251A58 Spring Steel

251A58 spring steel stockholders and suppliers, delivering to the whole of the UK. BS970 251A58 is a silicon manganese spring steel supplied in flat bar and is suitable for oil hardening and tempering. When used in the oil hardened and tempered condition EN45 offers excellent spring characteristics. 251A58 is commonly used in the automotive industries for the manufacture and repair of leaf springs.

We welcome export enquiries for spring steel. Contact our sales office and consult our shipping policy for further details.

Related Specifications

BS970 1.0904 56Si7 55S6 55Si2Mn ASTM 9255
55SiMn7 250A53 250A57 C2133 55S2 55S6 56S7 55C2

Alternative spring steel grades we supply

CS70 | CS80 | CS95 | CS100 | EN42 | EN43 | EN47 | 735A50 | 6150 | 301

Form of Supply

West Yorkshire Steel are 251A58 spring steel suppliers in flat bar and a small range of round bar sizes.

Click here to contact our experienced sales team who will assist you with your 251A58 spring steel flat bar enquiry.

  • Flat

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251A58 is widely used in the motor vehicle industry and many general engineering applications. Typical applications include leaf springs, truncated conical springs, helical springs and spring plates.

Carbon 0.55-0.60% Phosphorous 0.035% max
Manganese 0.80-1.00% Sulphur 0.03-5% max
Silicon 1.80-2.10% Chromium 0.15-0.30%

Preheat the 251A58 carefully, then raise temperature to 1050°C for forging.  After forging cool slowly, preferably in a furnace.

Heat slowly to 640-680°C, soak well. Cool slowly in the furnace.

Heat the steel slowly to 650-700°C and thoroughly soak. Continue heating the steel to the final hardening temperature of 870-930°C and allow the component to be heated through. Quench in oil.

Temper the steel immediately after quenching whilst tools are still hand warm. Re-heat to the tempering temperature then soak for one hour per 25 millimetre of total thickness (2 hours minimum) Cool in air. For most 251A58 applications tempering will be between 400-550°C.

Temperature [°C] 400 450 500 550 600 650
Hardness [HRc] 56 50 47 43 37 33

Heat treatment temperatures, including rate of heating, cooling and soaking times etc. will vary due to factors such as the shape and size of each component. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities. Please consult your heat treatment provider for full guidance on heat treatment of 251A58 spring steel grade.

We recommend you contact your welding consumables supplier who should provide you full details and information on welding BS970 251A58 spring steel.

This silicon manganese spring steel grade is commonly supplied in the as rolled condition and available with cast and analysis certification, please request when placing any orders.

BS970 251A58 spring steel is supplied in accordance with our ISO 9001:2015 registration.