Incoloy DS Forgings (1.4862): Rings, Flanges, Bars & Discs

Q: Is Incoloy DS the same as Alloy 330 or UNS N08330?

They are related but not identical. Both are heat-resistant nickel-iron-chromium alloys with a silicon addition, and Incoloy DS is often cross-referenced to UNS N08330. The difference is silicon content: Incoloy DS (1.4862) contains 1.9 to 2.6 percent silicon, while Alloy 330 (1.4864, UNS N08330) is normally 0.75 to 1.5 percent silicon with a wider chromium range. Order to the specification named in the drawing and state the governing standard on the purchase order.

Q: What is the forging temperature range for Incoloy DS?

Hot working runs from 900 to 1200 degrees Celsius. Heavy reduction is carried out between 1000 and 1200 degrees Celsius, forging normally starts from 1200 degrees Celsius, and light finishing passes are possible down to 900 degrees Celsius. Cooling rate does not affect hardness, so air cooling is acceptable. Quenching should be avoided on forgings with large variation in cross-sectional area.

Q: Does Incoloy DS need heat treatment after forging?

Yes. Forgings are annealed between 1000 and 1150 degrees Celsius, with temperature and holding time determined by section thickness and the intended application. Cooling rate does not affect hardness, so either air cooling or quenching is satisfactory. Material that will be welded should be in the annealed condition. The 1 hour at 1150 degrees Celsius treatment gives higher creep rupture values.

Incoloy DS alloy description

Incoloy alloy DS was developed for woven wire furnace conveyor belts, where thin sections have to survive repeated thermal cycling without loss of section. The composition follows from that requirement: enough nickel to hold an austenitic structure and suppress sigma phase, chromium for passivation, and a silicon level well above that of a standard austenitic stainless steel.

The alloy addresses three failure mechanisms common in furnace service.

Oxidation

The oxide film formed at temperature is dense and adherent. It does not spall and re-form, which is the mechanism that consumes section thickness in cyclic service.

Green rot

In atmospheres that alternate between reducing and oxidising, often with a carburising component, chromium carbide precipitates at the grain boundaries and the chromium-depleted matrix oxidises preferentially. Incoloy DS resists this form of attack.

Sigma phase

Sigma is a hard, brittle iron-chromium intermetallic that precipitates between 600 and 900 °C in ferritic, duplex and marginally austenitic structures. At a nominal 37 percent nickel, Incoloy DS can be held in this range indefinitely without embrittlement.

Incoloy DS forgings are produced to customer drawing or written specification. Section sizes, ring proportions, supply condition and testing scope are set by the enquiry.

Temperature ranges for Incoloy DS

Forging, heat treatment and service life for this alloy are all defined by temperature. The four ranges are shown below on a single scale.

No sigma phase embrittlement: 600-900 °C

600-900 °C

Cyclic oxidation life: 890 °C to 1110 °C

>1000 h to 400 h to 50 h

Solution annealing: 1000-1150 °C

1000-1150 °C

Open-die forging: 900-1200 °C, heavy reduction 1000-1200 °C

900-1200 °C heavy 1000-1200

Sigma free range
Cyclic oxidation, time to breakaway
Annealing
Forging

Forging starts at approximately 1200 °C and light passes remain possible at 900 °C. Annealing is carried out between 1000 and 1150 °C. The alloy can be soaked anywhere between 600 and 900 °C without sigma phase embrittlement. In cyclic oxidation testing, time to breakaway exceeded 1000 h at 890-910 °C, fell to approximately 400 h at 990-1010 °C and to approximately 50 h at 1090-1110 °C. The melting range, 1330-1400 °C, lies beyond the right hand end of the scale.

