Steel 38B2
EN 38B2
38B2 (1.5515) is a medium-carbon boron steel from the EN 10083 family that delivers higher hardenability than plain carbon grades of similar cost.
Reference datasheet — 38B2 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 +AC+C condition
38B2 tempers and conditions
38B2 is supplied in 10 conditions, soft to hard. +AC+C 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 maximum cold-heading and thread-rolling ductility, and as the pre-condition before cold drawing. | 310 | 520 | 26 | 155 HB | — |
Annealed | General softening treatment for machining or light forming when full carbide spheroidizing is not required. | 330 | 560 | 23 | 165 HB | 8.8 % IACS |
Hot rolled | Mill-delivery hot-rolled coil before any softening; cheapest input for re-heating, forging or subsequent annealing. | 380 | 640 | 19 | 190 HB | 8.5 % IACS |
Normalized | Grain refinement after forging or hot forming, giving uniform ferrite-pearlite before hardening. | 400 | 660 | 19 | 195 HB | 8.5 % IACS |
+AC+CDefault Spheroidize annealed and cold drawn | The standard stocked cold-heading wire condition: sized, straight, lubricant-carrier coated and ready for multi-station header feeding. | 540 | 640 | 12 | 195 HB | — |
+QT | High-temperature temper (600–650 °C) for shafts, pins and machine parts where impact toughness matters more than strength. | 560 | 750 | 18 | 20 HRC | — |
Cold drawn | Sized cold-drawn bar/wire for machined parts and light upsetting where full spheroidized ductility is not needed. | 620 | 720 | 9 | 215 HB | 8.3 % IACS |
+QT | Standard fastener heat treatment for M5–M16 class 8.8 bolts and screws; good toughness with low plating-embrittlement risk. | 720 | 880 | 14 | 27 HRC | — |
+QT | High-strength fastener condition (lower tempering temperature); watch hydrogen embrittlement during electroplating — use zinc-flake coatings. | 990 | 1,100 | 11 | 35 HRC | — |
Hardened | As-quenched martensitic condition used to verify boron hardenability (Jominy) — must be tempered before service. | 1,400 | 1,900 | 3 | 54 HRC | — |
What is 38B2?
38B2 (1.5515) is a medium-carbon boron steel from the EN 10083 family that delivers higher hardenability than plain carbon grades of similar cost. It is supplied as cold-heading wire, bar and forging stock for quenched and tempered fasteners and shafts; the default condition on file gives about 540 MPa yield, 640 MPa tensile, 12 % elongation and 195 HB (92 HRB), with formability rated 70. Limits are a maximum service temperature around 250 °C, restricted weldability (score 40, CE ≈ 0.5–0.55) and no corrosion resistance without coating. Use 33B2 for lower strength classes or 41Cr4 where section sizes exceed boron hardenability. 38B2 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). 38B2 has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 70% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
What is 38B2 used for?
- high-strength bolts
- cold-headed parts
- shafts
Advantages
- Forms and bends easily — 70/100, better than 86% of steel grades
Limitations
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
38B2 properties
Typical room-temperature values for 38B2-+AC+C; bars are the position among steel grades.
Physical3
38B2 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical13
38B2 has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 70% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
38B2 is rated for continuous service to 250°C (482 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
38B2 conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 38B2 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
38B2's machinability is good (55/100, better than 62% of steel grades); weldability fair (40/100); formability very good (70/100).
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. 38B2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 38B2
Is 38B2 easy to machine?
Machine in +AC or +A condition (≈62–68 % of 1212); after Q&T above 32 HRC use coated carbide, rigid setups and reduced feeds — sulphur is low so chips are stringy.
Can 38B2 be welded?
CE ≈ 0.5–0.55: preheat 200–250 °C, use low-hydrogen consumables and temper after welding; boron aggravates HAZ hardening, so welding of hardened parts is not recommended.
Can 38B2 be formed, bent or molded?
Excellent multi-station cold heading and thread rolling in +AC/+AC+C with phosphate+soap or polymer carrier; hot forging 1100–1200 °C, austenitize 850–880 °C, oil or polymer quench, temper 400–650 °C to the target class.
38B2 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 | 0.36 – 0.42 | 0.39 |
| Silow Si preferred for cold heading | ≤ 0.3 | 0.15 |
| Mn | 0.5 – 0.8 | 0.65 |
| P | ≤ 0.03 | 0.02 |
| Sup to 0.035 in some Q&T bar specifications | ≤ 0.03 | 0.01 |
| Crresidual | ≤ 0.3 | 0.15 |
| Niresidual | ≤ 0.3 | 0.1 |
| Moresidual | ≤ 0.1 | 0.03 |
| Curesidual | ≤ 0.25 | 0.1 |
| Beffective (soluble) boron controls hardenability | 8×10⁻⁴ – 0.01 | 0 |
| Tiadded to fix nitrogen and protect boron | ≤ 0.05 | 0.03 |
| Algrain refining / N fixing | 0.02 – 0.06 | 0.03 |
| Fe | balance |
What surface finishes work on 38B2?
No natural corrosion resistance — zinc or zinc-nickel electroplate (bake 200 °C/4 h if ≥320 HV), zinc-flake (Dacromet/Geomet) for 10.9 parts, or phosphate + oil for as-headed blanks.
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 38B2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5515
How much does 38B2 cost?
38B2 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
38B2 — frequently asked
What is 38B2 used for?
38B2 is typically used for high-strength bolts, cold-headed parts and shafts. In short: higher strength than 33B2; boron-hardenable fastener steel; preheat before welding.
What is the yield strength of 38B2?
38B2 has a typical yield strength of 540 MPa (78.3 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 70% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 38B2 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in +AC or +A condition (≈62–68 % of 1212); after Q&T above 32 HRC use coated carbide, rigid setups and reduced feeds — sulphur is low so chips are stringy.
Can 38B2 be welded?
With care — weldability is rated fair (40/100). CE ≈ 0.5–0.55: preheat 200–250 °C, use low-hydrogen consumables and temper after welding; boron aggravates HAZ hardening, so welding of hardened parts is not recommended.
What surface finishes work on 38B2?
No natural corrosion resistance — zinc or zinc-nickel electroplate (bake 200 °C/4 h if ≥320 HV), zinc-flake (Dacromet/Geomet) for 10.9 parts, or phosphate + oil for as-headed blanks.
Can 38B2 be formed, bent or molded?
Excellent multi-station cold heading and thread rolling in +AC/+AC+C with phosphate+soap or polymer carrier; hot forging 1100–1200 °C, austenitize 850–880 °C, oil or polymer quench, temper 400–650 °C to the target class.
What is the maximum service temperature of 38B2?
38B2 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 38B2 cost?
38B2 is a budget-cost steel ($), 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 10263-4 Steel rod, bars and wire for cold heading and cold extrusion — Part 4: Quench and tempered steels — CEN (2018)
- EN 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- ISO 898-1 Mechanical properties of fasteners made of carbon steel and alloy steel — ISO (2013)
- ASM Handbook Vol. 1: Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4: Heat Treating (boron hardenability) — ASM International (1991)
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.