Steel 1552 QT-28-32HRC
Hardness band
AISI/SAE 1552 · UNS G15520
General-purpose quenched-and-tempered condition for shafts and highly stressed machined parts needing strength with usable toughness.
Values for the QT-28-32HRC condition
Other 1552 tempers and conditions
1552 is listed in 8 conditions; see the grade overview at 1552.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition — choose for heavy machining, cold forming or before re-hardening. | 365 | 635 | 22 | 187 HB | — |
HRDefault Hot rolled | Standard stock condition for heavy shafts and forging/heat-treat blanks where scale and loose tolerances are acceptable. | 415 | 725 | 15 | 207 HB | — |
Normalized | Uniform fine pearlitic structure for forgings — better toughness and consistency than as-rolled. | 440 | 760 | 18 | 217 HB | — |
Annealed and Cold Drawn | Pick for precision-tolerance bar with a bright finish and raised yield strength for shafting and machined parts. | 565 | 670 | 12 | 197 HB | — |
Induction hardened | Use when a hard wear surface (≥55 HRC) is needed on a tough Q&T or normalized core, e.g. journals and spline shafts. | 620 | 900 | 14 | 57 HRC | — |
Cold drawn | Highest as-supplied yield strength and best surface/tolerance in unheat-treated bar; residual stresses can cause bow when machined asymmetrically. | 635 | 745 | 10 | 217 HB | — |
QT-28-32HRCThis page oil quenched and tempered ~540–590 °C | General-purpose quenched-and-tempered condition for shafts and highly stressed machined parts needing strength with usable toughness. | 800 | 965 | 16 | 30 HRC | — |
oil quenched and tempered ~425–480 °C | High-strength/wear condition for spring-type, cam and heavy-duty shaft parts; toughness and machinability drop noticeably. | 1,105 | 1,275 | 11 | 40 HRC | — |
What is 1552 QT-28-32HRC?
1552 QT-28-32HRC is 1552 heat treated to QT-28-32HRC — general-purpose quenched-and-tempered condition for shafts and highly stressed machined parts needing strength with usable toughness. 1552 QT-28-32HRC has a yield strength of 800 MPa (116 ksi) and a tensile strength of 965 MPa (140 ksi) — stronger than 86% of steel grades. Elongation at break is 16% and the elastic modulus is 200 GPa (29 Msi). 1552 QT-28-32HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). HR is the default condition FabDigit quotes; QT-28-32HRC is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High strength — 800 MPa (116 ksi), better than 86% 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 — 10 % IACS, better than 83% of steel grades
Limitations
- Difficult to weld — 20/100, worse than 84% of steel grades
- Low fracture toughness — 65 MPa·√m (59.2 ksi·√in), worse than 75% of steel grades
1552 QT-28-32HRC properties
Typical room-temperature values for 1552 QT-28-32HRC; 15 are specific to this condition. Other listed values are 1552 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1552 QT-28-32HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
1552 QT-28-32HRC has a yield strength of 800 MPa (116 ksi) and a tensile strength of 965 MPa (140 ksi) — stronger than 86% of steel grades. Elongation at break is 16% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1552 QT-28-32HRC is rated for continuous service to 425°C (797 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
1552 QT-28-32HRC conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 1552 QT-28-32HRC takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
1552 QT-28-32HRC's machinability is fair (42/100, worse than 73% of steel grades); weldability poor (20/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1552 QT-28-32HRC
Is 1552 easy to machine?
Machines like 1050 at ~55 % of 1212; run annealed or ≤32 HRC, use rigid setups, carbide at 90–150 m/min with flood coolant.
Can 1552 be welded?
Poor weldability (CE ≈ 0.7–0.8) — preheat 200–320 °C, low-hydrogen consumables and immediate post-weld temper/slow cool to avoid HAZ cracking.
Can 1552 be formed, bent or molded?
Cold form only in the annealed condition with generous bend radii (≥2t); hot forge 1100–1200 °C and finish above 850 °C, then normalize.
What surface finishes work on 1552?
No inherent corrosion protection — oil, phosphate-and-oil, black oxide, zinc or hard chrome plating; grinds and polishes well when hardened.
1552 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 | 0.47 – 0.55 | 0.51 |
| Mnhigh-Mn 15xx series | 1.2 – 1.5 | 1.35 |
| P | ≤ 0.04 | 0.02 |
| Smax; not a resulfurized 11xx/12xx grade | ≤ 0.05 | 0.03 |
| Sitypical for killed bar; not specified for all product forms | 0.15 – 0.35 | 0.25 |
| Fe | balance | — |
1552 QT-28-32HRC — frequently asked
What is 1552 QT-28-32HRC used for?
1552 QT-28-32HRC is typically used for leaf and coil springs, heavy-duty shafts, wear plates and agricultural implement parts. In short: strongest free-machining carbon steel; machinability 52 vs 1212; wear-resistant when hardened.
What is the yield strength of 1552 QT-28-32HRC?
1552 QT-28-32HRC has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 965 MPa (140 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 1552 QT-28-32HRC easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machines like 1050 at ~55 % of 1212; run annealed or ≤32 HRC, use rigid setups, carbide at 90–150 m/min with flood coolant.
Can 1552 QT-28-32HRC be welded?
Not readily — weldability is rated poor (20/100). Poor weldability (CE ≈ 0.7–0.8) — preheat 200–320 °C, low-hydrogen consumables and immediate post-weld temper/slow cool to avoid HAZ cracking.
What surface finishes work on 1552 QT-28-32HRC?
No inherent corrosion protection — oil, phosphate-and-oil, black oxide, zinc or hard chrome plating; grinds and polishes well when hardened.
Can 1552 QT-28-32HRC be formed, bent or molded?
Cold form only in the annealed condition with generous bend radii (≥2t); hot forge 1100–1200 °C and finish above 850 °C, then normalize.
What is the maximum service temperature of 1552 QT-28-32HRC?
1552 QT-28-32HRC 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 1552-HR and 1552-CD?
HR is the default condition — standard stock condition for heavy shafts and forging/heat-treat blanks where scale and loose tolerances are acceptable. CD: highest as-supplied yield strength and best surface/tolerance in unheat-treated bar; residual stresses can cause bow when machined asymmetrically. Yield strength is 415 MPa in HR versus 635 MPa in CD.
Sources
- SAE J403 – Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A29/A29M – Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- ASTM A108 – Steel Bar, Carbon and Alloy, Cold-Finished — ASTM (2018)
- ASM Handbook Vol.1 – Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 – Heat Treating — ASM International (1991)
- ASM Handbook Vol.16 – Machining — ASM International (1989)
- GB/T 699 (50Mn/55Mn comparable grades) — SAC (2015)
- Mysteel / SMM carbon steel bar price references (2025)
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.