1. Chemical Composition & Mechanical Properties of Leaf Spring Steels
Choosing the wrong leaf spring material for a given blade thickness causes incomplete core martensite transformation during oil quenching, leading to rapid arch sagging or brittle eye fracture. Below is our laboratory metallographic and mechanical comparison across JIS G 4801, SAE J404, DIN EN 10089, and GB/T 1222 standards:
| Steel Grade | Equivalent Standards | Carbon & Alloying Elements | Tensile / Yield Strength | Quenched & Tempered Hardness | Max Hardenable Thickness & Use Case |
|---|---|---|---|---|---|
| SUP9 | SAE 5155 / DIN 55Cr3 / 55CrMnA | 0.52–0.60% C, 0.65–0.95% Mn, 0.65–0.95% Cr | ≥1,225 MPa / ≥1,080 MPa | 388–461 HBW (41–48 HRC) | t ≤ 20 mm; TRA-2726, Mitsubishi MC413899/F |
| SUP9A | SAE 5160H / 60CrMnA | 0.56–0.64% C, 0.70–1.00% Mn, 0.70–1.00% Cr | ≥1,275 MPa / ≥1,125 MPa | 401–461 HBW (42–48 HRC) | t ≤ 28 mm; Heavy Truck Multi-Leaf Springs |
| SUP11A | SAE 51B60H / 60CrMnBA | 0.56–0.64% C, Cr-Mn + 0.0005–0.0035% Boron | ≥1,325 MPa / ≥1,175 MPa | 401–477 HBW (43–49 HRC) | t ≤ 45 mm; 24T Bogie Packs & Mining Trucks |
| 50CrVA | DIN 51CrV4 / SAE 6150 / SUP10 | 0.47–0.55% C, 0.80–1.10% Cr, 0.10–0.25% V | ≥1,375 MPa / ≥1,225 MPa | 415–477 HBW (44–50 HRC) | t ≤ 56 mm; BPW 880368, TRA-021 Mono-Leaf |
| 60Si2Mn | SAE 9260 / DIN 60SiCr7 / SUP7 | 0.56–0.64% C, 1.50–2.00% Si, 0.60–0.90% Mn | ≥1,274 MPa / ≥1,176 MPa | 375–444 HBW (40–46 HRC) | t ≤ 14 mm; 750lb–1750lb Utility Trailer Springs |
2. Heat Treatment, Decarburization Control & Load-Simulated Stress Shot-Peening
Even premium virgin SUP9A or 50CrVA spring steel will fail prematurely if surface carbon is lost during furnace heating. At XIANGZEWO’s IATF 16949:2016 plant, every batch is verified by metallographic microscope (total decarburization layer ≤0.20 mm), quenched in temperature-controlled polymer/oil baths, tempered in hot-air circulating furnaces, and stress shot-peened under rated load to guarantee ≥180,000 bench fatigue cycles.
Complete XIANGZEWO Leaf Spring Engineering Guides, Category Hubs & OEM Part Number Directory
Explore our direct IATF 16949:2016 factory technical guides, suspension architecture comparisons, and OEM replacement specification pages (2-hop direct engineering index):
1. Core Suspension Hubs & Custom Engineering Services
China Leaf Spring Manufacturer Home |
All Heavy-Duty Leaf Springs |
Commercial Truck Leaf Springs |
Utility & Semi-Trailer Leaf Springs |
Custom Leaf Springs by Drawing |
Parabolic Leaf Spring Services & Testing |
Parabolic Tapered Springs |
Multi-Leaf Springs |
Long Taper Springs |
Z-Leaf Air Suspension Springs |
Agricultural Leaf Springs |
OEM Catalog Shop |
About XIANGZEWO Factory |
Manufacturing FAQ |
Technical Blog |
Request a 24h OEM Quote
2. Truck & Trailer Brand Category Hubs
Isuzu Leaf Springs |
Scania Leaf Springs |
Mitsubishi Fuso & Canter Leaf Springs |
BPW Trailer & Bogie Leaf Springs |
Hutchens / American TRA Trailer Springs |
Semi-Trailer Bogie & Germany-Type Springs |
Air Link Trailing Arm Springs |
Air Beam Suspension Springs |
Ford Truck Leaf Springs |
Freightliner Leaf Springs |
International Navistar Leaf Springs |
Nissan UD Leaf Springs |
Toyota & Hino Leaf Springs |
Light-Duty & Export Truck Leaf Springs |
Volvo Truck Springs |
MAN Truck Springs |
Mercedes-Benz Truck Springs |
Hendrickson Suspension Springs |
Mack Truck Springs |
Iveco Truck Springs |
Kamaz Truck Springs |
GAZ Light Truck Springs |
Hyundai Truck Springs |
Volkswagen Commercial Springs |
Specialty OEM Leaf Springs
3. Direct OEM Part Number Specification Pages (30 Verified Models)
Trailer & Bogie Series:
Hutchens TRA-2726 (3L 76×20mm) |
Hutchens TRA-2727 Parabolic |
Hutchens TRA-2728 Low-Arch |
Hutchens TRA-2732 (8-Leaf) |
Hutchens TRA-2740 (3L 76×24mm) |
Reyco TRA-2260 (8-Leaf) |
Fruehauf TRA-699 (4-Leaf) |
Fruehauf TRA-021 Mono-Leaf (50CrVA) |
