A spring is a flexible elastic object used to store mechanical energy. Springs are usually made out of hardened steel. Small springs can be produced from pre-hardened (hardened and tempered) stock, while larger ones are made from annealed steel and hardened after fabrication. Spring Steel Strip is quite literally, steel used in the production of springs. This range of steels normally contains between 0.40% and 0.80% carbon, with alloying elements added for the higher integrity products such as automotive clutches etc. Coil springs are normally produced from steel wire, whilst steel strip is used for the production of flat springs. Spring steels are also used in a number of applications where hardness or resistance to bending is required, such as lock parts or tools.
| Spring steels are supplied either in the annealed condition for forming and blanking, or in the ready hardened, more commonly referred to as hardened and tempered. Steel supplied in the annealed condition is usually hardened after the stamping and forming operation in component form. The choice of supply condition is determined by the component production method, as ready hardened steel is difficult to process. Hardened and tempered strip is more suitable for flat components or where the production is primarily laser cutting or plain blanking. Hardening in component form is usually however more expensive than the premium paid for ready hardened steel. The hardening and heat treatment of steel is a complex area of metallurgy and beyond the scope of this site, but links for further reference can be located on the right side of the page. |
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| At BSS Steelstrip, we stock the following grades, which can be supplied from .stock in small quantities:-Carbon Spring Steels- CS70, CS80, CS95, CS100, 75CR1, EN8, EN9- Euronorm C67S, C75S, C85S, C95S and C100S
Stainless Spring Steels- Type 420 Type 4301 Telephone Steve on 01709 820070 |
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We will add more commonly used spring steels in due course. Please check back at a later date.
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The analyses are given for guidance only as the various international standards are not identical, in addition many steelmakers restrict analyses, particularly carbon.
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Common Spring Steel Grades Equivalents
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Euronorm
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Germany
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UK
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USA
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EN 10132 – 4
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DIN 17222
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BS 1449
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SAE
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%C
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%Mn
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%Si
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%S
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%P
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%Al
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%Cr
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%V
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| C50E |
CK 45
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.45-.55
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.50-.90
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.05-.35
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.040 max
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.045 max
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| C50E |
CK 50
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CS50
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1050
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.45-.55
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.50-.90
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.05-.35
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.040 max
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.045 max
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–
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– |
–
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CK 55
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1055
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.50-0.60
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C67S
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CK67/C67
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CS70
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1070
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.68 – .73
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.60 – .85
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.15 – .25
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.01 max
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.02 max
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–
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.20 – .30
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–
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C75S
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CK75/C75
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CS70
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1074
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.70 – .75
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.60 – .80
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.15 – .30
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.025 max
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.025 max
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.02 – .05
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.20 – .30
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–
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75Cr1
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75Cr1
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.74-0.80
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.65 – 0.80
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.25 0.40
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.010 max
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.025 max
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0.30-0.45
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C85S
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CK85
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CS80
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1084
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.80 – .90
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.40 – .70
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.15 – .35
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.025 max
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.025 max
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–
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.40 max
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–
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50CrV4
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50CV4
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735A50
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6150
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.47-0.55
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.70-1.10
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.15-0.40
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.035 max
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.035 max
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–
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–
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.10-.20
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CK101
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CS95
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1095
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.90-1.00
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.30-.60
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.05-.35
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.025 max
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.025 max
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More detail on Euronorm EN10132 including mechanical properties can be found here
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USA AISI and SAE Spring Steels
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Grade
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% C
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% Mng
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% P
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% S
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1050
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.47 – .55
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.60 – .90
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0.04
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0.05
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1055
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.52 – .60
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.60 – .90
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0.04
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0.05
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1060
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.55 – .66
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.60 – .90
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0.04
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0.05
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1065
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.59 – .70
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.60 – .90
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0.04
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0.05
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1070
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.65 – .76
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.60 – .90
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0.04
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0.05
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1074
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.69 – .80
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.50 – .80
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0.04
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0.05
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1080
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.74 – .88
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.60 – .90
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0.04
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0.05
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1085
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.80 – .94
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.70 – 1.00
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0.04
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0.05
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1095
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.90 – 1.04
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.30 – .50
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0.04
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0.05
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Due to numerous requests below I have added some of the older spring steel grades which are often quoted
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Old BS970 spring steels
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Euronorm
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Germany
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UK
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USA
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BS970
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%C
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%Mn
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%Si
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%S
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%P
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%Al
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%Cr
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%V
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En8
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0.35-0.45
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0.60-1.00
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0.05-0.35
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0.06max
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0.06max
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En8a
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0.33-0.38
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0.70-0.90
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0.05-0.35
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0.06max
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0.06max
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– |
–
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En9
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0.50-0.60
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0.50-0.90
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0.05-0.35
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0.06max
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0.06max
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En 42
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0.70-0.85
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0.55-0.75
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0.10-0.40
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0.06max
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0.06max
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–
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