Rock drill cross bits

When sourcing cross bits, you must prioritize Tungsten Carbide Grade (typically YK05 or K25) for the inserts, as this determines wear resistance. The body material should be high-strength alloy steel (e.g., 20CrNiMo or 35CrMo) that has undergone vacuum heat treatment to prevent premature fracturing. Ensure the taper angle (typically 7°, 11°, or 12°) matches your drill rods exactly to prevent energy loss and shank breakage.

For hard, abrasive rock, choose a smaller diameter (32mm-45mm) to increase penetration pressure. For softer or fractured formations, larger diameters are acceptable. Ensure the bit has dual or multiple flushing holes to effectively clear rock chips; inadequate flushing leads to secondary grinding, which significantly reduces the lifespan of the carbide inserts and increases fuel consumption of the rig.

Suppliers should ideally hold ISO 9001:2015 certification for quality management. For mining applications, check if the products meet MA (Mining Safety) certification standards. It is critical to request Material Test Reports (MTRs) to verify the chemical composition of the steel and the hardness (HRC) of the bit body, which should typically fall between 38-42 HRC for optimal toughness.

Cross bits are preferred in highly fissured or fractured rock because they are less likely to get stuck compared to button bits. A key performance benchmark is the total drilling footage; high-quality cross bits should achieve at least 100-300 meters depending on rock hardness (Protodyakonov scale). If the bit shows carbide pop-out before 50 meters, it indicates poor brazing technology or low-quality bonding agents.

Always request a pre-shipment inspection (PSI) by a third party like SGS or Intertek. Specifically, ask for a ultrasonic flaw detection test on a random sample to ensure there are no internal cracks in the steel. When sourcing via Made-in-China.com, prioritize Audited Suppliers who have had their manufacturing facilities and QC processes verified on-site.

Focus on the Cost-Per-Meter (CPM) rather than just the unit price. Negotiate for tiered pricing where the unit cost drops by 10-15% for orders exceeding 1,000 pieces. Additionally, ask the supplier to include a wear-and-tear warranty or a small percentage of free replacement units (1-2%) in the first container to cover potential manufacturing defects.

Rock bits are heavy and prone to rust during sea transit. Insist on anti-rust oil coating and individual plastic wrapping for each bit. For bulk shipping, bits should be packed in reinforced wooden crates (fumigated) rather than cartons to prevent box collapse. Ensure the Incoterms are clearly defined; CIF or DAP is often preferred for buyers who want the supplier to handle the complexities of international freight and insurance.

Use Secured Payment services provided by professional platforms like Made-in-China.com to ensure funds are only released upon confirmation of shipment. Stay updated on Anti-Dumping Duties (ADD); some regions impose higher tariffs on Chinese steel products. Verify the HS Code (typically 8207.19) with your local customs broker to calculate accurate import duties before finalizing the contract.