Choosing powder metallurgy materials means you must consider a handful of different factors, including desired part performance, market availability, and more. While all of these factors play a role in the decision-making process, many manufacturers only want to ask one question: “How much does it cost?”
Cost is an understandably big part of your decision, and it’s best to consult with a powder metallurgy manufacturer to determine how to save money without sacrificing part performance and quality. Sometimes the cost of powdered metal may not initially look attractive, but when you add all the surrounding factors, it’s actually quite appealing.
Your real goal, rather than comparing grades of metal like you might with traditional machining, should be to learn how processes change powder metallurgy costs as you ask for increasingly high properties.
Choosing Powder Metallurgy Materials: Cost
To Machine or Not to Machine?
Simply looking at the cost of raw steel vs. powder is not a good way to compare your options. The advantages of powder metallurgy come later down the line. Because PM is a net-shape process, there’s very little or no secondary machining necessary and minimal material waste.
PM is capable of tolerances that are suitable for a variety of applications. Tolerances can directly impact pricing. As you require tighter tolerances, additional secondary operations may be necessary to meet those demands.
Base Metals
The most common material in PM is an iron-copper-carbon base and it has evolved to solve certain strength requirements. However, newer applications require newer materials.
Depending on your application, you may need to focus on:
- Strength
- Porosity
- Need for heat treatment
- Toughness
- Magnetic properties
- Corrosion resistance (stainless steels)
Those factors determine the materials, alloys, and processing you choose.
As you add alloying elements to the base material, the price goes up.
Iron is the least costly powder metal material. Pure iron is the most inexpensive, while more exotic iron-based materials get a little more expensive.
Don’t confuse low cost with low quality -- iron powder offers great performance traits in a variety of applications.
Powder Metallurgy Prices: The Outlook
The powder metal industry has a long history of improving materials and processes that can replace conventional metal forming processes and reduce costs.
Much like real estate preaches “location, location, location,” powder metallurgy is often defined by:
- Density
- Density
- Density
The concern has always been this: How does a customer obtain the properties they want at a competitive price? Engineers have historically needed to use processes like powder forging, which will give you full density of 7.8 g/cm³. Full density greatly improves strength and durability but doubles the price.
The idea behind this graph is to show a relative cost of these advanced processes compared to conventional press-and-sinter technology. This method (represented by the bottom-left dot) is not material-dependent, just process-dependent.
Standard press-and-sinter technology maxes out at about 7.1 g/cm³ density. Double-press double-sinter, a popular method for increasing density, can achieve up to 7.4 density, but there’s a huge increase in cost.
Some advanced compaction processes can achieve the same density, but at a lower cost than the double press and double sinter method.
If we could combine advanced compaction with high temperature sintering, we can see even more improvements to density.
We can take these processes even further by pairing advanced compaction with ultra-high-temperature sintering, which allows a density of 7.6 g/cm³ without the exorbitant cost of powder forging.
Advanced Compaction & Ultra-High-Temperature Sintering
So what do density and process have to do with the performance of the component?
Look at powder metal vs. machined parts and precision casting. You can achieve full density and its related benefits, but at a huge price. These are certainly all viable technologies, but they’re cost-prohibitive for many projects.
In this way, the question of “What’s the cheapest powder metal material?” should instead be posed as, “How can we balance material and process to reach a productive compromise?”
To do that, some powder metal manufacturers have invested in technologies that don't necessarily get you to full density, but perhaps close enough. With advanced compaction technology, you can get your part to 7.4 g/cm³ -- and achieve good material properties at minimal additional cost.
Typically when the industry tries to reach that level of density, it takes the approach of the second green dot (double press and sinter). But, again, the cost penalty is substantial.
You can move your cost-efficiency forward if you couple advanced compaction with high-temperature sintering (the middle dark-blue dot). You can take it even further with ultra-high-temperature sintering (the dark-blue dot on the right). Even going well beyond 7.4 g/cm³ density with ultra-high-temp sintering, you’re still not at the cost level of the double-press, double-sinter process many PM manufacturers offer.
Conversations With Your PM Partner
In the end, a powder metallurgy manufacturer will always follow the buyer’s specifications. But getting your manufacturer to be a partner in the design process may help optimize your component.
A small parts manufacturer with experience in advanced materials can steer customers toward affordable, yet high-performing choices.
Because Horizon specializes in advanced compaction methods and innovative sintering practices, we offer the opportunity to substantially improve PM part performance, often competing with conventionally forged materials.
Powder Metallurgy Costs Are Only Half the Story
If your component fits the mold for using powder metallurgy, everything you just read should act as a pricing model of sorts.
PM is all about efficiency, and new technologies and non-traditional MPIF material options allow you to reduce manufacturing costs without sacrificing your high-performing design.
Work with your powder metal parts manufacturer to find the greatest value for your part. This may mean you’ll be encouraged to try different material choices and blends.
If you have more questions about powder metallurgy cost and specific material cost, feel free to reach out. You can also use the button below to ask us a question about how your small metal part design can be better, smarter, and more affordable.