11436 Semi-Trailer Spring (9L 76×14mm) |
T410012 Germany-Type Trailer Spring (11L 100×12mm) |
BPW 24T Bogie Spring (18L 90×13/17mm) |
1.75" 4-Leaf Mobile Home & Utility Trailer Spring (750lb–1750lb) |
1.75" Tapered Mono-Leaf RV & Boat Trailer Spring |
80×20×1600mm 12-Leaf Heavy Trailer Pack
Commercial Truck & Air Suspension Series:
Isuzu 1-51130-961-0 Parabolic/Multi-Leaf |
Scania 1421060 Air Suspension Spring (100×47/45mm) |
BPW 880368 Air Link Spring (100×38mm 51CrV4) |
Forged Z-Type Air Beam Trailing Arm |
Mitsubishi MC413899/F, L200 MR448146 & Canter MB294519 |
Nissan UD 54010-Z3007-FA Parabolic (90×12mm 9L) |
Ford 43-698 Front Truck Pack (9L 100mm) |
Ford 43-1199 (431199) Truck Pack (4L 63mm) |
Freightliner 46-1189 Class 8 Pack (13L 76mm) |
International 55-031 Navistar Pack (13L 76mm) |
HPF5 Light Truck Spring (6L 70×11/13mm) |
IE2F P60/10/6V Light Commercial Spring |
TC P60/8/2 Light-Duty 3+2 Leaf Spring |
NDT P60/8/2 Front Parabolic Light Truck Spring |
3" Variable-Section Heavy Truck Parabolic Spring |
6–56mm Custom OEM Truck & Bus Leaf Springs (MAN/Volvo/Hino/YUTONG)
4. Technical Calculators, Load Charts & Industry Guides
Types of Leaf Springs: Cantilever, Semi-Elliptical & Full Elliptical Guide |
Interactive Leaf Spring Rate & Load Capacity Calculator |
110+ OEM Truck & Trailer Leaf Spring Cross-Reference Chart |
Parabolic Leaf Spring Services vs. Semi-Elliptic Multi-Leaf Guide |
3-Leaf to 6-Leaf Trailer Leaf Spring Load Chart (705lb–5000lb) |
Custom Truck Leaf Springs |
Agricultural Trailer Leaf Springs |
Automotive Aftermarket Leaf Springs |
Oilfield & Frac Trailer Leaf Springs |
Mining Dump Truck Leaf Springs |
Military-Wrap Tactical Leaf Springs |
Construction Mixer & Lowboy Leaf Springs |
Engineering Guides Archive |
Custom Industry Archive
Additional OEM Suspension Configurations: For specialized heavy-duty axle and air-suspension applications, compare our 24T Heavy-Duty Bogie Multi-Leaf Suspension Spring Pack, Custom OEM Heavy Truck SUP9/50CrVA Leaf Spring Assembly engineered with shot-peened SUP9A and 50CrVA alloy steel.
Selecting between 60Si2Mn, SUP9, SUP9A, and 50CrVA directly impacts low-temperature Charpy impact toughness and decarburization resistance across our leaf springs and truck spring production: for example, sub-zero Russian and Eurasian routes specify SUP9A or 50CrVA on the customized light truck front leaf spring for Russia market and HPF5 Russia-market light truck leaf spring, while standard urban delivery fleets utilize the auto part light-duty truck leaf spring and SUP steel light truck leaf spring.
Thick-section hardenability in SUP11A and 50CrVA (51CrV4) is mandatory for our new Z-type air beam spring (under air beam spring and air link spring), OEM customization heavy truck leaf spring, custom heavy truck suspension trailer leaf springs, and OEM high-quality various-type truck leaf springs. In contrast, 60Si2Mn and SUP9 deliver optimal cost-to-elasticity for our custom mobile home leaf spring and OEM mobile home leaf springs in the trailer spring, TRA-type leaf spring, and trailer-type leaf spring categories.
Review metallurgical heat-treatment standards across BPW leaf spring, Scania leaf spring, Isuzu leaf spring, Mitsubishi leaf spring, Ford leaf spring, Freightliner leaf spring, International leaf spring, Nissan leaf spring, and other custom leaf spring lines, as well as our metallurgy engineering guides and industry application resources.
Frequently Asked Engineering and OEM Procurement Questions (FAQ)
What material is best for heavy-duty truck and trailer leaf springs?
SUP9 (SAE 5155) and SUP9A (SAE 5160H) are the industry standard for multi-leaf truck and trailer springs up to 28 mm thick. For thick parabolic springs and Z-type air suspension arms (28 mm to 56 mm thick), 50CrVA (DIN 51CrV4) and SUP11A boron-alloy steel provide superior core hardenability and fatigue life.
