Stainless Steel 403
AISI/SAE 403 · UNS S40300 · EN 1.4000
403 is a low-silicon, controlled-composition version of Type 410 (UNS S40300), a hardenable 12 % Cr martensitic stainless used for turbine and compressor blades where forgeability and microstructural uniformity are critical.
Values for the Hardened & Tempered condition
403 tempers and conditions
403 is supplied in 5 conditions, soft to hard. Hardened & Tempered is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
subcritical/full anneal, ferrite + carbides | Choose for maximum machinability, cold forming and bending before heat treatment. | 290 | 515 | 30 | 155 HB | — |
Annealed and cold drawn bar (ASTM A484 finish) | Choose for straight, size-tolerant bar stock with higher as-supplied strength and good surface finish. | 550 | 655 | 15 | 200 HB | — |
Q&T, high-temperature temper ~620–680 °C | Choose when maximum toughness and steam-side stability matter more than strength (long blades, thick sections). | 585 | 760 | 23 | 22 HRC | — |
Hardened & TemperedDefault austenitize ~980 °C, oil/air quench, temper 600–680 °C | Standard supply condition for turbine blades and shafts: balanced strength, ductility and steam corrosion resistance. | 655 | 830 | 20 | 26 HRC | — |
Q&T, low-temperature temper ~200–370 °C | Choose for wear parts, valve trim and cutting/knife-type components where hardness beats toughness. | 1,000 | 1,280 | 12 | 41 HRC | — |
What is 403?
403 is a low-silicon, controlled-composition version of Type 410 (UNS S40300), a hardenable 12 % Cr martensitic stainless used for turbine and compressor blades where forgeability and microstructural uniformity are critical. Quenched and tempered it provides 655 MPa yield, 830 MPa tensile, 20 % elongation and 262 HB (26 HRC) with service to 540 °C; stock covers annealed, cold-drawn and Q&T bar tempered at 205 °C or 620 °C. Corrosion resistance is limited to mild atmospheres and fresh water, welding needs preheat and post-weld temper, and machining runs slow — 410 covers general hardenable work and 416 is the choice when machinability governs. 403 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,480°C (2,696 °F). 403 has a yield strength of 655 MPa (95 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 90% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
What is 403 used for?
- Steam turbine blades
- Axial compressor blades
- Turbine blade forgings and roots
- Valve bodies and valve trim
- Pump shafts
- High-temperature bolting
- Blade attachment hardware
Advantages
- High electrical conductivity — 3 % IACS, better than 95% of stainless steel grades
- High strength — 655 MPa (95 ksi), better than 90% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades
- Low embodied carbon — 3.8 kg CO₂/kg, better than 77% of stainless steel grades
Limitations
- Difficult to weld — 35/100, worse than 86% of stainless steel grades
- Needs corrosion protection — 45/100, worse than 85% of stainless steel grades
- Low fracture toughness — 70 MPa·√m (63.7 ksi·√in), worse than 83% of stainless steel grades
- Limited ductility — 20%, worse than 79% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
403 properties
Typical room-temperature values for 403-Hardened & Tempered; bars are the position among stainless steel grades.
Physical3
403 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,480°C (2,696 °F).
Mechanical16
403 has a yield strength of 655 MPa (95 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 90% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
403 is rated for continuous service to 540°C (1,004 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades. Thermal expansion is 9.9 µm/m·K (5.5 µin/in·°F).
Electrical3
403 conducts electricity at 3 % IACS, better than 95% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 85% of stainless steel grades.
Sustainability4
Producing a kilogram of 403 takes about 48 MJ of energy and emits 3.8 kg of CO₂ — less than 85% of stainless steel grades. Typical recycled content is 60%.
Manufacturability8
403's machinability is fair (42/100, better than 79% of stainless steel grades); weldability fair (35/100); formability poor (25/100).
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. 403 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 403
Is 403 easy to machine?
Machine in the annealed or high-tempered condition with sharp, rigid tooling, positive rake and generous coolant; expect ~45–55% of AISI 1212 rates and stringy chips below 25 HRC.
Can 403 be welded?
Weldable by GTAW/SMAW with 410/410NiMo filler but requires 200–300 °C preheat, controlled interpass and 650–750 °C post-weld temper to avoid hard, crack-prone martensite in the HAZ.
Can 403 be formed, bent or molded?
Cold-form only in the annealed state with generous bend radii (≥2t); hot work 1150–1200 °C, stop above ~900 °C, then slow-cool or anneal to avoid quench cracking.
Manufacturability
The process limits FabDigit applies to 403. Every 403 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair42 / 100 |
|---|---|
| ISO material group | M.4 |
| Cutting speed (rough / finish) | 140 / 170 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair25 / 100 |
|---|---|
| Weldability | Poor35 / 100 |
403 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 |
|---|---|---|
| C | ≤ 0.15 | 0.12 |
| Mn | ≤ 1 | 0.5 |
| Silower than 410 — key distinction of 403 | ≤ 0.5 | 0.3 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 11.5 – 13 | 12.2 |
| Nirestricted in turbine-quality practice | ≤ 0.5 | 0.3 |
| Fe | balance |
What surface finishes work on 403?
Passivate (ASTM A967 nitric or citric) after machining; takes a fine mechanical or electropolished finish, and can be hard chrome plated or nitrided for wear service — do not anodize.
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).
Plating
Organic Coating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 403 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S40300
- EN / DIN / Werkstoff-Nr.
- 1.4000
- Similar grades
- S41000
How much does 403 cost?
403 is a premium-cost stainless steel ($$$), pricier than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
403 — frequently asked
What is 403 used for?
403 is typically used for steam turbine blades, axial compressor blades, turbine blade forgings and roots, valve bodies and valve trim, pump shafts and high-temperature bolting. In short: hardenable martensitic forging.
What is the yield strength of 403?
403 has a typical yield strength of 655 MPa (95 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 90% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 403 easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% of stainless steel grades). Machine in the annealed or high-tempered condition with sharp, rigid tooling, positive rake and generous coolant; expect ~45–55% of AISI 1212 rates and stringy chips below 25 HRC.
Can 403 be welded?
With care — weldability is rated fair (35/100). Weldable by GTAW/SMAW with 410/410NiMo filler but requires 200–300 °C preheat, controlled interpass and 650–750 °C post-weld temper to avoid hard, crack-prone martensite in the HAZ.
What surface finishes work on 403?
Passivate (ASTM A967 nitric or citric) after machining; takes a fine mechanical or electropolished finish, and can be hard chrome plated or nitrided for wear service — do not anodize.
Can 403 be formed, bent or molded?
Cold-form only in the annealed state with generous bend radii (≥2t); hot work 1150–1200 °C, stop above ~900 °C, then slow-cool or anneal to avoid quench cracking.
What is the maximum service temperature of 403?
403 is rated for continuous use to about 540°C (1,004 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 403 cost?
403 is a premium-cost stainless steel ($$$), pricier than about 58% 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.
Can FabDigit make parts in 403?
Yes — 403 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A276/A276M Stainless Steel Bars and Shapes — ASTM (2023)
- ASTM A484/A484M General Requirements for Stainless Steel Bars, Billets and Forgings — ASTM (2022)
- EN 10088-1 Stainless steels — List of stainless steels (X6Cr13, 1.4000) — CEN (2014)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- GB/T 1220 (1Cr12 / 12Cr13 ) — SAC (2007)
- SMM / Mysteel (2025)
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.