Stainless Steel 1.4125 Cryo
Heat-treated state
EN 1.4125
Cryo = hardened, deep-frozen (−80 °C) and tempered
Sub-zero treatment converts retained austenite for maximum hardness and dimensional stability in bearings and gauges.
Values for the Cryo condition
Other 1.4125 tempers and conditions
1.4125 is listed in 8 conditions; see the grade overview at 1.4125.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ADefault Annealed | Standard stock condition for machining before hardening; softest and most workable state. | 450 | 760 | 14 | 250 HB | — |
Annealed and cold drawn bar | Cold-drawn annealed bar for tight tolerance and better surface before hardening; slightly higher strength, lower ductility. | 650 | 880 | 10 | 29 HRC | — |
Hardened, tempered 450–550 °C | Used only when elevated-temperature stability is needed; corrosion resistance and toughness drop markedly. | 1,650 | 1,800 | 3 | 54 HRC | 2.7 % IACS |
Hardened, tempered 250–350 °C | Slightly lower hardness with better stress relief for larger tooling and valve components. | 1,790 | 1,900 | 3 | 56 HRC | — |
Quenched and tempered | Generic delivered hardened condition per EN 10088-3 for wear parts; specify tempering temperature for the exact hardness. | 1,900 | 1,970 | 2 | 58 HRC | — |
As-quenched | Intermediate state only — extremely brittle and stressed; always temper before service. | 1,900 | 2,000 | 0.5 | 63 HRC | — |
Hardened, tempered 150–200 °C | Maximum hardness with best corrosion resistance — standard for bearing races/balls and premium knife blades. | 1,930 | 2,030 | 2 | 59 HRC | — |
CryoThis page Hardened, deep-frozen (−80 °C) and tempered | Sub-zero treatment converts retained austenite for maximum hardness and dimensional stability in bearings and gauges. | — | 2,100 | 1 | 61 HRC | — |
What is 1.4125 Cryo?
1.4125 Cryo is 1.4125 heat treated to Cryo — sub-zero treatment converts retained austenite for maximum hardness and dimensional stability in bearings and gauges. 1.4125 Cryo has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 1% and the elastic modulus is 200 GPa (29 Msi). 1.4125 Cryo has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,370°C (2,498 °F). +A is the default condition FabDigit quotes; Cryo is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 90/100, better than 100% 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
- Limited ductility — 1%, worse than 100% of stainless steel grades
- Limited service temperature — 180°C (356 °F), worse than 100% of stainless steel grades
- Difficult to machine — 5/100, worse than 100% of stainless steel grades
- Difficult to weld — 15/100, worse than 98% of stainless steel grades
- Needs corrosion protection — 46/100, worse than 82% of stainless steel grades
1.4125 Cryo properties
Typical room-temperature values for 1.4125 Cryo; 10 are specific to this condition. Other listed values are 1.4125 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4125 Cryo has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical14
1.4125 Cryo has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 1% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4125 Cryo is rated for continuous service to 180°C (356 °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 10.2 µm/m·K (5.67 µin/in·°F).
Electrical3
1.4125 Cryo conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (46/100), worse than 82% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4125 Cryo takes about 55 MJ of energy and emits 5.2 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
1.4125 Cryo's machinability is not recommended (5/100, worse than 100% of stainless steel grades); weldability poor (15/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4125 Cryo
Is 1.4125 easy to machine?
Machine only in the annealed condition with sharp carbide tooling, low speed and rigid setups; hardened parts require grinding or EDM.
Can 1.4125 be welded?
Essentially not recommended — high carbon causes cracking; if unavoidable preheat 250–350 °C, use matching or austenitic filler and immediately anneal/temper.
Can 1.4125 be formed, bent or molded?
Cold forming is very limited (annealed sheet only, generous radii); hot work 1100→850 °C followed by slow cool and spheroidize anneal.
What surface finishes work on 1.4125?
Takes a high mirror polish when fully hardened; passivate in nitric or citric acid after grinding, and avoid tempering above ~400 °C which degrades corrosion resistance.
1.4125 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 |
|---|---|---|
| CEN 10088-3 X105CrMo17; GB 9Cr18Mo 0.95–1.10 | 0.95 – 1.2 | 1.05 |
| Si | ≤ 1 | 0.4 |
| Mn | ≤ 1 | 0.5 |
| P | ≤ 0.04 | — |
| SEN often ≤0.015 for bearing/knife quality | ≤ 0.03 | — |
| Cr | 16 – 18 | 17 |
| MoAISI 440C: Mo ≤ 0.75 | 0.4 – 0.8 | 0.55 |
| Niresidual | ≤ 0.5 | — |
| Fe | balance | — |
1.4125 Cryo — frequently asked
What is 1.4125 Cryo used for?
1.4125 Cryo is typically used for knife blades, surgical scalpels, ball bearings, wear-resistant valve parts and precision gauges. In short: hardest common stainless; 440C wear-resistance benchmark; not weldable, wear-first grade.
What is the yield strength of 1.4125 Cryo?
1.4125 Cryo has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 70% of stainless steel grades. Strength varies by condition: see the 8 listed tempers.
Is 1.4125 Cryo easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 100% of stainless steel grades). Machine only in the annealed condition with sharp carbide tooling, low speed and rigid setups; hardened parts require grinding or EDM.
Can 1.4125 Cryo be welded?
Not readily — weldability is rated poor (15/100). Essentially not recommended — high carbon causes cracking; if unavoidable preheat 250–350 °C, use matching or austenitic filler and immediately anneal/temper.
What surface finishes work on 1.4125 Cryo?
Takes a high mirror polish when fully hardened; passivate in nitric or citric acid after grinding, and avoid tempering above ~400 °C which degrades corrosion resistance.
Can 1.4125 Cryo be formed, bent or molded?
Cold forming is very limited (annealed sheet only, generous radii); hot work 1100→850 °C followed by slow cool and spheroidize anneal.
What is the maximum service temperature of 1.4125 Cryo?
1.4125 Cryo is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4125 +A and 1.4125-QT150?
+A is the default condition — standard stock condition for machining before hardening; softest and most workable state. QT150: maximum hardness with best corrosion resistance — standard for bearing races/balls and premium knife blades. Yield strength is 450 MPa in +A versus 1,930 MPa in QT150.
Sources
- EN 10088-3 Stainless steels – semi-finished products, bars, rods (X105CrMo17 / 1.4125) — CEN (2014)
- ASTM A276 / A484 Stainless Steel Bars and Shapes (Type 440C) — ASTM (2017)
- GB/T 1220 (9Cr18Mo) — SAC (2007)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Martensitic stainless bar/strip datasheets (Sandvik, Böhler N685, Aubert & Duval) — various producers (2023)
- 9Cr18Mo/440C — 1688 / Mysteel (2026)
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.