Spring Steel: Properties, and Uses

Spring steel is a high-performance material, renowned for its exceptional strength and elasticity. It is widely used in a range of industries, from automotive to aerospace, due to its unique combination of properties. This article delves into the properties of spring steel and its diverse applications.

Properties, and Uses of Spring Steel:

55Si2Mn
Properties: High strength, good elastic limit, high yield ratio, good toughness after heat treatment, poor weldability, low cold deformation plasticity, good machinability, higher quenching, and oil hardening properties than 65 and 65Mn steels. The critical quenching diameter in oil is about 25~57mm, and in water is about 44~88mm. This steel is suitable for oil quenching and water quenching, but there is a tendency to form cracks. There is no tendency of embrittlement after tempering, and it has good resistance to tempering and relaxation. The content of inclusions in the steel is high, rolling is difficult, surface defects are easy to occur, and decarburization tendency is large. It is suitable for use after quenching and tempering.

Application: It is suitable for manufacturing flat springs with medium and constant load, spiral springs with diameter <25mm, slow conflict springs, and high-stress springs such as cylinder safety valves.

55Si2MnB
Properties: The properties are similar to those of 55Si2Mn steel, but the critical quenching diameter in oil is higher, about 90~180mm, and the fatigue strength is also significantly improved.

Application: It is suitable for manufacturing steel plate springs with medium and small cross-sections, such as front and rear auxiliary steel plate springs on automobiles.

55SiMnVB
Properties: The strength, toughness, plasticity, and quenching hardening property are higher than those of 60Si2MnA steel. The critical quenching diameter in oil is about 50~107mm. The hot working performance is good, the surface decarburization tendency during heat treatment is small, and the tempering property is good.

Application: It is suitable for manufacturing steel spring with medium cross-section size, such as plate springs and spiral springs, which can replace 60SiMnA steel.

60SiMn、60Si2MnA
Properties: Compared with 55Si2Mn steel, both the strength and elastic limit of 60SiMn and 60Si2MnA steel are slightly higher (with 60Si2MnA steel being better). The quenching hardenability is also better, with the critical quenching diameter in oil being about 37~73mm. Other properties remain the same. The main usage status is under quenching and tempering.

Applications: This steel is widely used. It is suitable for manufacturing flat springs or spiral springs with a diameter ≤30mm that are subject to greater loads in the railway, automobile, and tractor industries. It can also be used for sheet springs that are subject to stress and vibration in the lower part of the car or train box, as well as springs for safety valves and check valves with a working temperature of <250℃ in non-corrosive media. It is also suitable for large and important coiled springs that can withstand alternating loads and high stress, as well as severely worn mechanical parts.

60Si2CrA
Properties: Compared with 60Si2MnA steel, 60Si2CrA steel has similar plasticity but higher tensile strength and yield point. The thermal treatment overheat sensitivity and decarburization tendency are small, the quenching hardenability is high, and the critical quenching diameter in oil is about 37~114mm, but there is a tendency for embrittlement after tempering. It is generally used after quenching and tempering.

Applications: It is suitable for manufacturing springs that can withstand high stress and operate at a temperature of <300℃, such as speed governor springs, steam turbine air seal springs, high-pressure water pump diaphragm springs, and condenser support springs.

60Si2CRVA
Properties and applications are similar to those of 60Si2CrA steel, but it has a better elastic limit and high-temperature mechanical properties.

Applications: It is suitable for manufacturing heat-resistant springs that operate at temperatures of <300~350℃ and important springs that can withstand impact stress and high loads.

55CeMnA、60CrMnA
Properties: These steels have high strength and plasticity, but poor weldability and acceptable machinability. The quenching hardenability is better than that of silicon manganese or silicon chromium spring steel. The critical quenching diameter in oil is high, and the decarburization tendency is lower than that of silicon manganeine steel. There is a significant tendency towards embrittlement after tempering, so it is necessary to choose the appropriate tempering temperature and cooling rate. They are generally used after quenching and tempering.

Applications: These steels are suitable for manufacturing plate springs and large-diameter spiral springs (up to 50mm) that are subject to greater loads and stress conditions in the automotive and tractor industries.

60CrMnMoA
Properties: This steel has the same comprehensive mechanical properties as 60CrMnA steel after heat treatment. Additionally, it has better quenching hardenability. The critical quenching diameter in oil is about 100mm, and there is no embrittlement tendency after tempering.

Applications: This steel is suitable for manufacturing large-diameter spiral springs (up to 100mm) that are subject to heavy load stress in the automotive and tractor industries.

50CrVA
Properties: This steel has high toughness, strength, and elastic limit, as well as fatigue strength. It has a lower elastic modulus, higher yield ratio, and good quenching hardenability. The oil can quench the round bar specimens with a diameter of 30~45mm. The steel has small tendencies towards overheating and decarburization during heat treatment, and it also has good impact toughness. However, its weldability is poor, its cold deformation plasticity is low, and it has a sensitivity to white spot formation during hot working. It is mainly used after quenching and tempering.

Applications: This steel is suitable for manufacturing large-section high-load important springs, as well as valve springs and piston springs that operate at temperatures below 300℃. It can also be used for important quenched and tempered parts with large cross-sections that are not subject to corrosion and operate at temperatures below 400℃ in non-corrosive media.

60W4MnBA
Properties: This steel has performance characteristics similar to 60CrMnA steel, but it has better quenching hardenability. The critical quenching diameter in oil is about 100~150mm.

Applications: This steel is suitable for manufacturing large springs, such as the stacking spring on bulldozers, large spiral springs, and torsion springs on ships.

30W4Cr2VA
Properties: This is a high-strength heat-resistant spring steel with good room temperature and high-temperature mechanical properties, especially high quenching hardenability. It has excellent dimensional stability after tempering, good hot workability, and is suitable for use in the quenched and tempered conditions.

Applications: This steel is suitable for manufacturing hot springs that operate at temperatures up to 500℃, such as the main safety springs of boilers and the sealing spring blades of steam turbines.

SUP9A
Properties and Application Range: This steel has higher strength, plasticity, and toughness, good quenching hardenability, lower overheating sensitivity than manganese steel, higher than silicon manganese steel, smaller decarburization tendency than silicon manganese steel, and greater embrittlement after tempering. It is used in the automotive and tractor industries to make plate springs and large-diameter spiral springs that are subject to heavy loads and high stress.

Conclusion

Thank you for reading our article and we hope it can help you to have a better understanding of the properties and uses of spring steel. If you want to learn more about spring steel, we’d advise you to visit Sino Stainless Steel for more information.

As a leading supplier of stainless steel across the world, Sino Stainless Steel provides customers with high-quality stainless steel products such as stainless steel strips, stainless steel coils, stainless steel plates, stainless steel sheets, stainless steel bars, and stainless steel pipes at a very competitive price.