Waterjet is a simple and fast way to make flat springs. The advantage is in starting with bulk material that has already been heat-treated to the desired spring temper by a predictable industrial process. Waterjet is a "cold" cut, no heat affected zone, and hardened steel cuts only slightly slower than annealed. Waterjet can still create stress risers in the cut edges; this is generally not an issue, but critical applications should take this into account in the design engineering process.
We like 1075 and 1095 carbon steel, and 301 spring-tempered stainless steel. The material is inexpensive and readily available in many thicknesses and several tempers, the latter depending on your need for forming to shape after cutting.
We also press-form flat springs into precise shapes, using standard press brake tooling, urethane dies and shop-made tooling as appropriate.
Flat springs in 1095 blue tempered spring steel. These are cut in stacked strips, then broken apart and hand finished by the customer.
This is also 1095 blue tempered spring steel; waterjet cut, then each piece bump-formed on the press brake to a precise profile, guided by a program once the forming was dialed in. The cutting and forming was done in the as-hardened condition at RC50