SS 347 Heavy Hex NutASTM A193 · ASME B18.2.2 · Manufacturer, stockist & exporter, India
AISI 347 · UNS S34700
An SS 347 heavy hex nut is a thicker and wider hexagon nut for pressure bolting, made from SS 347 to ASTM A193 B8C. Heavy hex nuts go with stud bolts on flanges. They spread load better and resist thread stripping at high preload. Made to ASME B18.2.2.
- ASTM A193
- ASME B18.2.2
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an SS 347 Heavy Hex Nut?
- What it is
- A thicker and wider hexagon nut for pressure bolting
- Material
- ASTM A193 B8C
- Dimensions
- ASME B18.2.2
- Grade
- SS 347 · UNS S34700
- Best at
- Welded high-temperature piping in refineries and power plants
SS 347 Heavy Hex Nut Specification
| Product | SS 347 Heavy Hex Nut |
|---|---|
| Material standard | ASTM A193 B8C |
| Dimensional standard | ASME B18.2.2 |
| Sizes | M10 – M64 · ½" – 4" (others on request) |
| Threads | UNC · UN-8 · metric coarse |
| Testing | PMI · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
When to Choose a Heavy Hex Nut
Heavy hex nuts go with stud bolts on flanges. They spread load better and resist thread stripping at high preload. Made to ASME B18.2.2.
- Thicker than standard hex nuts
- ASME B18.2.2
- Paired with A193 studs
More on choosing: Heavy hex nut guide.
SS 347 Heavy Hex Nut: Why 347 for heavy hex nuts
Heavy hex nuts go with stud bolts on flanges. They spread load better and resist thread stripping at high preload. Made to ASME B18.2.2. In SS 347, the choice usually comes down to the medium and temperature — the rows here are the points buyers check for this exact combination.
| Why this grade | Stainless fasteners resist atmospheric and process corrosion. SS 347 is picked for welded high-temperature piping in refineries and power plants. |
|---|---|
| Typical service | Refinery hydroprocessing — Reactor effluent piping and exchangers. |
| Bolting | ASTM A193 B8C studs with A194 8C nuts |
SS 347 Heavy Hex Nut Chemical Composition
| Element | Weight % |
|---|---|
| Chromium | 17.0 – 19.0 |
| Nickel | 9.0 – 13.0 |
| Niobium | 10 × C min, 1.00 max |
| Carbon | 0.08 max |
| Manganese | 2.00 max |
| Silicon | 0.75 max |
| Phosphorus | 0.045 max |
| Sulphur | 0.030 max |
SS 347 Heavy Hex Nut Mechanical Properties
| Annealed plate & sheet | Value |
|---|---|
| Tensile strength | 515 MPa · 75 ksi |
| Yield strength 0.2% | 205 MPa · 30 ksi |
| Elongation | 40% |
| Hardness | 201 HB max |
Full chemistry, properties and equivalents are on the SS 347 grade page.
Other SS 347 fasteners
SS 347 Heavy Hex Nuts for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 347 Heavy Hex Nut — questions buyers ask
Why use heavy hex nuts on flanges?
They provide more thread engagement and bearing area for the high preload flange joints need.
What nut is used with SS 347 heavy hex nuts?
ASTM A194 8C heavy hex nuts.
Which standard covers SS 347 heavy hex nuts?
The material is ASTM A193 B8C; dimensions follow ASME B18.2.2. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a SS 347 heavy hex nut?
The alloy price, the size and dimensions, quantity, and the testing and documents required. Send your list and we quote the same working day.
What documents do you supply?
EN 10204 3.1 mill certificates as standard, 3.2 with third-party inspection on request, plus dimensional and PMI reports.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026