Steel 5135-HR (Hot rolled)
Supply condition
AISI/SAE 5135 · UNS G51350
Cheapest mill condition for parts that will be fully heat treated after machining.
Values for the HR condition
Other 5135 tempers and conditions
5135 is listed in 10 conditions; see the grade overview at 5135.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Softest, most machinable and most formable condition; standard stock for parts that will be Q&T later. | 300 | 570 | 28 | 165 HB | — |
HRThis page Hot rolled | Cheapest mill condition for parts that will be fully heat treated after machining. | 420 | 700 | 22 | 200 HB | — |
Normalized | Uniform fine-grain structure with moderate strength; good baseline for forgings and for parts not requiring Q&T. | 440 | 740 | 24 | 217 HB | — |
Cold drawn | Close tolerance, bright-finish bar with raised yield strength for shafts and studs used without further heat treatment. | 620 | 720 | 13 | 212 HB | — |
Q&T 650 °C | Softest tempered condition; choose when toughness and machinability outrank strength. | 720 | 850 | 22 | 24 HRC | — |
Q&T 540 °C | Choose oil quenched and tempered at 540 °C (≈30 HRC) for shafts, axles and connecting rods needing the classic strength/toughness balance of 830 MPa yield with 17% elongation. | 830 | 1,010 | 17 | 31 HRC | — |
Induction hardened | Selective surface hardening for journals, spline and gear teeth needing wear resistance over a tough core. | 830 | 1,010 | 15 | 55 HRC | 7.5 % IACS |
Q&T 425 °C | High-strength condition (≈38-40 HRC) for gears, spline shafts and high-tensile fasteners. | 1,120 | 1,240 | 15 | 39 HRC | — |
Q&T 315 °C | Very high strength for springs and highly stressed wear parts; ductility still low. | 1,360 | 1,500 | 12 | 45 HRC | — |
Q&T 205 °C | Maximum hardness and wear resistance; use only for lightly loaded, non-impact wear parts. | 1,450 | 1,660 | 10 | 49 HRC | — |
What is 5135-HR?
5135-HR is 5135 supplied in the HR condition — cheapest mill condition for parts that will be fully heat treated after machining. 5135-HR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi). 5135-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). A is the default condition FabDigit quotes; HR is available on request or by drawing note.
5135-HR properties
Typical room-temperature values for 5135-HR; 11 are specific to this condition. Other listed values are 5135 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
5135-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).
Mechanical14
5135-HR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
5135-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 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
5135-HR conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 5135-HR takes about 27 MJ of energy and emits 2.1 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 30%.
Manufacturability7
5135-HR's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (48/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 5135-HR
Is 5135 easy to machine?
Machine in the annealed or ≤32 HRC condition with carbide tooling and rigid setups; expect ~60 % of 1212 speed and grind rather than turn above 45 HRC.
Can 5135 be welded?
Weldable with low-hydrogen consumables but needs 200–320 °C preheat, controlled interpass and immediate stress-relief/temper to avoid martensitic HAZ cracking; weld before hardening where possible.
Can 5135 be formed, bent or molded?
Cold form only in the annealed/spheroidized state with generous bend radii; hot forge 1100–1200 °C, finish above 850 °C and slow-cool or normalize afterwards.
What surface finishes work on 5135?
No anodizing — protect by zinc or hard-chrome plating, phosphate + oil, black oxide or paint; nitriding and induction hardening give excellent wear surfaces.
5135 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 5135 / GB 35Cr | 0.33 – 0.38 | 0.35 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.6 – 0.8 | 0.7 |
| CrGB 35Cr: 0.80–1.10 | 0.8 – 1.05 | 0.95 |
| P | ≤ 0.04 | — |
| Smax; 0.015–0.035 for resulfurized variants | ≤ 0.04 | — |
| Niresidual (GB/T 3077) | ≤ 0.3 | — |
| Curesidual | ≤ 0.25 | — |
| Fe | balance | — |
5135-HR — frequently asked
What is 5135-HR used for?
5135-HR is typically used for gears, shafts, connecting rods, structural forgings and springs. In short: higher-carbon 51xx workhorse; good hardenability and wear; nitriding-friendly chromium steel.
What is the yield strength of 5135-HR?
5135-HR has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 5135-HR easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in the annealed or ≤32 HRC condition with carbide tooling and rigid setups; expect ~60 % of 1212 speed and grind rather than turn above 45 HRC.
Can 5135-HR be welded?
With care — weldability is rated fair (48/100). Weldable with low-hydrogen consumables but needs 200–320 °C preheat, controlled interpass and immediate stress-relief/temper to avoid martensitic HAZ cracking; weld before hardening where possible.
What surface finishes work on 5135-HR?
No anodizing — protect by zinc or hard-chrome plating, phosphate + oil, black oxide or paint; nitriding and induction hardening give excellent wear surfaces.
Can 5135-HR be formed, bent or molded?
Cold form only in the annealed/spheroidized state with generous bend radii; hot forge 1100–1200 °C, finish above 850 °C and slow-cool or normalize afterwards.
What is the maximum service temperature of 5135-HR?
5135-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 5135-A and 5135-QT205?
A is the default condition — softest, most machinable and most formable condition; standard stock for parts that will be Q&T later. QT205: maximum hardness and wear resistance; use only for lightly loaded, non-impact wear parts. Yield strength is 300 MPa in A versus 1,450 MPa in QT205.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — SAE International (2019)
- GB/T 3077 (35Cr) — SAC/ (2015)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4A — Steel Heat Treating Fundamentals and Processes — ASM International (2013)
- 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.