Steel 20Kh
GOST 20Kh (20Х)
20Kh (20Х) is a chromium case-hardening steel of the GOST family, functionally interchangeable with 20Cr, hardened by carburizing rather than by core alloying.
Reference datasheet — 20Kh is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the A condition
20Kh tempers and conditions
20Kh is supplied in 7 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
20Kh (20Х) is a chromium case-hardening steel of the GOST family, functionally interchangeable with 20Cr, hardened by carburizing rather than by core alloying. It is a general-purpose choice for gears, shafts and bushings and is widely available as hot-rolled, annealed, normalized and cold-drawn bar and tube. In the soft condition it runs about 300 MPa yield, 490 MPa tensile, 26 % elongation and 156 HB (82 HRB), with machinability 60, formability 65 and a listed maximum service temperature of 400 °C. Hardenability is limited in heavy sections and there is no corrosion resistance; 18KhGT / 20CrMnTi is the step up for higher-loaded gears. 20Kh 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). 20Kh has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 86% of steel grades. Elongation at break is 26% and the elastic modulus is 211 GPa (30.6 Msi).
What is 20Kh used for?
- gears
- shafts
- bushings
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Forms and bends easily — 65/100, better than 81% of steel grades
Limitations
- Low strength — 300 MPa (43.5 ksi), worse than 86% of steel grades
20Kh properties
Typical room-temperature values for 20Kh-A; bars are the position among steel grades.
Physical3
20Kh 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 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 86% of steel grades. Elongation at break is 26% and the elastic modulus is 211 GPa (30.6 Msi).
Thermal6
20Kh 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 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 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's machinability is good (60/100, better than 83% of steel grades); weldability good (62/100); formability good (65/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 20Kh is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 20Kh
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.
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 | — |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 20Kh in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- GOST
- 20Х
- Similar grades
- 20Cr
How much does 20Kh cost?
20Kh is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
20Kh — frequently asked
What is 20Kh used for?
20Kh 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?
20Kh has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 86% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 20Kh easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% 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 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?
No anodizing (ferrous) — protect with phosphate + oil, black oxide, zinc or hard chrome; carburized surfaces polish and hone well.
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 is the maximum service temperature of 20Kh?
20Kh 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.
How much does 20Kh cost?
20Kh is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.