Steel 8637-HR (Hot rolled)
Supply condition
AISI/SAE 8637 · UNS G86370
Cheapest stock form for parts that will be heat treated by the user after rough machining.
Values for the HR condition
Other 8637 tempers and conditions
8637 is listed in 13 conditions; see the grade overview at 8637.
Compare all 13 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. | 400 | 660 | 22 | 187 HB | — |
HRThis page Hot rolled | Cheapest stock form for parts that will be heat treated by the user after rough machining. | 470 | 760 | 20 | 217 HB | — |
Normalized | Uniform fine-grain structure with moderate strength; used as a pre-machining or as-supplied forging condition. | 620 | 900 | 20 | 26 HRC | — |
Cold drawn | Bright, size-accurate bar with raised yield strength for shafting that will not be re-heat-treated. | 650 | 760 | 14 | 223 HB | — |
Q&T 650 °C | Highest toughness/ductility temper for impact-loaded or low-temperature service. | 720 | 820 | 23 | 23 HRC | — |
QT28-32HRCDefault quenched and tempered to 28–32 HRC | Most commonly stocked/ordered condition: tough machinable bar for shafts, gears and hydraulic bodies. | 860 | 965 | 19 | 30 HRC | — |
Q&T 540 °C | Standard machinery temper: tough, ~30 HRC, good fatigue life for shafts and connecting rods. | 860 | 965 | 20 | 30 HRC | — |
Induction hardened | Pick when a tough ~30 HRC core with a hard 55–58 HRC wear surface is needed on journals or splines. | 860 | 965 | 15 | 56 HRC | 7 % IACS |
quenched and tempered to 32–36 HRC | Higher-strength machinery band for gear blanks and heavily loaded pins where some machining remains. | 1,000 | 1,105 | 17 | 34 HRC | — |
Q&T 425 °C | Good strength/toughness compromise for heavily loaded gears and shafts. | 1,105 | 1,210 | 17 | 38 HRC | — |
quenched and tempered to 38–42 HRC | High-hardness through-hardened band for wear-critical shafts and tooling components; machining is difficult. | 1,180 | 1,310 | 14 | 40 HRC | — |
Q&T 315 °C | Very high strength for springs and highly stressed fasteners; still limited ductility. | 1,345 | 1,480 | 13 | 45 HRC | — |
Q&T 205 °C | Maximum hardness and wear resistance, low toughness — for wear surfaces, not shock-loaded parts. | 1,600 | 1,795 | 11 | 52 HRC | — |
What is 8637-HR?
8637-HR is 8637 supplied in the HR condition — cheapest stock form for parts that will be heat treated by the user after rough machining. 8637-HR has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 57% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi). 8637-HR 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). QT28-32HRC is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
8637-HR properties
Typical room-temperature values for 8637-HR; 11 are specific to this condition. Other listed values are 8637 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
8637-HR 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
8637-HR has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 57% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8637-HR is rated for continuous service to 400°C (752 °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
8637-HR conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 8637-HR takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 35%.
Manufacturability7
8637-HR's machinability is fair (52/100, better than 52% of steel grades); weldability fair (35/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8637-HR
Is 8637 easy to machine?
Machine at ≤32 HRC with rigid setups, carbide inserts and generous coolant; finish-grind after hardening for tight tolerances.
Can 8637 be welded?
Weldable only with care — preheat 200–300 °C, low-hydrogen consumables, and immediate post-weld temper below the part's tempering temperature.
Can 8637 be formed, bent or molded?
Hot forge 1100–1200 °C then normalize; cold forming limited to annealed/spheroidized bar with generous bend radii.
What surface finishes work on 8637?
No anodizing (ferrous): use black oxide, manganese phosphate, zinc or hard-chrome plating with 190 °C hydrogen bake-out above ~1000 MPa strength.
8637 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 |
|---|---|---|
| CSAE J404 heat analysis | 0.35 – 0.4 | 0.38 |
| Mn | 0.75 – 1 | 0.88 |
| 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 | 0.02 |
| Smax; H-grade/resulfurized variants differ | ≤ 0.04 | 0.02 |
| Fe | balance | — |
8637-HR — frequently asked
What is 8637-HR used for?
8637-HR is typically used for heavy-duty shafts, gears, axles and high-strength fasteners. In short: through-hardening 86xx grade; higher strength than 8630; 400 °C service limit.
What is the yield strength of 8637-HR?
8637-HR has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 57% of steel grades. Strength varies by condition: see the 13 listed tempers.
Is 8637-HR easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machine at ≤32 HRC with rigid setups, carbide inserts and generous coolant; finish-grind after hardening for tight tolerances.
Can 8637-HR be welded?
With care — weldability is rated fair (35/100). Weldable only with care — preheat 200–300 °C, low-hydrogen consumables, and immediate post-weld temper below the part's tempering temperature.
What surface finishes work on 8637-HR?
No anodizing (ferrous): use black oxide, manganese phosphate, zinc or hard-chrome plating with 190 °C hydrogen bake-out above ~1000 MPa strength.
Can 8637-HR be formed, bent or molded?
Hot forge 1100–1200 °C then normalize; cold forming limited to annealed/spheroidized bar with generous bend radii.
What is the maximum service temperature of 8637-HR?
8637-HR 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 8637 QT28-32HRC and 8637-QT205?
QT28-32HRC is the default condition — most commonly stocked/ordered condition: tough machinable bar for shafts, gears and hydraulic bodies. QT205: maximum hardness and wear resistance, low toughness — for wear surfaces, not shock-loaded parts. Yield strength is 860 MPa in QT28-32HRC versus 1,600 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)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — SAE International (2019)
- 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)
- Machinery's Handbook, 31st ed. — Industrial Press (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.