Stainless Steel S42300-QT590
Heat-treated state
UNS S42300
QT590 = q&T 590 °C
Higher-strength condition for blades, valve stems and wear parts where service temperature stays below ~480 °C.
Values for the QT590 condition
Other S42300 tempers and conditions
S42300 is listed in 5 conditions; see the grade overview at S42300.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest supply condition for rough machining, forming or re-heat-treatment by the customer. | 520 | 760 | 20 | 235 HB | — |
Normalized and tempered | Moderate-strength, high-toughness bar/forging condition for large sections and high-temperature bolting. | 700 | 900 | 18 | 26 HRC | — |
QT650Default Q&T 650 °C | Standard turbine-blade / high-temperature service condition: best balance of strength, toughness and creep stability. | 850 | 1,000 | 17 | 30 HRC | — |
QT590This page Q&T 590 °C | Higher-strength condition for blades, valve stems and wear parts where service temperature stays below ~480 °C. | 1,000 | 1,170 | 14 | 36 HRC | — |
Hardened + low temper | Maximum hardness/edge-retention condition for cutlery, surgical and wear components; low toughness, avoid the 400–550 °C temper-embrittlement band. | 1,350 | 1,650 | 8 | 49 HRC | — |
What is S42300-QT590?
S42300-QT590 is S42300 heat treated to QT590 — higher-strength condition for blades, valve stems and wear parts where service temperature stays below ~480 °C. S42300-QT590 has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,170 MPa (170 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 14% and the elastic modulus is 200 GPa (29 Msi). S42300-QT590 has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 58% of stainless steel grades. It melts at 1,425°C (2,597 °F). QT650 is the default condition FabDigit quotes; QT590 is available on request or by drawing note.
Advantages
- High strength — 1,000 MPa (145 ksi), better than 98% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
- Conducts heat well — 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades
Limitations
- Difficult to weld — 25/100, worse than 92% of stainless steel grades
- Limited ductility — 14%, worse than 91% of stainless steel grades
- Needs corrosion protection — 42/100, worse than 90% of stainless steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 88% of stainless steel grades
- Limited formability — 20/100, worse than 86% of stainless steel grades
S42300-QT590 properties
Typical room-temperature values for S42300-QT590; 14 are specific to this condition. Other listed values are S42300 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S42300-QT590 has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 58% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
S42300-QT590 has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,170 MPa (170 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 14% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S42300-QT590 is rated for continuous service to 480°C (896 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades. Thermal expansion is 11.2 µm/m·K (6.22 µin/in·°F).
Electrical3
S42300-QT590 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 90% of stainless steel grades.
Sustainability4
Producing a kilogram of S42300-QT590 takes about 53 MJ of energy and emits 4.8 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 45%.
Manufacturability6
S42300-QT590's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability poor (25/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S42300-QT590
Is S42300 easy to machine?
Machine in the annealed or 28–32 HRC condition with rigid setups, sharp carbide tooling, slow speeds and generous coolant; above ~40 HRC switch to CBN/ceramic or grinding.
Can S42300 be welded?
Air-hardening: preheat 200–300 °C, use matching 12Cr-Mo-V or austenitic filler, and temper immediately after welding (~650–700 °C) to restore toughness and avoid cold cracking.
Can S42300 be formed, bent or molded?
Hot work at 1050–1180 °C with slow cooling to an anneal; cold forming is essentially limited to light bending in the annealed state.
What surface finishes work on S42300?
Takes a fine polish and holds an edge; passivate after machining and avoid chloride exposure — hard-chrome, nitriding or PVD coatings are used where wear or corrosion demands more.
S42300 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 | 0.27 – 0.32 | 0.3 |
| Mn | 0.95 – 1.65 | 1.1 |
| Si | ≤ 0.5 | 0.3 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cr | 11 – 12 | 11.5 |
| Mo | 2.5 – 3 | 2.75 |
| V | 0.2 – 0.3 | 0.25 |
| Nimax, residual | ≤ 0.5 | — |
| Nspecified in some turbine-blade specifications | 0.05 – 0.1 | 0.06 |
| Fe | balance | — |
S42300-QT590 — frequently asked
What is S42300-QT590 used for?
S42300-QT590 is typically used for premium knife blades, surgical and dental instruments, high-end cutlery and wear-resistant tooling components. In short: higher-toughness 420 upgrade; fine-edge blade steel; air-hardening Cr-Mo-V martensitic.
What is the yield strength of S42300-QT590?
S42300-QT590 has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,170 MPa (170 ksi) — stronger than 98% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is S42300-QT590 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Machine in the annealed or 28–32 HRC condition with rigid setups, sharp carbide tooling, slow speeds and generous coolant; above ~40 HRC switch to CBN/ceramic or grinding.
Can S42300-QT590 be welded?
Not readily — weldability is rated poor (25/100). Air-hardening: preheat 200–300 °C, use matching 12Cr-Mo-V or austenitic filler, and temper immediately after welding (~650–700 °C) to restore toughness and avoid cold cracking.
What surface finishes work on S42300-QT590?
Takes a fine polish and holds an edge; passivate after machining and avoid chloride exposure — hard-chrome, nitriding or PVD coatings are used where wear or corrosion demands more.
Can S42300-QT590 be formed, bent or molded?
Hot work at 1050–1180 °C with slow cooling to an anneal; cold forming is essentially limited to light bending in the annealed state.
What is the maximum service temperature of S42300-QT590?
S42300-QT590 is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S42300-QT650 and S42300-QT200?
QT650 is the default condition — standard turbine-blade / high-temperature service condition: best balance of strength, toughness and creep stability. QT200: maximum hardness/edge-retention condition for cutlery, surgical and wear components; low toughness, avoid the 400–550 °C temper-embrittlement band. Yield strength is 850 MPa in QT650 versus 1,350 MPa in QT200.
Sources
- ASTM A565/A565M — Martensitic Stainless Steel Bars for High-Temperature Service (Grade 619) — ASTM International (2019)
- SAE J1086 / ASTM DS-56 — Metals & Alloys in the Unified Numbering System (UNS S42300) — SAE/ASTM (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- Machinery's Handbook, machinability ratings for martensitic stainless — Industrial Press (2020)
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.