Flexible graphite

When evaluating flexible graphite, you must prioritize carbon content, which should ideally be ≥99% for high-temperature applications to ensure chemical inertness. Density is another critical factor, typically ranging from 0.7 to 1.1 g/cm³; higher density offers better mechanical strength but may reduce compressibility. Additionally, verify the leachable chloride content (should be <50 ppm) to prevent galvanic corrosion on stainless steel flanges.

The choice depends on the operating pressure and handling requirements. Homogenous sheets are excellent for standard gaskets but are fragile. For high-pressure environments, select reinforced laminates featuring inserts like 316L stainless steel foil, tanged (perforated) metal, or polymer films. Tanged metal inserts provide the highest blow-out resistance and are preferred for steam and volatile chemical services.

Suppliers should demonstrate compliance with ISO 9001 for quality management. For specific industries, look for API 607 or API 6FB fire-safe certifications if the product is used in oil and gas. If the graphite is intended for oxygen service, it must meet BAM (Federal Institute for Materials Research and Testing) standards. For food or pharmaceutical applications, ensure the material is FDA compliant and free from hazardous binders.

Flexible graphite is primarily used in gaskets, packing rings, and heat shields. It excels in extreme temperatures, maintaining stability from -240°C to +450°C in oxidizing atmospheres, and up to 3000°C in non-oxidizing or inert environments. Its self-lubricating properties and high thermal conductivity make it ideal for dynamic sealing in pumps and valves.

Request a Material Test Report (MTR) and a Third-Party Inspection (TPI) before shipment. Low-cost suppliers may use clay fillers or lower-grade carbon which leads to oxidation and seal failure. Conduct a Loss on Ignition (LOI) test at 600°C; high-quality flexible graphite should show minimal weight loss. Using reputable platforms like Made-in-China.com allows you to filter for Audited Suppliers who have undergone verified onsite inspections.

Flexible graphite is extremely brittle in sheet form. Ensure the supplier uses sturdy wooden crates or heavy-duty cardboard tubes for rolls. Sheets should be interleaved with protective paper to prevent scratching or sticking. For cross-border logistics, specify moisture-proof packaging (vacuum sealing or silica gel packets) to prevent oxidation or degradation of metal inserts during long sea voyages.

Pricing is heavily influenced by the global price of natural flake graphite. Aim for long-term supply contracts to hedge against price volatility. For MOQs, many manufacturers on Made-in-China.com offer flexibility; you can negotiate a lower MOQ for trial samples by paying a slight premium, then move to volume-based discounts (typically 10-20%) for full container loads (FCL) or recurring monthly orders.

Always utilize Secured Payment services provided by professional B2B platforms to ensure funds are only released upon proof of shipment. For large orders, use Letters of Credit (L/C) or Telegraphic Transfer (T/T) with a 30% deposit and 70% balance against the Bill of Lading (B/L). Ensure all technical specifications, including tolerance levels (e.g., ±0.05mm thickness), are clearly documented in the Proforma Invoice to avoid disputes.