Alloy Spring Steel

Name: China Alloy Spring Steel Manufacturers Suppliers - Wholesale Alloy Spring Steel for Sale
Brand: Promisteel
SKU: 293458131

NAME: Alloy Spring Steel / Suspension Steel
BRAND: PROMISTEEL
GRADES: 60Si2Mn, 50CrV4, 5160, SUP9, 6150, 9260
SHAPES: Round Bar, Flat Bar, Wire Rod, Coil
DELIVERY CONDITION: Hot Rolled, Peeled, Spheroidizing Annealed
SURFACE: Black, Ground, Turned (Defect-free)
FATIGUE LIMIT: High Cycle (>2x10^6 Cycles)
APPLICATION: Leaf Springs, Coil Springs, Torsion Bars, Stabilizers
MOQ: 25 Tons

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Product Introduction

Alloy Spring Steel is the critical material behind the suspension systems of the world's vehicles and heavy machinery. Unlike simple carbon spring steels, Alloy Spring Steel is fortified with Manganese (Mn), Silicon (Si), Chromium (Cr), and Vanadium (V).

We specialize in supplying high-grade alloy spring steel that solves the two biggest challenges in spring manufacturing: Fatigue Failure and Load Loss (Sagging). By strictly controlling the inclusion content and surface decarburization depth during the rolling process, our steel ensures that leaf springs and coil springs maintain their elasticity and height even after millions of load cycles.

Product Specifications & Grade Equivalents

We cover the full spectrum of global spring steel standards, from the widely used Si-Mn series to the high-performance Cr-V series.

Table-1

Match your engineering specs with our global equivalents.

International Grade Comparison
GB (China)	ASTM / AISI (USA)	DIN (Germany)	JIS (Japan)	Characteristics / Use
60Si2Mn	9260	1.0909	SUP7	High Elastic Limit, Cost-Effective
55CrMnA	5155	1.7176	SUP9	Automotive Leaf Springs
60CrMnA	5160	1.716	SUP9A	Heavy Duty Leaf Springs
50CrV / 50CrVA	6150	1.8159 (51CrV4)	SUP10	High Fatigue & Temp Resistance
60Si2CrVA	9254	1.7102 (54SiCr6)	SUP12	High Stress Valve Springs

Table-2

Clean steel technology ensures low P/S impurities for maximum toughness.

Chemical Composition (Mass Fraction %)
Grade	C	Si	Mn	Cr	V
60Si2Mn / 9260	0.56~0.64	1.50~2.00	0.60~0.90	≤0.35	-
55CrMnA / SUP9	0.52~0.60	0.20~0.50	0.65~0.95	0.65~0.95	-
60CrMnA / 5160	0.56~0.64	0.20~0.50	0.70~1.00	0.70~1.00	-
50CrV / 6150	0.46~0.54	0.17~0.37	0.50~0.80	0.80~1.10	0.10~0.20

Table-3

Tailored dimensions for flat spring and coil spring production.

Supply Range & Formats
Product Form	Dimensions (mm)	Surface Condition	Typical Application
Flat Bar	Width: 40-150	Thickness: 5-40	Hot Rolled / Shot Blasted
Round Bar	Dia: 5.5 - 250	Hot Rolled / Peeled	Coil Springs, Torsion Bars
Wire Rod	Dia: 5.5 - 20	Pickled / Annealed	Cold Wound Springs

What Matters to Spring Manufacturers?

We understand that a spring is only as good as the steel it's made from. Here is how we address your production concerns:

Strict Decarburization Control

Surface carbon loss creates a soft layer that leads to microscopic cracks. We use advanced heating furnaces to minimize the decarburization layer (typically controlled within <1% of diameter), ensuring superior fatigue life.

High Fatigue Life (Cycle Life)

For automotive applications, our 50CrV4 (6150) and SUP9 grades are engineered to withstand millions of compression cycles without fracture, meeting OEM fatigue standards.

Excellent Hardenability

Unlike carbon steel, our Alloy Spring Steels (like 5160) ensure uniform hardness from the surface to the center, even in thick sections (e.g., heavy-duty truck leaf springs >20mm thick).

Sag Resistance (Anti-Settling)

The addition of Silicon (in 9260) and Vanadium (in 6150) significantly increases the Yield Strength/Tensile Strength ratio. This prevents the spring from losing height or "sagging" under long-term load.

Typical Applications

Alloy Spring Steel is the backbone of the transportation and industrial sectors:

Automotive Suspension:

Leaf Springs: Heavy trucks, trailers, and pickups (uses SUP9, 5160).
Coil Springs: Passenger cars and shock absorbers (uses 60Si2Mn, 50CrV4).
Stabilizer Bars / Torsion Bars: Require high toughness (uses 4140, 50CrV4).

Railway Industry:

Large diameter coil springs for train bogies and elastic rail clips (uses 60Si2CrVA).

Industrial Machinery:

Safety valve springs, crusher springs, and mining equipment sieves.

FAQ

Q1: What is the best steel for heavy-duty truck leaf springs?

A1: AISI 5160 (60CrMnA) or SUP9A is the industry standard for heavy-duty leaf springs. The Chromium content provides the deep hardenability needed for thick leaves, ensuring the spring doesn't permanently deform under heavy loads.

Q2: Why choose 50CrV4 (6150) over 60Si2Mn?

A2: While 60Si2Mn is cost-effective and widely used, 50CrV4 (6150) contains Vanadium. Vanadium refines the grain size and significantly improves toughness and heat resistance. If your spring operates in high-stress or high-temperature environments (like engine valve springs), 50CrV4 is the superior choice.

Q3: Does "Peeling" the round bar improve spring quality?

A3: Yes, absolutely. Peeling removes the surface layer of the hot-rolled bar, eliminating all surface defects, micro-cracks, and the decarburization layer. Using peeled bars is the best way to guarantee maximum fatigue life for high-end coil springs.

Q4: What is the difference between SUP9 and SUP9A?

A4: SUP9 is equivalent to 5155, while SUP9A is equivalent to 5160. SUP9A has slightly higher Carbon and Manganese, giving it higher strength and hardenability, making it suitable for thicker spring sections.

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