elasticity, and resistance to permanent deformation. Delivered in hot-rolled or cold-drawn states, these bars maintain uniform mechanical properties after quenching and tempering.
Technical Specifications
|
Common Grades |
GB/T: 60Si2Mn, 50CrVA, 65Mn DIN/EN: 1.7176 (51CrV4), 1.0961 (65Si7) AISI/SAE: 5160, 1074, 1080 |
|
Dimensional Range |
Thickness: 3.0 mm - 50.0 mm Width: 20.0 mm - 200.0 mm |
|
Condition |
Hot-rolled, cold-drawn, annealed (softened for stamping), or quenched and tempered. |
|
Edge Types |
Mill edge, slit edge, or deburred square edge. |
|
Tolerances |
Compliant with EN 10058 / ASTM A29 standards. |
|
Standard Lengths |
3,000 mm - 6,000 mm (custom cut-to-length available). |
Product Advantages
Consistent Hardenability:
Controlled silicon and manganese content ensures uniform grain structure during heat treatment.
Controlled Decarburization:
Maximum total decarburization depth is restricted to under 1.5% of thickness per side, preserving surface fatigue resistance.
Dimensional Stability:
Strict thickness and width control minimizes die clearance adjustments in automated stamping lines.
Straightness Control:
Mill camber does not exceed 1.5 mm per meter, ensuring smooth feeding in progressive stamping tools.
Applications
Automotive suspension leaf springs and stabilizer bars (compliant with automotive tier-2/tier-3 manufacturing demands).
Industrial shear blades, scrapers, and heavy-duty agricultural machinery tines.
Heavy-duty retaining rings, washers, and industrial fastening clips.
High-stress hand tools, putty knives, and masonry trowels.
Customization & Processing
Heat Treatment: In-house spheroidize annealing for improved cold formability; quenching and tempering lines yielding hardness up to 45-52 HRC.
Cutting Services: Saw cutting and shear cutting to exact production lengths with burr-free ends.
Surface Treatments: Shot blasting for scale removal, protective anti-rust oil coating, or un-oiled bare finish per customer specification.
Mill Capabilities: 3 rolling mills with an annual output of 80,000 metric tons, supporting custom cross-sectional profiles on a minimum order quantity (MOQ) basis.
Quality Control & Inspection
Chemical Analysis: Spectrometer testing on every heat ladle to verify carbon, silicon, manganese, chromium, and sulfur/phosphorus limits.
Mechanical Testing: Tensile strength, elongation, and Brinell/Rockwell hardness testing performed on samples from each batch.
Surface & Internal Defect Detection: Ultrasonic testing for internal inclusions and eddy current testing for surface cracks.
Documentation: EN 10204 3.1 Mill Test Certificate provided with every shipment.
Packaging & Shipping
Bundling:
Steel strapped bundles weighing 1,000 kg to 3,000 kg, secured with wooden runners for forklift handling.
Export Compliance:
ISPM 15 compliant heat-treated wooden pallets and skids for seamless customs clearance in Europe and North America.
Protection:
Plastic inner wrap combined with moisture-resistant woven outer packaging for sea freight protection, fully compliant with EU RoHS and REACH environmental standards.
Logistics:
Direct loading into 20-foot containers or open-top trucks from port-adjacent manufacturing facilities.
FAQ
Q: What is the difference between annealed and unannealed spring steel flat bars?
A: Annealed bars have a lower hardness and improved ductility, intended for parts requiring intensive cold stamping or bending prior to final heat treatment. Unannealed bars are delivered in the hot-rolled state for direct machining or immediate end-use.
Q: How do you control surface decarburization?
A: Heating furnaces utilize controlled atmosphere parameters and optimized soaking times to limit carbon depletion on the steel surface, keeping decarburization within strict technical limits.
Q: Can you supply custom chemical compositions outside standard grades?
A: Yes. Vacuum induction melting and custom alloying adjustments are available for orders meeting minimum tonnage thresholds.
Q: What is the standard MOQ for non-standard widths and thicknesses?
A: Minimum order quantities typically start at 3 metric tons per size for custom rollings, while standard stock items are available in smaller trial quantities.
Q: What documentation is included with the delivery?
A: Each shipment includes a commercial invoice, packing list, bill of lading, and an EN 10204 3.1 Material Test Report detailing actual chemical composition and mechanical test results.
Q: How are the flat bars protected against corrosion during ocean transit?
A: Bars are coated with a neutral rust-preventive oil, wrapped in moisture-barrier plastic film, and packed in heavy-duty strapped steel bundles loaded onto ISPM 15 compliant wooden supports.
Request a Quote
Provide your specifications below to receive a formal quotation, including material availability, mill lead time, and shipping terms (FOB/CIF).
Required Steel Grade: (E.g., 51CrV4 / 60Si2Mn)
Dimensions (Thickness x Width in mm):
Quantity (Metric Tons / Pieces):
Required Condition: (Annealed / Hot-Rolled / Quenched & Tempered)
Hot Tags: spring steel flat bar, China spring steel flat bar manufacturers, suppliers, factory