Steel 8MoB5-4
EN 8MoB5-4
8MoB5-4 (1.5450) is a low-carbon boron-molybdenum case-hardening steel from the EN 10084 family, supplied +A, +AC, +U, +N, +S, +FP, +TH, +C, CH+T or Q+T.
Reference datasheet — 8MoB5-4 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
8MoB5-4 tempers and conditions
8MoB5-4 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 |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for the most severe multi-station cold heading and thread rolling (lowest flow stress). | 230 | 390 | 34 | 125 HB | 8.6 % IACS |
+ADefault Annealed | Standard stock condition for cold-heading wire and rod before forming and case hardening. | 255 | 410 | 30 | 135 HB | — |
Treated to ferrite-pearlite structure and hardness range | Best for consistent automatic-lathe machining before carburizing. | 280 | 440 | 27 | 140 HB | 8.6 % IACS |
Treated for shearability | Delivery condition for bar that must be cold sheared into billets without cracking. | 290 | 450 | 26 | 150 HB | 8.6 % IACS |
Hot rolled | Mill as-rolled bar/rod for users who apply their own annealing or direct hot forming. | 300 | 470 | 25 | 150 HB | 8.6 % IACS |
Normalized | Grain refinement and uniform ferrite-pearlite before machining or carburizing. | 300 | 460 | 27 | 145 HB | 8.6 % IACS |
Treated to a specified hardness range | Bar supplied inside an agreed hardness band for stable machining and straightness. | 380 | 560 | 20 | 175 HB | 8.5 % IACS |
Cold drawn | Pick for close tolerance, bright finish and higher as-supplied strength before final heading or machining. | 470 | 560 | 12 | 175 HB | 8.5 % IACS |
Carburized, quenched and low-temperature tempered | Final service condition for case-hardened fasteners, pins and small gears needing a wear-resistant skin with a tough core. | 600 | 850 | 11 | 61 HRC | — |
Quenched and tempered | Used when only core strength is required (e.g. boron-hardened small fasteners without a hard case). | 620 | 780 | 14 | 24 HRC | 8.2 % IACS |
What is 8MoB5-4?
8MoB5-4 (1.5450) is a low-carbon boron-molybdenum case-hardening steel from the EN 10084 family, supplied +A, +AC, +U, +N, +S, +FP, +TH, +C, CH+T or Q+T. In the annealed default condition it gives 255 MPa yield, 410 MPa tensile, 30% elongation and 135 HB (75 HRB), with a formability score of 88/100 that suits cold-headed fasteners, pins and small carburized components in wire and bar. Boron and Mo raise HAZ hardenability despite the good base weldability (72/100), and the steel offers no corrosion resistance, so plating or phosphating is required. 15B2 is the lower-cost boron alternative where Mo hardenability is not needed. 8MoB5-4 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). 8MoB5-4 has a yield strength of 255 MPa (37 ksi) and a tensile strength of 410 MPa (59.5 ksi) — weaker than 93% of steel grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi).
What is 8MoB5-4 used for?
- fasteners
- pins
- small case-hardened parts
Advantages
- Forms and bends easily — 88/100, better than 98% of steel grades
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Readily welded — 72/100, better than 75% of steel grades
Limitations
- Low strength — 255 MPa (37 ksi), worse than 93% of steel grades
8MoB5-4 properties
Typical room-temperature values for 8MoB5-4-+A; bars are the position among steel grades.
Physical3
8MoB5-4 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
8MoB5-4 has a yield strength of 255 MPa (37 ksi) and a tensile strength of 410 MPa (59.5 ksi) — weaker than 93% of steel grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
8MoB5-4 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 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
8MoB5-4 conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 8MoB5-4 takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
8MoB5-4's machinability is good (55/100, better than 62% of steel grades); weldability very good (72/100); formability excellent (88/100).
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. 8MoB5-4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 8MoB5-4
Is 8MoB5-4 easy to machine?
Soft and somewhat gummy in the annealed state — use sharp positive-rake tools, high speed and generous coolant; machine before carburizing, since the 58–63 HRC case needs grinding.
Can 8MoB5-4 be welded?
Low carbon equivalent gives good weldability, but boron and Mo raise HAZ hardenability: use low hydrogen consumables, limit heat input and avoid welding after carburizing.
Can 8MoB5-4 be formed, bent or molded?
Excellent multi-station cold heading and thread rolling in +A/+AC condition; phosphate + soap or polymer lubricant coating on the wire is standard.
8MoB5-4 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 |
|---|---|---|
| Clow carbon for cold heading | 0.06 – 0.11 | 0.08 |
| Sikept low for cold formability | ≤ 0.3 | 0.15 |
| Mn | 0.3 – 0.7 | 0.5 |
| P | ≤ 0.03 | 0.02 |
| Smax (S-grades higher) | ≤ 0.03 | 0.01 |
| Mocore hardenability, temper-embrittlement resistance | 0.4 – 0.55 | 0.5 |
| Bhardenability booster; requires Ti/Al nitrogen fixing | 8×10⁻⁴ – 0.01 | 0 |
| Tiprotects effective boron by fixing N | 0.02 – 0.06 | 0.04 |
| Algrain refinement / deoxidation | 0.02 – 0.06 | 0.04 |
| Crresidual | ≤ 0.3 | 0.1 |
| Niresidual | ≤ 0.3 | 0.1 |
| Curesidual | ≤ 0.25 | 0.1 |
| Fe | balance |
What surface finishes work on 8MoB5-4?
No anodizing (ferrous); protect with zinc or zinc-nickel plating (bake to avoid hydrogen embrittlement on hardened parts), zinc-flake coatings, phosphating or black oxide plus oil.
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 8MoB5-4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5450
How much does 8MoB5-4 cost?
8MoB5-4 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
8MoB5-4 — frequently asked
What is 8MoB5-4 used for?
8MoB5-4 is typically used for fasteners, pins and small case-hardened parts. In short: excellent cold-heading formability; boron-Mo case-hardening grade; case to 58–63 HRC.
What is the yield strength of 8MoB5-4?
8MoB5-4 has a typical yield strength of 255 MPa (37 ksi) and a tensile strength of 410 MPa (59.5 ksi) — weaker than 93% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 8MoB5-4 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Soft and somewhat gummy in the annealed state — use sharp positive-rake tools, high speed and generous coolant; machine before carburizing, since the 58–63 HRC case needs grinding.
Can 8MoB5-4 be welded?
Yes — weldability is rated very good (72/100). Low carbon equivalent gives good weldability, but boron and Mo raise HAZ hardenability: use low hydrogen consumables, limit heat input and avoid welding after carburizing.
What surface finishes work on 8MoB5-4?
No anodizing (ferrous); protect with zinc or zinc-nickel plating (bake to avoid hydrogen embrittlement on hardened parts), zinc-flake coatings, phosphating or black oxide plus oil.
Can 8MoB5-4 be formed, bent or molded?
Excellent multi-station cold heading and thread rolling in +A/+AC condition; phosphate + soap or polymer lubricant coating on the wire is standard.
What is the maximum service temperature of 8MoB5-4?
8MoB5-4 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 8MoB5-4 cost?
8MoB5-4 is a budget-cost steel ($), 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
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN 10263-3/-4 — Steel rod, bars and wire for cold heading and cold extrusion — CEN (2017)
- EN 10027-2 — Numerical designation system (material number 1.5450) — CEN (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 (carburizing, boron hardenability) — ASM International (2013)
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.