Steel 25KhGT
GOST 25KhGT (25ХГТ)
25KhGT is a GOST chromium-manganese-titanium case-hardening (carburizing) steel, a higher-carbon variant of 18KhGT with increased core strength.
Reference datasheet — 25KhGT 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
25KhGT tempers and conditions
25KhGT 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 delivery condition of gear-steel bar: softest, best machinability before carburizing. | 400 | 620 | 18 | 197 HB | — |
Normalized | Uniform fine-grain structure and better chip control than annealed; typical pre-carburizing condition for forgings. | 500 | 760 | 15 | 217 HB | — |
Hot rolled | Lowest-cost mill condition for parts that will be fully heat treated after machining. | 520 | 800 | 14 | 20 HRC | 7.5 % IACS |
Cold drawn | Close-tolerance bright bar for automatic-lathe parts and shafts machined near net shape before carburizing. | 700 | 850 | 9 | 24 HRC | 7.5 % IACS |
Q&T to 28–34 HRC | Tough through-hardened condition for shafts and cores that will be induction- or nitride-treated later. | 850 | 1,000 | 13 | 31 HRC | — |
Carburized, quenched & low tempered | The service condition for gears: hard wear-resistant case with a strong, tough 30–40 HRC core. | 980 | 1,180 | 10 | 60 HRC | — |
Q&T | Maximum through-hardened strength for small, non-carburized highly loaded parts (pins, splines). | 1,220 | 1,420 | 9 | 44 HRC | — |
What is 25KhGT?
25KhGT is a GOST chromium-manganese-titanium case-hardening (carburizing) steel, a higher-carbon variant of 18KhGT with increased core strength. It is used for heavier-duty automotive and industrial gears and is supplied as hot-rolled, cold-drawn, annealed or normalized bar and forging stock; the default condition gives 400 MPa yield, 620 MPa tensile, 18 % elongation and 197 HB (92 HRB), with a carburized and low-tempered case of 58–62 HRC. Limits are poor weldability (CE approximately 0.65), a maximum service temperature of 350 °C and no inherent corrosion resistance, so plating or phosphating is required. Where core strength can be lower and weld repair matters more, 18KhGT is the nearest alternative. 25KhGT has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,425°C (2,597 °F). 25KhGT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 18% and the elastic modulus is 212 GPa (30.7 Msi).
What is 25KhGT used for?
- Automotive transmission gears
- Industrial gearbox gears
- Splined drive shafts
- Differential ring and pinion sets
- Sprockets and gear couplings
- Carburized pinion shafts
- Heavy-duty machine tool gears
25KhGT properties
Typical room-temperature values for 25KhGT-A; bars are the position among steel grades.
Physical3
25KhGT has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
25KhGT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 18% and the elastic modulus is 212 GPa (30.7 Msi).
Thermal6
25KhGT is rated for continuous service to 350°C (662 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
25KhGT conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 25KhGT takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
25KhGT's machinability is good (60/100, better than 83% of steel grades); weldability poor (30/100); formability fair (48/100).
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. 25KhGT is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 25KhGT
Is 25KhGT easy to machine?
Machine in the annealed/normalized state (≤217 HB) with carbide or coated HSS; leave 0.2–0.4 mm grinding stock on gear teeth for post-carburizing distortion.
Can 25KhGT be welded?
Poor weldability (CE ≈ 0.65): preheat 250–350 °C, low-hydrogen consumables and immediate stress relief; never weld carburized surfaces.
Can 25KhGT be formed, bent or molded?
Hot forge 1150–850 °C then slow-cool or isothermally anneal; cold heading only for small annealed parts due to high Cr-Mn work hardening.
25KhGT 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 |
|---|---|---|
| C | 0.22 – 0.29 | 0.25 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.8 – 1.1 | 0.95 |
| Cr | 1 – 1.3 | 1.15 |
| Tigrain refiner, allows direct quench after carburizing | 0.03 – 0.09 | 0.06 |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.3 | — |
| S | ≤ 0.04 | — |
| P | ≤ 0.04 | — |
| Fe | balance | — |
What surface finishes work on 25KhGT?
Gas or vacuum carburize 900–930 °C to 0.8–1.5 mm case, oil quench, temper 180–200 °C, then grind; protect with phosphate + oil, black oxide or zinc plating (bake to avoid H embrittlement).
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 25KhGT in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- GOST
- 25ХГТ
How much does 25KhGT cost?
25KhGT 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.
25KhGT — frequently asked
What is 25KhGT used for?
25KhGT is typically used for automotive transmission gears, industrial gearbox gears, splined drive shafts, differential ring and pinion sets, sprockets and gear couplings and carburized pinion shafts. In short: stronger core than 18KhGT; cr-Mn-Ti gear steel; 58-62 HRC case.
What is the yield strength of 25KhGT?
25KhGT has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 25KhGT easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machine in the annealed/normalized state (≤217 HB) with carbide or coated HSS; leave 0.2–0.4 mm grinding stock on gear teeth for post-carburizing distortion.
Can 25KhGT be welded?
Not readily — weldability is rated poor (30/100). Poor weldability (CE ≈ 0.65): preheat 250–350 °C, low-hydrogen consumables and immediate stress relief; never weld carburized surfaces.
What surface finishes work on 25KhGT?
Gas or vacuum carburize 900–930 °C to 0.8–1.5 mm case, oil quench, temper 180–200 °C, then grind; protect with phosphate + oil, black oxide or zinc plating (bake to avoid H embrittlement).
Can 25KhGT be formed, bent or molded?
Hot forge 1150–850 °C then slow-cool or isothermally anneal; cold heading only for small annealed parts due to high Cr-Mn work hardening.
What is the maximum service temperature of 25KhGT?
25KhGT is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 25KhGT-A and 25KhGT-QT200?
A is the default condition — standard delivery condition of gear-steel bar: softest, best machinability before carburizing. QT200: maximum through-hardened strength for small, non-carburized highly loaded parts (pins, splines). Yield strength is 400 MPa in A versus 1,220 MPa in QT200.
How much does 25KhGT cost?
25KhGT 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 — Alloyed structural steel bars — Gosstandart (2016)
- GB/T 3077 (25CrMnTi) — SAC (2015)
- Marochnik Stali — 25ХГТ steel grade data — Marochnik (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4A — Steel Heat Treating Fundamentals (carburizing) — ASM International (2013)
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.