Steel Fe-3Si HIP+MA
Heat-treated state
Closes residual LPBF porosity for fatigue-critical rotor parts while retaining the annealed magnetic state.
Values for the HIP+MA condition
Other Fe-3Si tempers and conditions
Fe-3Si is listed in 4 conditions; see the grade overview at Fe-3Si.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Magnetic anneal | Standard functional condition: grain growth plus C/N removal give minimum core loss and maximum permeability, at the cost of strength. | 330 | 450 | 12 | 180 HB | 24 W/m·K |
HIP+MAThis page hot isostatic pressed then magnetically annealed | Closes residual LPBF porosity for fatigue-critical rotor parts while retaining the annealed magnetic state. | 340 | 470 | 15 | 10 HRC | 3.8 % IACS |
Stress relieved | Removes build residual stress and limits distortion after wire-EDM removal, with modest magnetic improvement. | 400 | 500 | 6 | 18 HRC | 3.8 % IACS |
ABDefault As built (as printed) | Highest strength and hardness but high residual stress, fine cells and elevated core loss — use only for dimensional/mechanical trials. | 450 | 550 | 3 | 22 HRC | 21 W/m·K |
What is Fe-3Si HIP+MA?
Fe-3Si HIP+MA is Fe-3Si heat treated to HIP+MA — closes residual LPBF porosity for fatigue-critical rotor parts while retaining the annealed magnetic state. Fe-3Si HIP+MA has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 76% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi). Fe-3Si HIP+MA has a density of 7.68 g/cm³ (0.277 lb/in³), lighter than 96% of steel grades. It melts at 1,470°C (2,678 °F). AB is the default condition FabDigit quotes; HIP+MA is available on request or by drawing note.
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
Limitations
- Poor heat conductor — 26 W/m·K (15 BTU/hr·ft·°F), worse than 87% of steel grades
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 86% of steel grades
- Low electrical conductivity — 3.8 % IACS, worse than 84% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
Fe-3Si HIP+MA properties
Typical room-temperature values for Fe-3Si HIP+MA; 25 are specific to this condition. Other listed values are Fe-3Si reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Fe-3Si HIP+MA has a density of 7.68 g/cm³ (0.277 lb/in³), lighter than 96% of steel grades. It melts at 1,470°C (2,678 °F).
Mechanical16
Fe-3Si HIP+MA has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 76% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
Fe-3Si HIP+MA is rated for continuous service to 500°C (932 °F). It conducts heat at 26 W/m·K (15 BTU/hr·ft·°F), worse than 87% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
Fe-3Si HIP+MA conducts electricity at 3.8 % IACS, worse than 84% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of Fe-3Si HIP+MA takes about 35 MJ of energy and emits 2.4 kg of CO₂ — more than 87% of steel grades. Typical recycled content is 25%.
Manufacturability7
Fe-3Si HIP+MA's machinability is fair (48/100, worse than 57% of steel grades); weldability good (58/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Fe-3Si HIP+MA
Is Fe-3Si easy to machine?
Abrasive and burr-prone — use sharp coated carbide, positive rake, generous coolant and light finishing passes; wire-EDM is usual for separating printed cores from the plate.
Can Fe-3Si be welded?
Weldable by laser/TIG with low heat input, but HAZ grain growth and stress raise core loss and embrittle the joint — avoid weld beads across the magnetic circuit and re-anneal if possible.
Can Fe-3Si be formed, bent or molded?
Cold formability is poor above ~2.5% Si; punch/laser-cut thin laminations instead. LPBF prints well on a 200–500 °C heated plate with slow cooling to avoid solidification cracking.
What surface finishes work on Fe-3Si?
Bare Fe-3Si rusts quickly — apply phosphate/inorganic C-5 insulating coating, e-coat, varnish or epoxy impregnation; parts can be shot-peened or polished but any cold work must precede the final magnetic anneal.
Fe-3Si 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 |
|---|---|---|
| Siraises resistivity, lowers eddy-current loss | 2.5 – 3.5 | 3 |
| Ckept ultra-low; decarburised during magnetic anneal | ≤ 0.01 | 0.01 |
| Mn | ≤ 0.3 | 0.15 |
| Aloptional in NGO grades; deoxidation / added resistivity | ≤ 0.5 | 0.2 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.01 | 0 |
| N | ≤ 0.01 | 0 |
| OAM powder limit; higher O degrades magnetics | ≤ 0.05 | 0.02 |
| Fe | balance | — |
Fe-3Si HIP+MA — frequently asked
What is Fe-3Si HIP+MA used for?
Fe-3Si HIP+MA is typically used for AM motor cores/laminations, transformer components and magnetic actuators. In short: low-core-loss AM alloy; soft-magnetic motor core material; printable silicon steel.
What is the yield strength of Fe-3Si HIP+MA?
Fe-3Si HIP+MA has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is Fe-3Si HIP+MA easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Abrasive and burr-prone — use sharp coated carbide, positive rake, generous coolant and light finishing passes; wire-EDM is usual for separating printed cores from the plate.
Can Fe-3Si HIP+MA be welded?
Yes — weldability is rated good (58/100). Weldable by laser/TIG with low heat input, but HAZ grain growth and stress raise core loss and embrittle the joint — avoid weld beads across the magnetic circuit and re-anneal if possible.
What surface finishes work on Fe-3Si HIP+MA?
Bare Fe-3Si rusts quickly — apply phosphate/inorganic C-5 insulating coating, e-coat, varnish or epoxy impregnation; parts can be shot-peened or polished but any cold work must precede the final magnetic anneal.
Can Fe-3Si HIP+MA be formed, bent or molded?
Cold formability is poor above ~2.5% Si; punch/laser-cut thin laminations instead. LPBF prints well on a 200–500 °C heated plate with slow cooling to avoid solidification cracking.
What is the maximum service temperature of Fe-3Si HIP+MA?
Fe-3Si HIP+MA is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Fe-3Si-AB and Fe-3Si-MA?
AB is the default condition — highest strength and hardness but high residual stress, fine cells and elevated core loss — use only for dimensional/mechanical trials. MA: standard functional condition: grain growth plus C/N removal give minimum core loss and maximum permeability, at the cost of strength. Yield strength is 450 MPa in AB versus 330 MPa in MA.
Sources
- ASTM A876 — Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types — ASTM International (2018)
- ASTM A677 — Nonoriented Electrical Steel Fully Processed Types — ASTM International (2020)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Magnetically Soft Materials) — ASM International (1990)
- Ferromagnetism (Bozorth) — Fe-Si alloys — IEEE Press (1993)
- Gas-atomised soft magnetic Fe-Si powder for additive manufacturing — Höganäs / Sandvik Osprey (2023)
- Published LPBF Fe-3wt%Si mechanical and magnetic property studies — Additive Manufacturing / JMMM (2022)
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.