The case hardening process, also known as carburising is very old, and pre-dates controlled nitriding processes by some decades; I have seen drawings of racing crankshafts from the 1920s that were hardened by this method. Other race engine parts that are commonly carburised are camshafts, piston pins and gears. The case hardening of highly stressed gears has been the most popular surface hardening process for decades, not only for racing gears but for highly loaded gears in Read more…

The use of phosphate conversion surface treatments, usually referred to as ‘phosphating’, are common in industrial applications, often serving as an underlayer for further coating processes such as painting. However, they have a number of applications in race engines and transmissions where they are not combined with further coating processes. In these applications they are applied in order to improve lubrication or for corrosion resistance. In terms of lubrication, phosphate conversion Read more…

The use of aluminium in race engines is widespread; where it is allowed, it is generally used for structural castings and is also widely used for machined components. Pistons are also generally made from aluminium, and most race pistons are forged.

Aluminium has a number of properties that make it an attractive material for use in race engines. For example, it has low density, and some alloys possess good specific Read more…

There are a number of reasons why we might want to improve the level of surface finish on components for race engines and transmissions, but the chief among these are reliability and friction. By improving the level of surface finish, we generally mean reducing the level of roughness.

The effect of reducing roughness on component reliability is well known, and has been quantified for a Read more…

In the pages of Race Engine Technology and in these short web articles, there have been numerous mentions of the significant benefits of having residual compressive stresses present at the surface of a component. To recap, incorporating a method (or methods) of introducing residual compressive stress at a component’s surface is, in general, likely to improve the endurance limit of a component loaded in bending or torsion. Given that there are very few components that are loaded in a purely axial sense, this rule of thumb can be usefully Read more…

There are a great number of components in the race engine that need a hard, wear-resistant surface. Crankshafts, camshafts, cam followers, gears, sprockets, spindles and pump shafts are some example of components that are regularly treated in some way to increase the hardness of the surface. In some cases, there is a requirement that the part has a high level of strength throughout, and such components which are through-hardened. Camshafts, and cam followers are commonly produced in both surface-hardened and Read more…

There are often lots of shiny parts in a race engine, and some companies produce parts of a high surface finish as a sales point; there is a perception by some that a polished part is better quality and therefore has an inherently higher value.

There are very good reasons though why some parts benefit from having a high level of surface finish. One only has to look at the data presented in engineering textbooks on the subject of fatigue strength and cyclic Read more…

There is a vast array of metallic materials of all kinds whose mechanical properties are improved by heat treatment. Steels are commonly raised to high temperatures, quenched and subsequently tempered by raising the temperature to a carefully controlled level and maintained there for a known amount of time; aluminium and titanium alloys are often solution-treated by heating to a given temperature before quenching and age-hardening by heating. In the case of most steels after quenching, the steel is brittle, and tempering softens the material and gives it a level of ductility. Read more…

Many of us will be familiar with nitriding as a method of providing a hard wear-resistant surface on some engine components. An additional benefit is that the surface is put into a state of residual compressive stress by treatment. The benefit of doing so are that the fatigue life of the component is extended, even where there is no use made of the wear-resistant nature of the surface.

One point against nitriding though, in all of its forms, is Read more…

In a recent RET-Monitor article on the subject of surface treatments for magnesium, mention was made of plasma electrolytic oxidation treatments. One such treatment that has found application in motorsport is Keronite, and while it is popularly used for surface treatment of magnesium components, the process can also be used with the other popular light alloy materials, namely aluminium and titanium.

I discussed the process with Dr James Curran, principal materials engineer at Keronite. Much of the initial engine Read more…