What is a duplex pipe?
These pipes use a special alloy comprising iron, chromium, and nickel. a duplex pipe has two grades – ferritic and austenitic – for a unique microstructure.The most common composition is 22% chromium, 5% nickel, and 5% molybdenum. A duplex stainless steel pipe shows high strength, good welding performance, and superior corrosion resistance when exposed to chlorides and sulphides. It also exhibits excellent heat conductivity.
How is duplex seamless pipes manufactured?
The manufacturing process involves multiple steps, starting with melting steel in an electric arc furnace. This molten steel gets shifted to a converter (aod, or argon oxygen decarburization). The composition gets settled during this step by adding the alloying elements and eliminating the gases. The last step is casting into the desired shape, like a duplex seamless pipes. Manufacturers may perform further steps to meet client requirements, for instance, solution annealing, peeling, and pickling.
Specification of duplex pipe
|ASTM A 790 ASME SA 790||14mm - 250mm||0.3mm to 50 mm|
|SCH20, SCH30, SCH40, SCH80||Plain, treaded, beveled||Seamless pipes, welded pipes, ERW pipes, square pipes|
For what is a duplex welded pipe utilized?
These pipes are most frequent in heavy industries due to their strength and corrosion resistance. a DSS welded pipe is standard in the oil and gas sectors, chemical processing, and petrochemical industries. Its corrosion resistance helps it work dependably in wastewater treatment plants and seawater applications. Paper and nuclear plants and bridge construction projects also use these pipes.
Types of duplex steel round pipe
Duplex steel pipes
Duplex seamless pipe
Duplex welded pipe
Duplex stainless steel ERW pipe
What is the difference between a DSS pipe?
A stainless steel pipe has a minimum of 10% chromium in its composition. It is manufactured in ferritic (magnetic) and austenitic (non-magnetic) grades. In contrast, DSS pipes comprise ferritic and austenitic grades in their microstructure (50-50%). They display desirable properties like high strength, tolerance to stress corrosion cracking, and suitability for temperatures up to -50°c or lower.
Chemical composition of DSS welded pipe
What is a schedule chart and the price of a duplex pipe?
The schedule chart shows the wall thickness for the corresponding pressure and temperature. It will determine the inside diameter of the pipe. DSS round pipes can cost between rs. 500 to rs. 600 per kilogram. The price is less than austenitic stainless steel grades due to the lower nickel and molybdenum content.
Mechanical properties of duplex ERW pipes
|Grade||% Elongation||YS (MPa)||Hardness(BHN)||UTS (MPa)|
|S31803||25 min.||450 min.||293 max.||620 min.|
What are the grades and specifications of a duplex pipe?
Buyers can acquire a dss pipe in multiple grades. The common ones are 2205 (22% chromium, 5% nickel, and 3% molybdenum) and 2304 (23% chromium and 4% nickel, no molybdenum). The standard specification is a240 uns s31803 or s32205.
Equivalent grade of duplex seamless pipes
|Duplex||1.4462||S31803 / S32205|
Size chart of DSS pipes
| Pipe OD |
| Pipe WT |