The corresponding nut spec to SA193 is SA194. Technical Threads stocks ASME heavy hex nuts in a variety of common configurations, including the below:
ASME SA194 2H Heavy Hex Nuts Alloy Steel
ASME SA194 Grade 8 Heavy Hex Nuts Stainless Steel (304)
ASME SA194 Grade 8M Heavy Hex Nuts Stainless Steel (316)
ASME SA194 Grade 8F Heavy Hex Nuts Stainless Steel (303)
UN8 is the standard spec above 1″, but UNC SA194 is also supplied.
These are typically used with ASME SA193 bolts and studs, and are found on a variety of pressure vessels.
