UNS N04405 Monel R-405, Alloy R-405, W.Nr. 2.4361. The free-machining grade of alloy 400.

What UNS N04405 is

UNS N04405 is a solid-solution nickel-copper alloy containing a minimum of 63% nickel plus cobalt and 28.0 to 34.0% copper, with 0.025 to 0.060% sulfur added to improve machinability. It is the free-machining grade of alloy 400 and is sold under the trade name Monel R-405.

Nickel and copper are mutually soluble across the full composition range, so this alloy family is strengthened by solid solution rather than by precipitation. There is no ageing response. Strength comes from composition and from cold work only.

Sulfur is added on purpose. During solidification it forms nickel sulfide inclusions spread through the matrix. These inclusions break the chip during cutting, so chips do not run long or weld to the tool. Alloy 400 without the sulfur addition is difficult to machine. R-405 roughly doubles the usable cutting speed and makes automatic screw machine production practical.

The same inclusions cause problems at high temperature. Nickel sulfide melts well below the alloy itself. At welding and hot working temperatures it becomes a liquid film along the grain boundaries and the material tears when it is strained. This behaviour is called hot shortness. It is why N04405 is normally supplied as bar and nothing else.

Chemical composition

Limiting composition per ASTM B164 and the Special Metals technical bulletin for alloy R-405, in weight percent.

Source: ASTM B164 and Special Metals Corporation, MONEL alloy R-405 technical bulletin. Check analysis limits per ASTM B880.

Mechanical properties

Annealed UNS N04405 bar has a tensile strength of 485 to 585 MPa (70 to 85 ksi), a 0.2% offset yield strength of 170 to 275 MPa (25 to 40 ksi), 35 to 50% elongation and 60 to 76 HRB hardness.

Nominal ranges for rod and bar. Acceptance values are those of the ordered specification and section size. The mill test certificate governs.

Machinability

UNS N04405 rates at about 40 to 45% against AISI B1112 free cutting steel. Alloy 400 rates at about 20 to 30%. This is the reason the grade exists. The alloy still work hardens, so use a rigid setup, sharp positive rake tooling and a heavy positive feed, and do not let the tool dwell in the cut.

Physical properties

Special Metals states that the physical constants of alloy 400 may be used for alloy R-405. The values below are given on that basis.

Thermal and electrical values are alloy 400 constants applied to R-405 per the alloy producer. Request the mill certificate where a design depends on a specific value.

Can UNS N04405 be forged?

No. Forging is not recommended for UNS N04405, and the grade is not covered by ASTM B564. Where forged nickel-copper components are required, use UNS N04400 (Monel 400) to ASTM B564 or ASME SB-564. Corrosion resistance is the same and the chemistry is the same apart from sulfur.

What to specify instead

Both grades sit inside the same 63 Ni and 28 to 34 Cu window, so replacing N04405 with N04400 for a forged part costs nothing in corrosion performance. It only increases machining time, and it makes the part weldable and correctly certifiable.

What we supply

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. For this alloy family we cover two routes.

UNS N04405 bar and machined components

• Hot finished and cold drawn round bar to ASTM B164 or ASME SB-164, dia. 6 to 300 mm
• Centreless ground and peeled bar where surface finish is specified
• Finish machined parts to drawing, including valve stems, fasteners, nozzles, instrument bodies and screw machine components
• Certification to EN 10204 3.1, or 3.2 with third party witness such as TUV, SGS, BV or Lloyd's

UNS N04400 open-die forgings

• Forged rings and seamless rolled rings, OD up to 3000 mm
• Forged flanges, shafts, discs, blocks, sleeves, bushings, tube sheets, valve bodies and seat rings
• Melting route EAF plus AOD or VOD, with ESR remelt available where cleanliness is specified
• Solution annealing, machining allowance to drawing, and 100% ultrasonic testing

Both routes ship worldwide. Minimum order is set by the section size rather than by a fixed tonnage, and single piece prototypes are quoted.

