Specifications

Monel K-500 plate and sheet are available on enquiry.

Chemical composition and mechanical properties

Nickel includes cobalt. Limits as given in ASTM B127, B164 and B165 (alloy 400) and B865 (alloy K-500).

Annealed condition. Hot-rolled, cold-worked and stress-relieved conditions have higher strength, with size limits as given in each standard.

Background, equivalents and other product forms are on the Monel page.

Where Monel plate is used

Hydrofluoric acid service: Monel 400 plate is a standard material for vessels, settlers, acid coolers and piping components in refinery HF alkylation units, and in the production and handling of hydrofluoric acid and fluorine compounds, where it resists HF across a wide range of concentrations as long as air is excluded.

Marine and seawater: Monel sheet is used for sheathing, pump and valve parts, seawater-cooled heat exchanger components and offshore splash-zone cladding. It resists flowing seawater and does not suffer chloride stress corrosion cracking.

Chemical and process equipment: Plate is used for caustic soda evaporators, brine heaters and salt plants, crude oil distillation tower linings and overhead equipment where hydrochloric acid condenses, and equipment handling dilute sulphuric acid free of air.

Cladding and linings

For large vessels and towers, a solid Monel plate is often replaced by carbon steel plate clad with a thin layer of Monel 400, produced by roll bonding or explosion bonding, or by Monel sheet linings welded to the inside of a carbon steel shell. This keeps the corrosion resistance of Monel on the wetted surface while the carbon steel carries the pressure. Monel sheet for linings is supplied in thin gauges with a smooth surface for welding. Please mention cladding or lining use in the enquiry so the thickness and finish can be matched.

Fabrication

Monel 400 forms readily cold and hot. Cold forming is done in the annealed condition; heavy cold work raises strength and hardness and may need an intermediate anneal. Hot forming is carried out in a sulphur-free furnace atmosphere, because sulphur embrittles nickel alloys. Plates are welded with ERNiCu-7 filler by TIG or MIG and with matching covered electrodes by manual metal arc, on clean joints free of oil, paint, marking crayon and lead. No post-weld heat treatment is needed for corrosion resistance, although stress relief may be specified where stress corrosion cracking in HF vapour is a concern.

Cutting and machining

Monel plate is cut by plasma or water-jet; oxy-fuel cutting is not suitable for nickel alloys. Sheet is sheared or laser cut. The heat-affected edge from plasma cutting should be ground back before welding. In machining, Monel work-hardens, so rigid machines, sharp carbide tools, positive rake and continuous feed are used to cut beneath the hardened layer.

Ordering Monel sheets and plates

Please give the alloy and specification, thickness, width and length or cut sizes, condition, finish, quantity and any ultrasonic testing or third-party inspection. Sheets are packed flat on pallets with interleaving, and plates on wooden skids; each piece is marked with alloy, specification, heat number and size and is traceable to its mill test certificate.

Applications and related products

Monel sheets and plates are used for HF alkylation and acid equipment, heat exchangers and tube sheets, caustic and brine evaporators, tower linings, marine sheathing and offshore cladding, and pump and valve parts. Matching products include Monel pipes and tubes, Monel round bars, Monel flanges, Monel pipe fittings and Monel fasteners. Other materials are on our plates and sheets pages.