Steel does ×1 to Psychic

Generations VI to IX, single types. The other way round, Psychic against Steel, is ×½.

65 Steel and 102 Psychic species among the 1025 this site covers.

Attacker, Grass and Steel Kartana sprite

Kartana #0798

damage×1Generations VI to IX

Defender, Psychic and Flying Lugia sprite

Lugia #0249

Steel did not exist in Generation I, so Steel against Psychic has no value there.

Strongest Steel attackers

Kartana leads Steel at Atk 181

Sturdiest Psychic defenders

Dual types that change the answer