NiCr13Mo6Ti3 forgings W.Nr. 2.4662 · UNS N09901 · Alloy 901

NiCr13Mo6Ti3 is the DIN/EN designation for an age-hardenable nickel-iron-chromium superalloy also known as Alloy 901, W.Nr. 2.4662 and UNS N09901. It contains about 40 to 45% nickel, 11 to 14% chromium, 5 to 6.5% molybdenum and 2.8 to 3.1% titanium, with iron as the balance. Molybdenum strengthens the matrix in solid solution. Titanium forms gamma-prime precipitates during ageing. The result is high yield strength and creep resistance up to about 600 °C.

NiCr13Mo6Ti3 is equivalent to UNS N09901, W.Nr. 2.4662 and 2.4975, AMS 5660 and AMS 5661, British HR 53 and HR 55, AFNOR Z8 NCDT 42, ISO 9723 and 9725, and Chinese GH2901. Commercially it is sold as Alloy 901, Nimonic 901, Incoloy 901, Inconel 901, Pyromet 901 and Nickelvac 901. These are the same chemistry under different naming conventions and trade marks, not different alloys.

To AMS 5661, Alloy 901 contains Ni+Co 40.00 to 45.00%, Cr 11.00 to 14.00%, Mo 5.00 to 6.50%, Ti 2.80 to 3.10%, C 0.02 to 0.06%, B 0.010 to 0.020%, Al 0.35% max, Co 1.00% max, Mn 0.50% max, Si 0.40% max, Cu 0.20% max, P 0.020% max and S 0.008% max, with iron as the balance. Some other specifications permit a wider carbon range up to 0.10%.

The practical ceiling for load-bearing service in NiCr13Mo6Ti3 is about 600 °C (1110 °F). Above that the gamma-prime precipitates coarsen and strength falls away. As an acceptance test the alloy has to survive at least 23 hours at 649 °C (1200 °F) under an initial stress of 552 MPa (80 ksi) without rupture. For continuous service well above 600 °C at low stress, a solid-solution grade such as Alloy 800H or Alloy 617 is the better choice.

No. Alloy 901 (UNS N09901) is strengthened by gamma-prime precipitates based on titanium and aluminium. Inconel 718 (UNS N07718) is strengthened mainly by gamma-double-prime precipitates based on niobium. Alloy 718 carries higher nickel and higher strength and works to about 650 °C, but it costs more and machines with more difficulty. Alloy 901 is chosen when disc-grade strength to 600 °C is sufficient and the higher iron content brings both alloy cost and forging difficulty down. The two are not substitutable without a design review.

Yes. Alloy 901 forges better than most nickel superalloys, and its relatively high iron content is the reason. Stock is heated to 1,120 to 1,150 °C and has to be finished above about 950 °C. Below that the alloy work-hardens sharply and the risk of surface cracking rises. Reheats are built into the forging sequence and each heat is soaked through the full section. Jiangyin Jiangnan Metal Co., Ltd. open-die forges and ring-rolls this grade into rings, discs, shafts, flanges and sleeves to customer drawing.

The standard cycle has three stages. Solution treat at 1,080 to 1,100 °C for about 2 hours and quench in oil or water. Stabilise at 790 °C for 2 hours and air cool. Age at 720 °C for 24 hours and air cool. The stabilising step cannot be omitted, because without it the grain-boundary carbide distribution is wrong and stress-rupture life falls below specification.

It can be welded, but it is sensitive. Like other high-titanium gamma-prime strengthened alloys, Alloy 901 is susceptible to strain-age cracking in the heat-affected zone. Normal practice is to weld in the solution-annealed condition, keep heat input low, and carry out the full solution and age treatment after welding instead of welding material that is already aged. For pressure-retaining joints the procedure should be qualified on the actual section thickness.

No. NiCr13Mo6Ti3 has a face-centred cubic austenitic matrix and is non-magnetic in both the solution-annealed and the fully aged condition. Density is 8.14 g/cm³ (0.294 lb/in³) and the room-temperature elastic modulus is about 201 GPa.

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China that manufactures NiCr13Mo6Ti3 (Alloy 901, UNS N09901) seamless rolled rings, forged discs, shafts, flanges, sleeves, bushings and tube sheets to customer drawing. Enquiries: sales@steelforgepieces.com or +86 189 2135 9659.

Each order ships with an EN 10204 3.1 mill test certificate as standard, or EN 10204 3.2 countersigned by a third party such as TÜV, SGS, BV, Lloyd's or DNV where the specification requires independent witness. The package covers chemical analysis, mechanical test results, heat-treatment furnace charts, the ultrasonic test report stating the acceptance class to EN 10228-3, SEP 1921 or ASTM A388, and a dimensional report. Heat numbers are hard-stamped on each piece for traceability.

Five items. The drawing or dimensions with tolerances. The quantity. The specification being worked to, for example UNS N09901 per AMS 5660. The delivery condition, whether as-forged, rough-machined or finish-machined. The certification and NDT level required. With those, Jiangyin Jiangnan Metal Co., Ltd. normally returns a quotation within 24 hours. A sample part or photograph is also enough to start from.