Amigo Impex is a stainless steel fasteners manufacturer, stockist, supplier and exporter operating from Mumbai, India, since 2013. Cutting, machining, threading, fabrication, testing and packing are carried out in-house, allowing bolts, nuts, screws, studs and washers to be supplied with traceable material documentation.
Stainless steel fasteners are joining components manufactured from corrosion-resistant stainless steel grades containing chromium, covering threaded items such as bolts, nuts, screws and studs along with associated washers. The chromium-rich surface forms a passive oxide layer that helps protect the underlying metal in atmospheric, marine and industrial environments. The available range covers six grade groups: Stainless Steel 310, 316 & 316L, 317 & 317L, 321, 347 and 904L Fasteners. Bolts, screws and studs in Stainless Steel 316, 316L, 321 and 347 are supplied to ASTM F593, with matching nuts to ASTM F594 in the same alloy group. Stainless Steel 310, 317, 317L and 904L fasteners are machined from bar to the applicable material specification and to the dimensional standard stated on the order.
Metric diameters range from M3 to M56 and imperial diameters from 3/16 in to 2 in. Imperial sizes from 1/4 in to 1-1/2 in in the applicable alloy groups are supplied to ASTM F593 and F594. Metric sizes to M39 in the austenitic grades covered by ISO 3506-1 are supplied to that standard. Metric sizes above M39, imperial sizes outside the 1/4 in to 1-1/2 in band, and grades outside the scope of these standards are supplied to agreed properties and to drawing. The range includes stainless steel bolts, nuts, stud bolts, threaded rods, stainless steel screws, stainless steel washers, U-bolts, anchor bolts and eye bolts. Despatches cover pan-India from Mumbai, while export consignments are supplied to the USA, Gulf, Europe and Asia. Material test certificates accompany the applicable orders, while ready stock of approximately 60 to 70 tonnes supports standard requirements.
The required stainless steel fastener specification depends on the grade, applicable product standard, dimensions, thread system, head style and required documentation. The following table summarises the available supply range.
Stainless steel fastener orders may involve separate standards for the finished fastener, pressure-service bolting and dimensional requirements. The applicable specification is selected according to the grade, product form and drawing requirements.
| Standard | Scope |
|---|---|
| ASTM F593 | Stainless steel bolts, hex cap screws and studs |
| ASTM F594 | Stainless steel nuts |
| ASTM A193 | Alloy and stainless steel bolting for pressure and high-temperature service |
| ASTM A194 | Carbon, alloy and stainless steel nuts for pressure and high-temperature service |
| IS 1367 (Part 14/Sec 1) : 2023 and IS 1367 (Part 14/Sec 2) : 2023 | Technical supply conditions for threaded steel fasteners: mechanical properties of corrosion-resistant stainless steel fasteners. Section 1 covers bolts, screws and studs; Section 2 covers nuts. Identical with ISO 3506-1:2020 and ISO 3506-2:2020 under dual numbering. |
| DIN 931 / 933 / 934 / 912 | Metric bolt, nut and socket screw dimensions |
| ASME B18.2.1 / B18.2.2 | Inch-series bolt and nut dimensions |
Amigo Impex supplies six stainless steel fastener grade groups: Stainless Steel 310, 316 & 316L, 317 & 317L, 321, 347 and 904L. Each grade has a different balance of corrosion resistance, temperature capability and fabrication characteristics.
Stainless Steel 310 Fasteners are used for applications requiring resistance to elevated temperatures and oxidation. Their high chromium and nickel content makes them suitable for furnace, heat-treatment and high-temperature industrial equipment.
Stainless Steel 316 & 316L Fasteners contain molybdenum, which improves resistance to chloride-containing environments compared with conventional chromium-nickel stainless steel. They are commonly selected for marine, coastal, chemical-processing and other corrosive applications. The lower carbon content of 316L also makes it suitable where welding-related corrosion considerations are important.
Stainless Steel 317 & 317L Fasteners have higher molybdenum content than 316 grades, providing improved resistance in selected chloride and chemical-processing environments. These fasteners are suitable for demanding process equipment, scrubbers and chemical-service applications where additional corrosion resistance is required.
Stainless Steel 321 Fasteners are titanium-stabilised stainless steel fasteners designed for elevated-temperature applications. Titanium reduces the susceptibility to chromium carbide precipitation during prolonged exposure to elevated temperatures, making the grade suitable for heat exchangers, exhaust systems and thermal-processing equipment.
