Steel 8627-QT650
Heat-treated state
AISI/SAE 8627 · UNS G86270
QT650 = q&T 650 °C
Softest Q&T condition, maximum toughness and ductility for shock-loaded or later-machined parts.
Values for the QT650 condition
Other 8627 tempers and conditions
8627 is listed in 10 conditions; see the grade overview at 8627.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Softest and most machinable condition; standard supply state for bar that will be machined then carburized. | 380 | 560 | 30 | 156 HB | — |
Hot rolled | Cheapest mill condition for parts that will be fully heat treated after rough machining. | 400 | 640 | 24 | 185 HB | — |
Normalized | Uniform fine-grained structure with better core toughness and machined-surface finish before carburizing. | 430 | 690 | 25 | 195 HB | — |
Cold drawn | Tight-tolerance bright bar with raised yield strength for shafts and pins machined with light stock removal. | 620 | 720 | 15 | 217 HB | — |
QT650This page Q&T 650 °C | Softest Q&T condition, maximum toughness and ductility for shock-loaded or later-machined parts. | 635 | 795 | 23 | 22 HRC | — |
Carburized & hardened | Primary intended use: hard wear-resistant case (58–62 HRC) over a tough, higher-strength core than 8620. | 790 | 1,030 | 13 | 60 HRC | — |
Q&T 540 °C | Pick the oil quenched, 540 °C tempered state (~28–32 HRC) for machined shafts and tough cores, giving 830 MPa yield and 18% elongation with moderate machinability. | 830 | 965 | 18 | 30 HRC | — |
Q&T 425 °C | Balanced strength/toughness around 36–38 HRC for shafts and highly loaded fasteners. | 1,000 | 1,170 | 14 | 38 HRC | — |
Q&T 315 °C | High strength with slightly improved ductility; avoid this range if temper embrittlement/impact toughness matters. | 1,170 | 1,380 | 11 | 43 HRC | — |
Q&T 205 °C | Maximum through-hardened strength for wear parts where impact loading is low. | 1,240 | 1,500 | 10 | 46 HRC | — |
What is 8627-QT650?
8627-QT650 is 8627 heat treated to QT650 — softest Q&T condition, maximum toughness and ductility for shock-loaded or later-machined parts. 8627-QT650 has a yield strength of 635 MPa (92.1 ksi) and a tensile strength of 795 MPa (115 ksi) — stronger than 79% of steel grades. Elongation at break is 23% and the elastic modulus is 205 GPa (29.7 Msi). 8627-QT650 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). A is the default condition FabDigit quotes; QT650 is available on request or by drawing note.
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- High strength — 635 MPa (92.1 ksi), better than 79% of steel grades
8627-QT650 properties
Typical room-temperature values for 8627-QT650; 11 are specific to this condition. Other listed values are 8627 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
8627-QT650 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).
Mechanical13
8627-QT650 has a yield strength of 635 MPa (92.1 ksi) and a tensile strength of 795 MPa (115 ksi) — stronger than 79% of steel grades. Elongation at break is 23% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8627-QT650 is rated for continuous service to 500°C (932 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
8627-QT650 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 8627-QT650 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 35%.
Manufacturability7
8627-QT650's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (52/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8627-QT650
Is 8627 easy to machine?
Machines well annealed or normalized (~60–65 % of 1212) with carbide tooling; rough machine before carburizing and finish-grind the hardened case.
Can 8627 be welded?
Weldable with low-hydrogen consumables but the ~0.27 % C and Ni-Cr-Mo content require 200–300 °C preheat and post-weld stress relief/temper; do not weld after carburizing.
Can 8627 be formed, bent or molded?
Hot forge 1100–1200 °C with slow cooling or normalizing afterwards; cold forming limited to mild bending in the annealed condition.
What surface finishes work on 8627?
No anodizing — protect bare surfaces with black oxide, manganese phosphate, zinc or nickel plating; bake after plating to avoid hydrogen embrittlement when hardened.
8627 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 | 0.25 – 0.3 | 0.27 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 0.4 – 0.7 | 0.55 |
| Cr | 0.4 – 0.6 | 0.5 |
| Mo | 0.15 – 0.25 | 0.2 |
| P | ≤ 0.04 | — |
| Smax; H-grade/resulfurized variants differ | ≤ 0.04 | — |
| Fe | balance | — |
8627-QT650 — frequently asked
What is 8627-QT650 used for?
8627-QT650 is typically used for gears, shafts, axle components and heavy fasteners. In short: higher core strength carburizing; between 8625 and 8630; medium-section hardenability.
What is the yield strength of 8627-QT650?
8627-QT650 has a typical yield strength of 635 MPa (92.1 ksi) and a tensile strength of 795 MPa (115 ksi) — stronger than 79% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 8627-QT650 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machines well annealed or normalized (~60–65 % of 1212) with carbide tooling; rough machine before carburizing and finish-grind the hardened case.
Can 8627-QT650 be welded?
With care — weldability is rated fair (52/100). Weldable with low-hydrogen consumables but the ~0.27 % C and Ni-Cr-Mo content require 200–300 °C preheat and post-weld stress relief/temper; do not weld after carburizing.
What surface finishes work on 8627-QT650?
No anodizing — protect bare surfaces with black oxide, manganese phosphate, zinc or nickel plating; bake after plating to avoid hydrogen embrittlement when hardened.
Can 8627-QT650 be formed, bent or molded?
Hot forge 1100–1200 °C with slow cooling or normalizing afterwards; cold forming limited to mild bending in the annealed condition.
What is the maximum service temperature of 8627-QT650?
8627-QT650 is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 8627-A and 8627-QT205?
A is the default condition — softest and most machinable condition; standard supply state for bar that will be machined then carburized. QT205: maximum through-hardened strength for wear parts where impact loading is low. Yield strength is 380 MPa in A versus 1,240 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 — ASTM (2020)
- ASTM A322 — Steel Bars, Alloy, Standard Grades — ASTM (2020)
- 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.