Corrosion resistance and applications

UNS N04405 has the same corrosion resistance as alloy 400. It performs well in flowing seawater, brackish water, brine, steam, neutral and alkaline salts, caustic solutions, and in de-aerated hydrofluoric and hydrochloric acid. It is not suitable for strongly oxidising conditions such as nitric acid, wet chlorine, or aerated acids containing oxidising salts.

The alloy is one of the few economic materials of construction for de-aerated hydrofluoric acid. In seawater it tolerates high flow rates, unlike most copper alloys, and it resists chloride stress corrosion cracking, unlike austenitic stainless steels. In stagnant or fouled seawater it can suffer pitting and crevice attack, so it should be used in flowing service.

Typical uses for N04405 bar parts

• Valve internals: stems, seat rings, plugs and trim for ball, gate, globe, check and plug valves in seawater and HF service
• Fasteners and turned parts: bolts, studs, nuts, pins and bushings for marine and offshore structures
• Chemical processing: pump shafts, nozzles, instrument bodies and fittings for HF alkylation and chlor-alkali plants
• Oil and gas: instrument and control components listed under NACE MR0175 for sour service, subject to the hardness limits of that standard
• Marine: propeller shaft components, fittings and hardware in flowing seawater
• Desalination: turned components in brine heaters and evaporator bodies

Applications that use forged N04400

Pressure vessels and air receivers, shell and tube heat exchangers, columns and towers, tanks and silos, preheaters, process modules, crystallisers, wellhead and christmas tree bodies, feedwater and steam generator components, and pump and compressor casings. All of these are welded, pressure retaining or heavily hot worked, and all of them take N04400.

Standards, designations and equivalents

Specification lists are for reference and are not tied to any particular edition or revision. Order against the exact specification and revision your project requires.

Testing and certification

Every order ships with documentation traceable to the heat number. Standard scope:

• Chemical analysis by optical emission spectrometry on the heat, with product analysis on request. Check limits to ASTM B880.
• Tensile testing to ASTM E8/E8M or ISO 6892-1, at the frequency required by the ordered specification
• Hardness, Rockwell B or Brinell, including NACE MR0175 verification where sour service applies
• Positive material identification by portable XRF or OES before dispatch
• Ultrasonic testing of forged product to EN 10228-3, SEP 1921 or ASTM A388, to the ordered class
• Dimensional report against drawing, with machining allowance stated
• Certification to EN 10204 type 3.1 as standard, or type 3.2 with third party witness on request

Marking covers grade, specification, heat number, size and our mark, applied by hard stamp or paint to suit the material condition.

How to get an accurate quotation

Please include the following in your enquiry:

1. Grade and specification, for example UNS N04405 to ASTM B164, or UNS N04400 to ASTM B564
2. Form and dimensions: bar diameter and length, or ring OD by ID by height, or a drawing in PDF, DWG or STEP
3. Quantity in pieces or kilograms, and whether the requirement repeats
4. Condition: as forged, annealed, rough machined or finish machined, with the machining allowance you expect
5. Testing and certification: UT class, EN 10204 3.1 or 3.2, any third party witness, and NACE MR0175 if the service is sour
6. Destination port and required delivery date

Send it to sales@steelforgepieces.com or call +86 189 2135 9659. Quotations normally go out within one working day.

Sources

• Special Metals Corporation, MONEL nickel-copper alloy R-405 (UNS N04405), technical bulletin
• ASTM B164, Standard Specification for Nickel-Copper Alloy Rod, Bar, and Wire
• ASTM B564, Standard Specification for Nickel Alloy Forgings. The scope confirms N04400 and does not include N04405.
• ASTM B880, Chemical Check Analysis Limits for Nickel, Nickel Alloys and Cobalt Alloys
• ASME Boiler and Pressure Vessel Code, Section II Part B (SB-164, SB-564)
• NACE MR0175 and ISO 15156, materials for use in H2S containing environments

Data on this page is compiled for engineering reference. It is not a warranty of properties. The mill test certificate supplied with the material governs in all cases.