Steel 50B46
EN 50B46 · UNS G50461
50B46 is a chromium-boron steel (UNS G50461) widely used for high-strength fasteners and springs that must through-harden.
Reference datasheet — 50B46 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the A condition
50B46 tempers and conditions
50B46 is supplied in 11 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize Annealed | Pick for cold-headed bolts and screws: softest, most ductile carbide morphology. | 390 | 620 | 25 | 174 HB | 8.5 % IACS |
ADefault Solution annealed | Standard stocked soft condition for machining, cold forming and subsequent quench-and-temper. | 420 | 700 | 20 | 197 HB | — |
Hot rolled | Cheapest mill condition for bar/coil that will be re-heat-treated by the fabricator. | 470 | 800 | 16 | 20 HRC | 8 % IACS |
Normalized | Use to homogenize grain structure after forging before final hardening; note boron steels air-harden more than plain carbon steels. | 560 | 900 | 15 | 26 HRC | 8 % IACS |
Cold drawn | Choose for close-tolerance, bright-finish bar going straight to machining without further heat treatment. | 700 | 830 | 12 | 23 HRC | 8 % IACS |
Q&T 650 °C | Toughest quenched-and-tempered option (~950 MPa) where impact and machinability outrank strength. | 860 | 960 | 20 | 29 HRC | — |
Q&T 540 °C | General machined-component condition (~1150 MPa) with good ductility and impact. | 1,070 | 1,170 | 16 | 36 HRC | — |
Austempered | Use for thin springs, clips and tool blades where distortion and quench cracking must be minimized at high hardness. | 1,200 | 1,450 | 12 | 44 HRC | 7.5 % IACS |
Q&T 425 °C | Common bolt/spring balance of strength and toughness around 1400 MPa. | 1,310 | 1,430 | 13 | 44 HRC | — |
Q&T 315 °C | High-strength spring/tool condition; keep out of the 260–370 °C temper-embrittlement window if impact matters. | 1,520 | 1,720 | 10 | 50 HRC | — |
Q&T 205 °C | Maximum hardness and wear resistance for tillage tools and springs; very low toughness, avoid stress raisers. | 1,590 | 1,960 | 9 | 54 HRC | — |
What is 50B46?
50B46 is a chromium-boron steel (UNS G50461) widely used for high-strength fasteners and springs that must through-harden. Annealed material gives 420 MPa yield, 700 MPa tensile and 20 % elongation at 197 HB (92 HRB), and conditions on file cover hot-rolled, annealed, spheroidized, normalized, cold-drawn, QT205–QT650 tempers and an austempered state. Weldability is poor with a carbon equivalent of about 0.75, the steel has no inherent corrosion resistance so a coating must be specified, and machinability is 55. 50B44 is the nearest slightly lower-carbon alternative. 50B46 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). 50B46 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 20% and the elastic modulus is 205 GPa (29.7 Msi).
What is 50B46 used for?
- fasteners
- springs
- clutch parts
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
50B46 properties
Typical room-temperature values for 50B46-A; bars are the position among steel grades.
Physical3
50B46 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
50B46 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 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
50B46 is rated for continuous service to 350°C (662 °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 µm/m·K (6.67 µin/in·°F).
Electrical3
50B46 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 50B46 takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 25%.
Manufacturability8
50B46's machinability is good (55/100, better than 62% of steel grades); weldability poor (30/100); formability fair (50/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 50B46 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 50B46
Is 50B46 easy to machine?
Machine in the annealed or spheroidized condition (~60 % of 1212); above 40 HRC switch to carbide/CBN, rigid setups and low feeds, or grind.
Can 50B46 be welded?
Poor weldability — carbon equivalent ≈0.75; if unavoidable use low-hydrogen consumables, 250–350 °C preheat, controlled interpass and immediate post-weld temper.
Can 50B46 be formed, bent or molded?
Cold-head and cold-form only in spheroidize-annealed wire; hot forge 1100–1200 °C and normalize afterwards, then oil quench from 830–860 °C and temper to the target hardness.
50B46 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 | 0.44 – 0.49 | 0.46 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.15 – 0.35 | 0.25 |
| CrSAE 50B46 chromium range (some sources/orders to 0.40–0.60 for 5046-type) | 0.2 – 0.35 | 0.28 |
| Bboron addition for hardenability; effective B requires Ti/Al N-fixing | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.04 | |
| S | ≤ 0.04 | |
| Fe | balance |
What surface finishes work on 50B46?
No inherent corrosion resistance — specify zinc, zinc-nickel or Zn-flake coating, phosphate+oil or black oxide; bake plated parts ≥190 °C/4 h to relieve hydrogen when above ~1000 MPa.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 50B46 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G50461
How much does 50B46 cost?
50B46 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
50B46 — frequently asked
What is 50B46 used for?
50B46 is typically used for fasteners, springs and clutch parts. In short: through-hardening fastener steel; cheaper than 5146 equivalents; coating required for corrosion.
What is the yield strength of 50B46?
50B46 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 11 listed tempers.
Is 50B46 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the annealed or spheroidized condition (~60 % of 1212); above 40 HRC switch to carbide/CBN, rigid setups and low feeds, or grind.
Can 50B46 be welded?
Not readily — weldability is rated poor (30/100). Poor weldability — carbon equivalent ≈0.75; if unavoidable use low-hydrogen consumables, 250–350 °C preheat, controlled interpass and immediate post-weld temper.
What surface finishes work on 50B46?
No inherent corrosion resistance — specify zinc, zinc-nickel or Zn-flake coating, phosphate+oil or black oxide; bake plated parts ≥190 °C/4 h to relieve hydrogen when above ~1000 MPa.
Can 50B46 be formed, bent or molded?
Cold-head and cold-form only in spheroidize-annealed wire; hot forge 1100–1200 °C and normalize afterwards, then oil quench from 830–860 °C and temper to the target hardness.
What is the maximum service temperature of 50B46?
50B46 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 50B46-A and 50B46-QT205?
A is the default condition — standard stocked soft condition for machining, cold forming and subsequent quench-and-temper. QT205: maximum hardness and wear resistance for tillage tools and springs; very low toughness, avoid stress raisers. Yield strength is 420 MPa in A versus 1,590 MPa in QT205.
How much does 50B46 cost?
50B46 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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 — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- 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)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.