Based　on　a　modification　of　a　magnetohydrodynamic　turbulence　model,　a　numerical　study　was　performed　to　investigate　the　effects　of　transverse　uniform　and　gradient　magnetic　field　on　the　turbulent　flow　and　heat　transfer　characteristics　of　a　low　melting　point　molten　salt　in　a　stainless　steel　pipe.　With　the　Hartmann　number　from　0　to　80,　the　numerical　results　showed　that　the　fluid　flow　displayed　anisotropic　distributions　under　the　magnetic　field　with　decrease　of　velocity　in　the　mainstream　region,　and　decrease　of　turbulent　intensity,　whereas　the　flow　velocity　increased　in　the　boundary　layer　near　the　Hartmann　and　Roberts　wall.　Especially,　a　velocity　jet　phenomenon　was　observed　in　the　Roberts　boundary　layers　at　higher　Hartmann　number　in　the　uniform　magnetic　field　or　the　positive　gradient　magnetic　field.　Under　the　gradient　magnetic　field,　the　flow　and　heat　transfer　of　molten　salt　displayed　much　more　variations　than　under　the　uniform　magnetic　field.　The　magnetohydrodynamic　calculation　results　proposed　here　might　be　helpful　to　the　design　of　the　composite　heat　transfer　system　for　molten　salt　in　actual　industrial　applications.　©　2023　Elsevier　Masson　SAS