Casing

Buyers must prioritize API 5CT standards (American Petroleum Institute) for oil and gas applications, which categorize casing into grades like J55, K55, N80, L80, and P110. For construction or water wells, ensure compliance with ASTM A53 or ASTM A106. Always verify the Steel Grade, Wall Thickness (WT), and Outer Diameter (OD) to ensure the casing can withstand specific collapse pressure, burst pressure, and tensile strength requirements.

The choice of connection is vital for leak prevention. Common types include STC (Short Thread Coupled), LTC (Long Thread Coupled), and BTC (Buttress Thread Coupled). For high-pressure or deep-well environments, Premium Connections (gas-tight seals) are recommended. Ensure the supplier provides thread protectors during transit to prevent mechanical damage that could compromise the integrity of the string.

Depending on the environment (e.g., sour service with H2S), you should specify 3PE (Three-Layer Polyethylene) coating, FBE (Fusion Bonded Epoxy), or Galvanization. For offshore or highly corrosive soil, CRA (Corrosion Resistant Alloy) or specialized internal plastic coatings may be necessary to extend the service life and reduce maintenance costs.

Never finalize a purchase without a Mill Test Certificate (MTC) conforming to EN 10204 3.1 or 3.2. This document should detail the chemical composition, mechanical properties (yield/tensile strength), and NDT (Non-Destructive Testing) results, such as Ultrasonic Testing (UT), Hydrostatic Testing, and Magnetic Particle Inspection (MPI).

Engage a third-party inspection agency (such as SGS, BV, or Intertek) to perform a pre-shipment inspection (PSI). They should verify the heat numbers against the MTCs and conduct random dimension checks (length, weight, and wall thickness). Using Made-in-China.com's Secured Trading services can also provide a layer of financial protection until the inspection report is cleared.

Casing is heavy and bulky, usually requiring Breakbulk shipping or specialized 40ft containers with strict weight limits. Ensure the supplier uses seaworthy packaging, including steel strapping and wooden dunnage, to prevent shifting. Clarify Incoterms clearly; CIF (Cost, Insurance, and Freight) is common, but FOB (Free On Board) allows the buyer more control over the shipping line and transit times.

Steel prices fluctuate with the global market. Negotiate a formula-based pricing model linked to raw material indices if the contract is long-term. For spot buys, aim for a 5-10% discount on volumes exceeding 100 tons. Always confirm if the quoted price includes export tax rebates and specialized threading/coating costs to avoid hidden charges.

Check for Anti-Dumping Duties (ADD) and Countervailing Duties (CVD) on steel pipes originating from specific regions in your destination country. Ensure the Harmonized System (HS) Code (typically starting with 7304 or 7305) is correctly declared to avoid customs delays and unexpected tariff hikes.