Fasteners · ASME B18.6.3 · DIN 84 / 963
Machine Screw — ASME B18.6.3
Machine screw — a small-diameter screw for equipment assembly. Machine screws assemble instruments, panels and equipment. Pan, countersunk and cheese heads.
- ASME B18.6.3
- 18 grades
- EN 10204 3.1 / 3.2
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
Machine Screw: What to Know Before Ordering
- Pan, flat and cheese heads
- Slotted or Phillips
- M2 – M10 typical
Machine Screw Materials & Grades
| Grade | Material standard | Best for |
|---|---|---|
| Inconel 825 machine screw | ASTM B425 | Sulphuric and phosphoric acid service, chloride stress-corrosion cracking and sour gas |
| SS 904L machine screw | ASTM B649 | Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water |
| SS 304 machine screw | ASTM A193 B8 · A194 8 | General corrosion resistance, food, water and architectural work |
| SS 304L machine screw | ASTM A193 B8 · A194 8 | Welded tanks, piping and vessels in general corrosive service |
| SS 310 / 310S machine screw | ASTM A276 / A479 | Furnaces, burners and heat treatment at high temperature |
| SS 316 / 316L machine screw | ASTM A193 B8M · A194 8M | Chloride-bearing process fluids, marine air and pharmaceutical service |
| SS 321 machine screw | ASTM A193 B8T | High-temperature service between 425 and 815 °C |
| SS 347 machine screw | ASTM A193 B8C | Welded high-temperature piping in refineries and power plants |
| Duplex 2205 machine screw | ASTM A276 / A479 | Strength with chloride resistance at a stainless-steel budget |
| Super Duplex 2507 machine screw | ASTM A276 / A479 | Seawater and high-chloride service where strength also matters |
| Inconel 600 machine screw | ASTM B166 | High-temperature oxidation, caustic and nuclear service |
| Inconel 625 machine screw | ASTM B446 | Seawater, high strength and high temperature in one alloy |
| Inconel 718 machine screw | ASTM B637 | Very high strength at temperatures up to about 650 °C |
| Incoloy 800 / 800H / 800HT machine screw | ASTM B408 | Furnaces, petrochemical heaters and high-temperature piping |
| Hastelloy C276 machine screw | ASTM B574 | The most aggressive mixed acids, wet chlorine and hypochlorite |
| Hastelloy C22 machine screw | ASTM B574 | Mixed oxidising and reducing acids, and weld overlays |
| Monel 400 machine screw | ASTM B164 | Seawater, hydrofluoric acid and marine service |
| Monel K500 machine screw | ASTM B865 | High-strength pump shafts, bolting and springs in seawater |
Other fasteners
Stud boltA fully threaded rod supplied with two heavy hex nuts.Hex boltA bolt with a hexagonal head.Heavy hex nutA thicker and wider hexagon nut for pressure bolting.Hex nutA standard hexagon nut.WasherA flat or spring ring that spreads bolt load.Threaded rodA continuously threaded bar cut to length.U-boltA U-shaped bolt for clamping pipes to supports.Eye boltA bolt with a loop head for lifting or anchoring.Anchor boltA bolt that fixes structures or equipment to concrete.Foundation boltA heavy bolt set in concrete for machinery bases.Socket head cap screwA screw with a cylindrical head and hexagon socket.
Machine screw — questions buyers ask
What sizes are machine screws?
Usually small diameters, M2 to M10 or #2 to 3/8".
Which grades are machine screws available in?
Inconel 825, SS 904L, SS 304, SS 304L, SS 310 / 310S, SS 316 / 316L, SS 321, SS 347, Duplex 2205, Super Duplex 2507, Inconel 600, Inconel 625, Inconel 718, Incoloy 800 / 800H / 800HT, Hastelloy C276, Hastelloy C22, Monel 400, Monel K500.
Which standard covers machine screw dimensions?
ASME B18.6.3 · DIN 84 / 963. The material standard depends on the grade.
India · Gulf · South-East Asia · South America · Europe · USA · UKSend your machine screw requirement today.
Start RFQ