Chemical composition of Incoloy DS (1.4862)

Composition, percent by mass, maximum unless a range is stated. BS 3073: NA17
Element	Min %	Max %	Function
Ni + Co	34.50	41.00	Austenite stabiliser, suppresses sigma phase
Cr	17.00	19.00	Forms the protective chromium oxide
Si	1.90	2.60	Produces the adherent oxide film, carburisation resistance
Mn	0.80	1.50	Deoxidiser, sulphur control
C	-	0.10	Limited to restrict carbide precipitation
Cu	-	0.50	Residual
Ti	-	0.20	Residual
S	-	0.03	Residual, tighter limits available on request
Fe	Balance		Base

Composition to BS 3073: NA17, as published in Special Metals Corporation technical bulletin SMC-097. Where a project specification names a different standard, material is melted and certified to that standard. State the applicable standard on the enquiry.

Melting route

Incoloy DS forging stock is melted by EAF plus VOD. ESR remelting is available where the specification calls for improved cleanliness and homogeneity in heavy sections. Each heat is traceable by heat number through to the finished forging and the mill certificate.

Mechanical properties of Incoloy DS

Room temperature minimum values for annealed material are given first, followed by the reduction in strength with temperature.

Room temperature mechanical properties, annealed condition
Property	Metric	Imperial
Tensile strength	687 MPa min	99 ksi min
0.2 % proof stress	363 MPa min	52 ksi min
0.1 % proof stress	327 MPa	47 ksi
Elongation, 50 mm	37 % min	37 % min
Charpy V-notch at 20 °C	approx. 180 J	approx. 133 ft-lb
Young's modulus at 20 °C	194 GPa	28.1 x 10&sup6; psi

Elevated temperature tensile properties. Hot rolled plate, annealed 10 min at 1020 °C, air cooled
Temperature	0.2 % proof, MPa	Tensile, MPa	Elongation, %	Young's modulus, GPa
-196 °C	485	914	54.5	-
20 °C	301	670	47.6	194
200 °C	247	581	41.1	184
400 °C	219	593	46.7	171
600 °C	201	490	45.3	157
700 °C	185	351	56.7	149
800 °C	142	208	74.0	142
900 °C	71	119	90.9	132
1000 °C	42	73	111.3	118

Values are typical published data for wrought Incoloy DS, averaged over five casts, from Special Metals bulletin SMC-097. Acceptance values for a given forging depend on section size, test location and the governing standard, and are recorded on the mill certificate for the heat supplied.

Physical properties

Physical and thermal data
Property	Value	Condition
Density	7.86 g/cm3 (0.284 lb/in3)	Room temperature
Melting range	1330-1400 °C (2426-2552 °F)	-
Electrical resistivity	108 micro-ohm cm	20 °C
Specific heat	452 J/kg °C	20 °C; 716 J/kg °C at 1000 °C
Mean coefficient of expansion	15.0 x 10⁻⁶/°C	20-100 °C; 18.7 x 10⁻⁶/°C over 20-1000 °C
Dynamic Young's modulus	194 GPa	20 °C hot rolled plate; 118 GPa at 1000 °C
Torsional modulus	51.7 GPa	20 °C; 29.6 GPa at 1000 °C
Magnetic permeability	1.017	At 1000 oersted, effectively non-magnetic

The expansion coefficient matters where Incoloy DS parts are bolted or welded to lower alloy components. At 18.7 x 10⁻⁶/°C over 20-1000 °C the alloy expands appreciably more than ferritic steel, and joint design has to allow for the difference.

Creep rupture and cyclic oxidation

For furnace equipment the governing values are creep rupture stress and oxidation life rather than room temperature tensile strength. Both depend on the heat treatment applied, and the 1 h at 1150 °C anneal gives the higher creep rupture values.

Creep rupture stress, MPa. Hot rolled plate, annealed 1 h at 1150 °C, air cooled
Temperature	100 h	1 000 h	10 000 h
750 °C	72.3	48.8	32.9
850 °C	45.6	26.3	15.2
950 °C	29.2	15.4	8.1
1050 °C	11.4	6.7	3.9

Cyclic oxidation resistance
Temperature	Time to breakaway	Spalling rate	Weight change in 1 000 h
890 °C	over 1 000 h	-	+2.08 mg/cm2
910 °C	over 1 000 h	-	+3.19 mg/cm2
990 °C	400 h	0.112 mg/cm2/h	-50.4 mg/cm2
1090 °C	50 h	0.5 mg/cm2/h	-541 mg/cm2

Below approximately 910 °C the specimen gains weight because the oxide layer stays in place. Above approximately 990 °C it loses weight because the oxide spalls. Data from Special Metals bulletin SMC-097. Impact toughness is not significantly affected by long soaking: Charpy values after 10 000 h at 800-1000 °C remain within the range recorded for as-annealed material.

