Hardened Tempered Spring Steel Strips

Spring steel is a type of steel that is specifically used to make springs, strippers, scrapers, and elastic parts because it can return to its original shape after bending, compression, or extension. This ability, known as elasticity in the quenched and tempered state, arises due to the high yield strength of the steel, which comes from its specific composition and hardening process. Fabricating spring steel requires advanced technical skills to ensure high quality. Any defects on the surface, such as decarburization or irregularities, can reduce fatigue strength. Baomit strip steel ensures that the springs have a perfectly smooth surface for optimal efficiency and performance.

ParametersRecommendation
Thickness ToleranceT2 – T3
RoughnessClass 3
FlatnessClass 3
SurfaceBright, White / Blue / Yellow Polished
EdgesDeburring, Square, Round
Hardness44 – 52 HRC
Thickness0.10 – 4.50 mm
Width3 – 460 mm
Steel GradeC67S, C75S, C100S, 50CrV4

Hardened and Tempered Stainless Steel Strips

Our Advantages

• Excellent fatigue resistance

• Excellent punching and stamping properties

• Precise thickness and width tolerances

• Maximum straightness deviation of 1 mm / 3 m

• Good surface finish

• Consistent, uniform microstructure

Steel Grades

Comparison of Norms
EU / ENUSA / AISIChemical Composition
C67SSAE1070C: 0.65-0.73, Si: 0.15-0.35, Mn: 0.60-0.90, Ni: max 0.40, P: max 0.025, S: max 0.025, Cr: max 0.40, Mo: max 0.10
C75SSAE1075C: 0.60-1.20, Si: max 1.0, Mn: max 1.0, Ni: max 0.60, P: max 0.04, S: max 0.03, Cr: 16.0-18.0, Mo: max 0.75
50CrV4SAE6150C: 0.47-0.55, Si: max 0.40, Mn: 0.70-1.10, P: max 0.025, S: max 0.025, Cr: 0.90-1.20, V: 0.10-0.25

Manufacture Process

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Cold Rolling

cold rolling process

Slitting

slitting process

Heat Treatment

heat treatment process

Surface Polishing

surface polishing

Edging

edge process

Packaging

packing process

Thickness Tolerances

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Thickness (mm)Tolerances ± mm
T1T2T3T4T5
0.020 – 0.0400.0040.0030.002
0.040 – 0.1000.0060.0050.0040.0030.002
0.100 – 0.1250.0070.0050.0040.0030.002
0.125 – 0.1600.0090.0060.0050.0040.003
0.160 – 0.2000.0100.0070.0050.0040.003
0.200 – 0.2500.0110.0080.0060.0040.003
0.250 – 0.4000.0150.0110.0080.0060.004
0.400 – 0.6000.0200.0140.0100.0070.005
0.600 – 0.8000.0230.0170.0120.0080.006
0.800 – 1.0000.0270.0190.0130.0090.007
1.000 – 1.2500.0340.0240.0170.0120.008
1.250 – 1.6000.0390.0280.020
1.600 – 1.7500.0460.0330.023

Width Tolerances

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Thickness (mm)Width (mm)Tolerances ± mm
W1W2W3
≤0.25≤500.100.070.05
50 – 1250.150.110.07
>1250.200.150.10
0.25 – 0.50≤500.150.110.07
50 – 1250.200.150.10
>1250.250.200.15
0.50 – 1.00≤500.200.150.10
50 – 1250.250.200.15
>1250.300.250.15
1.00 – 1.60≤500.200.150.10
50 – 1250.300.250.15
>1250.350.250.20
1.60 – 1.75≤500.300.200.15
50 – 1250.350.300.20
>1250.400.300.20

Surface Roughness

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Available in white polished, blue polished and yellow.

Thickness (mm)Roughness
Class 1Class 2Class 3
≤0.50Ra≤ 0.30 µm
Rt≤ 3.00 µm
Ra≤0.25 µm
Rt≤ 2.50 µm
Ra≤ 0.20 µm
Rt≤ 2.00 µm
0.50 – 1.00Ra≤ 0.35 µm
Rt≤ 3.50 µm
Ra≤ 0.25 µm
Rt≤ 2.50 µm
Ra≤ 0.20 µm
Rt≤ 2.00 µm
1.00 – 1.75Ra≤ 0.40 µm
Rt≤ 4.00 µm
Ra≤ 0.30 µm
Rt≤ 3.00 µm
Ra≤ 0.30 µm
Rt≤ 3.00 µm

Flatness Deviation

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Maximum flatness deviation per inch strip width.

Thickness (mm)Flatness Deviation
Class 1Class 2Class 3Class 4
0.02 – 0.10P60P50P40P30
0.10 – 0.25P50P40P30P20
0.25 – 0.50P40P30P20P10
0.50 – 1.75P35P25P15P10

Straightness Deviation

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Strip Width (mm)Measured Length (3m)
Class 1Class 2Class 3
≤503 mm2 mm1 mm
50 – 1253 mm2 mm1 mm
>1253 mm2 mm1 mm

Hubei Baomit Steel Materials Co., Ltd.

Leading manufacturer of hardened and tempered steel strips and sheets. Baomit strip steel stands for precision, quality and high performance. Our materials are excellent in terms of comprehensive delivery indicators, such as straightness, flatness, mechanical properties and metallographic uniformity.