NiCr30FeMo Forgings UNS N06030  /  W.Nr. 2.4603  /  Alloy G-30

About NiCr30FeMo

NiCr30FeMo replaced Alloy G-3. The chromium content is higher and tungsten and cobalt were added, which improves behaviour in commercial phosphoric acid and in mixed oxidising acids such as nitric with hydrochloric, nitric with hydrofluoric, and sulphuric.

Molybdenum and copper give it moderate resistance to reducing acids. The alloy does not readily form grain boundary precipitates in the heat affected zone, so most fabrications can go into service as welded, without a post weld solution treatment. Against austenitic stainless steel it is far less prone to chloride stress corrosion cracking. In boiling 45 % magnesium chloride to ASTM G36, 316L cracks in about 2 hours and 254 SMO in about 24 hours, while NiCr30FeMo runs to roughly 168 hours.

When to specify it

• The medium is wet process phosphoric acid, especially in evaporators concentrating to about 54 % P₂O₅.
• The service involves nitric acid or nitric based mixed acids, including pickling and passivation lines.
• Chloride pitting, crevice attack or stress corrosion cracking has already taken out 316L, 254 SMO or Alloy 28 parts.
• The part must be welded and you want to avoid a solution treatment on every seam.

When another grade is better

NiCr30FeMo is a solid solution alloy. It cannot be strengthened by ageing and its room temperature yield strength is around 317 MPa. For high strength forgings use an age hardenable grade such as Inconel 725 or Incoloy 945. For strongly reducing hydrochloric acid duty, Hastelloy B-3 or Hastelloy C-276 will do better.

Chemical composition

Every heat is analysed before forging and analysed again on the finished part. The limits below are the standard wrought composition for UNS N06030 and W.Nr. 2.4603, in weight percent.

The low carbon ceiling of 0.03 % is what keeps chromium in solution instead of tied up as grain boundary carbide. That is why NiCr30FeMo tolerates welding without sensitising.

Mechanical and physical properties

Typical values for solution annealed NiCr30FeMo bar and plate at room temperature. Guaranteed minima for a given forging are agreed against the applicable ASTM specification and confirmed on the test certificate.

Forging and heat treatment

NiCr30FeMo has a narrow hot working range and work hardens faster than austenitic stainless steel. Worked too cold it tears; soaked too hot it suffers incipient melting. These are the parameters we work to.

A note on heat treatment

NiCr30FeMo cannot be quenched and tempered, normalised or age hardened the way carbon and alloy steels are. The only correct delivery condition is solution annealed, and that is how we ship it unless a drawing says otherwise in writing.

Specifications calling for a solution plus ageing cycle on UNS N06030 have usually been copied across from a precipitation hardening grade. If you find one in your documents, send it over and we will check it before the order goes in.

Forgings we produce

Everything is made to drawing or dimensional sketch. There is no standard catalogue for open-die work. The figures below are our overall open-die range. Sizes achievable in NiCr30FeMo are confirmed per enquiry, because nickel alloys need more press tonnage per unit area than steel.

Standards and codes

Ordering NiCr30FeMo forgings normally means citing ASTM B462 or ASME SB-462. The rest of the product form specifications are listed below so you can put the right line on the purchase order for whatever else the assembly needs.

ASME Section VIII Division 1 lists UNS N06030 to a maximum design temperature of 427 °C (800 °F) for plate, sheet, bar, forgings, fittings and pipe. Work from the current edition of the code for your design case.

Applications

Testing and certification

Raw material, forging, heat treatment, machining and inspection are all done in house, so a NiCr30FeMo forging stays traceable from heat number to final report.

Equivalent grades and alternatives

Related nickel alloy forgings we produce