Originally shared May 25, 2023

This week we have another article showcasing a very important aspect of powdered metal sintering: Safety and Environmental Concerns in Using Sintering Atmospheres coauthored by TAT Technologies President, Harb Nayar and Thomas Philips of Air Products and Chemicals, Inc. It was first published in Volume 7 of the ASM Handbook, Powder Metallurgy (2015), editors P. Samal & J. Newkirk.

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This article covers the potential safety hazards of powdered metal sintering and the requirements needed to prevent them. Here are some notable highlights:

  1. There are four intrinsic dangers associated with PM sintering

    1. Explosion

    2. Fire

    3. Poisoning

    4. Asphyxiation

  2. The characteristics, function, and risks of common sintering gases are explained and visualized in a simple table.

  3. Fire and explosions are possible even when small percentages of hazardous ingredients are present.

  4. Ammonia vapor, carbon monoxide, and methanol vapor, which are commonly used in the PM and heat treat industries, are highly toxic.

  5. Almost all inert atmospheres like nitrogen used in PM manufacturing have the ability to asphyxiate plant employees if not properly vented.

  6. It is critical that admixed lubricants are removed fully, cleanly, and safely to ensure a healthy plant environment. This can be achieved by Vaporizing the lubricant, immediately Sweeping it out towards the front end of the furnace, and Destroying it before it can enter the plant environment. (VSD)

  7. There are several viable methods to achieving VSD. They fall into three categories:

    1. Natural gas based: RBO, ADS and QDP

    2. H2O Vapor-based: “Wet N2”, FAST and Vulcan

    3. Preheated air-based: LBT