DIN 17222 Ck75 1.1248 Cold Rolled Steel Strips for Springs

Cold rolled steel strip for springs is distinguished by high dimensional accuracy and good surface quality and, in the cold rolled + hardened + tempered condition (H + A) offers the possibility of achieving high values of hardness, tensile strength and elastic limit.

Ck75 1.1248 Introduce

Ck75 1.1248 steel is one of the higher carbon steels used for high hardness in the fully hardened condition. In such condition the steel is more brittle than the lower carbon steels. Applications include springs.

Ck75 1.1248 Dimensions and permissible deviations

Thickness: 0.1 to 4mm; Tolerances: +/- 0.008 to 0.11 mm

Width: 10 to 600mm; Tolerances: +/- 0.15 to 0.60mm

Ck75 1.1248 Equivalent Grade

Ck75 1.1248 Chemical composition

Ck75 1.1248 Treatment condition on delivery

Cold rolled + soft annealed : G

Cold rolled + hardened + tempered : H + A

Ck75 1.1248 Mechanical properties in the cold rolled + soft annealed condition G

Ck75 1.1248 Tensile strength in the cold rolled + hardened + tempered condition (H + A)

Ck75 1.1248 Vickers hardness in the cold rolled + hardened + tempered condition (H + A)

Ck75 1.1248 Surface condition

Strip to be supplied in the

1 cold rolled + soft annealed G or

2 cold rolled + soft annealed + cold rolled (G + K) condition

must have a bright, metallically clean surface.

Cold rolled + hardened + tempered (H + A) strip is supplied, as agreed at the time of ordering, with

1 grey-blue (GR),

2 bright (8K),

3 polished (P) or

4 polished and colour-tempered (P & AF) surface.

Ck75 1.1248 Types of heat treatment

Approximate values for heat treatment and minimum hardness values in the hardened condition of cold rolled steel strips for springs

Ck75 1.1248 Acceptance testing and test certificates

EN 10204/3.1 with all relevant data reg. chem. composition, mech. properties and results of testing.