Stainless Steel 1.4740-SR (Stress relieved)
Heat-treated state
EN 1.4740
Used after heavy machining, weld repair or on complex thin/thick-section castings to remove residual stress without full softening.
Values for the SR condition
Other 1.4740 tempers and conditions
1.4740 is listed in 3 conditions; see the grade overview at 1.4740.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard delivery condition for EN 10295 heat-resistant castings — lowest hardness, best machinability before service. | 280 | 500 | 8 | 22 HRC | 2.2 % IACS |
SRThis page Stress relieved | Used after heavy machining, weld repair or on complex thin/thick-section castings to remove residual stress without full softening. | 290 | 520 | 6 | 24 HRC | 2.2 % IACS |
Spheroidize annealed | Cheapest route for rough furnace hardware that will be heat-cycled in service anyway; harder and more brittle than annealed. | 310 | 550 | 4 | 26 HRC | 2.2 % IACS |
What is 1.4740-SR?
1.4740-SR is 1.4740 heat treated to SR — used after heavy machining, weld repair or on complex thin/thick-section castings to remove residual stress without full softening. 1.4740-SR has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 72% of stainless steel grades. Elongation at break is 6% and the elastic modulus is 200 GPa (29 Msi). 1.4740-SR has a density of 7.6 g/cm³ (0.275 lb/in³), lighter than 98% of stainless steel grades. It melts at 1,400°C (2,552 °F). A is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High service temperature — 950°C (1,742 °F), better than 86% of stainless steel grades
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
- Conducts heat well — 22 W/m·K (12.7 BTU/hr·ft·°F), better than 77% of stainless steel grades
Limitations
- Limited formability — 4/100, worse than 100% of stainless steel grades
- Limited ductility — 6%, worse than 99% of stainless steel grades
- Low fracture toughness — 26 MPa·√m (23.7 ksi·√in), worse than 99% of stainless steel grades
- Difficult to weld — 22/100, worse than 94% of stainless steel grades
- Hard to polish — 50/100, worse than 93% of stainless steel grades
1.4740-SR properties
Typical room-temperature values for 1.4740-SR; 22 are specific to this condition. Other listed values are 1.4740 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4740-SR has a density of 7.6 g/cm³ (0.275 lb/in³), lighter than 98% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical17
1.4740-SR has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 72% of stainless steel grades. Elongation at break is 6% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4740-SR is rated for continuous service to 950°C (1,742 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), better than 77% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4740-SR conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4740-SR takes about 50 MJ of energy and emits 3.6 kg of CO₂ — less than 80% of stainless steel grades. Typical recycled content is 80%.
Manufacturability7
1.4740-SR's machinability is poor (29/100, worse than 76% of stainless steel grades); weldability poor (22/100); formability not recommended (4/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4740-SR
Is 1.4740 easy to machine?
Machine in the soft-annealed state with rigid setups, sharp carbide tooling, low speed and heavy positive feed; the Cr carbides are abrasive and the material work-hardens if rubbed.
Can 1.4740 be welded?
Only fair — preheat 200–300 °C, use matching or 25Cr-type/Ni-base filler, keep interpass warm and follow with an 800–850 °C anneal to restore what ductility the grade has.
Can 1.4740 be formed, bent or molded?
Casting-only grade: good fluidity from the high Si, but design generous fillets, use feeders on heavy sections and avoid abrupt section changes because of hot-tearing and low as-cast ductility.
What surface finishes work on 1.4740?
Shot-blast and pickle/passivate for a clean scale-free surface; the natural Cr-Si oxide formed in service is protective, so painting is unnecessary and polishing is limited by the cast carbide structure.
1.4740 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 | 0.3 – 0.5 | 0.4 |
| Sikey scaling-resistance addition | 1 – 2.5 | 1.8 |
| Mn | ≤ 1 | 0.6 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 16 – 19 | 17.5 |
| Niresidual | ≤ 1 | — |
| Moresidual, unless agreed | ≤ 0.5 | — |
| Fe | balance | — |
1.4740-SR — frequently asked
What is 1.4740-SR used for?
1.4740-SR is typically used for turbocharger housings, exhaust manifolds, high-temperature valve components and combustion equipment parts. In short: highest-temperature cast Cr-Si; 950 °C scaling resistance; casting-only, poor machinability.
What is the yield strength of 1.4740-SR?
1.4740-SR has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 72% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 1.4740-SR easy to machine?
Not especially — machinability is rated poor (29/100, worse than 76% of stainless steel grades). Machine in the soft-annealed state with rigid setups, sharp carbide tooling, low speed and heavy positive feed; the Cr carbides are abrasive and the material work-hardens if rubbed.
Can 1.4740-SR be welded?
Not readily — weldability is rated poor (22/100). Only fair — preheat 200–300 °C, use matching or 25Cr-type/Ni-base filler, keep interpass warm and follow with an 800–850 °C anneal to restore what ductility the grade has.
What surface finishes work on 1.4740-SR?
Shot-blast and pickle/passivate for a clean scale-free surface; the natural Cr-Si oxide formed in service is protective, so painting is unnecessary and polishing is limited by the cast carbide structure.
Can 1.4740-SR be formed, bent or molded?
Casting-only grade: good fluidity from the high Si, but design generous fillets, use feeders on heavy sections and avoid abrupt section changes because of hot-tearing and low as-cast ductility.
What is the maximum service temperature of 1.4740-SR?
1.4740-SR is rated for continuous use to about 950°C (1,742 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4740-A and 1.4740-AC?
A is the default condition — standard delivery condition for EN 10295 heat-resistant castings — lowest hardness, best machinability before service. AC: cheapest route for rough furnace hardware that will be heat-cycled in service anyway; harder and more brittle than annealed. Yield strength is 280 MPa in A versus 310 MPa in AC.
Sources
- EN 10295 — Heat resistant steel castings — CEN (2002)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Steel Casting Handbook (heat-resistant alloys section) — Steel Founders' Society of America (1995)
- Heat-resistant cast steel grade sheets (GX40CrSi13/17/24/28) — European heat-resistant casting foundries (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.