Corrosion and heat resistant alloy UNS N08800, INCOLOY 800, W.Nr.1.4876 for sheathing of electric heating element

PRODUCT

Corrosion and heat resistant alloys UNS N08800, INCOLOY® 800, VDM^® Alloy 800, W.Nr.1.4876, NS1101 for sheathing of electric heating elements

OVERVIEW

Alloy 800 is an austenitic iron-nickel-chromium alloy characterized by:

★ Good corrosion and heat resistance

★ Good mechanical properties at low and elevated temperatures up to 1500℉ (816℃)

★ Good resistance to oxidizing, reducing and nitriding conditions

★ Good workability

Alloy 800, 800H and 800HT series are heat and corrosion resistant alloys with a relatively low nickel content, maintaining the ultimate chemical properties for high temperature strength and resistance to oxidation, carburization and other types of high temperature corrosion, has set the industry standard in high temperature applications requiring optimum creep and rupture properties.

Alloy 800 is a widely used material for construction of equipment requiring corrosion resistance, heat resistance, strength, and stability for service up to 1500℉ (816℃). Alloy 800 offers general corrosion resistance to many aqueous media and, by virtue of its content of nickel, resists stress corrosion cracking. At elevated temperatures it offers resistance to oxidation, carburization, and sulfidation along with rupture and creep strength. For applications requiring greater resistance to stress rupture and creep, especially at temperatures above 1500℉ (816℃), alloys 800H and 800HT are used.

The chromium in the alloy imparts both aqueous and heat resistance. Iron provides resistance to internal oxidation. The nickel content maintains a ductile, austenitic structure. Thus, alloy 800 is readily formed, welded, and machined.

EQUIVALENT DESIGNATION

INCOLOY® 800, VDM® alloy 800, AMS 5766, 5871, AWS 020, W.Nr.1.4876, X10NiCrAlTi32-20(DIN), 25NC32-20(France), Nicral C(France), NA15(BS), NS1101(GB/T), GH20(GB/T)

PRODUCT FORM

Forging, plate, sheet, strip, tube and pipe, pipe fitting, bar, rod, wire, ring, fastener etc.

APPLICATION

Alloy 800 is used in a variety of applications involving exposure to corrosive environments and high temperatures.

It is used for heat treating equipment such as baskets, trays, and fixtures.

In chemical and petrochemical processing, the alloy is used for heat exchangers and other piping systems in nitric acid media especially where resistance to chloride stress-corrosion cracking is required.

In nuclear power plants, it is used for steam-generator tubing. The alloy is often used in domestic appliances for sheathing of electric heating elements.

In the production of paper pulp, digester-liquor heaters are often made of alloy 800.

In petroleum processing, the alloy is used for heat exchangers that air cool the process stream.

Typical fields of application are:

Heating element sheaths

Acetic anhydride cracking furnaces

Alloy 800 shall be used in the soft-annealed condition up to 600℃ (1112℉).

The solution-annealed version alloy 800 H shall be considered for application temperatures above 600℃ (1112℉).

CHEMICAL COMPOSITION (wt%):

PHYSICAL PROPERTIES

(1) Density:8.00 g/cm³

(2) Melting point:1350-1400℃

(3) Specific heat:(0-100℃)460J/(kg·℃)

(4) Magnetic property:no

(5) Permeability(21℃) and (15.9 kA/m): 1.014(Anneal), 1.009(Hot rolled)

(6) Curie temperature: Tc:-115℃

MECHANICAL PROPERTIES

Tensile Properties of alloy 800 as extruded tubing 5in (127mm) OD, 0.50in (12.7mm) wall. Full wall specimens

Tensile properties of alloy 800 cold drawn rod 1 inch (25mm) diameter

Impact strength

Alloy 800 has high impact strength at room temperature and remains tough at cryogenic temperatures. The results of Charpy keyhole tests performed at room and low temperatures on annealed plate are listed in Table below.

Note: 0.8in (20mm) thick plate, annealed 1800℉ (980℃). Each value is the average of three tests.

Fatigue Strength

The room temperature fatigue strength^a of alloy 800 rod in various conditions is shown in table below.

^aRotating beam tests on polished specimens.

^bAnnealed 1950℉ (1065℃) /10 min, air cool.

CORROSION RESISTANCE

Alloy 800, like many austenitic stainless steels, can be sensitized, or made susceptible to intergranular attack in some aggressive media, by exposure to the temperature range of 1000-1400℉ (540–760℃). The Huey test determines susceptibility to sensitization. The test involves exposure of a specimen to boiling 65% nitric acid for five consecutive 48-hour periods. An average corrosion rate for the five periods of substantially over about 24 mils penetration per year (0.61 mm/yr) indicates that the specimen is sensitized to some degree.

When alloy 800 is exposed to heat from welding or other operations, care should be taken to avoid sensitization if the material is to be pickled or subjected to other aggressive environments. Sensitization is not a problem in most high-temperature applications.

MICROSTRUCTURE

ASTM grain size:

Alloy 800: not specified

Alloy 800H: 5 or coarser

Alloy 800HT: 5 or coarser

Alloy 800 is an austenitic, solid-solution alloy. Titanium nitrides, titanium carbides, and chromium carbides normally appear in the alloy’s microstructure. The nitrides are stable at all temperatures below the melting point and are therefore unaffected by heat treatment.

