ASME B18.2.2 regular hex, ASTM A194 supplementary S7, for general fastener service
Standard hex nut companion to Ferralium 255 hex bolts in class 150 and 300 ASME B16.5 raised-face flange service, structural bolting, and general light-duty applications where the heavy hex pattern (see Ferralium 255 heavy hex nuts) is not required by the joint design. Ferralium 255 (UNS S32550, EN 1.4507) is a Cu-bearing super duplex grade meeting ASTM A194 supplementary requirement S7 with hardness ≤ 32 HRC and ferrite content 35 to 55%, qualified for NACE MR0175 / ISO 15156-3 sour-service per Table A.10. Per-heat EN 10204 type 3.2 MTC. RFQ: info@torqbolt.com / WhatsApp +91-22-66157017.
| Standard | Region | Size range | Thread class |
|---|---|---|---|
| ASME B18.2.2 regular hex | US, ASME flanges class 150 / 300 | 1/4" to 1-1/2" | 2B UNC, 2B UNF |
| ISO 4032 / DIN 934 | EU, general service | M3 to M64 | 6H metric coarse |
| ISO 8673 | EU, fine pitch | M8 to M64 | 6H metric fine |
Use the regular hex pattern with Ferralium 255 hex bolts on light-duty bolted joints where the bolt preload does not exceed the bearing limit of the smaller across-flats. For ASME B16.5 class 600 and above, raised-face flange joints, NORSOK L-005 piping bolted joints, and any service where the bolt yield is utilised above 50 percent, switch to heavy hex per Ferralium 255 heavy hex nuts.
EN 10204 type 3.2 MTC per heat: chemistry per ASTM A479, mechanicals per ASTM E8 and A370, hardness traverse, ferrite-content point count per ASTM E562, NACE MR0175 conformance with Table A.10 reference. NORSOK M-650 QTR available on request. Marking on the nut face: manufacturer ID, S7 (or S7M for metric), heat number for traceability.
