Specialist services

William Hughes, manufacturer of springs, bent wire-forms and assemblies, is responding to industry demand for single source solutions with new 'added-value' services.

Among the new controlled processes are steel and glass shot peening, ultrasonic cleaning and tensile testing to national standards such as AMS (Aerospace Materials Specifications).

Steel shot peening involves firing or blasting a known size of cut wire shot at a component, such as a spring, to create compressive residual stress layers that modify its mechanical properties. For many tasks, the aim is increased spring longevity. The process is defined by quality, size and intensity of shot, with established measurement techniques used to calculate how much stress is delivered.

After every eight machine working hours, the size of the shot is checked using a sieve shaker with different mesh sizes to ensure the shot size is correct. Visual screening under magnification checks shot quality, confirming it to be round and without sharp edges. Other tests include arc rise tests, using an Almen strip to measure shot intensity, and coverage testing.

The company also offers shot peening using glass, a finer and smaller media, that allows shot peening without contaminating component surfaces.