Chromium carbides precipitate in the alloy at temperatures between 1000-2000℉(540-1095℃). Consequently, alloy 800 is similar to other austenitic alloys in that it can be rendered susceptible to intergranular corrosion (sensitized) in certain aggressive environments by exposure to temperatures of 1000 to 1400℉ (540-760℃).

An important property of alloy 800 is its relative freedom from chloride stress-corrosion cracking. Extensive studies of stress-corrosion cracking of austenitic alloys in chloride solutions have shown that the tendency to crack decreases with increasing nickel content of alloy. For example, Inconel 600, with a nickel content of 76%, is considered to be immune to chloride-ion stress-corrosion cracking. Alloy 800 (32.5% Ni) can be made to crack in severe laboratory tests, but it has such high resistance that it is commonly used to replace materials that have failed in service from stress-corrosion cracking.

STANDARD SPECIFICATION

Alloy 800 is designated as UNS N08800 and Werkstoff Number 1.4876. It is listed in NACE MR0175 for oil and gas service. Alloy 800 is available as pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire.

Rod, Bar, Wire, Forgings

ASTM B 408 & ASME SB 408 (Rod & Bar)

ASTM B 564 & ASME SB 564 (Forgings)

ASME Code Case 1325 (All Product Forms)

ASME Code Case 1949 (Forgings)

SAE AMS 5766 (Rod & Bar)

ISO 9723 (Rod & Bar)

ISO 9724 (Wire)

ISO 9725 (Forgings)

BS 3076NA15 (Rod & Bar)

BS 3075NA15 (Wire)

VdTÜV 412 (All Products)

Plate, Sheet, and Strip

ASTM A240 / ASME SA240 (Plate, Sheet, and Strip)

ASTM A480 / ASME SA480 (Plate, Sheet, and Strip)

ASTM B409 / ASME SB409 (Plate, Sheet, and Strip)

ASTM B906 / ASME SB906 (Plate, Sheet, and Strip)

ASME Code Case 1325 (All Product Forms)

ASME Code Case 2339 (Plate)

SAE AMS 5871 (Plate, Sheet, and Strip)

BS 3072NA15 (Plate & Sheet)

BS 3073NA15 (Strip)

VdTÜV 412 (All Products)

ISO 6208 (plate, sheet and strip)

Pipe and Tubes

ASTM B163 / ASME SB163 (Seamless Condenser & Heat Exchanger Tubes)

ASTM B407 / ASME SB407 (Seamless Pipe & Tubes)

ASTM B829 / ASME SB 829 (Seamless Pipe & Tubes)

ASTM B514 / ASME SB514 (Welded Pipe)

ASTM B775 / ASME SB775 (Welded Pipe)

ASTM B515 / ASME SB515 (Welded Tubes)

ASTM B751 / ASME SB751(Welded Tubes)

ASME Code Case 1325 (All Product Forms)

ASME N-20 (Cold Worked Seamless Condenser and Heat Exchanger Tubes for Nuclear Service)

BS 3074NA15 (Seamless Pipe & Tubes)

VdTÜV 412 (All Products)

ISO 6207 (Seamless Tubing)

Other Product Forms

ASTM B366 / ASME SB366 (Fittings)

COMPETITIVE ADVANTAGE

(1) More than 50 years experience of research and develop in high temperature alloy, corrosion resistance alloy, precision alloy, refractory alloy, rare metal and precious metal material and products.
(2) 6 state key laboratories and calibration center.
(3) Hundreds of patent technologies.

BUSINESS TERM

With background of more than 50 years of material R&D experience, CMMC is a high-tech enterprise specialized in production of high temperature alloys, corrosion resistant alloys, precision alloys, wear resistant alloys, refractory alloys and other special alloys.

With main smelting equipments by CONSARC, including vacuum induction melting furnace (VIM 3 metric tons x 1 set), inert gas protective electric slag remelting furnace (IG-ESR 5 metric tons x 1 set, 10 metric tons x 2 sets), vacuum arc remelting furnace (VAR 10 metric tons x 1 set), CMMC has an annual production capacity of 3000 metric tons.

Established in 2016, CMMC stll having an investing plan of more than 30 million U.S.Dollars in the coming 5 years. CMMC aspires to become an internationally renowned supplier and leading brand of key materials for core components of high-end equipments in the application fields of aerospace, clean energy, petroleum, chemical engineering, medical, marine engineering, food and automobile, etc.

Our main products include forgings, bars, rods, tubulars, plates, sheets, strips, wire rods, precision wires, etc.

From ultra-pure smelting,  hot and cold forming, heat treatment, mechanical processing to finish machining, CMMC provides the whole process of one-stop professional services.

From demand idea to research and development, from technology innovation to promoting of products upgrading, from customer's puzzles and difficulties to final solution, from smelting to market, no matter wherever, whenever, whatever and however, CMMC always try to provide satisfactory one-stop service.

By providing better materials to make a better world, CMMC never give up the dream.