RAYCHIN LIMITED

Flush Mounting Design

The countersunk flat head design allows for complete flush installation, eliminating protruding surfaces. Ideal for applications requiring smooth surfaces, fluid flow optimization, or aesthetic appearance. Available in 82° (inch standard) and 90° (metric standard) head angles.

Multiple Drive Options

Available with hex socket, Torx, slotted, and Phillips drives to suit assembly requirements. Deep, accurate drive recesses ensure positive driver engagement and torque transfer without cam-out, even in difficult access situations.

Precision Countersunk Heads

Precision-formed heads with accurate head angles ensure proper seating in countersunk holes. Controlled head dimensions provide consistent flush mounting and prevent interference with mating surfaces.

Aerospace & Special Applications

Ideal for aerospace applications requiring flush aerodynamic surfaces, manifold covers, and equipment where flush mounting is essential in corrosive environments. Available with UNJF-3A threads per MIL-S-8879.

Incoloy 800 (UNS N08800 / 1.4876)

High-Temperature General Purpose: Nickel-iron-chromium alloy with excellent oxidation and carburization resistance up to 815°C. Good creep strength and resistance to sigma phase embrittlement. Ideal for heat exchangers, furnace components, and petrochemical applications. Minimum tensile strength: 585 MPa, yield strength: 240 MPa.

Incoloy 800H (UNS N08810 / 1.4958)

Enhanced High-Temperature Strength: Higher carbon content (0.05-0.10%) provides improved creep and rupture strength. Excellent performance up to 1150°C. Preferred for applications requiring long-term high-temperature stability such as ethylene furnace tubes and steam generators. Maintains structural integrity at extreme temperatures.

Incoloy 800HT (UNS N08811 / 1.4959)

Optimized High-Temperature Performance: Controlled chemistry with aluminum and titanium additions for enhanced creep resistance. Maximum service temperature up to 1150°C. Superior performance in cyclic temperature applications. Ideal for industrial furnace components, radiant tubes, and high-temperature structural fasteners.

Incoloy 825 (UNS N08825 / 2.4858)

Acid & Chloride Resistance: Nickel-iron-chromium alloy with molybdenum (2.5-3.5%) and copper (1.5-3%) additions. Exceptional resistance to sulfuric and phosphoric acids. Resists 40% H₂SO₄ at 100°C with <0.05mm/year corrosion rate. Ideal for chemical processing, acid storage, and marine applications. Maximum service temperature: 540°C in acid service.

Incoloy 925 (UNS N09925)

Sour Service Specialist: Precipitation-hardenable alloy with titanium additions (1.9-2.4%) providing significantly higher strength through aging. Excellent resistance to sulfide stress cracking in H₂S environments. Yield strength 760-965 MPa in aged condition. Ideal for oil & gas downhole tools, sour gas well equipment, and high-strength corrosion-resistant fasteners. Qualified per NACE MR0175.

Dimensional Standards

Our Incoloy flat head screws meet or exceed the following specifications:

Available in UNC, UNF, UNJF-3A, and metric coarse/fine thread configurations.

Material Specifications by Grade

• Incoloy 800: ASTM B408 / ASME SB408, ASTM B163, ASTM B407
• Incoloy 800H: ASTM B408 / ASME SB408, ASTM B163, ASTM B407
• Incoloy 800HT: ASTM B408 / ASME SB408, ASTM B163, ASTM B407
• Incoloy 825: ASTM B424 / ASME SB424, ASTM B423, NACE MR0175
• Incoloy 925: ASTM B805, API 6A, NACE MR0175

Surface Finish Options

• Passivated: Per ASTM A967 for maximum corrosion resistance
• Electropolished: For clean room and pharmaceutical applications
• PTFE Coated: For anti-galling and lubricity
• Silver Plating: Per AMS 2410 for high-temperature anti-seize

Exceptional High-Temperature Strength (800 Series)

Incoloy 800H and 800HT maintain useful strength up to 1150°C. At 900°C, tensile strength remains 130-180 MPa, significantly higher than 316H. Excellent creep rupture strength at 1000°C with 20-25 MPa for 1000 hours.

Superior Acid Resistance (825)

Incoloy 825 flat head screws resist 40% H₂SO₄ at 100°C with <0.05mm/year corrosion rate. Excellent performance in phosphoric acid service, including wet process phosphoric acid containing fluoride impurities.

Sour Service Excellence (925)

Incoloy 925 flat head screws offer yield strength up to 760 MPa in aged condition with exceptional resistance to sulfide stress cracking. Qualified per NACE MR0175 for H₂S environments up to 425°C.

Flush Mounting Design

The countersunk flat head design allows for complete flush installation, eliminating protruding surfaces. Ideal for applications requiring smooth surfaces, fluid flow optimization, or aesthetic appearance. Available in 82° (inch) and 90° (metric) head angles.

Chloride SCC Immunity

With high nickel content (30-46%), Incoloy flat head screws have excellent resistance to chloride stress corrosion cracking, making them ideal for marine environments and brackish water applications.

Precision Socket & Torx Drives

Deep, accurate hex sockets and Torx drives allow for maximum key engagement and torque transfer without cam-out. Available with standard hex, Torx, slotted, and Phillips drive options.