Steel 4028-QT205
Heat-treated state
AISI/SAE 4028 · UNS G40280
Maximum strength/wear condition for small machined parts where impact loading is low.
Values for the QT205 condition
Other 4028 tempers and conditions
4028 is listed in 10 conditions; see the grade overview at 4028.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest, most uniform condition — pick it for heavy cold forming, deep drilling/broaching or before final quench-and-temper. | 315 | 500 | 30 | 149 HB | — |
Hot rolled | Lowest-cost mill condition for parts that will be fully machined or subsequently heat treated. | 330 | 550 | 25 | 163 HB | — |
Normalized | Refines grain and homogenizes hot-worked bar or forgings before machining or hardening; better toughness than as-rolled. | 415 | 620 | 25 | 179 HB | — |
Induction hardened | Selective surface hardening of journals and gear teeth; 0.28 % C limits case hardness to about 50 HRC. | 450 | 620 | 10 | 48 HRC | 7.5 % IACS |
Cold drawn, stress relieved | Choose when cold-drawn bar must stay straight after asymmetric machining or hard turning. | 470 | 565 | 18 | 174 HB | 8 % IACS |
quenched and tempered at 650 °C (≈190 HB) | Softest hardened condition — used where machining after heat treatment and maximum ductility are needed. | 490 | 650 | 25 | 192 HB | — |
CDDefault Cold drawn | Standard stock condition for screw-machine work: tight tolerance, bright surface, higher yield and excellent chip control. | 505 | 585 | 16 | 179 HB | — |
quenched and tempered at 540 °C (≈20 HRC) | General-purpose quenched-and-tempered condition with the best toughness-to-strength compromise for this grade. | 570 | 745 | 20 | 19 HRC | — |
quenched and tempered at 425 °C (≈25 HRC) | Balanced strength/ductility for shafts and couplings machined from bar after heat treatment. | 650 | 850 | 16 | 25 HRC | — |
QT205This page quenched and tempered at 205 °C (≈30 HRC) | Maximum strength/wear condition for small machined parts where impact loading is low. | 745 | 1,000 | 12 | 31 HRC | — |
What is 4028-QT205?
4028-QT205 is 4028 heat treated to QT205 — maximum strength/wear condition for small machined parts where impact loading is low. 4028-QT205 has a yield strength of 745 MPa (108 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 83% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 4028-QT205 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). CD is the default condition FabDigit quotes; QT205 is available on request or by drawing note.
Advantages
- High strength — 745 MPa (108 ksi), better than 83% of steel grades
Limitations
- Limited service temperature — 175°C (347 °F), worse than 99% of steel grades
- Limited formability — 10/100, worse than 95% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
4028-QT205 properties
Typical room-temperature values for 4028-QT205; 14 are specific to this condition. Other listed values are 4028 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4028-QT205 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).
Mechanical15
4028-QT205 has a yield strength of 745 MPa (108 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 83% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4028-QT205 is rated for continuous service to 175°C (347 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
4028-QT205 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 4028-QT205 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 35%.
Manufacturability8
4028-QT205's machinability is fair (42/100, worse than 73% of steel grades); weldability poor (30/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4028-QT205
Is 4028 easy to machine?
Excellent for a moly alloy steel — MnS inclusions give short chips and ~75 % of AISI 1212; run carbide at 120–200 m/min in the cold-drawn or annealed state, avoid very low feeds that smear the sulfides.
Can 4028 be welded?
Poor: sulfur promotes hot cracking and the 0.28 C + Mo raises hardenability — avoid welding if possible, otherwise preheat 200–260 °C, use low-hydrogen consumables and post-weld temper.
Can 4028 be formed, bent or molded?
Only light cold forming (knurling, thread rolling, mild bending) — sulfide stringers give poor transverse ductility; hot forge 1150–1200 °C, finish above 900 °C, then normalize or anneal.
What surface finishes work on 4028?
No corrosion resistance in bare form: use zinc or zinc-nickel plating, black oxide, manganese phosphate + oil, or QPQ/nitrocarburizing; polishing is limited by sulfide pull-out.
4028 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 J404 | 0.25 – 0.3 | 0.28 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Mo | 0.2 – 0.3 | 0.25 |
| Sintentional resulfurizing addition — the 4027/4028 difference | 0.04 – 0.05 | 0.04 |
| P | ≤ 0.04 | — |
| Fe | balance | — |
4028-QT205 — frequently asked
What is 4028-QT205 used for?
4028-QT205 is typically used for bolts, fasteners and machined shafts. In short: free-machining 4027 variant; through-hardenable screw stock; poor welding, high machinability.
What is the yield strength of 4028-QT205?
4028-QT205 has a typical yield strength of 745 MPa (108 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 83% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 4028-QT205 easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Excellent for a moly alloy steel — MnS inclusions give short chips and ~75 % of AISI 1212; run carbide at 120–200 m/min in the cold-drawn or annealed state, avoid very low feeds that smear the sulfides.
Can 4028-QT205 be welded?
Not readily — weldability is rated poor (30/100). Poor: sulfur promotes hot cracking and the 0.28 C + Mo raises hardenability — avoid welding if possible, otherwise preheat 200–260 °C, use low-hydrogen consumables and post-weld temper.
What surface finishes work on 4028-QT205?
No corrosion resistance in bare form: use zinc or zinc-nickel plating, black oxide, manganese phosphate + oil, or QPQ/nitrocarburizing; polishing is limited by sulfide pull-out.
Can 4028-QT205 be formed, bent or molded?
Only light cold forming (knurling, thread rolling, mild bending) — sulfide stringers give poor transverse ductility; hot forge 1150–1200 °C, finish above 900 °C, then normalize or anneal.
What is the maximum service temperature of 4028-QT205?
4028-QT205 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 4028-CD and 4028-QT205?
CD is the default condition — standard stock condition for screw-machine work: tight tolerance, bright surface, higher yield and excellent chip control. QT205: maximum strength/wear condition for small machined parts where impact loading is low. Yield strength is 505 MPa in CD versus 745 MPa in QT205.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- ASTM A331 — Steel Bars, 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)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — SAE International (2019)
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.