RAYCHIN LIMITED

Hex Head Screws (DIN 931 / DIN 933 / ISO 4014 / ISO 4017)

Alloy 20 hex head screws manufactured to DIN 931 (partial thread), DIN 933 (full thread), ISO 4014, ISO 4017, and ASME B18.2.1 standards. Features a six-sided head for external wrenching, providing high torque capability and positive drive. Ideal for high-temperature corrosive applications up to 538°C in pressure vessels, flange connections, and structural assemblies. Available in sizes from M6 to M36 (metric) and 1/4" to 1-1/2" (inch). Precision rolled threads for superior strength and corrosion resistance.

Socket Head Cap Screws (DIN 912 / ISO 4762 / ASME B18.3)

Alloy 20 socket head cap screws manufactured to DIN 912, ISO 4762, and ASME B18.3 standards. Features a cylindrical head with hex socket drive, providing high clamping force and clean appearance. The controlled fillet under the head reduces stress concentration and improves fatigue life. Ideal for high-temperature corrosive applications up to 538°C. Available in sizes from M3 to M36 (metric) and #0 to 1" (inch). Precision rolled threads for superior fatigue resistance.

Torx Drive Screws (DIN 7380 / DIN 7991 / ISO 7380 / ISO 10642)

Alloy 20 Torx screws feature a 6-point star-shaped drive pattern (hexalobular per ISO 10664) that provides superior torque transfer and resistance to cam-out. Available in button head (DIN 7380, ISO 7380), flat head (DIN 7991, ISO 10642), and pan head configurations. The Torx drive allows for higher installation torque without damaging the recess. Ideal for applications requiring maximum torque transfer in corrosive environments. Available in sizes from M3 to M24.

Flat Head Screws (DIN 7991 / ISO 10642 / ASME B18.3)

Alloy 20 flat head screws manufactured to DIN 7991, ISO 10642, and ASME B18.3 standards. Features a countersunk head designed to sit flush with the surface for aerodynamic or aesthetic requirements. Available with 82° (inch) or 90° (metric) head angles. Torx, hex socket, or slotted drive options. Ideal for aerospace applications, manifold covers, and equipment where flush mounting is essential in corrosive environments. Precision rolled UNC, UNF, and metric threads. Sizes from M3 to M24 and #4 to 1".

Button Head & Pan Head Screws (DIN 7380 / DIN 7985 / ISO 7380 / ISO 7045)

Alloy 20 button head screws (DIN 7380, ISO 7380) feature a low-profile domed head for smooth appearance. Alloy 20 pan head screws (DIN 7985, ISO 7045, ASME B18.6.3) feature a rounded top head with flat bearing surface. Both styles available with Phillips, slotted, hex, or Torx drives. Ideal for general-purpose fastening in corrosive environments where aesthetics and cleanability are important. Available in sizes from M2 to M24 and #2 to 1".

Set Screws (DIN 913-916 / ISO 4026-4029 / ASME B18.3)

Alloy 20 set screws available with cup point (DIN 916, ISO 4026), cone point (DIN 914, ISO 4027), flat point (DIN 913, ISO 4028), and half-dog point (DIN 915, ISO 4029). Designed for securing rotating parts such as gears, pulleys, and shafts operating in corrosive environments. Available with hex socket or slotted drive. Ideal for chemical processing equipment, mixers, and agitators. Sizes from M2 to M24 and #0 to 1".

Metallurgical competence

Engineers on staff with deep expertise in nickel-based superalloys. We ensure proper solution annealing (1030-1120°C) for optimal corrosion resistance across all Alloy 20 screws. Every heat is verified by in-house PMI testing to confirm chemistry. With 32-38% nickel and copper-molybdenum additions, our screws provide exceptional resistance to sulfuric acid, phosphoric acid, and chloride stress corrosion cracking.

Global approvals & traceability

Our quality system is ISO 9001:2015 and AS9100D certified; we also comply with NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS. Full material traceability from melt to final packaging (EN 10204 3.1/3.2). Third-party inspections (ABS, DNV, Lloyds) available. All Alloy 20 screws meet applicable ASTM B473, ASME SB473, NACE MR0175, and all relevant screw standards.

Precision head forming & thread rolling

In-house CNC cold heading and precision thread rolling capabilities ensure consistent head dimensions and thread geometry. Precision rolled threads provide superior fatigue life and dimensional accuracy. Deep, accurate drive recesses for positive driver engagement. 100% thread and drive inspection available. Controlled underhead fillet for improved fatigue resistance.

Custom solutions

Need a special head style, unusual drive configuration, or custom material certification for your corrosive application? Our engineering team works with you to produce custom Alloy 20 screws to your drawing. We provide specialized surface treatments, passivation, and NACE MR0175 compliant processing per customer requirements.