In this article, we cover two true titans of the manufacturing world: Stainless Steel and Titanium. Why are they frequently compared? What are their individual strengths and most importantly, which material would be best for your next laser cut project? Onward!
At first blush, it might not be obvious why these metals are seen hanging out together so often: Stainless steel is heavily alloyed, while Titanium is often used in nearly elemental form, and if you compared two pieces with the same dimensions, the Stainless would outweigh the Titanium by close to 50%. Then there’s the cost difference: an identical sheet metal part can cost 5x more in Titanium vs. Stainless.
Those differences aside, application overlap between the two is quite common: in medical and dental fields, Stainless Steel dominated until the 1980s when Titanium began to replace it due to its higher biocompatibility and strength-to-density characteristics. Both are used in the aviation industry, from jet engines to cockpits to landing gear. In fabrication and machining, alloys of either material can be chosen which suit the application; such as welding, machining, or temperature resistance. Both Stainless and Titanium are impact-resistant, durable, and highly corrosion-resistant. So let’s dig into each material individually and use that information to get a better idea of which to use (spoiler alert: they both look fantastic coming off of our lasers).
Characteristics of Stainless Steel
Like mild steel, stainless steel begins with iron and carbon. Its unique characteristics are largely due to the addition of Chromium and Nickel, with Manganese, Silicon, Nitrogen, Phosphorus, and Sulphur being added to various grades.
The addition of so many different alloying elements means stainless steel has a wide range of grades spanning five different families.
Types of Stainless Steel
Each stainless family is defined by its unique crystalline structure and resultant material properties.
Ferritic stainless contains 12-18% chromium, and as its name implies, is magnetic.
- Because it has a lower nickel content than some of its peers, Ferritic grades are some of the most inexpensive to produce.
- Ferritic grades 409 and 430 are often used in exhaust systems and parts that require corrosion resistance but aren’t front and center.
Martensitic stainless steels are comparatively “high carbon”, containing up to 1.2% of that element.
- Alloy 410 is a common example that exhibits good corrosion resistance and is heat treatable.
- Because of the higher carbon content, Martensitic stainless is used in blades, scissors, and in medical tools.
Austenitic stainless is more commonly known as 300 Series Stainless and contains 18% Chromium and 8% Nickel, making it extremely corrosion resistant.
- 300 Series stainless accounts for over 70% of the total worldwide production.
- Grade 304 alone holds 50% of the stainless steel market share, because it is economical, weldable, and extremely corrosion-resistant.
- 304 is used in food service, exterior fixtures, high-wear areas, tubing, tanks, and much more.
- For an even higher corrosion resistance, grade 316 can be used.
- Here at SendCutSend, we like to think we contribute to that by offering both 304 Stainless and 316 Stainless in a wide range of thicknesses.
Duplex stainless has a uniform microstructure, composed of half ferrite and half austenite which gives it excellent mechanical properties, such as ultimate and tensile strength.
- The presence of up to 28% chromium and, in “super” duplex grades, molybdenum, give Duplex stainless an almost unrivaled corrosion resistance.
Precipitation Hardening stainless is where you turn if the ultimate in high strength, high hardness are critical to the application, but solid corrosion resistance is still necessary.
Pros and Cons of Stainless Steel
Although compared to mild steel, stainless seems expensive, the cost savings associated with a built-in, corrosion-resistant finish often outweigh the difference. Because of economies of scale, the actual cost to deliver a part in stainless can often be less expensive than that same part in a lower-cost raw alloy. When compared to carbon fiber or titanium, the cost savings for stainless become quite obvious.
Type 303 stainless is considered a “free machining” alloy, meaning it doesn’t gall or smear at the cutting tool edge, but instead produces chips which clear easily. Even the most common alloys, such as 304 and 316 can be machined with good results if the tooling is kept sharp and well lubricated.
Any arc welding process (TIG, MIG, MMA or SA) works well for stainless steel, with filler rods such as ER308L and ER 309 being common for all-stainless assemblies. Using an E70S2 or 312 filler rod gives excellent weld strength between mild and stainless steel.
Unlike more expensive materials, such as carbon fiber, titanium, stainless has an extremely high max operating temperature: 304 can be used up to 1600°F (870°C) while specialty alloys such as 310 are temperature resistant past 1895°F.
Cost effectiveness, like beauty, is in the eye of the beholder. If you need stainless steel for its material properties, nothing else will do the job as economically. If what you need is a prototype or something that will never see a corrosive environment, we offer plenty of other materials that will fit the bill for a little less money: For simple fitment, consider using hardboard which also makes a great template.If you need the metal look but not the strength, try using ACM. If you need a part that will stand up to abuse but may need modification, go with mild steel to get very similar tensile strength and weight.
Stainless steel is nearly 3x more dense than aluminum which is an obvious disadvantage since both materials are corrosion resistant, unless its ultimate strength is necessary for the application. If strength AND weight are critical, however, while stainless tips the scales at around 8 g/cm3, titanium comes in under 4.5 g/cm3 with very similar strength characteristics
When subjected to harsh chloride solutions or if the environmental conditions, such as seaside or on salted roadways, many stainless alloys develop pitting which can penetrate and continue under the chromium oxide layer. For this type of industrial chemical or automotive situation, a more exotic and costly stainless alloy or another material such as titanium, which has excellent chloride resistance even at high temperatures, may be used.
What is Titanium?
Looking at the list of Stainless steel’s weaknesses, it’s clear that because of its relatively light weight, high strength, and corrosion resistance, Titanium can often pick up where Stainless leaves off, so let’s get to know this top performer a little better.
