| Compression springs | Resist axial compression and return toward their original length when the load is removed. | Spring steel wire, stainless spring wire, or alloy spring steel, selected for the operating environment and load. | ASTM A228/A228M for music spring-quality wire; EN 10270-1 for patented cold-drawn non-alloy steel spring wire. | Load and deflection requirements, free length, outside diameter, end style, fatigue performance, and dimensional inspection. |
| Extension springs | Provide a resisting force when extended; end loops or hooks transfer the load to adjoining components. | Cold-drawn spring steel wire or corrosion-resistant stainless spring wire. | ASTM A228/A228M and EN 10270-1 are examples of wire specifications used for spring applications. | Initial tension, extended length, hook or loop design, load at working length, and protection against corrosion. |
| Torsion springs | Apply torque when their legs are rotated around the spring body. | Spring steel wire or stainless spring wire, depending on required strength and service conditions. | ASTM A228/A228M and EN 10270-1 are examples of applicable spring-wire standards. | Torque and angular travel, winding direction, leg geometry, mounting method, and cycle-life requirements. |
| Oil-tempered wire springs | Used in spring designs that call for oil-tempered wire properties, subject to the design and service requirements. | Oil-tempered carbon or alloy spring steel wire. | ASTM A229/A229M covers steel wire, oil-tempered, for mechanical springs; ASTM A401/A401M covers alloy steel wire, oil-tempered, for mechanical springs. | Wire specification, tensile requirements, heat-treatment controls, surface condition, and traceability documentation. |
| Stainless steel coil springs | Used where corrosion resistance is important and the selected grade meets the mechanical requirements. | Stainless spring wire, with grade selected according to the environment and design. | EN 10270-3 covers stainless spring steel wire. | Stainless grade, corrosion exposure, strength requirements, surface finish, and compatibility with the operating environment. |
| Custom coil springs | Made to a defined drawing or specification for a particular assembly or operating condition. | Carbon spring steel, alloy spring steel, or stainless spring wire, as specified for the design. | Material standards should be agreed in the purchase specification and matched to the selected wire type. | Drawing review, prototype capability, process controls, inspection records, change management, and delivery requirements. |