Steel GE300 +NT (Normalized and tempered)
Heat-treated state
EN 1.0558
Pick when residual stresses must be low and toughness/dimensional stability slightly better than plain +N, e.g. machined housings and gear blanks.
Values for the +NT condition
Other GE300 tempers and conditions
GE300 is listed in 5 conditions; see the grade overview at GE300.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Interim condition ordered when heavy machining or straightening precedes final normalizing/QT; lowest strength, best chip formation. | 270 | 500 | 22 | 148 HB | 10.5 % IACS |
Spheroidize annealed | Only for non-critical, lightly loaded castings — coarse dendritic structure, scattered properties and low impact energy; does not meet EN 10293 acceptance values. | 290 | 540 | 12 | 170 HB | 10 % IACS |
+NDefault Normalized | Standard delivery condition for GE300 castings: uniform fine grain, meets the full 300 MPa proof / 27 J impact specification at moderate cost. | 330 | 570 | 18 | 175 HB | — |
+NTThis page Normalized and tempered | Pick when residual stresses must be low and toughness/dimensional stability slightly better than plain +N, e.g. machined housings and gear blanks. | 335 | 555 | 19 | 168 HB | — |
Quenched and tempered | Choose for the highest strength and toughness combination in thicker sections or for fatigue-loaded parts; restricted to hardenable wall thicknesses (≈ up to 100 mm). | 390 | 630 | 18 | 14 HRC | — |
What is GE300 +NT?
GE300 +NT is GE300 heat treated to +NT — pick when residual stresses must be low and toughness/dimensional stability slightly better than plain +N, e.g. machined housings and gear blanks. GE300 +NT has a yield strength of 335 MPa (48.6 ksi) and a tensile strength of 555 MPa (80.5 ksi) — weaker than 77% of steel grades. Elongation at break is 19% and the elastic modulus is 207 GPa (30 Msi). GE300 +NT 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). +N is the default condition FabDigit quotes; +NT is available on request or by drawing note.
Advantages
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
Limitations
- Limited formability — 15/100, worse than 87% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Low strength — 335 MPa (48.6 ksi), worse than 77% of steel grades
- Low fracture toughness — 65 MPa·√m (59.2 ksi·√in), worse than 75% of steel grades
GE300 +NT properties
Typical room-temperature values for GE300 +NT; 10 are specific to this condition. Other listed values are GE300 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
GE300 +NT 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).
Mechanical16
GE300 +NT has a yield strength of 335 MPa (48.6 ksi) and a tensile strength of 555 MPa (80.5 ksi) — weaker than 77% of steel grades. Elongation at break is 19% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
GE300 +NT 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 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
GE300 +NT conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of GE300 +NT takes about 28 MJ of energy and emits 2.2 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 85%.
Manufacturability8
GE300 +NT's machinability is good (58/100, better than 75% of steel grades); weldability good (62/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with GE300 +NT
Is GE300 easy to machine?
Machines like normalized medium-carbon steel — carbide tools, 120–180 m/min turning; remove the hard casting skin and any sand inclusions with a first roughing pass at reduced feed.
Can GE300 be welded?
Weldable with low-hydrogen electrodes or MAG (E/G 46-class wire); with CEV ≈ 0.45 use 150–250 °C preheat on heavy sections and post-weld stress relief at 580–620 °C, then re-normalize for full-property repair welds.
Can GE300 be formed, bent or molded?
Green-sand, resin-sand or investment casting; feed generously (solidification shrinkage ≈ 2 %) with chills and risers, keep pouring at 1560–1620 °C and avoid abrupt section changes to prevent hot tears.
What surface finishes work on GE300?
Shot-blast and prime — the alloy has no inherent corrosion resistance; paint systems, zinc/phosphate coatings or hot-dip galvanizing are standard, and flame or induction surface hardening can be applied to wear faces.
GE300 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 |
|---|---|---|
| Ccarbon equivalent controlled for weldability | ≤ 0.23 | 0.2 |
| Si | ≤ 0.6 | 0.45 |
| Mn | ≤ 1.2 | 1 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Crresidual | ≤ 0.3 | — |
| Niresidual | ≤ 0.4 | — |
| Moresidual | ≤ 0.12 | — |
| Curesidual | ≤ 0.3 | — |
| Vresidual; total residual elements normally ≤ 1.0 % | ≤ 0.03 | — |
| Fe | balance | — |
GE300 +NT — frequently asked
What is GE300 +NT used for?
GE300 +NT is typically used for gearboxes, structural castings and machine frames. In short: higher-strength cast steel; tough at 330 MPa yield; surface-hardenable wear faces.
What is the yield strength of GE300 +NT?
GE300 +NT has a typical yield strength of 335 MPa (48.6 ksi) and a tensile strength of 555 MPa (80.5 ksi) — weaker than 77% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is GE300 +NT easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like normalized medium-carbon steel — carbide tools, 120–180 m/min turning; remove the hard casting skin and any sand inclusions with a first roughing pass at reduced feed.
Can GE300 +NT be welded?
Yes — weldability is rated good (62/100). Weldable with low-hydrogen electrodes or MAG (E/G 46-class wire); with CEV ≈ 0.45 use 150–250 °C preheat on heavy sections and post-weld stress relief at 580–620 °C, then re-normalize for full-property repair welds.
What surface finishes work on GE300 +NT?
Shot-blast and prime — the alloy has no inherent corrosion resistance; paint systems, zinc/phosphate coatings or hot-dip galvanizing are standard, and flame or induction surface hardening can be applied to wear faces.
Can GE300 +NT be formed, bent or molded?
Green-sand, resin-sand or investment casting; feed generously (solidification shrinkage ≈ 2 %) with chills and risers, keep pouring at 1560–1620 °C and avoid abrupt section changes to prevent hot tears.
What is the maximum service temperature of GE300 +NT?
GE300 +NT 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 GE300 +N and GE300-AC?
+N is the default condition — standard delivery condition for GE300 castings: uniform fine grain, meets the full 300 MPa proof / 27 J impact specification at moderate cost. AC: only for non-critical, lightly loaded castings — coarse dendritic structure, scattered properties and low impact energy; does not meet EN 10293 acceptance values. Yield strength is 330 MPa in +N versus 290 MPa in AC.
Sources
- EN 10293 — Steel castings for general engineering uses — CEN (2015)
- DIN 1681 — Cast steels for general purposes (GS-60, superseded) — DIN (1985)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
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.