316L, Inconel 718 or Ti-6Al-4V: when to choose each one

Three alloys cover the vast majority of laser powder bed fusion projects. They are not interchangeable, nor are they in the same price range, and choosing the wrong one is costly in two ways: the cost of the powder itself and the cost of discovering the problem too late.

The short rule: 316L if there's no other reason. Inconel 718 when temperature is critical. Ti-6Al-4V when weight or the human body is critical.

Compared by what they decide

316L	Inconel 718	Ti-6Al-4V
Family	Austenitic stainless steel	Nickel superalloy	Titanium alloy
Approximate density	~8.0 g/cm³	~8.2 g/cm³	~4.4 g/cm³
Service temperature	Up to approximately 300–400 °C	Up to approximately 650–700 °C sustained	Up to approximately 350–400 °C
Strength-to-weight ratio	Low	Medium	Best by far
Corrosion	Very good, excellent in marine with some variations	Very good, also in hot conditions	Excellent, almost inert
Biocompatibility	Limited	No	Yes
Ease of processing	Easiest, wide window	Medium	Demanding
Relative powder cost	Low	High	Very high
Typical post-processing	Stress relief	Relief + solution + aging	Relief, sometimes in emptiness

The values are industry-wide orders of magnitude to guide a decision. The values for your part depend on the manufacturing orientation, parameters, and heat treatment, and must be measured.

316L: the default answer

It's good old stainless steel and is by far the easiest to print on: it forgives parameterization errors, has the widest processing window, and the powder is the cheapest of the three.

Choose it for general industry, chemicals, food, tooling, functional prototypes, and anything else that doesn't have a requirement pushing it in another direction. If you're new to additive manufacturing, start here: you'll learn the process without having to wrestle with the material at the same time.

Its limits are temperature and mechanical resistance. Above a sustained temperature of about 300 degrees, it starts to become unusable.

Inconel 718: When the heat rules

It is the most widely used nickel superalloy in additive manufacturing, and for a very specific reason: it maintains its properties where steel cannot, at sustained temperatures of around 650-700 degrees Celsius. Applications include turbines, power generation, oil and gas, combustion chambers, and heat exchangers.

Two things to know before committing. First, heat treatment is neither optional nor simple: achieving its properties requires a solution and aging cycle, and this cycle is part of the cost and lead time from day one. Second, the price of the powder is in a different category.

If your part doesn't actually detect temperature, Inconel is a waste of money. It's a common mistake: people choose it because it sounds high-end and end up paying three times as much for a feature the part will never use.

Ti-6Al-4V: when weight or body is in charge

Half the density of steel with comparable strength. That's the key takeaway: where weight matters—aerospace, space, racing—titanium wins even if it costs more, because the savings aren't in the component itself, but in the wear and tear it carries throughout its lifespan.

And it is the biocompatible alloy par excellence: implants, instruments, prostheses.

In return, it is the most demanding of the three. The powder is expensive and reactive, with the safety implications that entails; the processing window is narrower; and oxygen must be monitored, because titanium absorbs it and that embrittles it—that's why, with titanium, the residual oxygen in the powder is a purchasing parameter, not a minor detail.

The decision tree

Four questions, in this order:

Does it touch the human body? → Ti-6Al-4V. (Or cobalt chromium, depending on the application.)
Does it operate at sustained temperatures above 400 °C? → Inconel 718.
Is the weight really a factor? → Ti-6Al-4V.
In any other case → 316L.

There's almost always only one candidate left. When there are two, the price of the powder decides, and the cheaper one usually wins.

The most expensive mistake

It's not about choosing the wrong alloy: it's about choosing well and not just specifying the conditions. An LPBF part doesn't have inherent properties; it has the properties determined by its orientation, sweep strategy, layer thickness, and heat treatment. The same alloy, in the same machine, will produce different results depending on its placement.

That's why a complete specification includes material and conditions. A yield strength number without specifying the direction it was measured in and the treatment it was subjected to is meaningless.

And the other four

These three cover most, but not all, of our needs. In the catalogue we work with seven: in addition to the three mentioned above, we have maraging tool steel for mold inserts, AlSi10Mg for weight reduction and heat dissipation, cobalt chromium for dental and wear applications, and GRCop-42 when a lot of heat needs to be evacuated from a small space.

And if your alloy isn't on any list, our machine parameterization is open: you can qualify your own material and save it as a parameter set. That's why technology centers are our natural customers.

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What can and can't be printed, with the honest list, in what materials can be printed on metal. Why those properties depend on how it was manufactured, in deformation and stress relief. And what to check in the powder before buying it, in how metal powder is manufactured.