Unlike many common metals, which for thousands of years have been reduced using carbon (think, the iron smelting used to produce all steel), Titanium has only been commercially viable since the 1940s. Although it is now relatively available in many grades, the high melting point, and chemical reduction process used to produce Titanium is time and chemical intensive, leading to its high cost.
While Stainless steel only acquires its unique properties when alloyed, Titanium is an element which can be, and often is, used in its “commercially pure” form. However Titanium is also commonly alloyed, and even within the commercially pure designation there are several grades, meaning that like all other useful metals, its properties can be tailored for specific applications.
Grades of Titanium
Titanium is typically categorized into either a commercially pure (CP) grade or an alloy designation, and in general, mechanical properties increase with grade number.
CP Grades 1-2
These are produced with the lowest amount of oxygen and trace iron, making them soft and ductile. This means Grade 1 is often used in pipe and tubing, or welded applications. Grade 2, which we supply as 0.04” sheet, has higher tensile strength and yield strength while remaining affordable compared to more highly processed grades.
CP Grades 3-4
These grades are significantly stronger than 1 & 2, with 4 being the strongest CP grade, but because of that they sacrifice some ductility. Both grade 3 & 4 are still weldable, and extremely durable, often being used in surgical equipment, high-value heat exchangers, chemical processing and aerospace.
Ti 6Al-4V (Grade 5)
Is the most common titanium alloy, accounting for around half the total worldwide demand of all titanium grades. In addition to the iron found in CP grades, Grade 5 also includes about 6% aluminum and around 4% vanadium, which increases the temperature resistance and nearly triples the ultimate tensile strength to 150 ksi. Because it basically sits as king of the metals hill by almost every metric, we offer Ti 6Al-4V, grade 5 Titanium in five different thicknesses. Use it in aircraft applications, engine and race car components, marine applications, or anywhere else where ultimate performance and weight reduction are critical.
Pros and Cons of Titanium
Like other corrosion-resistant materials which oxidize to form a barrier when exposed to oxygen in the air, the surface of Titanium begins to immediately oxidize, forming titanium oxide forming a thin passivation layer which protects the rest of the material from further corrosion. Unlike some other oxide layers, the titanium dioxide layer continues to thicken over time, reaching up to 25 nm after several years, giving it a corrosion resistance almost equal to platinum.
Titanium is a lightweight–in the best possible sense. It has the highest strength-to-weight ratio of any metallic element. Even in its unalloyed condition (which, remember, is ⅓ the ultimate strength of Grade 5) it is still as strong as some steels, at 40% the weight.
Titanium is one chill dude: getting it to react with anything is almost impossible at normal temperatures. Combine this with its low density and you have the recipe for the most prevalent hypoallergenic metal in use today in the medical industry for joints, bone repair, and any other sensitive body contact application.
Titanium is a high-cost material which makes it economically viable only when its unique material properties are required. For things like machining, Titanium can have a cost factor up to 30x that of Stainless because on top of the material cost, it is also relatively difficult to machine.
When done correctly, Titanium can be welded with excellent results, but because of its oxide layer and high reactivity with oxygen, nitrogen and carbon, (so basically, air), when heated, it is much less forgiving than steel alloys when welded. Embrittlement occurs in Titanium’s HAZ due to weld metal contamination from gas absorption or by dissolving contaminants on the surface of the metal.
Titanium vs. Stainless Steel: Which One is Right for Your Project?
|Price||❌||✔️||SS is several times less costly|
|Weight||✔️||❌||Ti is 40% the weight for equal strength|
|Tensile/Yield Strength||✔️||✔️||Nearly equivalent, grade dependant|
|Durability||❌||✔️||SS has better impact & scratch resistance|
|Composition||✔️||✔️||Wide range of available grades|
|Corrosion Resistance||✔️||❌||Clear winner, here|
|Hardness||❌||✔️||In general SS but it’s grade-dependent|
|Chemical Resistance||✔️||❌||At normal temps, Ti has the edge|
|Temp Resistance||❌||✔️||SS up to 2000°F, Ti up to 1500°F|
How to Use Stainless Steel and Titanium in Machining?
Titanium and Stainless Steel face many of the same challenges for the machinist: Common alloys of both gall easily rather than the chip breaking off cleanly at the cutter edge. Both also have a low coefficient of thermal conductivity, which means that it is easy to cause localized work hardening and promote premature tool wear. Titanium has the added challenge of being more flexible than most machined materials compared to its hardness, so care must be taken to fixture it as rigidly as possible.
However, when these concerns are addressed, Titanium and Stainless deliver excellent results when machined. For Titanium, ensure that the tool is kept in constant motion at lower speeds and higher feeds to reduce temperature buildup, along with high pressure coolant when possible.
For Stainless, choose Grade 303, which includes sulfur as one of the alloying elements, which improves the free machining characteristics of the alloy.
As always, if sheet metal parts are what your application calls for, our team of experts have dialed in the power and speed of our lasers, (and waterjets, CNCs, deburring machines, benders… you get the idea), to deliver the absolute best results for each unique material.
FAQs around Stainless Steel and Titanium
Type 304 is by far the most prevalent grade within the Stainless world. Likely followed by type 316, which improves upon 304’s already excellent corrosion resistance. In addition, both are easily welded, ductile enough to bend well, extremely durable, and relatively inexpensive. Here at SendCutSend we offer both 304 and 316 as well as many other materials to suit every application.
Whether you use 304 or 316 really depends on the application. If the pinnacle of corrosion resistance and sanitary or food-safe compatibility is necessary, pick Grade 316.
This is really an application-specific question. A great place to start is the table above, and for a deeper dive, check out our article on 304 or this informative piece on Titanium. In general, both will last longer than the rest of the parts required for that particular application.