Steel 25L-QT (Quenched and tempered)
Heat-treated state
GOST 25L
Pick for the highest strength and impact toughness of this grade in thinner sections; hardenability is limited by the low carbon and lack of alloying.
Values for the QT condition
Other 25L tempers and conditions
25L is listed in 6 conditions; see the grade overview at 25L.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
no heat treatment | Cheapest condition for lightly loaded, non-critical parts where coarse as-cast grain and residual stresses are acceptable. | 220 | 430 | 15 | 135 HB | 10 % IACS |
Annealed | Choose for maximum machinability, minimum residual stress and best dimensional stability before finish machining. | 225 | 440 | 23 | 130 HB | — |
Stress relieved | Used after weld repair or heavy machining to remove residual stress without altering the as-cast/normalized microstructure. | 235 | 450 | 20 | 138 HB | 10 % IACS |
N+TDefault Normalized and tempered | Default supply condition per GOST 977-88: refined grain plus stress relief, best all-round toughness/weld-repair behaviour. | 250 | 470 | 21 | 145 HB | — |
Normalized | Standard grain-refining treatment when slightly higher strength than annealed is wanted and stress relief is not critical. | 255 | 470 | 20 | 150 HB | — |
QTThis page Quenched and tempered | Pick for the highest strength and impact toughness of this grade in thinner sections; hardenability is limited by the low carbon and lack of alloying. | 360 | 580 | 17 | 185 HB | — |
What is 25L-QT?
25L-QT is 25L heat treated to QT — pick for the highest strength and impact toughness of this grade in thinner sections; hardenability is limited by the low carbon and lack of alloying. 25L-QT has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 580 MPa (84.1 ksi) — weaker than 72% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi). 25L-QT has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,460°C (2,660 °F). N+T is the default condition FabDigit quotes; QT is available on request or by drawing note.
Advantages
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Readily welded — 85/100, better than 83% of steel grades
25L-QT properties
Typical room-temperature values for 25L-QT; 10 are specific to this condition. Other listed values are 25L reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
25L-QT has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical15
25L-QT has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 580 MPa (84.1 ksi) — weaker than 72% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
25L-QT is rated for continuous service to 425°C (797 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
25L-QT conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 25L-QT takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 80%.
Manufacturability8
25L-QT's machinability is fair (52/100, better than 52% of steel grades); weldability excellent (85/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 25L-QT
Is 25L easy to machine?
Machines like normalized 1025/1030 steel at ~68 % of AISI 1212; use rigid setups and carbide tooling, watch for hard sand-burn skin and occasional shrinkage porosity on first cut.
Can 25L be welded?
Excellent weldability (CE ≈ 0.45): SMAW/GMAW with low-hydrogen E7018-class consumables, preheat 100–150 °C for sections over ~30 mm, PWHT 600–650 °C after major repair.
Can 25L be formed, bent or molded?
Sand or shell cast with generous risering — solidification shrinkage ~2 % and a wide freezing range make heavy sections prone to centreline porosity; normalize after casting to refine dendritic grain.
What surface finishes work on 25L?
Shot blast to remove scale, then paint, zinc-rich primer, hot-dip galvanize or phosphate; hard chrome or nitriding can be applied to wear faces, no anodizing.
25L 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 – 0.3 | 0.25 |
| Si | 0.2 – 0.52 | 0.35 |
| Mn | 0.35 – 0.9 | 0.6 |
| Smax, depends on acceptance group | ≤ 0.05 | — |
| P | ≤ 0.04 | — |
| Crresidual | ≤ 0.3 | — |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.3 | — |
| Fe | balance | — |
25L-QT — frequently asked
What is 25L-QT used for?
25L-QT is typically used for machine housings, general structural castings and pipe fittings. In short: most weldable GOST cast steel; low CE, easy weld repair; moderate strength general grade.
What is the yield strength of 25L-QT?
25L-QT has a typical yield strength of 360 MPa (52.2 ksi) and a tensile strength of 580 MPa (84.1 ksi) — weaker than 72% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 25L-QT easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machines like normalized 1025/1030 steel at ~68 % of AISI 1212; use rigid setups and carbide tooling, watch for hard sand-burn skin and occasional shrinkage porosity on first cut.
Can 25L-QT be welded?
Yes — weldability is rated excellent (85/100). Excellent weldability (CE ≈ 0.45): SMAW/GMAW with low-hydrogen E7018-class consumables, preheat 100–150 °C for sections over ~30 mm, PWHT 600–650 °C after major repair.
What surface finishes work on 25L-QT?
Shot blast to remove scale, then paint, zinc-rich primer, hot-dip galvanize or phosphate; hard chrome or nitriding can be applied to wear faces, no anodizing.
Can 25L-QT be formed, bent or molded?
Sand or shell cast with generous risering — solidification shrinkage ~2 % and a wide freezing range make heavy sections prone to centreline porosity; normalize after casting to refine dendritic grain.
What is the maximum service temperature of 25L-QT?
25L-QT is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 25L N+T and 25L-QT?
N+T is the default condition — default supply condition per GOST 977-88: refined grain plus stress relief, best all-round toughness/weld-repair behaviour. QT: pick for the highest strength and impact toughness of this grade in thinner sections; hardenability is limited by the low carbon and lack of alloying. Yield strength is 250 MPa in N+T versus 360 MPa in QT.
Sources
- GOST 977-88 Steel castings — General specifications — Gosstandart (1988)
- ASTM A27/A27M Steel Castings, Carbon, for General Application — ASTM (2020)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Marochnik / Russian steel grade database — 25Л — Marochnik Stalei (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.