Steel 1151 QT-38
Hardness band
AISI/SAE 1151 · UNS G11510
QT-38 = q&T 35–40 HRC
Highest practical through-hardened strength for this grade where wear resistance outweighs toughness.
Values for the QT-38 condition
Other 1151 tempers and conditions
1151 is listed in 9 conditions; see the grade overview at 1151.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition — for cold heading, deep boring or where maximum dimensional stability before hardening is wanted. | 320 | 585 | 22 | 167 HB | 10 % IACS |
Hot rolled | Lowest-cost as-rolled bar for parts that will be fully machined or later heat treated. | 360 | 655 | 15 | 192 HB | — |
Normalized | Uniform fine pearlitic structure — used to refine grain after hot forging and before quench-and-temper. | 415 | 720 | 18 | 16 HRC | 9.8 % IACS |
Cold drawn, stress relieved | Choose when straightness must be held after heavy asymmetric machining or before induction hardening. | 585 | 720 | 12 | 15 HRC | 9.5 % IACS |
CDDefault Cold drawn | Standard stocked condition: close tolerance, bright surface, higher strength and best chip control for screw-machine work. | 640 | 745 | 10 | 217 HB | — |
Induction hardened | Pick when a hard wear surface (55+ HRC case) is needed over a tough, already machined cold-drawn core. | 640 | 745 | 8 | 57 HRC | 8.5 % IACS |
Q&T 22–26 HRC | Tough general-purpose heat-treated condition for shafts and pins that still need some machining after heat treat. | 690 | 830 | 18 | 24 HRC | — |
Q&T 28–32 HRC | Most common heat-treated hardness band for wear-resisting shafts, gear blanks and hydraulic parts. | 800 | 965 | 15 | 30 HRC | — |
QT-38This page Q&T 35–40 HRC | Highest practical through-hardened strength for this grade where wear resistance outweighs toughness. | 1,030 | 1,210 | 11 | 38 HRC | — |
What is 1151 QT-38?
1151 QT-38 is 1151 heat treated to QT-38 — highest practical through-hardened strength for this grade where wear resistance outweighs toughness. 1151 QT-38 has a yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,210 MPa (175 ksi) — stronger than 93% of steel grades. Elongation at break is 11% and the elastic modulus is 200 GPa (29 Msi). 1151 QT-38 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). CD is the default condition FabDigit quotes; QT-38 is available on request or by drawing note.
Advantages
- High strength — 1,030 MPa (149 ksi), better than 93% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
- High electrical conductivity — 9.5 % IACS, better than 75% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 86% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
1151 QT-38 properties
Typical room-temperature values for 1151 QT-38; 11 are specific to this condition. Other listed values are 1151 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1151 QT-38 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
1151 QT-38 has a yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,210 MPa (175 ksi) — stronger than 93% of steel grades. Elongation at break is 11% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1151 QT-38 is rated for continuous service to 400°C (752 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
1151 QT-38 conducts electricity at 9.5 % IACS, better than 75% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 1151 QT-38 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
1151 QT-38's machinability is fair (45/100, worse than 65% of steel grades); weldability not recommended (10/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1151 QT-38
Is 1151 easy to machine?
Excellent chip breaking on automatic screw machines; run 15–25 % slower than 1215 and use positive-rake carbide with good coolant since the higher carbon raises cutting forces.
Can 1151 be welded?
Not recommended — high sulfur plus ~0.5 % C gives hot cracking and hard martensitic HAZ; if unavoidable, preheat 200–300 °C, low-hydrogen consumables and post-weld temper.
Can 1151 be formed, bent or molded?
Cold formability is poor in the drawn condition (sulfide stringers split on tight bends); anneal or hot form above 900 °C, forge 1150–1230 °C.
What surface finishes work on 1151?
Rusts quickly — protect with oil, zinc/black-oxide/phosphate coating or hard chrome; nitriding and induction hardening are effective for wear surfaces, mirror polishing is limited by inclusions.
1151 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 |
|---|---|---|
| Cheat analysis, SAE J403 | 0.48 – 0.55 | 0.51 |
| Mn | 0.7 – 1 | 0.85 |
| P | ≤ 0.04 | 0.02 |
| Sresulfurized for free machining | 0.08 – 0.13 | 0.1 |
| Sinot specified for 11xx resulfurized grades unless agreed | — | — |
| Fe | balance | — |
1151 QT-38 — frequently asked
What is 1151 QT-38 used for?
1151 QT-38 is typically used for shafts, spindles and wear-resistant machined parts. In short: hardest free-cutting 11xx grade; wear surfaces after hardening; effectively non-weldable.
What is the yield strength of 1151 QT-38?
1151 QT-38 has a typical yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,210 MPa (175 ksi) — stronger than 93% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 1151 QT-38 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Excellent chip breaking on automatic screw machines; run 15–25 % slower than 1215 and use positive-rake carbide with good coolant since the higher carbon raises cutting forces.
Can 1151 QT-38 be welded?
Not readily — weldability is rated not recommended (10/100). Not recommended — high sulfur plus ~0.5 % C gives hot cracking and hard martensitic HAZ; if unavoidable, preheat 200–300 °C, low-hydrogen consumables and post-weld temper.
What surface finishes work on 1151 QT-38?
Rusts quickly — protect with oil, zinc/black-oxide/phosphate coating or hard chrome; nitriding and induction hardening are effective for wear surfaces, mirror polishing is limited by inclusions.
Can 1151 QT-38 be formed, bent or molded?
Cold formability is poor in the drawn condition (sulfide stringers split on tight bends); anneal or hot form above 900 °C, forge 1150–1230 °C.
What is the maximum service temperature of 1151 QT-38?
1151 QT-38 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 1151-CD and 1151 QT-38?
CD is the default condition — standard stocked condition: close tolerance, bright surface, higher strength and best chip control for screw-machine work. QT-38: highest practical through-hardened strength for this grade where wear resistance outweighs toughness. Yield strength is 640 MPa in CD versus 1,030 MPa in QT-38.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- SAE J1397 — Estimated Mechanical Properties and Machinability of Steel Bars — SAE International (2009)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM International (2020)
- ASTM A108 — Steel Bar, Carbon and Alloy, Cold-Finished — ASTM International (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
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.