Spring Steel Round Bar
Introduction:
Spring steel round bar is a special elastic steel produced by EAF smelting, LF refining, VD vacuum degassing and controlled hot rolling. With optimized C, Si, Mn, Cr, V alloy matching, it features ultra-high elastic limit, superior fatigue resistance, excellent temper stability and outstanding hardenability.
Product Overview
Spring steel round bar is a special elastic steel produced by EAF smelting, LF refining, VD vacuum degassing and controlled hot rolling. With optimized C, Si, Mn, Cr, V alloy matching, it features ultra-high elastic limit, superior fatigue resistance, excellent temper stability and outstanding hardenability. Diameter range covers ø12–120 mm, covering domestic, European and Japanese mainstream grades: 65Mn, 60Si2Mn, 55Cr3, 50CrV, 51CrMnV, 51CrV4, 55CrMn, 60Si2CrVAT, SUP6, SUP7. Available in hot-rolled black bar, annealed, spheroidized annealed and peeled bright bar states. Widely used for automotive suspension springs, railway elastic fasteners, engineering machinery buffer springs, torsion bars, mold elastic parts and high-temperature heavy-load elastic components.
Representative Grades
|
Grade |
Executive Standard |
Core Performance & Application |
|
65Mn |
GB/T 1222 |
Carbon-manganese spring steel, good plasticity & low cost; small coil springs, spring washers, light-load elastic pins |
|
60Si2Mn / SUP6 |
GB/T 1222 / JIS G4801 |
Silicon-manganese spring steel, high elastic limit, max working temp ≤250℃; auto leaf springs, railway elastic clips, shock-absorbing springs |
|
SUP7 |
JIS G4801 |
High-strength silicon-manganese alloy spring steel, higher fatigue strength than SUP6; heavy-duty automotive suspension, large-diameter torsion bars |
|
55CrMn |
GB/T 1222 |
Cr-Mn spring steel, low decarburization tendency, stable strength; medium-load coil springs, agricultural machinery elastic parts |
|
55Cr3 |
EN 10089 |
European standard Cr spring steel, uniform hardening; medium-load industrial springs, cold forming elastic components |
|
50CrV / 51CrV4 |
GB/T 1222 / EN 10089 |
Cr-V series, excellent temper resistance up to 300℃, ultra-high toughness; heavy-duty large-section springs, engine valve springs |
|
51CrMnV |
GB/T 1222 |
Cr-Mn-V composite alloy, balanced strength & fatigue life; mining equipment buffer springs, heavy-duty torsion parts |
|
60Si2CrVAT |
GB/T 1222 |
High-grade high-temperature resistant spring steel, ultra-fine grain, anti-relaxation; high-speed engine springs, aerospace elastic components |
Grade Description
-
01
65Mn: Carbon manganese spring steel, high cost performance, suitable for small and medium-sized light-load elastic components.
-
02
60Si2Mn/SUP6/SUP7: Silicon-manganese spring steel. Silicon enhances the elastic limit, making it suitable for mainstream springs in automobiles and rail transportation. SUP7 has superior strength and fatigue performance compared to SUP6.
-
03
100Cr6 / SAE52100 / SUJ2: Internat55CrMn/55Cr3: Chromium-manganese and pure chromium spring steel, with low decarburization tendency and dimensional stability after heat treatment.ional universal bearing steel grades, consistent chemical composition and mechanical properties with domestic GCr15, for overseas export orders.
-
04
50CrV/51CrV4: Chromium-vanadium spring steel, with refined vanadium grains, high temperature resistance, and tempering resistance; the first choice for large-section heavy-duty springs.
-
05
51CrMnV: A chromium-manganese-vanadium composite alloy that balances hardenability and fatigue life.
-
06
60Si2CrVAT: High-end silicon-chromium-vanadium spring steel, with high purity and high-temperature relaxation resistance, used in high-end high-temperature elastic components.
