Stainless Steel S42030 QT-205
Heat-treated state
UNS S42030
QT-205 = hardened and tempered at 205 °C
Standard cutlery/blade and wear-part condition: near-peak hardness with usable toughness and best corrosion behaviour of the hardened states.
Values for the QT-205 condition
Other S42030 tempers and conditions
S42030 is listed in 8 conditions; see the grade overview at S42030.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stocking condition for bar, plate and forgings — soft, machinable, to be hardened after machining. | 380 | 690 | 22 | 210 HB | — |
Annealed and cold drawn bar | Cold-drawn bar for close tolerance and better surface finish on screw-machine parts. | 690 | 830 | 14 | 25 HRC | 3.1 % IACS |
Hardened and tempered at 650 °C | High-temper 'quenched and tempered structural' condition (~26–32 HRC) for shafts, bolts and forgings where ductility and machinability matter more than wear. | 690 | 900 | 18 | 29 HRC | — |
Hardened and tempered at 540 °C | Intermediate ~38–43 HRC condition for shafts and pump/valve components needing more toughness than blade tempers. | 1,030 | 1,280 | 13 | 40 HRC | — |
Hardened and tempered at 425 °C (800 °F) — embrittlement range, avoid… | Only used when a specific ~45–48 HRC level is required; toughness and corrosion resistance both drop in the 400–550 °C tempering range. | 1,330 | 1,550 | 10 | 47 HRC | 2.9 % IACS |
Hardened and tempered at 315 °C | Slightly tougher than 205 °C temper for shafts, valve parts and dies at ~48–52 HRC. | 1,400 | 1,650 | 9 | 50 HRC | — |
QT-205This page Hardened and tempered at 205 °C | Standard cutlery/blade and wear-part condition: near-peak hardness with usable toughness and best corrosion behaviour of the hardened states. | 1,480 | 1,750 | 8 | 52 HRC | — |
Hardened | Maximum hardness condition for cutting edges and wear surfaces where toughness demand is low. | 1,550 | 1,860 | 4 | 55 HRC | — |
What is S42030 QT-205?
S42030 QT-205 is S42030 heat treated to QT-205 — standard cutlery/blade and wear-part condition: near-peak hardness with usable toughness and best corrosion behaviour of the hardened states. S42030 QT-205 has a yield strength of 1,480 MPa (215 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 8% and the elastic modulus is 200 GPa (29 Msi). S42030 QT-205 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,450°C (2,642 °F). A is the default condition FabDigit quotes; QT-205 is available on request or by drawing note.
Advantages
- High strength — 1,480 MPa (215 ksi), better than 100% of stainless steel grades
- High electrical conductivity — 3.1 % IACS, better than 99% of stainless steel grades
- Polishes to a fine finish — 85/100, better than 97% 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
Limitations
- Limited service temperature — 200°C (392 °F), worse than 100% of stainless steel grades
- Difficult to machine — 12/100, worse than 100% of stainless steel grades
- Limited ductility — 8%, worse than 99% of stainless steel grades
- Difficult to weld — 25/100, worse than 92% of stainless steel grades
- Needs corrosion protection — 48/100, worse than 80% of stainless steel grades
S42030 QT-205 properties
Typical room-temperature values for S42030 QT-205; 14 are specific to this condition. Other listed values are S42030 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S42030 QT-205 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical15
S42030 QT-205 has a yield strength of 1,480 MPa (215 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 8% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S42030 QT-205 is rated for continuous service to 200°C (392 °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 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
S42030 QT-205 conducts electricity at 3.1 % IACS, better than 99% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of S42030 QT-205 takes about 48 MJ of energy and emits 4.3 kg of CO₂ — less than 85% of stainless steel grades. Typical recycled content is 50%.
Manufacturability6
S42030 QT-205's machinability is not recommended (12/100, worse than 100% of stainless steel grades); weldability poor (25/100); formability fair (38/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S42030 QT-205
Is S42030 easy to machine?
Machine in the annealed condition with sharp, rigid, positive-rake carbide tooling, generous feed and flood coolant; above ~45 HRC switch to grinding, EDM or ceramic/CBN hard turning.
Can S42030 be welded?
Poor weldability due to high carbon — preheat 200–320 °C, use 410/420 or austenitic (309/312) filler, and temper immediately after welding to avoid quench cracking.
Can S42030 be formed, bent or molded?
Cold form only in the annealed condition and with generous bend radii; hot work 1100–1200 °C, stop above ~900 °C and cool slowly followed by a full anneal.
What surface finishes work on S42030?
Takes an excellent mirror or satin polish; passivate in nitric or citric acid after machining/grinding, and avoid electroless/hard chrome hydrogen embrittlement without a post-plate bake.
S42030 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 |
|---|---|---|
| Ccarbon-adjusted (high-carbon) 420 variant; exact limits per the governing ASTM A276/A959 or purchase spec | 0.28 – 0.4 | 0.33 |
| Si | ≤ 1 | 0.4 |
| Mn | ≤ 1 | 0.5 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 12 – 14 | 13 |
| Niresidual/optional addition in some mill practices | ≤ 0.5 | — |
| Moresidual/optional addition in some mill practices | ≤ 0.5 | — |
| Fe | balance | — |
S42030 QT-205 — frequently asked
What is S42030 QT-205 used for?
S42030 QT-205 is typically used for knife blades, surgical instruments, molds and dies and wear plates. In short: classic hardenable blade steel; wide tempered range QT-205–QT-650; polishes to mirror finish.
What is the yield strength of S42030 QT-205?
S42030 QT-205 has a typical yield strength of 1,480 MPa (215 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 100% of stainless steel grades. Strength varies by condition: see the 8 listed tempers.
Is S42030 QT-205 easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 100% of stainless steel grades). Machine in the annealed condition with sharp, rigid, positive-rake carbide tooling, generous feed and flood coolant; above ~45 HRC switch to grinding, EDM or ceramic/CBN hard turning.
Can S42030 QT-205 be welded?
Not readily — weldability is rated poor (25/100). Poor weldability due to high carbon — preheat 200–320 °C, use 410/420 or austenitic (309/312) filler, and temper immediately after welding to avoid quench cracking.
What surface finishes work on S42030 QT-205?
Takes an excellent mirror or satin polish; passivate in nitric or citric acid after machining/grinding, and avoid electroless/hard chrome hydrogen embrittlement without a post-plate bake.
Can S42030 QT-205 be formed, bent or molded?
Cold form only in the annealed condition and with generous bend radii; hot work 1100–1200 °C, stop above ~900 °C and cool slowly followed by a full anneal.
What is the maximum service temperature of S42030 QT-205?
S42030 QT-205 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S42030-A and S42030-H?
A is the default condition — standard stocking condition for bar, plate and forgings — soft, machinable, to be hardened after machining. H: maximum hardness condition for cutting edges and wear surfaces where toughness demand is low. Yield strength is 380 MPa in A versus 1,550 MPa in H.
Sources
- ASTM A276/A276M — Stainless Steel Bars and Shapes — ASTM International (2023)
- ASTM A959 — Harmonized Standard Grade Compositions for Wrought Stainless Steels — ASTM International (2022)
- GB/T 1220 (4Cr13 / 3Cr13) — SAC (2007)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Type 420 Stainless Steel Product Data Bulletin — AK Steel / Cleveland-Cliffs (2018)
- UNS S42000/S42030 martensitic stainless property records — SAE/ASTM Metals & Alloys in the Unified Numbering System (2019)
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.