Stainless Steel 1.4057 +QT800
Heat-treated state · default condition
EN 1.4057 · UNS S43100 · AISI/SAE 431 · JIS SUS431 · GB 1Cr17Ni2
+QT800 = quenched and tempered, Rm 800–950 MPa
Standard stocked bar condition: balanced strength, toughness and corrosion resistance for shafts, valve stems and fasteners.
Values for the +QT800 condition
Other 1.4057 tempers and conditions
1.4057 is listed in 6 conditions; see the grade overview at 1.4057.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest deliverable condition for machining, forming or as a base for subsequent hardening; still relatively hard because of the Ni content. | 600 | 800 | 20 | 24 HRC | — |
Quenched and tempered, Rm 700–850 MPa | High-temperature tempered condition for large sections or where maximum toughness and ductility are preferred over strength. | 600 | 780 | 18 | 22 HRC | — |
+QT800DefaultThis page Quenched and tempered, Rm 800–950 MPa | Standard stocked bar condition: balanced strength, toughness and corrosion resistance for shafts, valve stems and fasteners. | 680 | 870 | 17 | 27 HRC | — |
Annealed and cold drawn bar | Cold-drawn ground/peeled bar for close tolerance and good surface finish before final hardening or for lightly loaded machined parts. | 720 | 900 | 12 | 29 HRC | 2.5 % IACS |
Quenched and tempered, Rm 900–1050 MPa | Higher-strength tempered condition for highly loaded shafts, bolts and pump components where some ductility can be traded for strength. | 780 | 970 | 15 | 31 HRC | — |
Hardened + low temper | Maximum hardness/wear resistance and best corrosion behaviour of the martensitic conditions; low toughness, use for cutlery-type edges, wear rings and small hardware. | 1,100 | 1,400 | 9 | 45 HRC | — |
What is 1.4057 +QT800?
1.4057 +QT800 is 1.4057 heat treated to +QT800 — standard stocked bar condition: balanced strength, toughness and corrosion resistance for shafts, valve stems and fasteners. 1.4057 +QT800 has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 91% of stainless steel grades. Elongation at break is 17% and the elastic modulus is 215 GPa (31.2 Msi). 1.4057 +QT800 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Advantages
- Conducts heat well — 25 W/m·K (14.4 BTU/hr·ft·°F), better than 93% of stainless steel grades
- High strength — 680 MPa (98.6 ksi), better than 91% of stainless steel grades
- Low embodied carbon — 3.8 kg CO₂/kg, better than 77% of stainless steel grades
Limitations
- Difficult to weld — 30/100, worse than 88% of stainless steel grades
- Limited ductility — 17%, worse than 86% of stainless steel grades
- Limited formability — 20/100, worse than 86% of stainless steel grades
- Low fracture toughness — 75 MPa·√m (68.3 ksi·√in), worse than 81% of stainless steel grades
- Needs corrosion protection — 48/100, worse than 80% of stainless steel grades
1.4057 +QT800 properties
Typical room-temperature values for 1.4057 +QT800; 18 are specific to this condition. Other listed values are 1.4057 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4057 +QT800 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
1.4057 +QT800 has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 91% of stainless steel grades. Elongation at break is 17% and the elastic modulus is 215 GPa (31.2 Msi).
Thermal6
1.4057 +QT800 is rated for continuous service to 500°C (932 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), better than 93% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4057 +QT800 conducts electricity at 2.5 % IACS, better than 75% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4057 +QT800 takes about 55 MJ of energy and emits 3.8 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
1.4057 +QT800's machinability is fair (38/100, better than 63% of stainless steel grades); weldability poor (30/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4057 +QT800
Is 1.4057 easy to machine?
Machine in the annealed or ≤300 HB tempered condition with rigid setups, positive-rake carbide, 60–110 m/min and heavy feeds to cut under the work-hardened skin; flood coolant essential.
Can 1.4057 be welded?
Poor weldability — preheat 200–300 °C, use 309L/430 or matching filler, and temper at 650–700 °C immediately after welding to restore toughness; avoid welding in the fully hardened state.
Can 1.4057 be formed, bent or molded?
Hot work at 1100–850 °C with slow cooling; cold forming limited to gentle bends in the annealed state, hardening by oil/air quench from 980–1050 °C then temper (avoid 450–550 °C temper embrittlement range).
What surface finishes work on 1.4057?
Takes a fine polish for shafting and decorative hardware; passivate per ASTM A967 after machining, and use hard chrome or electroless nickel where extra wear or chloride resistance is needed — no anodizing.
1.4057 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 | 0.12 – 0.22 | 0.17 |
| Si | ≤ 1 | 0.4 |
| Mn | ≤ 1.5 | 0.6 |
| P | ≤ 0.04 | — |
| SEN 10088-3 limits S to 0.015 % for most product forms; free-machining versions are supplied with controlled S | ≤ 0.03 | — |
| Cr | 15 – 17 | 16 |
| Ni | 1.5 – 2.5 | 2 |
| Mooptional/residual, restricted by some purchase specifications | ≤ 0.8 | — |
| N | ≤ 0.06 | — |
| Fe | balance | — |
1.4057 +QT800 — frequently asked
What is 1.4057 +QT800 used for?
1.4057 +QT800 is typically used for aerospace shafts, fasteners, valve components and pump shafts. In short: toughest martensitic stainless; best corrosion in 400-series; shaft-grade 431 equivalent.
What is the yield strength of 1.4057 +QT800?
1.4057 +QT800 has a typical yield strength of 680 MPa (98.6 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 91% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 1.4057 +QT800 easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Machine in the annealed or ≤300 HB tempered condition with rigid setups, positive-rake carbide, 60–110 m/min and heavy feeds to cut under the work-hardened skin; flood coolant essential.
Can 1.4057 +QT800 be welded?
Not readily — weldability is rated poor (30/100). Poor weldability — preheat 200–300 °C, use 309L/430 or matching filler, and temper at 650–700 °C immediately after welding to restore toughness; avoid welding in the fully hardened state.
What surface finishes work on 1.4057 +QT800?
Takes a fine polish for shafting and decorative hardware; passivate per ASTM A967 after machining, and use hard chrome or electroless nickel where extra wear or chloride resistance is needed — no anodizing.
Can 1.4057 +QT800 be formed, bent or molded?
Hot work at 1100–850 °C with slow cooling; cold forming limited to gentle bends in the annealed state, hardening by oil/air quench from 980–1050 °C then temper (avoid 450–550 °C temper embrittlement range).
What is the maximum service temperature of 1.4057 +QT800?
1.4057 +QT800 is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10088-3 Stainless steels — semi-finished products, bars, rods, sections — CEN (2014)
- EN 10088-1 Stainless steels — List of stainless steels (physical properties) — CEN (2014)
- ASTM A276/A276M Stainless Steel Bars and Shapes (UNS S43100) — ASTM (2017)
- GB/T 1220 (1Cr17Ni2 / 14Cr17Ni2) — SAC (2007)
- JIS G 4303 Stainless steel bars (SUS431) — JSA (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Martensitic stainless bar datasheets (1.4057 / 431) — Outokumpu / Sandvik / Böhler (2023)
- 1Cr17Ni2 (2025)
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.