UNS N07041 (Rene 41) Forgings

What is UNS N07041 (Rene 41)?

Rene 41 is a gamma prime strengthened nickel superalloy used for parts that must carry load at temperatures where stainless steels and iron-nickel alloys have already lost most of their strength.

Strength comes from the gamma prime phase, Ni3(Al,Ti), precipitated during ageing, together with solid solution strengthening from molybdenum and cobalt. In the 760 to 870 C range Rene 41 is stronger than Waspaloy and considerably stronger than Inconel 718.

The alloy is not easy to work. The hot working window is narrow, it work hardens quickly, and it is liable to strain age cracking if welded in the aged condition. Press schedule, reheat control and grain size control determine whether a forging passes ultrasonic inspection.

Reasons buyers specify Rene 41

• Useful stress rupture life up to 982 C (1800 F).
• Oxidation resistance from 18 to 20 percent chromium, which forms a protective Cr2O3 scale.
• Ductility is retained at cryogenic temperatures, which is why the alloy appears in rocket engine hardware.
• Material in the solution treated condition machines and forms reasonably well and is then aged to full strength.

UNS N07041 designations and equivalent specifications

A drawing that calls out any of the names below is calling out the same alloy.

Purchase orders for N07041 forgings often quote AMS 5545 in error. AMS 5545 is a flat product specification. For open-die forgings, rolled rings and forged bar the correct call-out is AMS 5712, or AMS 5713 where vacuum melted bar is required.

Chemical composition of UNS N07041

Composition limits in weight percent to AMS 5712. Each heat is checked by optical emission spectrometry and the result is reported on the mill certificate.

The aluminium, titanium and boron ranges are narrow. Titanium and aluminium set the volume fraction and the thermal stability of the gamma prime phase. Boron controls grain boundary strength and therefore stress rupture life. Material that runs low on titanium can still meet the tensile requirement and then fail creep testing.

Melting route

UNS N07041 contains reactive aluminium, titanium and boron and has to be vacuum melted. We work with ingot melted by VIM plus ESR, or VIM plus VAR where the customer specification or AMS 5713 calls for it. Air melted material is not suitable for this grade and we do not offer it.

Mechanical properties of UNS N07041 forgings

Room temperature minimum values after solution treatment and precipitation hardening, to AMS 5712. Actual test results for the heat supplied are reported on the certificate that ships with the order.

Typical physical properties

Physical property figures are published typical values for Rene 41 and are given for guidance. They are not guaranteed. Design values should be taken from the current issue of the governing specification or from your own qualification testing.

How is UNS N07041 heat treated?

Solution treatment at 1065 to 1080 C (1950 to 1975 F) with rapid cooling, followed by ageing at about 760 C (1400 F) for 16 hours and air cooling.

1. Solution treatment, 1065 to 1080 C (1950 to 1975 F). Dissolves gamma prime and carbides, homogenises the structure and sets grain size. Cooling has to be fast enough to keep the alloying elements in solution.
2. Precipitation hardening, 760 C (1400 F) for 16 hours, air cool. Precipitates fine coherent gamma prime and develops the 170 ksi tensile minimum.

Cycles vary between specifications. A solution treatment at the top of the range favours creep and stress rupture life and gives up some room temperature tensile strength. A lower solution treatment does the opposite. Where a customer specification or a GE process specification applies, we run that cycle and supply the furnace chart with the certificate.

Welding. Rene 41 is subject to strain age cracking. Weld in the solution treated condition and age afterwards. Fully aged material should not be welded without a qualified procedure.

UNS N07041 forged shapes we produce

The shapes below are open-die forged or ring rolled to drawing at our works in Jiangyin. Open-die forging uses no closed dies, so there is no tooling charge and no minimum quantity on a first article.

• Forged ringsto drawing
• Seamless rolled ringsring rolled
• Forged flangesweld neck, blind, custom
• Forged discs and blanksturbine wheel blanks
• Forged shafts and spindlesstepped, eccentric
• Forged sleevesthin and heavy wall
• Forged bushingsbored and faced
• Forged tube sheetsdrilled to drawing
• Hollow bar and forged tubetrepanned
• Forged round barpeeled or ground
• Forged blocks and rectanglessaw cut
• Near net open-die shapesto customer print

Forging capability

Testing, inspection and certification

Every forging is supplied with a document package covering chemistry, mechanical results, non-destructive testing and dimensions.

