We put Duplex 2205 and Stainless Steel 316L head-to-head to see which is best for downhole capillary tube applications!
Why the debate?
In a world full of custom alloys and specialty metallurgies for specialty capillary tube applications Duplex 2205 and Stainless Steel 316L stand out as the most common options for general downhole use. Their competitive pricing and overall durability and corrosion resistance make them perfect for most downhole applications.
Specialty alloys offer superior corrosion resistance, but they can come at a cost.
Through all of the shakeup that has happened to the steel industry over the past 3 years Duplex 2205 and Stainless Steel 316L have settled at comparable prices. So that leaves operators with the question, which material offer superior value for their downhole applications?
Figure 1: GEO PSI Downhole Capillary Tube
Physical & Mechanical Properties
A quick look at the physical and mechanical properties of these two materials highlights a clear winner, Duplex 2205.
Duplex 2205 is a nitrogen enhanced stainless steel alloy that provides superior strength and durability for downhole capillary tube. When heat-treated, the composition of 2205 produces a micro structure of a roughly equal mixture of austenitic and ferritic phases that results in a yield strength approximately double that of austenitic alloys such as 316L, as well as superior corrosion resistance in many hostile environments.
Duplex 2205
Stainless Steel 316L
Tensile Strength
Yeild Strength
Corrosion Resistance
Our Duplex 2205 Capillary Line is ideal for harsh oil & gas environments and can withstand external forces and deformation. It is utilized in oil and gas production, chemical injection, control line applications, etc.
In comparison to Duplex 2205, austenitic stainless steel like Stainless Steel 316L exhibits inferior mechanical properties, including lower tensile strength, yield strength, and resistance.
The graph and table below show how the Duplex 2205 is superior in every parameter.
0.25″
Properties
Duplex 2205
(0.035”)
Stainless Steel 316L
(0.035”)
Duplex 2205
(0.049””)
Stainless Steel 316L
(0.049”)
Burst Pressure
26,600 psi
21,800 psi
37,200 psi
29,400 psi
Internal Pressure
19,600 psi
8,400 psi
27,400 psi
11,700 psi
Collapse Pressure
16,800 psi
7,200 psi
22,000 psi
9,400 psi
Working Pressure
14,100 psi
6,000 psi
19,700 psi
8,400 psi
Test Pressure
16,200 psi
6,900 psi
22,700 psi
9,700 psi
0.375″
Properties
Duplex 2205
(0.035”)
Stainless Steel 316L
(0.035”)
Duplex 2205
(0.049””)
Stainless Steel 316L
(0.049”)
Burst Pressure
17,700 psi
14,000 psi
24,800 psi
19,600 psi
Internal Pressure
13,300 psi
5,600 psi
18,200 psi
7,800 psi
Collapse Pressure
11,800 psi
5,000 psi
15,900 psi
6,800 psi
Working Pressure
9,400 psi
4,000 psi
13,100 psi
5,600 psi
Test Pressure
10,800 psi
4,600 psi
15,100 psi
6,400 psi
Duplex 2205's Superior Value
As shown above Duplex 2205 possesses better mechanical properties and corrosion resistance than Stainless Steel 316L.
This provides more value to users as it is suitable for a wide-range of applications, including harsh environments.
Additionally, a thinner-walled Duplex 2205 capillary tube will perform just as well as a thicker-walled Stainless Steel 316L capillary tube. This means thinner walls for higher flow, and less overall material used reducing the weight and total cost.
Given the comparable prices of both materials, Duplex 2205 presents itself as a far more cost-effective solution over the long run.
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Read more on why Duplex 2205 is the superior choice for downhole capillary tube over Stainless Steel 316L.
Conclusion
While different materials all have their unique benefits and attributes which make them a preferable solution for different applications, we believe the choice between Duplex 2205 and Stainless Steel 316L is an easy one.
While both are the commonly used, we believe that Duplex 2205 has obvious benefits that should make it the go-to for users around the world. And while it significantly outperforms Stainless Steel 316L in all areas, our annealing process ensures it does this without detriment to its handling and ease of use in the field.
To learn more and view our selection of annealed Duplex 2205 Capillary Tube products visit the link below.
