Steel 20B46-HR (Hot rolled)
Supply condition
EN 20B46 · UNS G20461
Standard mill delivery form for bar that will be machined and heat treated by the user.
Values for the HR condition
Other 20B46 tempers and conditions
20B46 is listed in 13 conditions; see the grade overview at 20B46.
Compare all 13 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition — pick for deep machining, cold heading or before a subsequent hardening cycle. | 375 | 620 | 25 | 179 HB | 48 W/m·K |
HRThis page Hot rolled | Standard mill delivery form for bar that will be machined and heat treated by the user. | 420 | 720 | 20 | 207 HB | — |
Normalized | Uniform fine-grain structure for consistent machining and predictable response to later quenching. | 470 | 760 | 20 | 217 HB | — |
Cold drawn | Choose for close size tolerance, bright finish and higher as-supplied yield on parts used without heat treatment. | 670 | 790 | 12 | 229 HB | — |
Q&T 22–26 HRC | Toughest Q&T band — for shock-loaded links and shafts where impact energy outranks strength. | 700 | 840 | 20 | 24 HRC | — |
Q&T 28–32 HRC | General machine-shaft band with a good strength/toughness balance and still easy to machine. | 830 | 970 | 18 | 30 HRC | — |
QT30-34Default Q&T 30–34 HRC | Most commonly stocked/ordered condition for boron-steel axles, shafts and tie rods. | 880 | 1,030 | 16 | 32 HRC | — |
Induction hardened | Use where a wear-resistant, compressively stressed skin is needed on a tough shaft (journals, splines, axle shafts). | 880 | 1,030 | 15 | 57 HRC | 7.5 % IACS |
Q&T 33–37 HRC | Higher-strength band for drive shafts and highly loaded links where machining is mostly finished. | 1,000 | 1,120 | 15 | 35 HRC | — |
Q&T 38–42 HRC | High-strength band for grade 8-class fasteners and wear-loaded pins; notch sensitivity rises noticeably. | 1,170 | 1,300 | 13 | 40 HRC | — |
Q&T 45–50 HRC | Wear-oriented low-temper band for plough shares, tines and cutting edges; low ductility, avoid impact-notched designs. | 1,400 | 1,580 | 10 | 48 HRC | — |
Hardened | Order the H version when the part is designed to a Jominy end-quench band rather than to as-delivered mechanical properties. | 1,500 | 1,900 | 8 | 55 HRC | 7.5 % IACS |
As-quenched | Intermediate process state only — maximum hardness but brittle; must be tempered before service. | 1,520 | 1,950 | 2 | 55 HRC | 7 % IACS |
What is 20B46-HR?
20B46-HR is 20B46 supplied in the HR condition — standard mill delivery form for bar that will be machined and heat treated by the user. 20B46-HR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 53% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi). 20B46-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). QT30-34 is the default condition FabDigit quotes; HR is available on request or by drawing note.
20B46-HR properties
Typical room-temperature values for 20B46-HR; 11 are specific to this condition. Other listed values are 20B46 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20B46-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
20B46-HR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 53% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
20B46-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
20B46-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 20B46-HR takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability6
20B46-HR's machinability is good (55/100, better than 62% of steel grades); weldability poor (30/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20B46-HR
Is 20B46 easy to machine?
Machine in the annealed/normalized or ≤32 HRC Q&T state with coated carbide, ~120–170 m/min; above 38 HRC switch to rigid setups, negative-rake carbide or CBN and expect much lower tool life.
Can 20B46 be welded?
Weldable only with care — CE ≈ 0.6–0.7 means 200–300 °C preheat, low-hydrogen consumables, controlled interpass and immediate stress relief/temper at 550–650 °C; the HAZ hardens fully because of the boron.
Can 20B46 be formed, bent or molded?
Hot forge at 1100–1200 °C and finish above 900 °C, then normalize; cold heading is practical only in the annealed spheroidized condition, and press-hardened stampings are quenched directly in the die.
What surface finishes work on 20B46?
Requires a coating — phosphate + oil, zinc or zinc-nickel plating, mechanical galvanizing or paint; bake at 200 °C within 4 h of electroplating parts above ~1000 MPa to avoid hydrogen embrittlement.
20B46 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 |
|---|---|---|
| Cmedium-carbon; sets attainable as-quenched hardness ~55 HRC | 0.44 – 0.49 | 0.46 |
| Mnsources differ slightly on the band; confirm against the mill certificate | 0.75 – 1 | 0.88 |
| Sideoxidation | 0.15 – 0.35 | 0.25 |
| P | ≤ 0.04 | — |
| Smax; resulphurised variants are ordered separately for machining | ≤ 0.04 | — |
| Beffective (acid-soluble) boron; requires Ti/Al to fix N | 5×10⁻⁴ – 0 | 0 |
| Fe | balance | — |
20B46-HR — frequently asked
What is 20B46-HR used for?
20B46-HR is typically used for axle shafts, structural bolts and gears. In short: cr-Mo hardenability, less alloy; boron-hardened shaft steel; Q&T to 50 HRC.
What is the yield strength of 20B46-HR?
20B46-HR has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 13 listed tempers.
Is 20B46-HR easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the annealed/normalized or ≤32 HRC Q&T state with coated carbide, ~120–170 m/min; above 38 HRC switch to rigid setups, negative-rake carbide or CBN and expect much lower tool life.
Can 20B46-HR be welded?
Not readily — weldability is rated poor (30/100). Weldable only with care — CE ≈ 0.6–0.7 means 200–300 °C preheat, low-hydrogen consumables, controlled interpass and immediate stress relief/temper at 550–650 °C; the HAZ hardens fully because of the boron.
What surface finishes work on 20B46-HR?
Requires a coating — phosphate + oil, zinc or zinc-nickel plating, mechanical galvanizing or paint; bake at 200 °C within 4 h of electroplating parts above ~1000 MPa to avoid hydrogen embrittlement.
Can 20B46-HR be formed, bent or molded?
Hot forge at 1100–1200 °C and finish above 900 °C, then normalize; cold heading is practical only in the annealed spheroidized condition, and press-hardened stampings are quenched directly in the die.
What is the maximum service temperature of 20B46-HR?
20B46-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 20B46 QT30-34 and 20B46-AQ?
QT30-34 is the default condition — most commonly stocked/ordered condition for boron-steel axles, shafts and tie rods. AQ: intermediate process state only — maximum hardness but brittle; must be tempered before service. Yield strength is 880 MPa in QT30-34 versus 1,520 MPa in AQ.
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)
- ASTM A29/A29M — General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM International (2020)
- ASTM A370 / E140 — Mechanical Testing and Hardness Conversions for Steel — ASTM International (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (boron hardenability, tempering response) — ASM International (1991)
- Machinery's Handbook (machinability ratings, Q&T bar data) — Industrial Press (2020)
- UNS G20461 alloy record — SAE/ASTM Unified Numbering System (2017)
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.