Polishing Ferritic Stainless Steel
Whilst polishing familiar austenitic grades such as 304 and 316 (or to give them their correct designations of 1.4301 and 1.4401 respectively) is the bread and butter of a polishing company, over the last few years ferritic grades have become much more popular. This is often due to cost factors as of course Nickel is not an element in the majority of ferritic grades. However it can also be down to the application with many ferritic grades being chosen for deep drawing applications. From a practical point of view from a mechanical polisher, ferritic material absorb heat and pressure very well, meaning that there is less distortion of the surface when heat is applied. For thinner sheets, such as 0.5mm, this means that the sheets are less likely to curve or bow when the initial heat is applied to the surface. However with decorative finishes such as circle polishing (often described as engine turning or a watch case finish) ferritic material actively fights the traditional polishing process. Initially this wasn’t a problem as the majority of the material produced to a circle finish 5 years or so ago was austenitic, but as ferritic material became more and more popular obviously a solution was needed. Extensive research and trials carried out over quite a substantial period meant the at two finishes were developed to apply onto grades such as 430. To keep the cost down the first finish, ProCirc Satin is available at the same cost as circle finishes produced on 304 material and this is generally the most popular. It doesn’t look exactly the same, having a slightly more satin hue to the circle, but it has good consistency of pattern. A ProCirc Extra involves a pre-conditioning treatment that makes the surface easier to work with and produces a finish that’s virtually indistinguishable from the pattern on austenitic grades but it does incur additional costs. When it comes to bright or mirror polishing ferritic material, bright annealed grades tend to come up slightly brighter than their austenitic counterparts, although there is less grade comparison overall, rather it varies from Mill to Mill. This brief summary shows that whilst the chemical composition of ferritic steels varies compared to the ever popular austenitic grades, the quality of finish should not but if you are in any doubt then please contact us for more information. Contact us : Professional Polishing Services Ltd, Tel +44 (0) 121 555 6569 Fax + 44 (0) 121 555 6613 Email : admin@professionalpolishing.co.uk
Fe Cr Mo Mn S C Ni Ti Si N
= Iron = Chromium = Molybdenum = Manganese = Sulphur = Carbon =Nickel = Titanium = Silicon = Nitrogen