Steel CA6NM
UNS J91540 · ASTM A487 Gr. CA6NM, A743 CA6NM · EN GX4CrNi13-4, 1.4317 · GB ZG06Cr13Ni4
CA6NM (J91540, GX4CrNi13-4 / 1.4317) is a low-carbon 13Cr-4Ni martensitic stainless cast steel to ASTM A743/A487, where nickel and low carbon give toughness and weldability that CA15 lacks.
Reference datasheet — CA6NM is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the N+T condition
CA6NM tempers and conditions
CA6NM is supplied in 6 conditions, soft to hard. N+T is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Double tempered (e.g. 665 °C + 600 °C) for maximum toughness | Choose for large hydro runners, cold-climate or fracture-critical castings where low-temperature CVN and stable retained/reverted austenite matter more than peak strength. | 620 | 790 | 22 | 23 HRC | — |
ASTM A487 Gr. CA6NM Class A | Pressure-containing castings (valves, pump casings) certified to A487 Class A minimums with impact testing. | 660 | 830 | 18 | 25 HRC | 2.3 % IACS |
N+TDefault Normalized and tempered | Standard commercial condition for hydro turbine and pump castings — best all-round balance of 550 MPa+ yield, high toughness and ≤285 HB for machining. | 690 | 830 | 20 | 25 HRC | — |
ASTM A487 Gr. CA6NM Class B | Lower tempering temperature for higher guaranteed yield where thick-section strength governs; ductility and toughness are traded off. | 750 | 900 | 15 | 30 HRC | 2.3 % IACS |
Spheroidize annealed | Foundry-shipped condition for parts that will be austenitized and tempered by the buyer — brittle untempered martensite, not for service. | 800 | 1,000 | 8 | 37 HRC | 2.2 % IACS |
Q&T high strength | Pump impellers and wear-critical parts needing extra cavitation/erosion resistance; keep out of the ~450–550 °C embrittlement window and expect lower CVN. | 850 | 1,000 | 14 | 32 HRC | 2.3 % IACS |
Supply forms, finishes and certifications
Ways CA6NM is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
EN-QT | EN 10283 / EN 10213 GX4CrNi13-4 (1.4317) quenched & tempered | Certification |
NACE | NACE MR0175 / ISO 15156 sour service | Certification |
What is CA6NM?
CA6NM (J91540, GX4CrNi13-4 / 1.4317) is a low-carbon 13Cr-4Ni martensitic stainless cast steel to ASTM A743/A487, where nickel and low carbon give toughness and weldability that CA15 lacks. Tempered castings reach 690 MPa yield, 830 MPa tensile, 20 % elongation and about 260 HB (25 HRC) with service to 450 °C, which is why it dominates hydraulic turbine runners and large pump casings and impellers. It costs more than carbon or CrMo cast steel, needs preheat and a controlled temper after weld repair, and its corrosion resistance is limited to fresh water and mild chlorides; duplex stainless castings are used for seawater. CA6NM has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,425°C (2,597 °F). CA6NM has a yield strength of 690 MPa (100 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 80% of steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
What is CA6NM used for?
- hydraulic turbine runners
- pump casings and impellers
- valve bodies in erosive service
Advantages
- Good corrosion resistance — 55/100, better than 99% of steel grades
- Tough — resists crack growth — 150 MPa·√m (136.5 ksi·√in), better than 96% of steel grades
- High service temperature — 450°C (842 °F), better than 86% of steel grades
- High strength — 690 MPa (100 ksi), better than 80% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Low electrical conductivity — 2.3 % IACS, worse than 98% of steel grades
- High embodied carbon — 3.5 kg CO₂/kg, worse than 93% of steel grades
- Poor heat conductor — 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
CA6NM properties
Typical room-temperature values for CA6NM-N+T; bars are the position among steel grades.
Physical3
CA6NM has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
CA6NM has a yield strength of 690 MPa (100 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 80% of steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CA6NM is rated for continuous service to 450°C (842 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
CA6NM conducts electricity at 2.3 % IACS, worse than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), better than 99% of steel grades.
