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Corrosion Resistant Steels Cast Irons

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Cast Irons Prepared by Robert Merryfield What is Stainless Steel Any steel with 11% or more chromium Five General Categories of Stainless Steel Ferritic Martensitic ... – PowerPoint PPT presentation

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Title: Corrosion Resistant Steels Cast Irons


1
Corrosion Resistant SteelsCast Irons
  • Prepared by
  • Robert Merryfield

2
What is Stainless Steel
  • Any steel with 11 or more chromium

3
  • Five General Categories of Stainless Steel
  • Ferritic
  • Martensitic
  • Precipitation-Hardening
  • Austenitic
  • Duplex

4
Ferritic
  • Wholly Ferritic Structure-Balance of Chemistry
  • Wrought Designation-Type 442
  • Low Impact Properties
  • Replaced by 300 Series
  • Can not be hardened

5
Martensitic
  • 12 Chrome Steels (No nickel)
  • 400 Series
  • Wrought-410, 416, 440
  • Cast CA-15, CA-120, CA6-NM
  • Tough w/Hardness to500 HB
  • Applications
  • Pump Components Shafts and Sleeves
  • Hydraulic Cylinders
  • Wear Rings
  • Used in API Pumps not CPI

6
Precipitation-Hardening
  • Chrome-Nickel Steel
  • Martensitic Structure
  • Contains Copper-Precipitates
  • Designation
  • 17-4PH and 15-5PH Wrought
  • CB7Cu Cast
  • High Strength
  • 80,00 psi Tensile Solution Condition
  • 120,000 psi Aged Condition
  • Corrosion Resistance-Between 300 400 SS

7
Austenitic 300 Series
  • Most Prevalent in the CPI
  • Nickel gt8-Structure Austenitic
  • 18-8 SS (304) original
  • 316- Cast-CF8M 18 Cr-9Ni-2.5Mo
  • 316-Greater Pitting Resistance
  • Alloy 20- Cast CN7M 18 Cr-30 Ni-2 Mo

8
Austenitic Superalloys
  • Nickel Based
  • Nickel-Chromium-Molybdenum Alloys
  • Hastelloy C-276 Cast CW-12MW
  • Hastelloy C-22 Cast CX-2MW
  • Inconel 625 Cast CW-6MC
  • Nickel-Molybdenum Alloys
  • Hastelloy B Cast N7M

9
Duplex Stainless Steels
  • Metallurgical Structure 50 Ferrite-50Austenite
  • High Strength with Good Ductility
  • Excellent Resistance to SCC in Sea Water
  • Good Abrasion Resistance
  • Used in Fertilizer Plants
  • Grades
  • Ferallium 255 Cast CD4MCU
  • 2205

10
Additional Corrosion Resistant Alloys
  • Nickel
  • Used for Severe Caustic Environments
  • Nickel-Copper Monel Cast M-35
  • Excellent in Sea Water Applications
  • Zirconium Titanium
  • Excellent When SCC is Problem for Other SS

11
Cast Irons
  • Unalloyed Gray and Ductile
  • Corrosion resistance equal to or better than
    steel
  • Excellent dampening affect
  • Poor ductility but high compressive strength
  • low cost
  • High Nickel Austenitic Cast Iron (NiResist)
  • 18 or more Nickel content
  • Resist to Conc. Sulphuric Phosphoric Sea water

12
Cast Irons (Cont.)
  • High Chromium Cast Iron
  • Alloyed with 12 to 30 Cr
  • Resistant to Oxidizing Acids, i.e. Nitric Acid
  • Also saline solutions, organic acids and marine
    environments
  • Extremely Abrasion Resistant

13
Copper Alloys
  • Copper Alloys used in many environments because
  • Corrosion Resistance
  • Good Electrical and Thermal Conductivity
  • Ease of fabrication and welding
  • Resistance to biofouling

14
Brasses
  • Brass is an alloy of Copper and Zinc
  • Excellent corrosion resistance to aqueous
    solutions
  • Corrosion resistance decreases with Zinc content
    greater than 15.
  • Susceptible to dealloying or dezincification

