CNC Machining Duplex Stainless Steel (DSS) SAF 2205 Parts
Duplex Stainless Steel (DSS) SAF 2205 Refers To The Stainless Steel With Ferrite And Austenite Accounting For About 50% Respectively. Generally, The Stainless Steel With Fewer Phases Needs To Reach 30% At Least. When The Content Of c Is Low, The Content Of Cr Is 18%~28%, And The Content Of Ni Is 3%~10%. Some Steels Also Contain Alloying Elements Such As Mo, Cu, Nb, Ti And N.
Compared With Ferrite, This Kind Of Steel Has Higher Plasticity, Toughness, No Room Temperature Brittleness, Better Intergranular Corrosion Resistance And Weldability, And Maintains 475 Brittleness And High Thermal Conductivity Of Ferrite Stainless Steel, Which Has The Characteristics Of Superplasticity.
Compared With Austenitic Stainless Steel, It Has Higher Strength, Better Resistance To Intercrystalline Corrosion And Chloride Stress Corrosion. Duplex Stainless Steel Is a Nickel-Saving Stainless Steel With Excellent Pitting Resistance.
Historical Development
Duplex Stainless Steel Has Developed To The Third Generation Since Its Birth In The United States In The 1940s. Its Main Characteristic Is That Its Yield Strength Can Reach 400-550 Mpa, Which Is Twice That Of Ordinary Stainless Steel, So It Can Save Materials And Reduce The Cost Of Equipment Manufacturing.
In The Aspect Of Corrosion Resistance, Especially In The Condition Of Bad Medium Environment (Such As Seawater, High Chloride Ion Content), The Pitting Corrosion, Crevice Corrosion, Stress Corrosion And Corrosion Fatigue Properties Of Duplex Stainless Steel Are Obviously Better Than Those Of Ordinary Austenitic Stainless Steel, Which Can Be Comparable To That Of High Alloy Austenitic Stainless Steel.
Performance Characteristics
Due To The Characteristics Of Two-Phase Structure, Duplex Stainless Steel Has The Advantages Of Both Ferritic Stainless Steel And Austenitic Stainless Steel By Correctly Controlling Chemical Composition And Heat Treatment Process. It Combines The Excellent Toughness And Weldability Of Austenitic Stainless Steel With The High Strength And Chloride Stress Corrosion Resistance Of Ferritic Stainless Steel. Together, Duplex Stainless Steel Has Developed Rapidly As a Weldable Structural Material Due To Its Superior Properties. Since The 1980s, Duplex Stainless Steel Has Become a Kind Of Steel Juxtaposed With Martensitic, Austenitic And Ferritic Stainless Steel. Duplex Stainless Steel Has The Following Characteristics:
(1) Duplex Stainless Steel Containing Molybdenum Has Good Resistance To Chloride Stress Corrosion Under Low Stress. Generally, 18-8 Austenitic Stainless Steel Is Prone To Stress Corrosion Cracking In Neutral Chloride Solution Above 60 Degrees c. Heat Exchangers And Evaporators Made Of This Kind Of Stainless Steel Tend To Produce Stress Corrosion Cracking In Industrial Medium Of Trace Chloride And Hydrogen Sulfide, While Duplex Stainless Steel Has Good Resistance. Power.
(2) Duplex Stainless Steel Containing Molybdenum Has Good Pitting Resistance. The Critical Pitting Potential Of Duplex Stainless Steel Is Similar To That Of Austenitic Stainless Steel With The Same Equivalent Value Of Pitting Resistance (Pre=Cr%+3.3mo%+16n%). The Pitting Corrosion Resistance Of Duplex Stainless Steel And Austenitic Stainless Steel Is Similar To That Of Aisi 316l. The Pitting And Crevice Corrosion Resistance Of High Chromium Duplex Stainless Steel Containing 25% Cr, Especially Nitrogen, Is Better Than That Of Aisi 316l.
(3) It Has Good Corrosion Fatigue And Wear Corrosion Resistance. Under Certain Conditions Of Corrosive Media, It Is Suitable For Making Pumps, Valves And Other Power Equipment.
(4) Good Comprehensive Mechanical Properties. It Has High Strength And Fatigue Strength, And Its Yield Strength Is Twice That Of 18-8 Austenitic Stainless Steel. The Elongation Of Solid Solution Reached 25%, And The Toughness Value Of Ak (v Groove) Was Above 100 j.
(5) Weldability Is Good, Hot Cracking Tendency Is Small, Generally No Preheating Before Welding, No Heat Treatment After Welding, Can Be Dissimilar With 18-8 Austenitic Stainless Steel Or Carbon Steel Welding.
(6) Dual-Phase Stainless Steel With Low Chromium (18% Cr) Has Wider Hot Working Temperature Range Than 18-8 Austenitic Stainless Steel, And Has Less Resistance. It Can Be Directly Rolled To Produce Steel Without Forging. Hot Working Of Duplex Stainless Steel With High Chromium (25% Cr) Is Slightly More Difficult Than That Of Austenitic Stainless Steel. It Can Produce Plates, Pipes And Wires.
(7) The Work Hardening Effect Of Cold Working Is Greater Than That Of 18-8 Austenitic Stainless Steel. In The Initial Stage Of Tube And Plate Deformation, Larger Stress Is Required To Deform.
(8) Compared With Austenitic Stainless Steel, It Has Higher Thermal Conductivity And Smaller Linear Expansion Coefficient. It Is Suitable For Lining Equipment And Producing Clad Plates. It Is Also Suitable For Making The Core Of Heat Exchanger. The Heat Transfer Efficiency Is Higher Than That Of Austenitic Stainless Steel.
(9) There Are Still Various Brittle Tendencies Of High Chromium Ferritic Stainless Steel, Which Should Not Be Used In Working Conditions Higher Than 300 Degrees c. The Lower The Content Of Chromium In Duplex Stainless Steel, The Less Harmful The Brittle Phase Such As.
Purpose
It Is Used For Heat Exchangers, Cold Sprinklers And Devices Such As Refining, Chemical Fertilizer, Paper Making, Petroleum, Chemical Industry, Seawater Resistant, High Temperature Resistant, Concentrated Nitric Acid, Etc.