RAYCHIN LIMITED

Inconel Button Head Cap Screws – Design & Configurations

Critical Applications of Inconel Button Head Cap Screws

International Standards & Global Designations – Inconel Button Head Cap Screws

RAYCHIN LIMITED manufactures Inconel button head cap screws from material conforming to the most widely used national and international specifications. All material is traceable to the mill.

Chemical Composition (Weight %) – Inconel Alloys for Button Head Cap Screws

Our Inconel button head cap screws are produced from melts conforming to the following limits per ASTM/ASME/AMS.

Inconel 600 (UNS N06600 / 2.4816)

Inconel 625 (UNS N06625 / 2.4856)

Inconel 718 (UNS N07718 / 2.4668)

Metallurgical note: High nickel content (≥50%) provides exceptional resistance to chloride stress corrosion cracking. Chromium (14–23%) ensures oxidation resistance up to 1150°C. Molybdenum (in 625) and Nb+Ti (in 718/X-750) contribute to solid‑solution strengthening and precipitation hardening, giving these Inconel button head cap screws their signature high‑temperature strength and corrosion resistance.

Complete Mechanical & Physical Properties – Inconel Button Head Cap Screws (MPa / ksi)

Inconel button head cap screws are supplied in solution annealed (600, 625, 601) or age‑hardened (718, X‑750) condition per specification. Data represent typical values based on ASTM, AMS, and industry standards. ksi values (kilopound per square inch) are provided alongside MPa.

Mechanical Properties – Typical Values (room temperature) for Button Head Screws

Physical Properties (typical) – Inconel Button Head Cap Screws

High‑Temperature Performance of Inconel Button Head Cap Screws

Inconel superalloys retain significant strength at elevated temperatures, making Inconel button head cap screws ideal for gas turbines, furnace assemblies, and exhaust systems. Data below demonstrate the superiority of Inconel 718, 625, and 601 for high‑T applications.

Elevated Temperature Strength – Comparison by Grade

At 650°C, Inconel 718 retains about 80% of its room‑temperature tensile strength, outperforming many other alloys. Inconel 625 and 601 provide outstanding resistance to oxidation and carburization at even higher temperatures, making them excellent choices for high‑temperature button head screws.

High‑Temperature Limits & Oxidation Resistance

Exceptional Corrosion Resistance of Inconel Button Head Cap Screws

The high nickel and chromium content imparts resistance to a wide range of corrosive media: chlorides, acids, and alkalis. Inconel 625 and Inconel 718 button head cap screws are particularly resistant to pitting and crevice corrosion in seawater and sour environments.

• Chloride stress corrosion cracking (SCC): All Inconel grades exhibit high resistance due to Ni >40%; immune to chloride-ion SCC.
• Sulfuric & Hydrochloric acids: Inconel 625 shows exceptional performance in reducing acids (Mo addition).
• Sour service (H₂S): Inconel 625 & 718 qualified per NACE MR0175/ISO 15156 for oil & gas.
• Oxidation & carburization: Inconel 601 outperforms due to aluminum addition.
• Seawater: Inconel 625 resists pitting and crevice corrosion, used extensively in marine fasteners.
• High-purity water & alkalis: Inconel 600 offers excellent corrosion resistance in nuclear applications.

Manufacturing Standards – Inconel Button Head Cap Screws

All Inconel button head cap screws are manufactured and tested to meet:

We offer surface finishes: passivation (ASTM A967), silver plating (AMS 2410 for anti‑seize), PTFE coating, electropolish, and zinc‑nickel plating. Full traceability and destructive/non‑destructive testing available (UT, MPI, PMI).