15
Bronzes
  • Bronzes are Copper and Tin
  • Addition of Tin and Phosphorus to copper
    produces good resistance to flowing seawater
  • Aluminum Bronze
  • Excellent resistance to impingement corrosion
  • Al provides increased corrosion resistance
  • Resistant to Phosphoric, Sulfuric, NaCl
  • Especially resistant to brackish water

16
Labour proprietary materials
  • R-55 55 Nickel material designed for
    H2SO4 at higher temperatures
  • A-48 Duplex material, similar to CD4MCu
  • Elcomet K similar to Alloy 20
  • Y-17 similar to Hastelloy C
  • Y-30 similar to Hastelloy B

17
So, all I need is the Ph value to select a
suitable material?
  • Nothe 1-14 Ph range only tells us part of the
    story.

18
What info do you need?
  • Concentration of all the chemicals
  • Normal and maximum temperatures
  • Presence of solids
  • Life expectancy of the material

19
(No Transcript)
20
Corrosion Resistant Chart Sulfuric Acid
21
Most common chemicals
  • H2SO4 - Sulfuric Acid
  • HCl - Hydrochloric Acid
  • NaOH - Sodium Hydroxide (Caustic)
  • H2O2 - Hydrogen Peroxide
  • H2O - Water

22
H2SO4 (Sulfuric Acid)
  • Properties Clear, odorless, oily. s.g. up
    to 1.84
  • Hazards Strong irritant to tissue.
    Reacts violently with water.
  • Global Production 165 million t/yr
  • Distribution Trains, Trucks, Barges
  • Uses Fertilizers, Paints, Explosives,
    Batteries, PP, Specialty Chemicals, WTP

23
H2SO4 contd
  • Materials See chart
  • Pump types ANSI, Taber, Self Priming
  • Seals Carbon/Ceramic (gt90)
  • T.C. or special Carbon Viton elastomers
    (Teflon above 125o F)
  • DO NOT FLUSH WITH WATER

24
H2O2 (Hydrogen Peroxide)
  • Properties Stable s.g 1.2
  • Hazards Fire ExplosiveToxic and
    strongly irritating. Releases Oxygen when
    transferred
  • Distribution Trains, Trucks
  • Uses Bleaching textiles, Wood Pulp
    Hair Rocket Fuel Water Treatment PP
  • Pump Matl 316SS or Aluminum

25
H2O2 contd
  • Pump types Self Primers or TFA
  • Mech. Seals SiC/SiC or GFT/Ceramic Viton or
    Teflon
  • Major customers FMC Dupont Elf
    Autochem Tank Car Manufacturers
  • Specials Pump to be pickled to ensure
    clean inside.

26
Sodium Hydroxide (NaOH)
  • Properties White. s.g 1.55 max. lt 80cP
    viscosity
  • Hazards strong irritant. Corrosive to
    tissue
  • Distribution Trains, Trucks, Barges
  • Uses Chemical manufacture PP
    detergents electro plating food additive
    bleaching dyeing
  • Pump types ANSI Self Primer Taber

27
Sodium Hydroxide contd
  • Pump materials 50 lt125F- Iron, Steel gt125F-
    316SS 73 or gt170F - Nickel
  • Mechanical seals Carbon/T.C. (no SiC) EPR
    (no Viton)

28
Hydrochloric Acid (HCl)
  • Properties Colorless -slightly yellow,
    fuming. Concentration lt38 s.g. 1.19
  • Hazards Toxic, strong irritant to
    tissue.
  • Uses Pickling, scale removing, food
    processing, pharmaceuticals
  • Pump types ANSI Self Pimer Taber

29
Hydrochloric Acid contd
  • Pump materials Hast. B/C, FRP lt30
  • Mechanical seals Carbon/Ceramic Viton

30
Water (H2O)
  • Hazards drowning or shortage.
  • Properties Steep Pv curve (limiting us to
    350o F max.)
  • Specials High temp. water has no
    lubricity.
  • Pump matl D.I. or SS
  • Mech. Seal Carbon/Ceramic (cold water)
    see supplement for Hot water.
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