NITRONIC 60® (Alloy 218) (UNS S21800)


Cr 17, Mn 8, Ni 8.5, Si 4, N 0.13, C 0.10, Fe Bal.

High Performance Alloys stocks and produces this grade in the following forms: Bar, wire, sheet, plate, coil, fasteners and forgings. Request quote on this grade. See our on-line catalog for sizes stocked

 

Overview

  • Download Brochure 40 pg PDF

  • Download Bulletin 2 pg PDF
  •  

    Austenitic Stainless

    Nitronic 60 is truly an all purpose metal. This fully austenitic alloy was originally designed as a temperature alloy, and subsequently has good high temperature properties for temperatures around 1800ºF. The oxidation resistance of Nitronic 60 is similar to Type 309 S.S., and far superior to Type 304S.S. This grade is best known for its wear and galling resistance.

    The additions of Silicon and Manganese have given this alloy a matrix to inhibit wear, galling, and fretting even in the annealed condition. Higher strengths are attainable through cold working the material and is still fully austenitic after severe cold-working. This working does not enhance the anti-galling properties as is normal for carbon steels and some stainless steels. The benefit to the cold or hot work put into the material is added strength and hardness, and the wear resistance does not decrease noticeably. Chromium and Nickel additions give it comparable corrosion to 304 and 316 stainless steels, while having approximately twice the yield strength. The high mechanical strength in annealed parts permits use of reduced cross sections for weight, and cost reductions through the use of thinner stock.

    Several data sheets are available on the wear compatibility of this alloy with dissimilar couples, as well as self-mated coupled results. Download PDF or call for your own booklet!

    If your galling problem occurs at less than 1500ºF, then you should think about switching to this alloy . Nitronic 60 has a better cost advantage than any other alloy available. Other materials require an additional amount of heat treating to raise their hardness, where NITRONIC 60 is excellent in the annealed condition. See more information on NITRONIC 60 HS (High Strength) properties on the NITRONIC 60HS page.

     

    Characteristics

    Corrosion Properties
    The corrosion resistance of Armco NITRONIC 60 Stainless Steel falls between that of types 304 and 316. However, experience shows that in a wear system, a galling or siezure failure occurs first, followed by dimensional loss due to wear, and finally corrosion. Galling and wear must be the first concerns of the design engineer. Although the general corrosion resistance of NITRONIC 60 is not quite as good as Type 316, it does offer better chloride pitting resistance, stress corrosion cracking resistance and crevice corrosion resistance than Type 316 in laboratory conditions. Corrosion tests are not normally performed with NITRONIC 60 High Strength.

    Corrosion Resistance
    Nitronic 60’s uniform corrosion resistance is better than 304 stainless in most environments. The yield strength of Nitronic 60 is nearly twice that of 304 and 316 stainless steels. Chloride pitting resistance is superior to that of type 316 stainless; Nitronic 60 provides excellent high temperature oxidation resistance and low temperature impact.
    Applications using Nitronic 60 are valve stems, seats, and trim, fastening systems, screening, pins, bushings and roller bearings, pump shafts and rings. Other uses include wear plates, rails guides, and bridge pins.

    Wear Resistance
    This alloy provides a significant lower cost way to fight wear and galling compared to Nickel or Cobalt based alloys.

     

    Wear Compatibility of NITRONIC 60 wear compared to Cobalt 6B and
    17-4PH Against Various Alloys
    Alloy Hardness 17-4 PH
    (HRC 43)
    NIT 60
    (HRB 95)
    Cobalt 6B
    (HRC 48)
    304 HRB 99 24.7 6 3.1
    316 HRB 91 18.5 4.3 5.5
    17-4 PH HRC 31.5 66.1 4.9 2.7
    17-4 PH HRC 43 52.8 5.4 3.8
    NIT 32 HRB 95 17.2 3.2 2
    NIT 50 HRB 99 15.7 3.5 2.9
    NIT 60 HRB 95 5.4 2.8 1.9
    Cobalt 6B HRC 48 3.8 1.9 1
    Chrome Plate --- 3.3 2.1 0.3
    Silicon Bronze HRB 93 2 2.2 1.9
    K-500 Monel HRC 34 34.1 22.9 18.8
    416 HRC 24 --- 5.5 43
    431 HRC 32 --- 3 1
    Waspaloy HRC 36 --- 3.1 2.4
    IN 718 HRC 38 --- 3.1 2.7
    IN X-750 HRC 36 --- 5.5 8
    Weight Loss of Couple (mg/1000 cycles)

    This wear data republished from Armco brochure. NITRONIC is a trademark of AK Steel.

