In some instances a spring is required to operate in a corrosive environment which means some form of surface protection is needed. The options of protection available will depend on the application of the spring.
If cost is an issue, or where the material needs to be of a required strength, than it may not be possible to design a spring with materials that will not corrode.
An obvious choice is the use of nickel alloys, they are excellent for corrosion resistance, however the cost can be prohibitive. A simple method is to simply oil or grease the springs, this should give a sufficient level of corrosion protection for springs in transit or when in storage (as long as the storage conditions are not too testing).
Another effective method of protecting springs from corrosion is through either plastic coating or painting. The only issue with using either of these methods is that the protection is only effective until it is damaged, it will then be liable to corrosion underneath the finish.
The easiest option is to manufacture the spring from carbon steel, wire drawn with a galvanised coating which should be sufficient enough in most circumstances, if not, a better protection is required. A popular method is to use a metallic finish which can be obtained by electroplating the spring. In order to ensure the maximum corrosion resistance it’s vital to use the correct electroplated metal.
Zinc plate and cadmium (rarely used due to its toxicity) corrode in preference to steel and will protect the surface even when the coating is damaged.
Nickel, copper and chromium plate will lead to the steel corroding when damaged so is not recommended. Nickel plate is only recommend when the component needs to undergo soldering and so it’s widely used in the electronics industry. There is a risk of hydrogen embrittlement when electroplating which can lead to component failure when it’s loaded.
A de-embrittlement process must be carried out in order to minimise the risk, this process involves the component being held at an elevated temperature of 190-200°C for up to 24 hours to allow the hydrogen to dissipate.
If low alloy spring steels such as BS2083 685A55 are to be used then they should not be electroplated under any circumstances due to the high risk of hydrogen embrittlement.
In contrast, a mechanical zinc or zinc alloy plate will provide zero risk of hydrogen embrittlement and an equally effective corrosion resistance, all be it costly.
The other options available include coating the spring with a resin impregnated with zinc flakes, they can have either a black or silver finish. They provide a superior protection to mechanical or electroplating and avoid the risks associated with hydrogen embrittlement.
Due to increased demand for the design and manufacture of progression tools, SSP have recently re-designed and renovated some of their floor space to incorporate a new and modern office space. This new area reflects the continued investment and development of the business.
The new dedicated work space will accommodate five members of the CAD design, production and material controls team. The team will be able to design components on new computers using the latest CAD tool design technology which also links directly to their EDM and machining centre.
Every single component is designed and manufactured individually by SSP to suit the requirements of their customers. This new dedicated ‘design space’ will enable the team to produce tailored designs in a modern and spacious area.
The new space will also allow Production Manager Mike Hales to focus more on the production process throughout the factory, as well as providing a dedicated hub to source materials that meet customer requirements.
The new air conditioning system which has recently been installed throughout the whole factory is now also operational within the new office space.
Tim Page, Managing Director said “The demand for press work has grown significantly in the last year, designing and building this new office space is part of our continuing plans for expansion and development at SSP”.