The material of a component chosen for a machine build can play a crucial role in the equipment‚’s performance and life expectancy. Popular materials such as 52100 Bearing Steel and 440C Stainless Steel bring their own advantages and disadvantages to a machine. Even so, they often need a coating so that they can withstand the elements of harsh environments.
Various coating methods are available to meet application requirements and satisfy design functions. To examine various coating methods, engineers at Misumi conducted corrosion resistance tests. The test samples were flanged type linear bushings. The test method corresponded to cyclic test pursuant to JIS H 8502 (complex corrosion test method) with the following conditions:
1 Salt water spray test (5% NaCl, 35⼠C)
2 hours
2 Dry (60⼠C)
3 Wet (85% rel. H, 50⼠C)
The use of coatings on components made of steel will often impart longer wear life as well as other properties. This chart shows how well several popular coatings resist corrosion on linear bushings made of two types of steel.
The appearance of the test samples were then compared with the original condition after 72 hours and 168 hours elasped.
Low Temperature Black Chrome plating (LTBC) uses an electrochemical reaction below 0‚°C. Through the plating process, an alloy-like diffusion layer forms at the outer margin of the part, allowing chrome particles to completely integrate the base material and create an inseparable bond. Thus, the plating can neither be peeled nor flaked off. The surface consists of a uniform film creating a resistant rust protection layer. For example, LTBC-plated shafts and components
provide service life exceeding 10 years and, in some cases up to 20 years and beyond. Components with this plating have fracture-resistant surfaces with a high level of alternate-bending strength. The tolerances of the components remain practically unaffected. These components can be used in applications specifying corrosion resistance or minimal light reflection making LTBC suitable for use in optical applications requiring low light reflection.
High Carbon chromium 52100 Bearing Steel features a rigid construction but is susceptible to corrosion in harsh environments.
Stainless steel will rust, but it rusts at a slow rate, which creates the perception that it does not rust. When exposed to a harsh environment, 440C Stainless Steel exhibits other corrosion properties. Furthermore, it has a martensitic microstructure that exhibits magnetic properties and offers corrosion resistance that is lower than the common austenitic grades. This material is also fit for hardening.
Electroless Nickel Plating (EN) is an anti-corrosion coating process used for steel, stainless steel and copper materials. It offers high corrosion and abrasion resistance and 500 Vickers hardness (HV). Furthermore, it will give conductivity to a non-metal surface. The process involves the chemical reduction of nickel ions and the deposit of nickel metal. Good for harsh environments, EN is suitable for corrosion resistance in adverse conditions.
Misumi USA Inc.
www.misumiusa.com
::Design World::
Filed Under: Materials • advanced
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