201 Type 1 Ni-Resist Iron

Dura-Bar Ni-Resist irons contain an austenitic matrix of approximately 10% alloy carbides. The austenitic structure is suitable for corrosive environments in sour well oils, salts, salt water acids and alkalies. The iron is relatively soft and chrome is added to produce carbides that help improve wear resistance. Ni-Resist is denser than gray or ductile irons and has a higher coefficient of thermal expansion. Dura-Bar Type 1 Ni-Resist is manufactured to produce a material conforming to ASTM A436. To learn more, download the Dura-Bar 201 Type 1 Ni-Resist Iron Product Brief.

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Ni-Resist Iron 201 Type 1

Microstructure

The microstructure consists of Types I & II nodular graphite as defined in ASTM A247. The matrix is ferrite with approximately 5–25% pearlite. The edge or rim will have a higher nodular count and will be mostly ferrite. Chill carbides will be less than 5% in any field at 100x and will be well dispersed.

Microstructure area diagram

Center Area

100x, etched in 5% Nital

65-45-12 ductile iron microstructure at center

Edge Area

100x, etched in 5% Nital

65-45-12 ductile iron microstructure at edge

Heat Treat Response

Austenitic alloys cannot be hardened by heat treatment. They may be softened and homogenized by heating to 1800-1900° F (980-1040° C) for three to five hours and air-cooling. This breaks down some of the carbides and most of those remaining will be spheroidized. Anneal softens the material without detrimental effect on the strength properties. Type 1 Ni-Resist should not be used in applications involving service above 1300° F (430° C).


Stock Sizes

Rounds

Dura-Bar rounds

0.000" to 00.000"

As-cast round bars are made to clean up at the nominal size. Additional stock is added to allow for out-of-round and normal imperfections in the as-cast surface. Stock allowance is a function of the bar diameter - see Stock Allowances for details. Other finishes available are Centerless Grinding and Centerless Turning, for demanding tolerance applications.


Technical Specifications

Chemical Composition

Carbon and silicon targets are specified for each bar size in order to control the size and shape of the graphite flake. Titanium is added as an inoculant in order to produce the Type D graphite structure.

ElementPercentage
Carbon3.00% Max
Silicon1.00 - 2.80%
Manganese0.50 - 1.50%
Nickel13.50 -17.50% Max
Copper5.50 - 7.50%
Chromium1.50 - 2.50%
Sulfur0.12% Max

Mechanical Properties

Brinell hardness values for nominal as-cast diameters are shown in the table. Hardness properties listed are minimum, maximum across the bar. Hardness values for rectangles and squares are a function of the height and width ratios and will be supplied on request. BHN in the center of bars 1.750" and smaller may be lower than the values shown because of thermal center microshrinkage.

Size RangeBHN
InchesmmMinMax
1.000 - 6.00025 - 152131183

The tensile strength will be approximately 25,000 psi for bars up to 3.00" diameter and 20,000 psi for bars larger than 3.00". Tensile strength tests in bars 1.750" and smaller may not be accurate because of thermal center microshrinkage.

Mechanical Properties
Tensile strength psi (min)20,000
Yield strength psi (min)N/A
Elongation (min)N/A

Typical Applications

Miscellaneous:

Insecticide Pumps, Piston Ring Inserts, Sea Water Valves

Transportation:

Valve Guides

Visit our applications list for more detailed information on 201 Type 1 applications.