Forging, heat treatment, machining and welding

Hot working and open-die forging

The hot working range is 900-1200 °C. Heavy reduction is taken between 1000 and 1200 °C, forging normally starts from 1200 °C, and light finishing passes are possible down to 900 °C. Cooling rate does not affect hardness, so air cooling and quenching are both acceptable. Quenching should be avoided on forgings with large variation in cross-sectional area.

Annealing

Anneal between 1000 and 1150 °C, with temperature and holding time set by section thickness and the intended application. Furnace fuel should preferably be sulphur free: natural gas, town gas, distillate fuel oil and electric heating are all suitable. The atmosphere should be held slightly oxidising. Bright annealing is carried out in dry hydrogen or cracked ammonia.

Cold working and machining

Cold working procedures follow those used for carbon and stainless steels. The work hardening rate is higher than low carbon steel and lower than 18/8 stainless steel. Machining gives the best results in the annealed condition, followed by hot rolled, as rolled and hot forged material. Use rigid heavy duty equipment and tooling large enough to carry the cutting loads and dissipate heat.

Welding

Incoloy DS is joined to itself and to other metals by standard processes, provided the parent material is in the annealed condition. Shielded metal arc welding uses an INCO-WELD A type electrode. Inert-gas shielded arc welding uses NC 80/20 filler metal. Welding slag must be removed completely, as residues cause corrosion in service.

Pickling

A fused caustic soda pre-treatment, followed by a cold water rinse, acid pickling in HNO3 and FeCl3 at approximately 65 °C for 5 to 20 minutes, and a final cold water rinse.

Incoloy DS forged product forms

All items below are produced to drawing or written specification. A rough envelope and a target weight are sufficient to start a quotation.

Rings and seamless rolled rings

Forged rings and radial-axial rolled rings for retorts, muffles, flange blanks, bearing races and furnace hardware, in rectangular or contoured profile.

Flanges

Weld neck, slip on, blind, lap joint, orifice and special profile flanges, and flange blanks for machining by the customer.

Bars, billets and blocks

Forged round bar, square bar, flat bar and rectangular blocks for valve components, fasteners and machined furnace parts.

Discs, blanks and tube sheets

Forged discs, blanks and drilled or undrilled tube sheets for shell and tube heat exchangers and pressure equipment.

Shafts, spindles and gear blanks

Straight and stepped shafts, eccentric shafts, spindles, crankshafts, gear blanks and pinion blanks for high temperature rotating equipment.

Sleeves, bushings and hollow bar

Forged and bored sleeves, bushings, cylinders and hollow sections, reducing machining time and material loss on long bores.

Valve components

Valve bodies, bonnets, seat rings, stems, blocks and closures for ball, gate, globe, check, plug and strainer assemblies.

Nozzles, wheels, manifolds and rolls

Forged nozzles, wheel blanks, manifolds, rolls and other bespoke shapes for high temperature process equipment.

Size and weight capability

Open-die forging envelope. Confirm your part with our engineering team
Form	Dimensional range	Single piece weight
Forged and rolled rings	OD 200-3000 mm, height max 800 mm, wall min 20 mm	10-8000 kg
Flanges	DN 15 to DN 2000	1-5000 kg
Round bar	Dia. 60-800 mm, length max 6000 mm	10-6000 kg
Discs and tube sheets	Dia. max 2500 mm, thickness max 500 mm	20-8000 kg
Shafts and spindles	Dia. 80-900 mm, length max 8000 mm	50-10 000 kg
Sleeves and hollow bar	OD 150-1500 mm, ID min 60 mm	20-5000 kg

Supply condition: as forged, rough machined, or finish machined to drawing. Surface options include shot blasting, pickling and passivation. Parts outside this envelope may still be feasible. Send the drawing for confirmation.

