Stainless Steel CB30
UNS J91803 · ASTM A743 Grade CB30
A 19-22Cr/2Ni cast corrosion-resistant steel with a predominantly ferritic/martensitic structure, used where CA-type grades lack sufficient corrosion resistance in nitric acid and mild chemical service.
Reference datasheet — CB30 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 HT condition
CB30 tempers and conditions
CB30 is supplied in 3 conditions, soft to hard. HT is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Only for non-critical, non-corrosive duty; grain-boundary carbides lower ductility and corrosion resistance, so A743 does not accept it for service. | 400 | 620 | 8 | 17 HRC | 2.5 % IACS |
Stress relieved | Applied after weld repair of CB-30 castings to restore ductility and reduce cracking risk in service. | 400 | 640 | 14 | 190 HB | 2.5 % IACS |
HTDefault Heat treated (annealed ≈790 °C min, air cooled) per ASTM A743 | Standard supply condition for A743 CB-30 castings: best combination of corrosion resistance and machinability. | 415 | 655 | 15 | 13 HRC | 2.5 % IACS |
Supply forms, finishes and certifications
Ways CB30 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
HT-FC | Full anneal (≈790–815 °C, furnace cooled) for maximum… | Supply form |
What is CB30?
A 19-22Cr/2Ni cast corrosion-resistant steel with a predominantly ferritic/martensitic structure, used where CA-type grades lack sufficient corrosion resistance in nitric acid and mild chemical service. CB30 has a density of 7.53 g/cm³ (0.272 lb/in³), lighter than 99% of stainless steel grades. It melts at 1,425°C (2,597 °F). CB30 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 200 GPa (29 Msi).
What is CB30 used for?
- valve bodies
- pump casings
- nitric acid service fittings
- chemical process equipment
Advantages
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
- Conducts heat well — 23 W/m·K (13.3 BTU/hr·ft·°F), better than 78% of stainless steel grades
Limitations
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 95% of stainless steel grades
- Limited formability — 10/100, worse than 95% of stainless steel grades
- Limited ductility — 15%, worse than 89% of stainless steel grades
- Hard to polish — 55/100, worse than 89% of stainless steel grades
- Difficult to weld — 30/100, worse than 88% of stainless steel grades
CB30 properties
Typical room-temperature values for CB30-HT; bars are the position among stainless steel grades.
Physical3
CB30 has a density of 7.53 g/cm³ (0.272 lb/in³), lighter than 99% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical17
CB30 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CB30 is rated for continuous service to 400°C (752 °F). It conducts heat at 23 W/m·K (13.3 BTU/hr·ft·°F), better than 78% of stainless steel grades. Thermal expansion is 10.4 µm/m·K (5.78 µin/in·°F).
Electrical3
CB30 conducts electricity at 2.5 % IACS, better than 75% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 71% of stainless steel grades.
Sustainability4
Producing a kilogram of CB30 takes about 53 MJ of energy and emits 3.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
CB30's machinability is fair (42/100, better than 79% of stainless steel grades); weldability poor (30/100); formability not recommended (10/100).
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 stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. CB30 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CB30
Is CB30 easy to machine?
Machine in the annealed condition with rigid setups, sharp carbide tooling, low speed/high feed and flood coolant; hard carbides cause abrasive tool wear.
Can CB30 be welded?
Weldable with 309/310 austenitic or matching Cr filler, but requires 200–300 °C preheat, low heat input and a post-weld anneal at ~790 °C to avoid brittle grain-boundary structure.
Can CB30 be formed, bent or molded?
Casting-only alloy — good fluidity but high shrinkage; use generous risers, controlled pour temperature and slow cooling to prevent hot tearing; no cold forming.
CB30 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 |
|---|---|---|
| Cmax per ASTM A743 | ≤ 0.3 | 0.25 |
| Mn | ≤ 1 | 0.7 |
| Si | ≤ 1.5 | 1 |
| P | ≤ 0.04 | |
| S | ≤ 0.04 | |
| Crsome editions list 18–21 | 18 – 22 | 20 |
| Ni | ≤ 2 | 1 |
| Moresidual, not intentionally added | ≤ 0.5 | |
| Fe | balance |
What surface finishes work on CB30?
Passivate in nitric acid (ASTM A967) after machining; can be shot blasted, ground and buffed, but cast carbides limit mirror polish; no anodizing.
Surface treatments FabDigit runs on stainless 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).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel CB30 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J91803
- ASTM
- A743 Grade CB30
How much does CB30 cost?
CB30 is a premium-cost stainless 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.
CB30 — frequently asked
What is CB30 used for?
CB30 is typically used for valve bodies, pump casings, nitric acid service fittings and chemical process equipment. In short: nitric-acid cast stainless; stronger than CA-type grades; casting-only alloy.
What is the yield strength of CB30?
CB30 has a typical yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is CB30 easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% of stainless steel grades). Machine in the annealed condition with rigid setups, sharp carbide tooling, low speed/high feed and flood coolant; hard carbides cause abrasive tool wear.
Can CB30 be welded?
Not readily — weldability is rated poor (30/100). Weldable with 309/310 austenitic or matching Cr filler, but requires 200–300 °C preheat, low heat input and a post-weld anneal at ~790 °C to avoid brittle grain-boundary structure.
What surface finishes work on CB30?
Passivate in nitric acid (ASTM A967) after machining; can be shot blasted, ground and buffed, but cast carbides limit mirror polish; no anodizing.
Can CB30 be formed, bent or molded?
Casting-only alloy — good fluidity but high shrinkage; use generous risers, controlled pour temperature and slow cooling to prevent hot tearing; no cold forming.
What is the maximum service temperature of CB30?
CB30 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CB30-HT and CB30-F?
HT is the default condition — standard supply condition for A743 CB-30 castings: best combination of corrosion resistance and machinability. F: only for non-critical, non-corrosive duty; grain-boundary carbides lower ductility and corrosion resistance, so A743 does not accept it for service. Yield strength is 415 MPa in HT versus 400 MPa in F.
How much does CB30 cost?
CB30 is a premium-cost stainless 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)
- ASM Handbook Vol.1 — Cast Stainless Steels (ACI grades) — ASM International (1990)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- Steel Castings Handbook, 6th ed. (SFSA) — Steel Founders' Society of America (1995)
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.