Steel 23QG090-SRA

23QG090-SRA is typically used for EHV power transformer cores, energy-efficient transformer cores, generator step-up transformer cores, low-loss wound cores, laser-scribed core laminations and slit strip for stacked core building. In short: lowest core loss available; hi-B high-permeability grade; thinnest 0.23 mm gauge.

23QG090-SRA has a typical yield strength of 295 MPa (42.8 ksi) and a tensile strength of 335 MPa (48.6 ksi) — weaker than 87% of steel grades. Strength varies by condition: see the 2 listed tempers.

Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Processed mainly by precision blanking, slitting and cross-cutting; the high silicon content and hard coating are abrasive, so use carbide or coated dies, hold burrs to about 15 µm or less, and avoid grinding heat that degrades magnetic properties.

Not readily — weldability is rated poor (25/100). TIG or laser welding can be used on fittings, but the heat-affected zone loses its grain orientation and coating and core loss rises sharply; cores themselves are stacked, banded or bonded rather than welded.

Delivered with a forsterite base layer plus phosphate tension insulating coating and needs no further painting; keep sheared edges dry or apply a rust-preventive varnish before assembly, and never pickle or shot blast the surface.

The material is brittle and strongly anisotropic, so only flat shearing along the rolling direction and large-radius winding for wound cores are practical; stress-relief anneal at about 800 °C in protective atmosphere after forming, except for laser-scribed material.

23QG090-SRA is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.