Applications for Incoloy DS forgings

Heat treatment and furnace equipment

Light sections subject to repeated thermal cycling.
Retorts, muffles, radiant tube components, jigs and fixtures, conveyor belt hardware, roller hearth parts, fan hubs, basket components
Petrochemical and process plant

Static equipment operating at temperature in carburising or fluctuating atmospheres.
Columns and towers, tanks and silos, preheaters, process modules, shell and tube heat exchangers, tube sheets, pressure vessel flanges
Power generation and rotating equipment

Forged rotating components for turbines, compressors and drive trains at elevated temperature.
Turbine components, gas compressor parts, gearbox blanks, spindles, gears, generator and nitrogen generator hardware
Oil and gas, offshore and onshore

Subsea and topside components requiring corrosion resistant forged sections.
Wellhead and christmas tree parts, deepwater production system components, industrial air compressor parts, manifolds
Valves and flow control

Forged bodies and internals for high temperature and corrosive service.
Ball, gate, globe, check and plug valves, strainers, seat rings, stems, valve blocks and closures
Automotive, appliance and general engineering

High temperature components produced in repeat batches.
Automobile exhaust valves, boiler tube supports, die casting inserts and cores, crystalliser equipment, domestic appliance components

Testing, inspection and certification

Ultrasonic testing

To EN 10228-3, SEP 1921 or ASTM A388, with the acceptance class agreed before production. Quality class and scanning plan are stated on the certificate.

Chemical analysis

Ladle and product analysis by spectrometer, with PMI on the finished forging where the specification or the end user requires it.

Mechanical testing

Tensile, hardness and Charpy impact testing from integral or separately forged test blanks, heat treated with the parts they represent.

Additional NDT

Dye penetrant testing, magnetic particle testing where applicable, dimensional inspection reports, grain size and intergranular corrosion testing on request.

Certificates

EN 10204 3.1 as standard. EN 10204 3.2 issued with a third party inspection body such as TUV, SGS, BV, Lloyd's Register or a customer nominated inspector.

Traceability

Heat number hard stamped or laser marked on every piece and carried through to the certificate, so the forging can be traced back to its melt.

Third party witness points, pre-inspection meetings and customer inspection and test plans are accepted. Send the ITP with the enquiry so that witnessing costs are included in the quotation.

Incoloy DS compared with Alloy 330 and Incoloy 800H

These three grades are frequently substituted for one another. The differences that affect selection are silicon content, carbon control and pressure code coverage.

Nominal comparison. Confirm against the standard named in the specification
Comparison point	Incoloy DS	Alloy 330	Incoloy 800H
Werkstoff / UNS	1.4862, often cross-referenced N08330	1.4864, UNS N08330	1.4958, UNS N08810
Nickel, %	34.5-41.0	34.0-37.0	30.0-35.0
Chromium, %	17.0-19.0	17.0-20.0	19.0-23.0
Silicon, %	1.9-2.6	0.75-1.5	max 1.0
Carbon, %	max 0.10	max 0.08 to 0.15, standard dependent	0.05-0.10, controlled
Main advantage	Carburisation, green rot and sigma resistance in cycling furnace atmospheres	General heat resistance, wide availability	Creep strength with controlled grain size, ASME code coverage
Limitation	No ASME pressure code approval, higher silicon affects weld practice	Lower silicon gives less carburisation resistance	Requires the coarse grain 800H or 800HT heat treatment to reach its creep values

Incoloy DS is selected where the furnace atmosphere is the limiting factor. Alloy 330 is a widely available general heat resistant grade. Incoloy 800H and 800HT apply where a pressure code and long term creep allowables govern the design. All three are forged at the same works: AISI 330 forgings, Incoloy 800H forgings, Incoloy 800HT forgings.

Incoloy DS questions and answers

What is Incoloy DS (1.4862)?

