Industries such as mining, forestry and construction require the use of heavy-duty machines that are often subject to intense working conditions resulting in extreme wear and tear. In many cases, equipment wear parts made with steel castings are responsible for extending machine operating life and reducing downtime. These types of castings, for example, provide mining wear parts for a wide range of equipment including crushers, chute liners, mine car wheels and pumps. When resistance to heat or corrosion is needed, wear parts produced with stainless steel provide the solution.
An Overview of Stainless Steels
To be classified as corrosion resistant, stainless steel will contain a minimum of 10.5% chromium to provide additional resistance in aqueous environments where corrosion is a factor. The chromium content enables the formation of a protective film that increases corrosion resistance and, at higher temperatures, improves resistance to oxidation and enhances rupture strength. When classified as corrosion-resistant, stainless steel castings are designed for use in conditions where operating temperatures are below 1200 degrees Fahrenheit.
Heat resistant stainless steel castings are manufactured for use in environments where operating temperatures exceed 1200 degrees Fahrenheit. They have higher carbon contents, as much as 0.75%, in comparison to corrosion resistant stainless steels. At extreme temperatures, the greater carbon content improves structural strength and reduces ductility.
Carbon content is what distinguishes heat resistant stainless castings from those that are corrosion resistant. Carbon content must usually be less than 0.20 % for stainless steel castings to perform well in environments that are corrosive.
Machining and Welding
The machining of stainless castings is more challenging compared to carbon steel and requires slower cutting speeds and feeds. When stainless steel castings require welding to improve casting quality or during fabrication, it’s important that welds are of the highest standard so that product performance is not negatively affected. Experienced Ontario manufacturers such as Wabi Iron & Steel Corp. can provide quality, customized wear parts in steel or stainless steel to meet abrasion, corrosion and heat resistant applications.
(Properties of Stainless Steel and Nickel-Based Alloy Castings) www.stainless-steel-world.net/pdf/11022.pdf