Product Specifications
|
Item |
Specific Parameters |
|
Product Form |
Hot rolled round bar;Forged round bar;Peeled bright bar |
|
Diameter Range |
ø12 mm – ø120 mm |
|
Standard Length |
3m / 6m / 9m; customized fixed-length cutting supported |
|
Delivery Condition |
Hot rolled (AR) / Full annealing / Spheroidized annealing / Quenched & tempered (QT) |
|
Surface Treatment |
Hot rolling oxide scale; shot blasting, peeling & grinding optional |
|
Size Tolerance |
Comply with GB/T702, EN10089, JIS G4801 standard tolerance |
|
Decarburization Control |
Strictly limited thin total decarburization layer, meets spring steel high-standard requirements |
|
Straightness |
Standard grade ≤3mm/m; precision peeled bar ≤1.5mm/m |
Core Advantages
1. Complete Domestic & International Grade Coverage: Integrate GB, EN, JIS spring steel series, match light, medium, heavy load and high-temperature working conditions, satisfy domestic manufacturing and export orders simultaneously.
2. Excellent Elastic & Fatigue Performance: Optimized alloy formula delivers high elastic limit and yield ratio, effectively avoid permanent deformation; fine grain structure greatly extend service life under cyclic alternating load.
3. Superior Hardenability & Temper Stability: Si, Cr, V composite alloying improves through-hardening capacity for medium-large diameter bars; Cr-V grades maintain stable elasticity at working temperature up to 300℃ without softening.
4. Strict Surface & Metallurgical Control: Low decarburization layer, minimal surface cracks and defects; EAF+LF+VD triple refining reduces harmful impurities, uniform internal metallographic structure.
5. Good Formability in Annealed State: Annealed/spheroidized bars with moderate hardness, easy coiling, bending, cold forming and machining.
6. Diversified Deep Processing Service: Support annealing, spheroidizing, QT heat treatment, peeling, straightening, fixed cutting and non-destructive testing customization.
Main Application Fields
-
Automotive Industry
Suspension coil springs, leaf springs, stabilizer bars, clutch springs, engine valve springs, shock absorber elastic parts.
-
Railway Transportation
Rail elastic fasteners, bogie buffer springs, vehicle suspension springs, coupler damping components.
-
Engineering & Agricultural Machinery
Excavator buffer springs, harvester elastic parts, heavy-duty torsion bars, machinery safety valve springs.
-
Mold & Hardware Manufacturing
Mold ejector springs, spring washers, retaining rings, flat springs, high-strength elastic pins.
-
Heavy-Duty Industrial Equipment
Large-diameter torsion springs, pressure equipment buffer components, mining machinery shock-absorbing parts.
-
High-Temperature Special Equipment
60Si2CrVAT high-grade steel for high-speed engine springs, aerospace elastic connecting elements.
Packaging & Services
- 1. Executive Standards: GB/T 1222-2007, EN 10089, JIS G4801; support customized technical requirements for special spring grades.
- 2. Full Inspection Items: Chemical composition analysis, tensile test, hardness test, decarburization layer measurement, metallographic grain inspection, fatigue performance sampling test; optional ultrasonic flaw detection (UT), magnetic particle inspection (MPI).
- 3. Material Certification: EN10204 MTC 3.1 mill test certificate; SGS, BV third-party factory inspection and certification available.
- 4. Packaging: Steel wire bundled, waterproof plastic film wrapped, end anti-collision protective caps; container and bulk vessel shipment supported.
- 5. MOQ: 1 ton per grade; mixed grades and mixed sizes can be loaded in one container.
- 6. Custom Processing: Spheroidizing annealing, quenching & tempering, peeling & grinding, fixed-length cutting, shot blasting rust removal, stress relief heat treatment.
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- WhatsApp: +86-185 9567 2991
- Email: martinliu@rongtianmetal.com
- Tel: +86-185 9567 2991
- Address: 8F, Bldg 2, Jinke Zhihui Valley No. 65 Hongyuan Rd., Jinshui Dist. Zhengzhou, China.