     

    Chemistry

    Chemical Requirements

    Ni

    Cr

    Mn

    Si

    N

    Mo

    C

    Max

    9.00

    18.00

    9.00

    4.5

    0.018

    0.75

    0.10

    Min

    8.00

    16.00

    7.00

    3.5

    0.08

     

     

    Tensile Data

    Mechanical Property Requirements under 0.5"

    Ultimate Tensile

    Yield Strength (0.2% OS)

    Elong. in 4D

    R/A

    Hardness

    Min

    105 KSi

    55 KSi

    35%

    55%

    Max

    Min

    724 MPa

    379 MPa

    Max

     

    Mechanical Property Requirements over 0.5"

    Ultimate Tensile

    Yield Strength (0.2% OS)

    Elong.

    R/A

    Hardness

    Min

    95 KSi

    50 KSi

    35%

    55%

    Max

    Min

    655 MPa

    345 MPa

    Max

     

    There are other high strength properties available for sizes of bar, wire, sheet and plate. Inquire with a sales associate at High Performance Alloys for more information. See bulletin, or brochure on the material (above) for a quick overview.

     

    Specifications

    Form

    Standard

    Metal Type

    UNS S21800

    Bar

    ASTM A193 ASTM A194 ASTM A276 ASTM A479 AMS 5848

    Wire

    Sheet

    ASTM A240

    Plate

    ASTM A240

    Fitting

     

    Forging

    ASTM A182
    ASTM A193 ASTM A 194 ASTM A276 ASTM A479 AMS 5848

    Weld Wire

    A5.9 ER218

    Werkstof No

     

     

    Applications

    • Automotive valves - can withstand gas temperatures of upto 1500°F for a minimum of 50,000 miles.
    • Fastener galling - capable of frequent assembly and disassembly, allowing more use of the fastener before the threads are torn up, also helps to eliminate corroded or frozen fasteners.
    • Pins - Used in roller prosthetics & chains to ensure a better fit of parts (closer tolerance, non-lubricated) and longer lasting.
    • Marine shafts - better corrosion than types 304 and 316, with double the yield strength.
    • Pin and hanger expansion joints for bridges - better corrosion, galling-resistance, low temperature toughness, & high charpy values at sub-zero temps compared to the A36 and A588 carbon steels commonly used.

     

    Carburization Resistance

    Armco NITRONIC 60 stainless retained the best combination of strength and ductility after exposure compared to Types 316L and 309, as shown below.
    Alloy Exposed UTS 0.2% YS Elon. Bend
    (Ksi) (Ksi) % in 4XD 1.5T
    NITRONIC 60 No 116.0 49.5 74.0 180°
    NITRONIC 60 Yes 91.5 58.0 19.0 100°
    Type 316L No 76.0 30.0 74.4 180°
    Type 316L Yes 65.0 36.0 21.3 110°
    Type 309 No 99.0 54.0 64.7 180°
    Type 309 Yes 85.5 45.5 14.0 75°

     

    Machining

    MACHINING DATA
    Carbide tools are suggested
    for rates better than 50% of Type 304.
    Machining Type Suggested starting rates are:
    Single Point turning : Roughing - 0.15" depth, 0.015"/rev feed -175 SFM
    Finishing - 0.025" depth, 0.007"/rev feed - 200 SFM
    Drilling : 1/4" Dia hole - 0.004"/rev feed - 60 SFM
    1/2" Dia hole - 0.007"/rev feed - 60 SFM
    3/4" Dia hole - 0.010"/rev feed - 60 SFM
    Reaming : Feed - same as drilling - 100 SFM
    Side and Slot Milling : Roughing - 0.25" depth - 0.007"/tooth feed - 125SFM
    Finishing - 0.050" depth - 0.009"/tooth feed - 140SFM
    These rates are for carbide tools,
    Type C-2 for roughing, drilling and reaming.
    Type C-3 for finishing.

     

    Material in this bulletin has been reprinted from Armco Bulletin No S-45, other Armco sources, and HPAlloys data.

    NITRONIC ® is a registered trademark of AK Steel.