Compression spring made out of stainless
302 used in automotive industry

Compression spring made out of .090 music
wire used in offshore equipment

Extension spring made out of .040 stainless
.302 used in oil and gas industry

Extension spring made out .060 stainless used I'm military

Compression springs:

A compression spring is an open coil helical spring that offers resistance to compressive force applied axially. Compression springs are commonly coiled as a constant diameter cylinder, below are several types of compression springs including:

• conical compression springs

• concave compression springs

• convex compression springs

These are used individually or in conjunction with each other. Round wire is predominant in compression springs because it is readily available and adaptable to standard coiler tooling.

Extension Springs:

Extension springs are closed-coiled helical springs that extend under a pulling force. Many design considerations must be made with extension springs including; initial tension, stress and deflection of hooks, hook end types. 

There are a variety of extension spring end types. Machine loop and hook over center, side loop, full loop over center, no hook, extended hook, hook end with swivel, v-hook over center, double twisted full loop over center, and many more.

Torsion Springs

Torsion springs are helical springs that exert a torque or rotary force and are subject to bending stresses. Torsion springs should always wind up from the free position - never to unwind from the free position. As they wind up, torsion springs reduce in diameter and their length becomes longer. Such springs should be supported over a rod whenever possible. Some spacing should remain between coils to minimize friction which can alter torque and deflection. 

Flat Springs

Flat springs are used to keep forces within restricted space conditions. Several materials are used including flat, high carbon spring steel, phosphor-bronze, beryllium-copper, stainless steel, nickel-silver and high-nickel specialty alloys. Formulas used to design flat springs involve small deflections, never more than 25% of the spring free length. Katy Spring can assist customers with the sometimes complicated designs of these types of springs, also known as beam designs.