Sustainability4
Producing a kilogram of CA6NM takes about 40 MJ of energy and emits 3.5 kg of CO₂ — more than 91% of steel grades. Typical recycled content is 70%.
Manufacturability7
CA6NM's machinability is fair (40/100, worse than 77% of steel grades); weldability very good (70/100); formability poor (15/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. CA6NM is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CA6NM
Is CA6NM easy to machine?
Machine after tempering at 230–285 HB using rigid setups, positive-rake carbide and heavy feeds to cut under the work-hardened layer; low speeds with copious coolant.
Can CA6NM be welded?
Very good for a martensitic stainless — use E410NiMo/ER410NiMo filler, preheat 100–150 °C, interpass <150 °C and PWHT/temper at 595–620 °C for major weld repairs.
Can CA6NM be formed, bent or molded?
Sand or investment cast only; feed heavy sections generously and always austenitize+temper the casting — cold forming is not applicable.
CA6NM chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Clow carbon is key to weldability | ≤ 0.06 | 0.04 |
| Mn | ≤ 1 | 0.7 |
| Si | ≤ 1 | 0.6 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 11.5 – 14 | 12.8 |
| Ni | 3.5 – 4.5 | 4 |
| Mo | 0.4 – 1 | 0.6 |
| Fe | balance |
What surface finishes work on CA6NM?
Passivate or pickle after machining to restore the chromium oxide film; polishes to a fine finish, and hard/thermal-spray coatings are common on cavitation zones.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel CA6NM in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J91540
- ASTM
- A487 Gr. CA6NMA743 CA6NMA743/A487 Gr. CA6NM
- EN / DIN / Werkstoff-Nr.
- GX4CrNi13-41.43171.6982GX3CrNi13-4
- GB (China)
- ZG06Cr13Ni4
- Also called
- ZG06Cr13Ni4Mo
How much does CA6NM cost?
CA6NM is a premium-cost steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
CA6NM — frequently asked
What is CA6NM used for?
CA6NM is typically used for hydraulic turbine runners, pump casings and impellers and valve bodies in erosive service. In short: toughest martensitic stainless casting; weldable 13Cr-4Ni grade; cavitation-resistant turbine steel.
What is the yield strength of CA6NM?
CA6NM has a typical yield strength of 690 MPa (100 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is CA6NM easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machine after tempering at 230–285 HB using rigid setups, positive-rake carbide and heavy feeds to cut under the work-hardened layer; low speeds with copious coolant.
Can CA6NM be welded?
Yes — weldability is rated very good (70/100). Very good for a martensitic stainless — use E410NiMo/ER410NiMo filler, preheat 100–150 °C, interpass <150 °C and PWHT/temper at 595–620 °C for major weld repairs.
What surface finishes work on CA6NM?
Passivate or pickle after machining to restore the chromium oxide film; polishes to a fine finish, and hard/thermal-spray coatings are common on cavitation zones.
Can CA6NM be formed, bent or molded?
Sand or investment cast only; feed heavy sections generously and always austenitize+temper the casting — cold forming is not applicable.
What is the maximum service temperature of CA6NM?
CA6NM is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CA6NM N+T and CA6NM QT-HS?
N+T is the default condition — standard commercial condition for hydro turbine and pump castings — best all-round balance of 550 MPa+ yield, high toughness and ≤285 HB for machining. QT-HS: pump impellers and wear-critical parts needing extra cavitation/erosion resistance; keep out of the ~450–550 °C embrittlement window and expect lower CVN. Yield strength is 690 MPa in N+T versus 850 MPa in QT-HS.
How much does CA6NM cost?
CA6NM is a premium-cost steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application — ASTM International (2019)
- ASTM A487/A487M — Steel Castings Suitable for Pressure Service — ASTM International (2020)
- EN 10283 — Corrosion resistant steel castings (GX4CrNi13-4, 1.4317) — CEN (2010)
- GB/T 6967 / GB/T 2100 (ZG06Cr13Ni4Mo) — SAC (2009)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- NACE MR0175 / ISO 15156-3 materials for H2S-containing environments — NACE/ISO (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.