How do you get rid of the white layer after nitriding?

1. The use of several patented processes: U.S. Patent 2,960,421 achieves the removal of the iron-nitride white layer by a diffusion process. Parts are copper plated all over and then heated to and held at 975ºF (525ºC) for periods up to 40 hours depending on the thickness of the white layer to be removed.

What is white layer in nitriding?

The white layer consists in a mixture of iron nitrides: Fe4N – γ´ and/or Fe2,3N – ε. The diffusion layer is located bellow the white layer, and it is formed by the diffusion of nitrogen into the metal.

How can white layer formation be avoided during nitriding process?

The key to controlling the White layer formation was the introduction of a Boost-Diffusion technique during the Nitriding phase. Surface hardness and depth of nitride zone were then recorded from microhardness measurements and metallography.

What is a nitriding layer?

Nitriding is a ferritic thermochemical method used to diffuse nitrogen into the surface of steels and cast irons. This creates a case-hardened layer that has strongly enhanced mechanical properties. In gas nitriding, the heated surface of the metal is treated with a nitrogen bearing gas, usually ammonia (NH3).

When to remove the white layer of nitriding?

Obviously in dynamic mechanical environments — the exact environments found in many industries using nitriding — cracking, breaking, and shearing can easily lead to partial or full system failure. McQuaid and Ketcham rightly identified that this white layer must be avoided or removed.

What’s the name of the surgery to remove adenoids?

Adenoid Removal. Medically reviewed by Elaine K. Luo, MD, specialty in Internal Medicine, on August 16, 2017 — Written by Sandy Calhoun. Adenoid removal, also called an adenoidectomy, is a common surgery to remove the adenoids.

How is isotropic superfinishing used in nitriding?

Isotropic superfinishing is an ideal method of removing the problematic white layer created during the nitriding process. Developed in the early 20th century, nitriding has evolved into a standard process across many industrial applications.

When do adenoids need to be removed in children?

Sometimes, when the adenoids become enlarged and inhibit a child’s breathing or lead to ear infections, they need to be removed in an adenoidectomy. An adenoidectomy is mostly done in children between ages 1 and 7.