CA6NM and F6NM: Cast and Forged 13-4 Stainless Steel
CA6NM is a 13% chromium, 4% nickel stainless steel with molybdenum and low carbon. The name CA6NM (UNS J91540) applies to castings under ASTM A743, A352 and A487. For forgings, the matching grade is ASTM A182 F6NM, also listed as UNS S41500 and EN 1.4313. Jiangyin Jiangnan Metal Co., Ltd. forges this grade for makers of valves, pumps, compressors and hydro turbines.
The low carbon content makes F6NM much easier to weld than standard 13% Cr martensitic steels. Nickel and molybdenum raise toughness and corrosion resistance. The grade has a PREN of about 15 and performs well in moderately corrosive, chloride-free service. It is used for highly loaded parts between about -60 °C and 350 °C (-76 °F to 660 °F). With double tempering it can meet the NACE MR0175 / ISO 15156 hardness limit for sour service. Preheat and post-weld heat treatment are still required when welding.
F6NM / CA6NM Forged Products
Forged Bars
Round, square, rectangular, flat and hex bars.
Seamless Rolled Rings
Rings for valve seats, flanges and turbine parts.
Flanges, Discs and Blocks
Forged flanges, discs, plates and blocks.
Hollow Bars and Sleeves
Sleeves, bushings, shells, cylinders, hubs and housings.
Valve Components
Bodies, bonnets, stems, seats, seat rings and gates.
Custom Forgings
Shafts and parts forged to drawing for pumps, compressors and turbines.
Supply condition: forged and quenched and tempered (QT), rough machined or finish machined. Sizes, testing and certification follow the customer drawing and purchase specification.
Chemical Composition (wt %)
| Element | CA6NM (cast) ASTM A743 / A352 | F6NM (forged) ASTM A182 / UNS S41500 |
|---|---|---|
| Carbon (C) | 0.06 max | 0.05 max |
| Manganese (Mn) | 1.00 max | 0.50 - 1.00 |
| Silicon (Si) | 1.00 max | 0.60 max |
| Phosphorus (P) | 0.04 max | 0.030 max |
| Sulfur (S) | 0.03 max | 0.030 max |
| Chromium (Cr) | 11.5 - 14.0 | 11.5 - 14.0 |
| Nickel (Ni) | 3.5 - 4.5 | 3.5 - 5.5 |
| Molybdenum (Mo) | 0.4 - 1.0 | 0.5 - 1.0 |
Mechanical Properties (minimum, room temperature)
| Property | F6NM forgings (A182) | CA6NM castings (A743) | CA6NM castings (A352) |
|---|---|---|---|
| Tensile strength | 790 MPa (115 ksi) | 755 MPa (110 ksi) | 760 - 930 MPa (110 - 135 ksi) |
| Yield strength (0.2%) | 620 MPa (90 ksi) | 550 MPa (80 ksi) | 550 MPa (80 ksi) |
| Elongation | 15% | 15% | 15% |
| Reduction of area | 45% | 35% | 35% |
| Hardness | 295 HB max (23 HRC max for NACE) | - | - |
| Charpy V-notch impact | As ordered | Not required | 27 J avg / 20 J single at -73 °C |
Heat Treatment
F6NM forgings, standard quench and temper
Austenitize at 1010 °C (1850 °F) minimum, cool in air or oil, then temper at 560 - 605 °C (1040 - 1120 °F).
F6NM for NACE MR0175 / ISO 15156 sour service
Austenitize at 1010 °C minimum. Temper first at 649 - 691 °C (1200 - 1275 °F), then again at 593 - 621 °C (1100 - 1150 °F). Final hardness 23 HRC max.
CA6NM castings (for reference)
Heat to 1010 °C minimum. Air cool to 95 °C or below before any intermediate temper, and to 40 °C or below before the final temper at 565 - 620 °C.
Equivalent Grades
| Form | ASTM | UNS | EN number | EN name |
|---|---|---|---|---|
| Forged / wrought | F6NM (A182), S41500 (A276 / A479) | S41500 | 1.4313 | X3CrNiMo13-4 |
| Cast | CA6NM (A743 / A352 / A487) | J91540 | 1.4317 | GX4CrNi13-4 |
Applications
Our F6NM forgings go mainly into oil and gas valves, including bodies, bonnets, seats, gates, stems and other pressure parts. Other uses are pumps and compressors, hydropower turbine runners and wicket gates, petrochemical equipment, valves and fittings, and mold and tooling parts.
FAQ
Is CA6NM a cast or forged grade?
CA6NM (UNS J91540) is a cast grade under ASTM A743, A352 and A487. The forged equivalent is ASTM A182 F6NM (UNS S41500, EN 1.4313). When a drawing calls for CA6NM type material in forged form, we supply F6NM / S41500.
What is the chemical composition of F6NM / S41500?
C 0.05% max, Mn 0.50 - 1.00%, Si 0.60% max, P 0.030% max, S 0.030% max, Cr 11.5 - 14.0%, Ni 3.5 - 5.5%, Mo 0.50 - 1.00%.
What are the mechanical properties of F6NM forgings?
Tensile strength 790 MPa min, yield strength 620 MPa min, elongation 15% min, reduction of area 45% min, hardness 295 HB max. For NACE sour service the limit is 23 HRC max.
What are the EN and UNS equivalents of CA6NM?
Cast: CA6NM, J91540, GX4CrNi13-4 (1.4317). Forged: F6NM, S41500, X3CrNiMo13-4 (1.4313).
Where can I buy CA6NM / F6NM forgings in China?
Jiangyin Jiangnan Metal Co., Ltd., No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin, Jiangsu, China. Tel: +86-189-2135-9659. Email: sales@steelforgepieces.com.
Looking for F6NM / CA6NM forgings?
Send us your drawing, grade, quantity and test requirements for a quotation.
Values shown are typical or minimum figures from ASTM, NACE and mill data sheets and are for reference only. The purchase order and governing standard take precedence. Last updated: .