DIN 17222 Ck55 1.1203 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.

Ck55 1.1203 Introduce

Ck55 steel has a higher (0.55%) carbon content for greater strength than the lower carbon alloys. It is hardenable by heat treatment, quench and tempering.

Ck55 1.1203 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

Ck55 1.1203 Equivalent Grade

Ck55 1.1203 Chemical composition

Ck55 1.1203 Treatment condition on delivery

Cold rolled + soft annealed : G

Cold rolled + hardened + tempered : H + A

Ck55 1.1203 Mechanical properties in the cold rolled + soft annealed condition G

Ck55 1.1203 Tensile strength in the cold rolled + hardened + tempered condition (H + A)

Ck55 1.1203 Vickers hardness in the cold rolled + hardened + tempered condition (H + A)

Ck55 1.1203 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.

Ck55 1.1203 Types of heat treatment

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

Ck55 1.1203 Acceptance testing and test certificates

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