Steel 15B48
EN 15B48 · UNS G15481
15B48 is a higher-carbon manganese-boron steel (UNS G15481) used where deeper hardenability and increased core strength are needed in cold-headed parts.
Reference datasheet — 15B48 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
15B48 tempers and conditions
15B48 is supplied in 10 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stocked condition: softest, most ductile structure for cold heading, upsetting and thread rolling before quench-and-temper. | 385 | 585 | 22 | 170 HB | — |
Hot rolled | Cheapest mill condition for parts that will be hot forged or fully re-heat-treated later. | 420 | 700 | 15 | 201 HB | — |
Normalized | Use to homogenize forgings and refine grain before final hardening or machining. | 450 | 760 | 18 | 17 HRC | 9.5 % IACS |
Cold drawn | Pick for straight, close-tolerance bar where moderate strength without heat treatment is enough. | 670 | 780 | 10 | 20 HRC | 9.5 % IACS |
quenched and tempered (~540 °C) | Toughest quench-and-temper level; used when impact loading or later machining matters more than peak strength. | 830 | 965 | 16 | 30 HRC | — |
quenched and tempered (~480 °C) | Balanced strength/toughness for grade 8-class cold-headed fasteners and shafting. | 1,050 | 1,170 | 13 | 36 HRC | — |
Induction hardened | Choose when only a wear-resistant surface layer is needed on a tough, previously Q&T or normalized core. | 1,250 | 1,550 | 6 | 55 HRC | 8.5 % IACS |
quenched and tempered (~400 °C) | High-strength condition for chain, socket screws and hand tools needing wear resistance with some ductility. | 1,280 | 1,400 | 10 | 43 HRC | — |
quenched and low tempered (~205 °C) | Maximum strength and wear resistance for track links, cutting edges and tools where toughness is secondary. | 1,500 | 1,720 | 7 | 50 HRC | — |
As-quenched, untempered | Intermediate state only — full martensitic hardness but brittle; must be tempered before service. | 1,650 | 2,050 | 2 | 57 HRC | 7.5 % IACS |
What is 15B48?
15B48 is a higher-carbon manganese-boron steel (UNS G15481) used where deeper hardenability and increased core strength are needed in cold-headed parts. Cold-heading quality spheroidized wire forms readily (formability 65), and the file covers hot-rolled, annealed, cold-drawn, normalized, as-quenched, induction-hardened and Q&T bands from 28–32 HRC to 48–52 HRC. The default condition gives 385 MPa yield, 585 MPa tensile, 22 % elongation and 170 HB (87 HRB), with service to 425 °C. Carbon equivalent near 0.7 makes welding impractical; 15B41 is the lower-carbon alternative. 15B48 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). 15B48 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 65% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
What is 15B48 used for?
- High-tensile bolts
- Automotive fasteners
- Cold-headed studs and pins
- Induction-hardened shafts
- Track and linkage components
- Hardened washers and sleeves
Advantages
- Forms and bends easily — 65/100, better than 81% of steel grades
- High electrical conductivity — 9.5 % IACS, better than 75% of steel grades
15B48 properties
Typical room-temperature values for 15B48-A; bars are the position among steel grades.
Physical3
15B48 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).
Mechanical13
15B48 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 65% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
15B48 is rated for continuous service to 425°C (797 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
15B48 conducts electricity at 9.5 % IACS, better than 75% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 15B48 takes about 27 MJ of energy and emits 2 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 30%.
Manufacturability7
15B48's machinability is good (55/100, better than 62% of steel grades); weldability fair (35/100); formability good (65/100).
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. 15B48 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 15B48
Is 15B48 easy to machine?
Machine in the spheroidize-annealed or ≤32 HRC condition with rigid setups and coated carbide; above 40 HRC expect grinding or CBN finishing only.
Can 15B48 be welded?
Poor weldability (Ceq ≈ 0.7): preheat 200–300 °C, low-hydrogen consumables and immediate post-weld temper, otherwise expect HAZ martensite cracking.
Can 15B48 be formed, bent or molded?
Excellent for cold heading/upsetting and thread rolling as CHQ spheroidized wire; hot forge 1100–1200 °C and normalize before hardening.
15B48 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 |
|---|---|---|
| Cboron-treated medium-carbon base | 0.44 – 0.53 | 0.48 |
| Mn | 1 – 1.3 | 1.15 |
| Sihot-rolled/CHQ deoxidation range | 0.15 – 0.35 | 0.25 |
| Bsoluble boron; Ti/Al used to tie up nitrogen | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.03 | |
| Smax; lower for CHQ wire | ≤ 0.05 | |
| Fe | balance |
What surface finishes work on 15B48?
Not anodizable — protect with zinc or zinc-nickel plate, zinc-flake, or phosphate-and-oil; bake within 4 h after plating on parts above ~1000 MPa to avoid hydrogen embrittlement.
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 15B48 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G15481
How much does 15B48 cost?
15B48 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.
15B48 — frequently asked
What is 15B48 used for?
15B48 is typically used for high-tensile bolts, automotive fasteners, cold-headed studs and pins, induction-hardened shafts, track and linkage components and hardened washers and sleeves. In short: deep-hardening CHQ wire; hardens to 48–52 HRC; effectively non-weldable.
What is the yield strength of 15B48?
15B48 has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 15B48 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the spheroidize-annealed or ≤32 HRC condition with rigid setups and coated carbide; above 40 HRC expect grinding or CBN finishing only.
Can 15B48 be welded?
With care — weldability is rated fair (35/100). Poor weldability (Ceq ≈ 0.7): preheat 200–300 °C, low-hydrogen consumables and immediate post-weld temper, otherwise expect HAZ martensite cracking.
What surface finishes work on 15B48?
Not anodizable — protect with zinc or zinc-nickel plate, zinc-flake, or phosphate-and-oil; bake within 4 h after plating on parts above ~1000 MPa to avoid hydrogen embrittlement.
Can 15B48 be formed, bent or molded?
Excellent for cold heading/upsetting and thread rolling as CHQ spheroidized wire; hot forge 1100–1200 °C and normalize before hardening.
What is the maximum service temperature of 15B48?
15B48 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 15B48-A and 15B48-Q?
A is the default condition — standard stocked condition: softest, most ductile structure for cold heading, upsetting and thread rolling before quench-and-temper. Q: intermediate state only — full martensitic hardness but brittle; must be tempered before service. Yield strength is 385 MPa in A versus 1,650 MPa in Q.
How much does 15B48 cost?
15B48 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 Alloy H Steels — SAE International (2019)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- ASTM A510/A510M — General Requirements for Wire Rods and Coarse Round Wire, Carbon Steel and Alloy Steel — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (boron steels, hardenability) — ASM International (1991)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- GB/T 6478 / GB/T 3077 — / (ML45MnB comparison) — SAC (2015)
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.