Stainless Steel 347 Fasteners use niobium stabilisation to improve resistance to intergranular corrosion after exposure to elevated temperatures. They are used in high-temperature equipment, process piping and applications where thermal cycling is part of service.
Stainless Steel 904L Fasteners contain high levels of nickel, chromium and molybdenum along with copper, giving the grade strong resistance to a range of aggressive chemical environments. They are suitable for selected sulphuric acid, phosphoric acid and chemical-processing applications where conventional stainless steel grades may not provide sufficient resistance.
Metric and imperial stainless steel fasteners are supplied according to the required grade, fastener type and thread configuration. Non-standard dimensions can be machined to drawing, subject to material availability and production requirements.
Sizes above M39 fall outside the diameter limits of ISO 3506-1. These are supplied to agreed mechanical properties confirmed at the time of order.
| Parameter | Range |
|---|---|
| Bolt and Screw Diameter | M3 to M56; 3/16 in to 2 in |
| Nut Size | M3 to M56; 3/16 in to 2 in (matched to the bolt alloy group) |
| Length (bolts, screws, set screws) | 3 mm to 200 mm; longer to order |
| Length (studs and threaded rods) | to drawing; rod stocked in 1 m and 3 m lengths |
| Length (U-bolts, anchor bolts, eye bolts) | to drawing |
| Thread Standards | Metric coarse and fine, UNC, UNF, BSW, BSF |
| Custom Dimensions | Non-standard diameters, lengths and head configurations to drawing |
Thread form and head configuration are selected according to the application drawing and assembly requirements. Available configurations include:
The stainless steel fastener range includes the following forms, subject to grade, dimensions and production requirements:
Stud bolt assemblies are available for flange connections, while other fastener forms can be produced according to the application and purchase-order requirements.
Small stainless steel fastener lots are packed in sealed bags and cartons, while bulk consignments can be supplied in protective wooden cases. Export consignments receive suitable packaging for international transport. Each package is identified with the applicable grade, size, heat number and specification.
Despatch from Mumbai covers pan-India, while export orders are supplied to the USA, Gulf, Europe and Asia. Ready-stock items can generally be dispatched within 1 to 2 days. Made-to-order requirements typically require around 30 days, subject to grade, dimensions and quantity.
Before dispatch, stainless steel fastener lots undergo dimensional inspection, thread gauging and positive material identification as applicable to the order. Material test certificates are supplied with the applicable consignments, and third-party inspection can be arranged when required by the purchase order. Amigo Impex operates under AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018 certifications.
Contact Amigo Impex with the required grade, size and quantity for a current quotation.
Request a Quote60–70 tonnes held in Mumbai, with urgent requirements dispatched within one to two days.
AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018, with an MTC on every order.
Cutting, machining, threading, fabrication and testing all handled at our own Mumbai facility.
Original mill certificates plus our own test reports, so every batch can be traced back.
Non-standard sizes and specifications made to order.
Dispatched from Mumbai to every major Indian city, and exported to USA, Gulf, Europe, Asia
Stainless steel fasteners are connecting components made of corrosion-resistant stainless steel grades that contain chromium, and they include threaded items like bolts, nuts, screws, and studs, as well as accompanying washers.
Stainless Steel 316 and 316L fasteners are commonly selected for marine and coastal applications because their molybdenum content improves resistance to chloride-containing environments. The final grade should be selected according to seawater conditions, temperature and exposure.
No, stainless steel fasteners are corrosion resistant but are not completely immune to corrosion in every environment. Chlorides, deposits, high temperatures and unsuitable grade selection can cause staining, pitting or other forms of corrosion.
Stainless steel fastener diameters range from M3 to M56 in metric sizes and from 3/16 in to 2 in in imperial sizes. Bolts, screws and set screws are supplied from 3 mm to 200 mm long, with longer lengths to order. Threaded rod is stocked in 1 m and 3 m lengths, and studs, U-bolts, anchor bolts and eye bolts are made to drawing.
Applicable stainless steel fastener consignments are supplied with material test documentation. Third-party inspection reports and additional inspection documentation can also be arranged when required by the purchase order.
Stainless steel fasteners are used across industries where corrosion resistance, elevated-temperature performance or chemical resistance is required. Major application sectors include:
