Steel 15B30 · temper
Steel 15B30 Annealed
Properties of the Annealed condition, compared with the other 15B30 tempers.
Use when maximum cold formability, deep drawing or heavy machining precedes final hardening.
What is 15B30 Annealed?
15B30 Annealed is 15B30 in the Annealed temper — use when maximum cold formability, deep drawing or heavy machining precedes final hardening. 15B30 Annealed has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 80% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi). 15B30 Annealed 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). HR is the default condition FabDigit quotes; Annealed is available on request or by drawing note.
Advantages
- Easy to machine — 63/100, better than 92% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Forms and bends easily — 65/100, better than 81% of steel grades
Limitations
- Low strength — 320 MPa (46.4 ksi), worse than 80% of steel grades
15B30 Annealed properties
Typical room-temperature values for 15B30 Annealed — 12 properties are specific to this condition; the rest are grade-level values shared by every 15B30 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
15B30 Annealed 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
15B30 Annealed has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 80% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
15B30 Annealed is rated for continuous service to 400°C (752 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
15B30 Annealed conducts electricity at 9 % IACS, better than 70% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of 15B30 Annealed takes about 24 MJ of energy and emits 2 kg of CO₂ — less than 97% of steel grades. Typical recycled content is 30%.
Manufacturability7
15B30 Annealed's machinability is good (63/100, better than 92% of steel grades); weldability fair (50/100); formability good (65/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 15B30 tempers and conditions
15B30 is also supplied in 7 other conditions. The full side-by-side table is on the 15B30 overview.
- HRDefaultDefault stock condition for bar, coil and plate that will be formed/machined and then quench-and-tempered.380 MPa yield · 179 HB
- QT 45-50 HRCHighest practical hardness for this carbon level — wear plates, harrow discs, cutting edges where impact loads are modest.1,330 MPa yield · 48 HRC
- QT 38-42 HRCBalance of hardness and toughness typical of track links, tillage tools and grade-8 style fasteners.1,100 MPa yield · 40 HRC
- QT 28-32 HRCTough, moderately hard condition for shafts, links and structural parts needing impact resistance.800 MPa yield · 30 HRC
- CDChoose for straight, size-accurate bright bar with higher as-supplied yield strength for machined parts.630 MPa yield · 217 HB
- CRPick for tighter thickness tolerance and better surface on strip that is blanked then heat treated.580 MPa yield · 207 HB
- NormalizedPick to homogenize forged or hot-rolled structure and get uniform mid-range strength before final machining.390 MPa yield · 179 HB
- AnnealedUse when maximum cold formability, deep drawing or heavy machining precedes final hardening.320 MPa yield · 156 HB
Working with 15B30 Annealed
Is 15B30 easy to machine?
Machine in the annealed or hot-rolled state (~60% of AISI 1212); carbide tooling and rigid setups above 30 HRC, and expect rapid tool wear beyond 40 HRC.
Can 15B30 be welded?
Weldability is limited by high Mn plus boron — use low-hydrogen consumables, 150–250 °C preheat, controlled interpass and post-weld tempering to avoid HAZ martensite cracking.
Can 15B30 be formed, bent or molded?
Hot forge 1100–1200 °C; cold bending and roll forming are practical only in the annealed/spheroidized condition with generous bend radii, then quench and temper.
What surface finishes work on 15B30?
No natural corrosion protection — phosphate + oil, black oxide, paint/e-coat, zinc or Zn-Ni plating; bake after plating to relieve hydrogen embrittlement risk above 35 HRC.
15B30 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 | 0.28 – 0.33 | 0.3 |
| Mnhigh-Mn 15xx series | 1.2 – 1.5 | 1.35 |
| Sitypical killed-steel range (SAE J403 heat analysis) | 0.15 – 0.3 | 0.22 |
| P | ≤ 0.03 | — |
| S | ≤ 0.05 | — |
| Bboron addition for hardenability; requires Ti/Al N-control | 5×10⁻⁴ – 0 | 0 |
| Fe | balance | — |
15B30 Annealed — frequently asked
What is 15B30 Annealed used for?
15B30 Annealed is typically used for bolts, threaded fasteners and inserts. In short: hot-stamping boron steel.
What is the yield strength of 15B30 Annealed?
15B30 Annealed has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 80% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 15B30 Annealed easy to machine?
Reasonably — machinability is rated good (63/100, better than 92% of steel grades). Machine in the annealed or hot-rolled state (~60% of AISI 1212); carbide tooling and rigid setups above 30 HRC, and expect rapid tool wear beyond 40 HRC.
Can 15B30 Annealed be welded?
With care — weldability is rated fair (50/100). Weldability is limited by high Mn plus boron — use low-hydrogen consumables, 150–250 °C preheat, controlled interpass and post-weld tempering to avoid HAZ martensite cracking.
What surface finishes work on 15B30 Annealed?
No natural corrosion protection — phosphate + oil, black oxide, paint/e-coat, zinc or Zn-Ni plating; bake after plating to relieve hydrogen embrittlement risk above 35 HRC.
Can 15B30 Annealed be formed, bent or molded?
Hot forge 1100–1200 °C; cold bending and roll forming are practical only in the annealed/spheroidized condition with generous bend radii, then quench and temper.
What is the maximum service temperature of 15B30 Annealed?
15B30 Annealed 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 15B30-HR and 15B30-CD?
HR is the default condition — default stock condition for bar, coil and plate that will be formed/machined and then quench-and-tempered. CD: choose for straight, size-accurate bright bar with higher as-supplied yield strength for machined parts. Yield strength is 380 MPa in HR versus 630 MPa in CD.
Can FabDigit make parts in 15B30 Annealed?
Yes — 15B30 Annealed is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- SAE J404 / J1268 — Alloy & Hardenability of Boron Steels — SAE International (2019)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4: Heat Treating — ASM International (1991)
- ASM Handbook Vol. 16: Machining — ASM International (1989)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
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.