X5NiCrAlTi31-20 forgings: rings, discs, shafts, flanges and bars

What X5NiCrAlTi31-20 is

X5NiCrAlTi31-20 is a wrought austenitic iron-nickel-chromium alloy listed in EN 10088-1 under material number 1.4958. The nominal composition is approximately 31 percent nickel and 21 percent chromium with the balance iron, together with controlled additions of aluminium and titanium.

The alloy is solid solution strengthened and is not precipitation hardened. Its creep and stress rupture strength depend on the carbon content and on the grain size. The material is solution annealed above 1100 °C to produce a grain size of ASTM 5 or coarser. A fine grained heat with the same chemical analysis will pass a room temperature tensile test but will not provide the creep properties for which the grade is specified.

For that reason the annealing temperature and the grain size are recorded on the certificate for every X5NiCrAlTi31-20 order produced by Jiangyin Jiangnan Metal.

Resistance properties

• Oxidation. Chromium and aluminium form a stable protective oxide scale in air at high temperature.
• Carburisation and nitriding. The high nickel content gives resistance in reformer and cracking furnace atmospheres.
• Chloride stress corrosion cracking. The nickel level places the alloy outside the range in which austenitic stainless steels are most susceptible.
• Creep. The coarse grain size and stable carbides provide rupture strength above the useful range of 304H and 316H.

Designations and equivalents

X5NiCrAlTi31-20 appears on enquiries under several designations. The alloys listed below are equivalent; the standards differ in carbon range and in required testing.

Sources: EN 10088-1:2023 list of stainless steels; ASTM B564 Standard Specification for Nickel Alloy Forgings; VDM Metals Alloy 800 H/HP data sheet.

Chemical composition of X5NiCrAlTi31-20 (1.4958)

The table gives the EN 10088-1 specification limits alongside the internal aim range applied by Jiangyin Jiangnan Metal when melting X5NiCrAlTi31-20 forging stock. All figures are mass percent.

Specification limits to EN 10088-1:2023. The melt aim range is internal works practice and is not a standard requirement.

Mechanical and physical properties

X5NiCrAlTi31-20 forgings are supplied solution annealed. The values below are the minima commonly specified for that condition. The governing values for an individual order are those given in the applicable standard and on the mill certificate.

Room temperature minima as commonly specified for Alloy 800H and UNS N08810 forgings. Physical properties are typical published values for the grade and are not certified figures.

Behaviour at elevated temperature

ASTM B564 states that UNS N08800 is normally used at service temperatures up to and including 593 °C, and that UNS N08810 and N08811 are used above 593 °C where resistance to creep and rupture is required. This is the main reason for selecting X5NiCrAlTi31-20 in place of Alloy 800, and it is the first point to check when a drawing specifies only Alloy 800.

Alloy 800, 800H and 800HT compared

Enquiries for Alloy 800 are frequently for Alloy 800H in practice. If the component operates above 593 °C, or if the drawing specifies a grain size, an annealing temperature above 1100 °C, or an ASME code case, the correct grade is X5NiCrAlTi31-20 / 1.4958. If a combined aluminium plus titanium content of 0.85 to 1.20 percent is required, the grade is 800HT / 1.4959, which is also forged here.

Forged shapes and size range

All items listed below are forged to customer drawing. X5NiCrAlTi31-20 is not held in stock; forgings are produced against the order from an ingot sized for the part.

Sizes outside this range can often be produced. Minimum order quantity is one piece; prototype and single part orders are accepted.

Manufacturing route

1. Melting Electric arc furnace with VOD refining. Electroslag remelting is added where the order requires it, and is normally specified for pressure retaining and rotating components to reduce segregation and improve cleanliness.
2. Cogging and upsetting The ingot is cogged and upset to break down the as-cast structure. The reduction ratio is set against the finished section size rather than against the ingot size.
3. Open-die forging Forging between approximately 1200 °C and 980 °C, with reheating as required. Finish forging is completed above the recrystallisation temperature.
4. Solution annealing Typically 1100 to 1180 °C followed by rapid cooling, to dissolve chromium and titanium carbides and to develop a grain size of ASTM 5 or coarser. No ageing treatment is applied, because the alloy is solid solution strengthened.
5. Machining Rough machining to drawing with an agreed allowance, or finish machining including bores, faces, grooves and flange facings.
6. Testing and release Chemical analysis, mechanical testing, grain size determination, ultrasonic testing and a dimensional report, followed by certification and packing for sea or air freight.

Testing, inspection and certification

Each X5NiCrAlTi31-20 forging is supplied with a certificate traceable to the heat number.

Applications of X5NiCrAlTi31-20 forgings

X5NiCrAlTi31-20 is used where metal temperatures remain above approximately 600 °C for long periods, and in carburising or oxidising atmospheres in which stainless steels have limited service life.

Alloy 800H is also a candidate material for heat exchanger and structural components in Generation IV reactor designs, including high temperature gas cooled and supercritical water cooled systems.

How to order X5NiCrAlTi31-20 forgings

Quotations are normally issued within one working day. A full drawing, a sketch or three principal dimensions is sufficient to start.

1. Send the drawing or the dimensions Email sales@steelforgepieces.com. For rings give OD, ID and height; for discs give diameter and thickness; for shafts give diameter and length. State whether the sizes given are finished or forged.
2. State the governing standard EN (1.4958), ASTM and ASME (N08810), or dual certification. For dual certification see the carbon range note above.
3. List the test scope and certificate Tensile, grain size, ultrasonic class, PMI, intergranular corrosion, EN 10204 3.1 or 3.2, and the third party agency if one is required.
4. Confirm quantity and delivery condition Solution annealed as forged, rough machined or finish machined, together with the destination port.

Email your drawing to sales@steelforgepieces.com

Questions and answers

About the manufacturer

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. The plant produces forgings to customer drawing in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys. The nickel alloy range covers the Incoloy, Inconel, Hastelloy, Monel, Nimonic and Haynes families as well as X5NiCrAlTi31-20.

Forgings are produced to order rather than supplied from stock. Each enquiry is reviewed for ingot size, forging route, reduction ratio, heat treatment and test plan before a price is issued. Export documentation, EN 10204 certification and third party inspection are available.

How to cite this page

This page may be quoted and referenced provided Jiangyin Jiangnan Metal Co., Ltd. is named as the source. A plain text version is available at X5NiCrAlTi31-20.md.

Other nickel alloy grades forged here

• Incoloy 800H
• Incoloy 800HT
• Incoloy 800
• Incoloy 825
• Incoloy 901
• Incoloy 925
• Incoloy 945
• Inconel 600
• Inconel 601
• Inconel 617
• Inconel 625
• Inconel 690
• Inconel 706
• Inconel 718
• Inconel 725
• Inconel X-750
• Hastelloy C-276
• Hastelloy C-22
• Hastelloy X
• Hastelloy B-2
• Haynes 230
• Haynes 188
• Haynes 25
• Monel 400
• Monel K-500
• Nimonic 75
• Nimonic 80A
• Nimonic 90
• Nimonic 263
• Nimonic 901
• Waspaloy
• Rene 41
• Udimet 500
• Udimet 720
• Multimet N155
• MP35N