Stainless Steel 1.4122 +QT800
Heat-treated state
EN 1.4122
+QT800 = quenched and tempered, Rm 800–1000 MPa
Higher-strength Q&T bar used for shafts and mould plates where extra yield strength is required with acceptable toughness.
Values for the +QT800 condition
Other 1.4122 tempers and conditions
1.4122 is listed in 7 conditions; see the grade overview at 1.4122.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ADefault Annealed | Mill-stocked condition for machining, forming and subsequent hardening; max hardness limited by EN 10088-3. | 460 | 780 | 18 | 22 HRC | — |
Quenched and tempered, Rm 650–850 MPa | Lowest-strength Q&T delivery condition of EN 10088-3, chosen when toughness and machinability outweigh hardness. | 520 | 750 | 16 | 20 HRC | — |
Quenched and tempered, Rm 750–950 MPa | Standard supply condition for valve stems, pump shafts and fasteners needing balanced strength, toughness and corrosion resistance. | 620 | 850 | 14 | 26 HRC | — |
Cold drawn | Choose for close-tolerance shafting and screw-machine stock supplied ready-to-machine before hardening. | 650 | 880 | 12 | 27 HRC | 2.9 % IACS |
+QT800This page Quenched and tempered, Rm 800–1000 MPa | Higher-strength Q&T bar used for shafts and mould plates where extra yield strength is required with acceptable toughness. | 680 | 900 | 12 | 30 HRC | 2.9 % IACS |
Hardened and tempered to 44–48 HRC | Mid-hardness condition for mould inserts, dies and shafts needing wear resistance with some residual toughness. | 1,200 | 1,450 | 6 | 46 HRC | — |
Hardened and low-temper, 50–54 HRC | Maximum hardness and corrosion resistance condition for knife blades, scissors, wear rings and cutting tools. | 1,500 | 1,800 | 3 | 52 HRC | — |
What is 1.4122 +QT800?
1.4122 +QT800 is 1.4122 heat treated to +QT800 — higher-strength Q&T bar used for shafts and mould plates where extra yield strength is required with acceptable toughness. 1.4122 +QT800 has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 91% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 216 GPa (31.3 Msi). 1.4122 +QT800 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,420°C (2,588 °F). +A is the default condition FabDigit quotes; +QT800 is available on request or by drawing note.
Advantages
- Conducts heat well — 29 W/m·K (16.8 BTU/hr·ft·°F), better than 97% of stainless steel grades
- High strength — 680 MPa (98.6 ksi), better than 91% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
Limitations
- Difficult to weld — 15/100, worse than 98% of stainless steel grades
- Limited ductility — 12%, worse than 95% of stainless steel grades
- Needs corrosion protection — 38/100, worse than 95% of stainless steel grades
- Limited formability — 12/100, worse than 93% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
1.4122 +QT800 properties
Typical room-temperature values for 1.4122 +QT800; 22 are specific to this condition. Other listed values are 1.4122 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4122 +QT800 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
1.4122 +QT800 has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 91% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 216 GPa (31.3 Msi).
Thermal6
1.4122 +QT800 is rated for continuous service to 400°C (752 °F). It conducts heat at 29 W/m·K (16.8 BTU/hr·ft·°F), better than 97% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4122 +QT800 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 95% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4122 +QT800 takes about 55 MJ of energy and emits 4.8 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 50%.
Manufacturability6
1.4122 +QT800's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability poor (15/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4122 +QT800
Is 1.4122 easy to machine?
Machine in the annealed condition with sharp, rigid tooling, positive-rake carbide and generous coolant; above ~45 HRC use ceramic/CBN or grind and EDM.
Can 1.4122 be welded?
Poor weldability — preheat 200–300 °C, use matching or austenitic (309/312) filler, and temper immediately after welding to avoid martensitic cracking.
Can 1.4122 be formed, bent or molded?
Cold forming is limited to gentle bends in the annealed state; hot work at 1050–850 °C followed by slow cooling and soft annealing at 750–800 °C.
What surface finishes work on 1.4122?
Takes a high mirror polish when hardened and vacuum-melted quality is used; passivate after machining, and hard chrome or nitriding can be applied for extra wear resistance.
1.4122 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 | 0.33 – 0.45 | 0.39 |
| Si | ≤ 1 | 0.4 |
| Mn | ≤ 1.5 | 0.6 |
| Pimpurity | ≤ 0.04 | — |
| Simpurity | ≤ 0.03 | — |
| Cr | 15.5 – 17.5 | 16.5 |
| Mo | 0.8 – 1.3 | 1.05 |
| Niresidual/optional addition | ≤ 1 | 0.4 |
| Fe | balance | — |
1.4122 +QT800 — frequently asked
What is 1.4122 +QT800 used for?
1.4122 +QT800 is typically used for plastic injection mold plates, valve parts, cutlery, surgical instruments and pump shafts. In short: mo-bearing 420 upgrade; hardens to 52 HRC; mould-plate martensitic grade.
What is the yield strength of 1.4122 +QT800?
1.4122 +QT800 has a typical yield strength of 680 MPa (98.6 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 91% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 1.4122 +QT800 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Machine in the annealed condition with sharp, rigid tooling, positive-rake carbide and generous coolant; above ~45 HRC use ceramic/CBN or grind and EDM.
Can 1.4122 +QT800 be welded?
Not readily — weldability is rated poor (15/100). Poor weldability — preheat 200–300 °C, use matching or austenitic (309/312) filler, and temper immediately after welding to avoid martensitic cracking.
What surface finishes work on 1.4122 +QT800?
Takes a high mirror polish when hardened and vacuum-melted quality is used; passivate after machining, and hard chrome or nitriding can be applied for extra wear resistance.
Can 1.4122 +QT800 be formed, bent or molded?
Cold forming is limited to gentle bends in the annealed state; hot work at 1050–850 °C followed by slow cooling and soft annealing at 750–800 °C.
What is the maximum service temperature of 1.4122 +QT800?
1.4122 +QT800 is rated for continuous use to about 400°C (752 °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)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
- Martensitic stainless bar/mould steel datasheets (X39CrMo17-1 class) — European stainless bar producers (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.