Steel 20Kh-HR (Hot rolled)
Supply condition
GOST 20Kh (20Х)
Cheapest mill condition for parts that will be fully heat treated after machining.
Values for the HR 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 | — |
HRThis page 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 | — |
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-HR?
20Kh-HR is 20Kh supplied in the HR condition — cheapest mill condition for parts that will be fully heat treated after machining. 20Kh-HR has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 78% of steel grades. Elongation at break is 22% and the elastic modulus is 211 GPa (30.6 Msi). 20Kh-HR 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; HR 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
Limitations
- Low strength — 330 MPa (47.9 ksi), worse than 78% of steel grades
20Kh-HR properties
Typical room-temperature values for 20Kh-HR; 10 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-HR 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-HR has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 78% of steel grades. Elongation at break is 22% and the elastic modulus is 211 GPa (30.6 Msi).
Thermal6
20Kh-HR is rated for continuous service to 400°C (752 °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-HR 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-HR 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-HR's machinability is good (56/100, better than 71% of steel grades); weldability good (62/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20Kh-HR
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-HR — frequently asked
What is 20Kh-HR used for?
20Kh-HR 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-HR?
20Kh-HR has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 78% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 20Kh-HR easy to machine?
Reasonably — machinability is rated good (56/100, better than 71% 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-HR be welded?
Yes — weldability is rated good (62/100). 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-HR?
No anodizing (ferrous) — protect with phosphate + oil, black oxide, zinc or hard chrome; carburized surfaces polish and hone well.
Can 20Kh-HR 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-HR?
20Kh-HR 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.
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.