Sintering is a thermal process largely exclusive to powder metallurgy (PM). The powder metallurgy sintering process frees engineers from many limitations inherent to traditional design in both structural and magnetic applications:
Today, advanced powder metallurgy processes can provide strength and design flexibility superior to casting. And PM requires less secondary machining, allowing for more material flexibility than forging.
Whether you haven’t considered sintering as a solution, or your current sintered part hasn’t unleashed its full potential, this guide will give you several great takeaways:
Use this e-book to match your application, required properties, and budget to a sintering technique. With the right alloys and heat-treating conditions in place, you can create powder metal parts that perform better than you ever imagined possible:
What is sintered metal? Fortunately, while the fine details are quite complex, the basics are easy to understand. Keep reading to not only better understand sintered parts, but also how the powder metal process can create high-strength parts that are viable in many more applications than you realize.
Resource: What is Sintered Metal?
If you could ask the metals involved, they’d probably tell you it’s a simple matter of hot vs. hotter. But from a quality and flexibility standpoint, there are very significant differences between the two processes. These differences will help an engineering team decide how and when to use melting or sintering for metal parts manufacturing.
Resource: Powdered Metal: What’s the Difference Between Sintering and Melting?
What is sintering in powder metallurgy (PM)? Conventional sintering processes are the bread and butter of improving a part with PM. This process heats the compacted part to fuse the loosely bonded particles for improved strength and hardness. After sintering, the powder metal part is often heat treated by reheating to permit quenching and tempering. This further increases the hardness and strength of the compacted component.
Resource: Skipping Steps: Sinter Hardening vs. Conventional Sintering Processes
Sintered parts start out as powder compacts, sometimes referred to as “green” parts. Heating these in a furnace -- a process known as sintering -- bonds the powder grains together, to create hard components ready for use.
Sintering of iron based PM parts is usually done at around 2020-2100°F. When done at higher temperatures, the process is called “high-temperature sintering.” High-temperature sintering changes part properties and can have amazing performance implications. Anyone specifying or purchasing sintered metal parts should know the differences and understand how this process can benefit both price and performance.
Resource: Beginner's Look at High-Temperature Sintered Parts
Sintering is a powder metallurgy processing step in which particles fuse into either a solid or porous body (sintered neck formation) at a temperature below the melting point of the major element in the powder.
Think of ice cubes melting together in a glass of water. The longer the ice sits in the water, the harder it is to break those cubes up. That’s a good analogy of sintered neck formation.
Resource: Advances in Powder Metallurgy: Ultra-High-Temperature Sintering
Optimizing a project for powder metallurgy isn’t just a matter of pouring a mix into a Play-Doh machine and cranking it out. The sintering process in powder metallurgy alone offers several tweaks that can give you different, nuanced results.
One of the most exciting processes for those designing a complex part is called sinter bonding. In this process, the manufacturer bonds two pieces together during sintering.
The implications could be big for your project, no matter the industry.
Attaching components to one another requires in-depth understanding of the qualities of the metals in each component.
Everyone knows about welding. Fewer know about sinter bonding and sinter brazing, useful processes that are specific to powder metallurgy. Compared with traditional brazing, sinter brazing uses different materials.
You may not realize it, but sinter bonding and sinter brazing are two distinct metal forming processes in powder metallurgy. Both are great techniques for optimizing your powder metal part, but there are quirks and unique qualities in each.
You may even be able to replace tried-and-true processes like welding! Let’s discover what you can do with each of these powder metal-specific techniques.
Resource: Soft Magnetic Composites: A Visual Crash Course on Improving Motor Efficiency
If you still don’t have a good handle of whether sintering can expand your design options and improve material properties, ask our world-class team directly. You can also keep learning on your own by scrolling to the resources below.
Our team includes Senior Advanced Materials Engineer Fran Hanejko and Director of Technology & Business Development Tom Freemer. Fran is a highly respected industry expert who’s published several research papers on sintering and powder metallurgy. Tom has collaborated with design engineers across several industries to create innovative PM solutions through advanced manufacturing techniques and material alloys.
Fran and Tom have extensive experience in powder metallurgy, including several years with a world-leading raw material supplier. If you have design or performance questions for them, get in touch here.
The Metal Powder Industries Federation recently republished an interesting article about the early history of powder metallurgy (PM) that was originally printed in a 1944 issue of the Saturday Evening Post. It notes that General Motors began making significant quantities of PM parts during WW2 as a way to cost effectively mass produce many small intricate parts that helped in the war effort. These parts were often difficult to cast or machine; thus, PM offered the ability to mass produce these components while meeting all design strength requirements in a cost-effective manner.
Engineers who are tasked with designing and specifying electric motors for new and updated applications are now facing three interdependent challenges: optimizing operating efficiency, simplifying the manufacturing processes to reduce cost, and addressing the emerging concern of recyclability and sustainability.
Until after World War II, the US power tool market was largely focused on the industrial metal working and wood working industries. The home and professional markets were largely left unaddressed. It wasn’t until the 1950s that equipment makers realized the potential of the home and professional sectors. Shown below is a photograph of three drill types. The image on the left is a brace and bit. Prior to the early 1950s, this was perhaps the most common drill type used by homeowners. (Yes, it was my dad’s and yes it still works!) On the right is a ¼-inch corded electric drill, typically used by homeowners around the 1950s, and in the center is a late 90s cordless electric drill. The technology only continues to progress!
In 2012, the total energy consumption of the United States was estimated to be 96 quadrillion BTUs (96 x 10^15). Figure 1 illustrates how this usage breaks down by sector. At the time of this study, energy consumed by the transportation sector was almost entirely from gasoline or diesel fuels. In the remaining residential, commercial and industrial sectors, it is estimated that approximately 35% of the energy is consumed by electric motor systems.
In the intricate array of modern manufacturing, the Powder Metallurgy (PM) industry stands as a dynamic force, continually shaping the future as a sustainable metal forming technology. As we navigate through the current landscape of PM, it becomes evident that innovation is not merely a choice but a necessity.
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