Steel CrWMn QT50-52
Hardness band
GB CrWMn
QT50-52 = q&T 50–52 HRC
Maximum-toughness setting for heavy sections, mandrels and tool bodies; wear resistance drops noticeably.
Values for the QT50-52 condition
Other CrWMn tempers and conditions
CrWMn is listed in 9 conditions; see the grade overview at CrWMn.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stocked condition (≤255 HB) for machining tools before hardening. | 480 | 750 | 18 | 229 HB | — |
Stress relieved | Intermediate treatment on roughed-out precision tools to minimise movement during subsequent hardening. | 490 | 760 | 17 | 20 HRC | 7.2 % IACS |
Hot rolled | Mill as-rolled or as-forged bar before spheroidizing; hard and unmachinable, normally annealed before use. | 600 | 950 | 10 | 31 HRC | 7.2 % IACS |
QT50-52This page Q&T 50–52 HRC | Maximum-toughness setting for heavy sections, mandrels and tool bodies; wear resistance drops noticeably. | 1,500 | 1,750 | 7 | 51 HRC | — |
Q&T 54–56 HRC | Tougher setting for larger dies and shock-loaded tooling where chipping is the failure mode. | 1,650 | 1,900 | 5 | 55 HRC | — |
Q&T 57–59 HRC | Balanced hardness/toughness for shear blades, cold forming punches and tools seeing moderate impact. | 1,800 | 2,050 | 3 | 58 HRC | — |
Q&T 60–62 HRC | Most common working hardness: good wear resistance with slightly improved toughness for taps, broaches and blanking dies. | 1,950 | 2,250 | 1.5 | 61 HRC | — |
Hardened + deep cryogenic (-70…-196 °C) + double temper, ~62 HRC | Choose for gauges and precision tools where retained austenite must be eliminated for long-term dimensional stability. | 1,950 | 2,350 | 1 | 62 HRC | 6.5 % IACS |
Q&T 62–64 HRC | Maximum hardness and wear resistance for gauges, reamers and fine blanking punches in light-shock service. | 2,050 | 2,400 | 1 | 63 HRC | — |
What is CrWMn QT50-52?
CrWMn QT50-52 is CrWMn heat treated to QT50-52 — maximum-toughness setting for heavy sections, mandrels and tool bodies; wear resistance drops noticeably. CrWMn QT50-52 has a yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Elongation at break is 7% and the elastic modulus is 210 GPa (30.5 Msi). CrWMn QT50-52 has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F). A is the default condition FabDigit quotes; QT50-52 is available on request or by drawing note.
Advantages
- High strength — 1,500 MPa (218 ksi), better than 97% of steel grades
- Polishes to a fine finish — 75/100, better than 94% of steel grades
Limitations
- Difficult to machine — 20/100, worse than 97% of steel grades
- Limited ductility — 7%, worse than 96% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
CrWMn QT50-52 properties
Typical room-temperature values for CrWMn QT50-52; 12 are specific to this condition. Other listed values are CrWMn reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
CrWMn QT50-52 has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
CrWMn QT50-52 has a yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Elongation at break is 7% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
CrWMn QT50-52 is rated for continuous service to 300°C (572 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
CrWMn QT50-52 conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of CrWMn QT50-52 takes about 34 MJ of energy and emits 2.5 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 40%.
Manufacturability8
CrWMn QT50-52's machinability is poor (20/100, worse than 97% of 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 CrWMn QT50-52
Is CrWMn easy to machine?
Machine in the spheroidize-annealed condition (≈45 % of B1112) with sharp HSS or coated carbide; above 55 HRC only grinding, EDM or CBN turning is practical.
Can CrWMn be welded?
Essentially non-weldable for structural joints; repair only with matching/Cr-alloy filler at 300–400 °C preheat followed by immediate re-temper.
Can CrWMn be formed, bent or molded?
Hot forge 1050–850 °C with slow furnace cooling and mandatory spheroidize anneal at 770–790 °C; cold forming is limited to light bending of annealed thin stock.
What surface finishes work on CrWMn?
Takes a mirror polish when hardened; protect with black oxide, phosphate, oil or thin hard chrome — nitriding at ≤180 °C-safe processes only, since higher temperatures over-temper the tool.
CrWMn 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 |
|---|---|---|
| CGB/T 1299 CrWMn | 0.9 – 1.05 | 0.97 |
| Si | 0.15 – 0.35 | 0.25 |
| Mnraises hardenability, low distortion | 0.8 – 1.1 | 0.95 |
| Cr | 0.9 – 1.2 | 1.05 |
| Wforms fine carbides for wear resistance | 1.2 – 1.6 | 1.4 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Niresidual, max | ≤ 0.25 | — |
| Curesidual, max | ≤ 0.3 | — |
| Fe | balance | — |
CrWMn QT50-52 — frequently asked
What is CrWMn QT50-52 used for?
CrWMn QT50-52 is typically used for gauges, precision dies, broaches and thread tools. In short: low-distortion oil-hardening grade; direct O1 counterpart; mirror-polishable when hardened.
What is the yield strength of CrWMn QT50-52?
CrWMn QT50-52 has a typical yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is CrWMn QT50-52 easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of steel grades). Machine in the spheroidize-annealed condition (≈45 % of B1112) with sharp HSS or coated carbide; above 55 HRC only grinding, EDM or CBN turning is practical.
Can CrWMn QT50-52 be welded?
Not readily — weldability is rated poor (15/100). Essentially non-weldable for structural joints; repair only with matching/Cr-alloy filler at 300–400 °C preheat followed by immediate re-temper.
What surface finishes work on CrWMn QT50-52?
Takes a mirror polish when hardened; protect with black oxide, phosphate, oil or thin hard chrome — nitriding at ≤180 °C-safe processes only, since higher temperatures over-temper the tool.
Can CrWMn QT50-52 be formed, bent or molded?
Hot forge 1050–850 °C with slow furnace cooling and mandatory spheroidize anneal at 770–790 °C; cold forming is limited to light bending of annealed thin stock.
What is the maximum service temperature of CrWMn QT50-52?
CrWMn QT50-52 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CrWMn-A and CrWMn QT62-64?
A is the default condition — standard stocked condition (≤255 HB) for machining tools before hardening. QT62-64: maximum hardness and wear resistance for gauges, reamers and fine blanking punches in light-shock service. Yield strength is 480 MPa in A versus 2,050 MPa in QT62-64.
Sources
- GB/T 1299 Tool and Die Steels ( CrWMn) (2014)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys (O1 tool steel) — ASM International (1990)
- ASM Handbook Vol. 16: Machining (tool steel machinability ratings) — ASM International (1989)
- Cold work tool steel 1.2510 / 105WCr6 datasheet — Böhler / Voestalpine (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.