Steel 20Kh-QT200
Heat-treated state
GOST 20Kh (20Х)
QT200 = q&T
The standard GOST acceptance condition and the core condition of a carburized part; strong and reasonably tough.
Values for the QT200 condition
Other 20Kh tempers and conditions
20Kh is listed in 7 conditions; see the grade overview at 20Kh.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stocked soft condition for machining and cold forming before carburizing. | 300 | 490 | 26 | 156 HB | — |
Hot rolled | Cheapest mill condition for parts that will be fully heat treated after machining. | 330 | 550 | 22 | 175 HB | — |
Normalized | Uniform fine grain and better machined surface finish than annealed; usual pre-carburizing condition. | 360 | 570 | 24 | 180 HB | — |
Cold drawn | Choose for close-tolerance bright bar and higher as-supplied strength on non-heat-treated parts. | 540 | 650 | 12 | 200 HB | — |
oil quench + ~450 °C temper (higher-toughness core) | Use when the part is not carburized and toughness matters more than surface hardness. | 540 | 720 | 17 | 18 HRC | — |
QT200This page Q&T | The standard GOST acceptance condition and the core condition of a carburized part; strong and reasonably tough. | 680 | 850 | 13 | 26 HRC | — |
Carburized and hardened | Final service condition for gears, pins and shafts needing a hard wear surface over a tough core. | 700 | 900 | 10 | 60 HRC | — |
What is 20Kh-QT200?
20Kh-QT200 is 20Kh heat treated to QT200 — the standard GOST acceptance condition and the core condition of a carburized part; strong and reasonably tough. 20Kh-QT200 has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 80% of steel grades. Elongation at break is 13% and the elastic modulus is 211 GPa (30.6 Msi). 20Kh-QT200 has a density of 7.82 g/cm³ (0.283 lb/in³), lighter than 82% of steel grades. It melts at 1,460°C (2,660 °F). A is the default condition FabDigit quotes; QT200 is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Forms and bends easily — 65/100, better than 81% of steel grades
- High strength — 680 MPa (98.6 ksi), better than 80% of steel grades
Limitations
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
20Kh-QT200 properties
Typical room-temperature values for 20Kh-QT200; 16 are specific to this condition. Other listed values are 20Kh reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20Kh-QT200 has a density of 7.82 g/cm³ (0.283 lb/in³), lighter than 82% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical15
20Kh-QT200 has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 80% of steel grades. Elongation at break is 13% and the elastic modulus is 211 GPa (30.6 Msi).
Thermal6
20Kh-QT200 is rated for continuous service to 180°C (356 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
20Kh-QT200 conducts electricity at 8.2 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 20Kh-QT200 takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
20Kh-QT200's machinability is fair (42/100, worse than 73% of steel grades); weldability fair (35/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20Kh-QT200
Is 20Kh easy to machine?
Machine in the annealed or normalized state (≈65 % of 1212); after carburizing and hardening only grinding or EDM is practical — leave 0.1–0.3 mm grind stock.
Can 20Kh be welded?
Weldable in the soft condition with low-hydrogen consumables; preheat 150–200 °C for sections over ~25 mm and avoid welding carburized surfaces.
Can 20Kh be formed, bent or molded?
Good cold heading and bending when spheroidize annealed; hot forge 1150–850 °C followed by normalizing to restore grain size before carburizing.
What surface finishes work on 20Kh?
No anodizing (ferrous) — protect with phosphate + oil, black oxide, zinc or hard chrome; carburized surfaces polish and hone well.
20Kh 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 |
|---|---|---|
| CGOST 4543 / GB/T 3077 20Cr | 0.17 – 0.23 | 0.2 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.5 – 0.8 | 0.65 |
| Cr | 0.7 – 1 | 0.85 |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.3 | — |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
20Kh-QT200 — frequently asked
What is 20Kh-QT200 used for?
20Kh-QT200 is typically used for gears, shafts and bushings. In short: baseline chromium carburizing steel; best formability in family; widely available bar stock.
What is the yield strength of 20Kh-QT200?
20Kh-QT200 has a typical yield strength of 680 MPa (98.6 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 20Kh-QT200 easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine in the annealed or normalized state (≈65 % of 1212); after carburizing and hardening only grinding or EDM is practical — leave 0.1–0.3 mm grind stock.
Can 20Kh-QT200 be welded?
With care — weldability is rated fair (35/100). Weldable in the soft condition with low-hydrogen consumables; preheat 150–200 °C for sections over ~25 mm and avoid welding carburized surfaces.
What surface finishes work on 20Kh-QT200?
No anodizing (ferrous) — protect with phosphate + oil, black oxide, zinc or hard chrome; carburized surfaces polish and hone well.
Can 20Kh-QT200 be formed, bent or molded?
Good cold heading and bending when spheroidize annealed; hot forge 1150–850 °C followed by normalizing to restore grain size before carburizing.
What is the maximum service temperature of 20Kh-QT200?
20Kh-QT200 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 20Kh-A and 20Kh-CH?
A is the default condition — standard stocked soft condition for machining and cold forming before carburizing. CH: final service condition for gears, pins and shafts needing a hard wear surface over a tough core. Yield strength is 300 MPa in A versus 700 MPa in CH.
Sources
- GOST 4543 — Alloy structural steel bars (20Х) — Gosstandart / Rosstandart (2016)
- GB/T 3077 — Alloy structural steels (20Cr) — SAC (2015)
- Marochnik stali i splavov — steel 20Kh datasheet — Marochnik (2020)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4: Heat Treating (carburizing of Cr steels) — ASM International (1991)
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.