Incoloy DS, Werkstoff number 1.4862, is a nickel-iron-chromium alloy containing 34.5 to 41 percent nickel, 17 to 19 percent chromium and 1.9 to 2.6 percent silicon. The silicon content produces an adherent protective oxide film, giving resistance to oxidation, carburisation and green rot at high temperature. The alloy was developed for woven wire furnace conveyor belts and is now used in heat treatment and high temperature process equipment.

Jiangyin Jiangnan Metal Co., Ltd. supplies it as open-die forgings: rings, flanges, bars, discs, shafts and sleeves, made to customer drawing.

Is Incoloy DS the same as Alloy 330 or UNS N08330?

They are related but not identical. Both are heat resistant nickel-iron-chromium alloys with a silicon addition, and Incoloy DS is often cross-referenced to UNS N08330. The difference is silicon content: Incoloy DS (1.4862) contains 1.9 to 2.6 percent silicon, while Alloy 330 (1.4864, UNS N08330) is normally 0.75 to 1.5 percent silicon with a wider chromium range.

Order to the specification named in the drawing and state the governing standard on the purchase order. If the document says Incoloy DS or equivalent, tell us which properties drive the design and we will confirm what can be substituted.

What is the maximum service temperature of Incoloy DS?

It depends on the duty. In cyclic oxidation testing, time to breakaway exceeded 1000 h at 890-910 °C, fell to approximately 400 h at 990-1010 °C, and to approximately 50 h at 1090-1110 °C.

Continuous service is normally planned below approximately 1000 °C, with short excursions above that. The alloy does not form sigma phase when held anywhere between 600 and 900 °C, which is the range in which many austenitic grades become brittle.

What is the forging temperature range for Incoloy DS?

Hot working runs from 900 °C to 1200 °C. Heavy reduction is taken between 1000 °C and 1200 °C, forging normally starts from 1200 °C, and light finishing passes are possible down to 900 °C. Cooling rate does not affect hardness, so air cooling is acceptable. Quenching should be avoided on forgings with large variation in cross-sectional area.

Does Incoloy DS need heat treatment after forging?

Yes. Forgings are annealed between 1000 °C and 1150 °C, with temperature and holding time set by section thickness and the intended application. Cooling rate does not affect hardness, so either air cooling or quenching is satisfactory. Material that will be welded should be in the annealed condition, and the 1 h at 1150 °C treatment gives the higher creep rupture values.

What forms of Incoloy DS forgings can Jiangyin Jiangnan Metal supply?

Forged and seamless rolled rings, flanges, round bars and billets, discs and blanks, shafts, spindles and eccentric shafts, sleeves, bushings and hollow bars, tube sheets, nozzles, valve bodies, seat rings and stems, wheels, manifolds and rolls. All are produced to customer drawing or specification at our works in Jiangyin, Jiangsu Province, China, and can be supplied as forged, rough machined or finish machined.

What testing and certification comes with the forgings?

Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388 as agreed, plus chemical analysis, mechanical testing and a dimensional inspection report. Certificates are issued to EN 10204 3.1, or 3.2 with a third party inspection body such as TUV, SGS, BV or Lloyd's Register.

PMI, grain size and intergranular corrosion testing and additional NDT can be added. Send the ITP with the enquiry so that it is priced from the start.

Can Incoloy DS be welded?

Yes, by standard processes, provided the parent material is in the annealed condition. Shielded metal arc welding uses an INCO-WELD A type electrode. Inert-gas shielded arc welding uses NC 80/20 filler metal. Welding slag must be removed completely, as residues cause corrosion in service.

How do I request a quotation for Incoloy DS forgings?

Send the drawing, or the dimensions, quantity, required standard and testing scope, to sales@steelforgepieces.com, or call +86 189 2135 9659. Jiangyin Jiangnan Metal Co., Ltd. is located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Quotations for standard open-die shapes are normally returned within one business day.

Other nickel alloy forgings we produce

Same process and same certification, different chemistry. Every grade below is forged to drawing at the same works.

Incoloy DS forgings

Summary