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SUP7 SUP9A SUP10 SUP11A 5160 Spring Steel Flat Bar for Leaf Spring

  • 20+ Years of experiences (since 1999)
  • Implementing ISO 9001-2015
  • Annual output (tons): 1,800,000+
  • Warranty: 18 months since shipping date
  • Market shares: 50%+ in China
  • Material characteristics: With excellent comprehensive property, high tensile strength and fatigue limit, high elastic limitation and yield ratio, but also has excellent plasticity and toughness.At the same time, it also has the favorable hardenailty and the surface quality.Moreover, it has favorable cold working performance and heat treatment technology property.

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WONDEE Spring flat bar application

Spring steel flat bar is a name given to a wide range of steels used in the manufacture of different products, including swords, saw blades, springs and many more. These steels are generally low-alloy manganese, medium-carbon steel or high-carbon steel with a very high yield strength.

The axle is widely applied to mainly used in automobile leaf spring, steering arm of air suspension, spring clamps, antennas, springs, and vehicle coil springs, leaf springs, and s-tines.

For more about WONDEE Leaf Springs Project, please click:

leaf springs project


Services quality management systemImplementing ISO9001-2015
Product technical standardImplementing GB/T 33164.1-2016, JIS, DIN, ASTM
Thickness tolerance±0.50 mm
Thickness tolerance±0.80 mm
Side bending≤0.25%
Plane bending≤0.50%
Surface quality:All thickness Max defect depth: 0.15mm
Sales volume (tons)1,800,000+
Warranty18 months since shipping date

Comprehensive Info of  Spring Steel Flat Bar:

Land area (square meters)2,800,000+
Sales volume (tons)1,800,000+
Number of employees8000+
Technical professionals1200+
Market shares50%+ in China
Overseas marketIt takes more than 30% of total quantity of the spring steel flat bar imports in the countries of Southeast Asia, Sout America, North Africa and so on.
Available certificatesCOC; PVOC; CIQ; SONCAP; BV; C/O; FORM E.
Executive standardsGB, JIS, DIN, ASTM and technical agreement. (GB/T 33164.1-2016; JIS G 4801:2011; EN 10089:2002; EN 10092-1-2003; ASTM A322;ASTM A304-04; SAE J1268;SAE J404).
Grades of spring steel flat bar60Si2Mn; 50CrV; 55CrMn; 55SiMnVB;60CrMn;28SiMnB;51CrMnV; 52CrMnMoV; 60Si2CrV; 60CrMnB; 55SiMnVB; 50CrVA 55CrMnA; 60CrMnA; 28MnSiB; 60CrMnBA; SUP7; SUP9; SUP9A; SUP10; SUP11A; 55Cr3;   51CrV4; 61SiCr7; 52CrMoV4; 5160; 5160H; 6150; 6150H; 51B60; 51B60H; SAE5160; SAE5160H; SAE6150; SAE6150H; SAE51B60; SAE51B60H; 52CrMnBA; 50CrMnVA; FAS3550; NHS3.
Width x thickness44.5x6; 44.5x8; 45x6; 45x8; 50x6; 50x7; 50x8; 50x9; 50x13; 60x6; 60x7; 60x8; 60x9; 60x10; 60x12; 60x14; 70x6; 70x7; 70x8; 70x9; 70x10; 70x11; 70x12; 70x13; 70x14; 70x6; 75x10; 75x1 1; 75x12; 75x13; 75x14; 75x15; 75x16; 75x18; 75x10;   75x11; 80x10; 80x11; 80x12; 80x13; 80x14; 90x10; 90x11; 90x12; 90x13; 90x14; 90x15; 90x16; 90x18; 90x20; 90x22; 90x25; 100x12; 100x14; 100x16; 100x18; 100x20; 100x22; 100x25; 120x12; 120x 14;   120x16; 120x18; 120x20 ...
Width rangefrom 44.5 mm to 140 mm
Thickness rangefrom 6 mm to 59 mm
Length rangefrom  3000mm to 7000mm
ComponentsCutting flat bar, Semi-leaf spring etc.
Standards implementedISO9001-2015, GB/T 33164.1-2016, JIS, DIN, ASTM
PaymentTT, LC, DP
Lead timeAbout 30 days
MOQ10 tons


WONDEE Spring steel flat bar (9)

Available sizes of spring steel flat bars (With x Thickness)(mm)
44.5x6 60x6 70x6 75x10 80x10 90x10 100x12
44.5x8 60x7 70x7 75x11 80x11 90x11 100x14
45x6 60x8 70x8 75x12 80x12 90x12 100x16
45x8 60x9 70x9 75x13 80x13 90x13 100x18
50x6 60x10 70x10 75x14 80x14 90x14 100x20
50x7 60x12 70x11 75x15 ... 90x15 100x22
50x8 60x14 70x12 75x16
90x16 100x25
50x9 ... 70x13 75x18
90x18 120x12
70x14 ...
90x20 120x14

90x22 120x16

90x25 120x18

... 120x20

Remark:Other sizes are available according to customers' request

Spring flat bar grade correspondence table
1 60Si2Mn 61SiCr7 9260 SUP7 250A58 61SC7
2 55CrMnA 55Cr3 5155 SUP9
3 60CrMnA 65MnCr4 5160 SUP9A

4 50CrVA 50CrV4 6150 SUP10

5 60CrMnBA 60CrB3 51B60 SUP11A


About production processes of leaf springs, please kindly visit YOUTUBE link:

How to make leaf springs

Workshops and production of WONDEE Autoparts spring steel flat bar :

WONDEE Spring steel flat bar (8)

WONDEE Spring steel flat bar (10)

WONDEE Spring steel flat bar (7)


Conainter loading of WONDEE Autoparts spring steel flat bar: 

WONDEE Spring steel flat bar (11)

In addition to supplying spring steel flat bar, WONDEE Autoparts also supply different types of semi trailer components as below:




Xinhe Industrial Park, Xiamen, Fujian, China 361006





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