Non-destructive testing

• Ultrasonic testing to EN 10228-3, SEP 1921, ASTM A388 or AMS 2375, to the acceptance class stated on the order.
• Liquid penetrant inspection to ASTM E165 or ASME Section V for surface indications.
• Dimensional inspection against the customer drawing, with a signed report.

Chemical and mechanical testing

• Chemical analysis by optical emission spectrometry, with combustion analysis for carbon and sulphur.
• Room temperature and elevated temperature tensile testing.
• Hardness survey, grain size to ASTM E112, and stress rupture testing on request.

Certification

Mill test certificates are issued to EN 10204 3.1 as standard. EN 10204 3.2 certification witnessed by a third party such as TUV, BV, SGS, Lloyd's Register or DNV is available on request and should be stated at order stage. Heat traceability is maintained from ingot through to the shipped part.

Where UNS N07041 forgings are used

Rene 41 is specified where a part is both hot and heavily loaded, and where a lower cost alloy has already been tried and found short.

Aerospace and propulsion

Jet engine hot section hardware, combustion chamber components, afterburner parts, turbine wheels and blades, torque rings, engine mount hardware and structural fasteners. Rocket engine components use the combination of hot strength and retained ductility at cryogenic temperatures.

Industrial gas turbines and power generation

Rolled rings, discs and shafts for land based and marine gas turbines, hot gas path hardware, and high temperature bolting for turbine casings.

Oil, gas and process industries

Forged flanges, valve bodies, valve seat rings, valve stems and valve blocks for high temperature service, subsea and deepwater production hardware, and wellhead and Christmas tree components that need both strength and hot corrosion resistance.

Chemical, pressure and heat transfer equipment

Forged tube sheets, shell flanges, nozzles and forged tubes for shell and tube heat exchangers, pressure vessels, reformers, columns and towers operating above the range of stainless steels.

Heavy machinery and tooling

Hot work tooling, extrusion dies, forging rolls and mandrels, high temperature springs, and shafts for chemical and plunger pumps.

Rene 41 compared with Waspaloy and Inconel 718

The three alloys overlap in application. The table covers the points customers raise most often when deciding what to put on a drawing.

If a legacy drawing is unclear about which grade it really needs, send the drawing together with the service conditions. We forge all three grades.

Request a quotation for UNS N07041 forgings

Send a drawing and we will quote against it. Without a drawing, the six items below are enough for a budgetary price.

1. Shape and dimensions, or a drawing in PDF, STEP or DWG.
2. Quantity, and whether this is a prototype or a repeat order.
3. Specification: AMS 5712, a customer specification, or a GE process specification.
4. Delivery condition: as forged, solution treated, or solution treated and aged.
5. Machining: black, rough machined with allowance, or finish machined.
6. Testing and certification: ultrasonic acceptance class, EN 10204 3.1 or 3.2, third party witness.

Quotations are normally returned within one working day. Email sales@steelforgepieces.com or call +86 189 2135 9659.

Email your UNS N07041 enquiry

Related nickel alloy forgings

Other superalloy grades we forge. Where Rene 41 is over specified for the service conditions, one of these is usually the answer.

• Inconel 718UNS N07718, weldable
• Inconel X-750UNS N07750, springs
• Inconel 625UNS N06625, corrosion
• Inconel 617UNS N06617, 1100 C
• Inconel 600UNS N06600
• Inconel 690UNS N06690, nuclear
• Incoloy 901UNS N09901, discs
• Incoloy 925UNS N09925, sour service
• Incoloy 945UNS N09945
• Incoloy 825UNS N08825
• Hastelloy XUNS N06002, combustors
• Hastelloy C-276UNS N10276
• Hastelloy C-22UNS N06022
• Alloy 59UNS N06059
• Alloy 602 CAUNS N06025
• All nickel alloy gradesfull index