DUPLEX STAINLESS STEEL TYPE GRADE AND STANDARD
|Name||ASTM F SERIES||UNS SERIES||DIN STANDARD|
•Lean Duplex SS – lower nickel and no molybdenum – 2101, 2102, 2202, 2304
•Duplex SS – higher nickel and molybdenum – 2205, 2003, 2404
•Super Duplex – 25Chromium and higher nickel and molybdenum “plus” – 2507, 255 and Z100
•Hyper Duplex – More Cr, Ni, Mo and N – 2707
•Duplex Stainless Steels have roughly twice the yield strength of their counterpart austenitic grades.
•This allows equipment designers to use thinner gauge material for vessel construction!
Duplex stainless steel advantage:
1. Compared with austenitic stainless steel
1) The yield strength is more than twice as high as that of ordinary austenitic stainless steel, and it has sufficient plastic toughness required for molding. The thickness of the tank or pressure vessel made of duplex stainless steel is 30-50% lower than that of the commonly used austenitic stainless steel, which is beneficial to reduce the cost.
2) It has excellent resistance to stress corrosion cracking, especially in the environment containing chloride ions, even the duplex alloy with the lowest alloy content has higher resistance to stress corrosion cracking than austenitic stainless steel. Stress corrosion is A prominent problem that ordinary austenitic stainless steel is difficult to solve.
3) The most common 2205 duplex stainless steel used in many media has better corrosion resistance than ordinary 316L austenitic stainless steel, while super duplex stainless steel has high corrosion resistance. In some media, such as acetic acid and formic acid. It can even replace high-alloy austenitic stainless steels and even corrosion-resistant alloys.
4) It has good resistance to local corrosion. Compared with austenitic stainless steel with the same alloy content, it has better wear resistance and corrosion fatigue resistance than austenitic stainless steel.
5) The austenitic stainless steel has a low coefficient of linear expansion and is close to carbon steel. It is suitable for connection with carbon steel and has important engineering significance, such as producing composite plates or linings.
2. Compared with ferritic stainless steel, the advantages of duplex stainless steel are as follows:
1) The comprehensive mechanical properties are higher than that of ferritic stainless steel, especially plastic toughness. Not as sensitive to brittleness as ferritic stainless steel.
2) In addition to stress corrosion resistance, other local corrosion resistance is superior to ferritic stainless steel.
3) Cold working process performance and cold forming performance are much better than ferritic stainless steel.
4) The welding performance is much better than that of ferritic stainless steel. Generally, no heat treatment is required after preheating without welding.
5) The application range is wider than that of ferritic stainless steel.
Application Due to the high strength of duplex steel, it tends to save material, such as reducing the wall thickness of the pipe. The use of SAF2205 and SAF2507W as examples. SAF2205 is suitable for use in chlorine-containing environments and is suitable for use in refinery or other process media mixed with chloride. SAF 2205 is especially suitable for use in heat exchangers containing aqueous chlorine or brackish water as the cooling medium. The material is also suitable for dilute sulfuric acid solutions and pure organic acids and mixtures thereof. Such as: oil pipelines in the oil and gas industry: desalting of crude oil in refineries, purification of sulfur-containing gases, wastewater treatment equipment; cooling systems using brackish water or chlorine-containing solutions.
SAKY STEEL ensure that all our materials go through strict quality tests before dispatching them to our clients.
• Mechanical Testing Such as Tensile of Area
• Hardness Test
• Chemical Analysis – Spectro Analysis
• Positive Material Identification – PMI Testing
• Flattening Test
• Micro and MacroTest
• Pitting Resistance Test
• Flaring Test
• Intergranular Corrosion (IGC) Test
Post time: Sep-11-2019