50CrVA Spring Steel

50CrVA spring steel has good mechanical properties and process performance, high hardenability, adding vanadium to refine the grain of the steel, reduce overheating sensitivity, improve strength and toughness, have high fatigue strength, and have a relatively high yield ratio. high. However, 50CrVA spring steel has poor weldability and low plasticity due to cold deformation. It is a higher-grade spring, used as a high-load important spring with a larger section and a valve spring, piston spring, and safety valve spring with an operating temperature of <300 ℃.

Generally, the supply specification of the sheet material is between 1.5 and 10.0 mm, and it is often annealed, and more than 10 to 30 mm is mostly in the non-annealed state. There are few stocks on the market, so it is often necessary to order futures. The steel coil is in a hot-rolled state, and spheroidizing annealing is used to reduce the hardness in order to create conditions for further processing.

FUSHUN Steel's 50CrVA is generally annealed sheet, eliminating the need for re-annealing. Medium-carbon alloy spring steel, the final heat treatment is quenching and tempering. After heat treatment, the steel has good toughness, high ratio limit and strength limit, and high fatigue strength, similar to the hardenability of 65Si2MnWA. Hardenability, low overheating sensitivity; when the parts are used at 300 ℃, their elasticity can still be maintained. The cutting performance of steel is still good, but the plasticity is low during cold deformation and the weldability is poor.

Dimensional tolerances

Wire in coils

The tolerances level for the wire diameter is based on EN 10218-2:1996 level:

- T5 for wire diameter up to and including 0,80 mm;

- T4 for 0,80 mm up to 10,00 mm;

- T3 above 10,00 mm.

Wire in cut lengths

Chemical Composition:

Mechanical Propoerties:

Heat treatment specification and metallographic structure:

Heat treatment specification:

hot-rolled steel is delivered in heat-treated or non-heat-treated state, and cold-drawn steel is delivered in annealed state.

Metallographic structure:

quenched at 850℃±20℃, oil-cooled; tempered at 500℃±50℃ (for special needs, ±30℃), the organization is tempered troostite or a mixed organization of troostite and sorbite.

Critical point temperature (approximate value) Ac1=752℃, Ac3=788℃, Ar3=746℃, Ar1=688℃.

Quenching and tempering treatment specification:

quenching temperature 860-880℃, oil cooling; tempering temperature 500±10℃, water and oil cooling.

Equivalent Grade:

American : G61500

Japanese : SUP10

German : 50CrV4

British : 735A51

French : 50CrV4

Oil hardened spring steel wire Surface finish

The wire shall be protected against corrosion and mechanical damage. Unless otherwise specified the wire shall be delivered in slightly oiled condition.

Oil hardened spring steel wire Surface quality

The surface of the wire shall be smooth and permissible depth of surface defects at the coil ends shall be in accordance with Table.

By in-line control of surface defects the areas of the coil with defects above the level of Table 7 shall be marked. In-line testing is not performed for FD-grades.

The number of defective parts that can be tolerated may be agreed between the parties.

Surface decarburization

The wire grades according to this standard shall be free from total decarburization. The maximum depths of the partially decarburized zone shall be checked at the end of the coils.

Testing and inspection

Coiling test

Torsion test

heat analysis;

result of the tensile test

result of the torsion test

actual wire diameter

Tensile test

Information to be supplied by the purchaser

The purchaser shall clearly state in his enquiry or order the product and following information :

a)the desired quantity;

b)the number of this European Standard: EN 10270-2;

c)wire grade

d)the nominal wire diameter;

e)the form of delivery and unit mass;

f)the type of inspection document;

g)any particular agreement made.