Select high-quality carbon steel raw materials conforming to industrial standards. Conduct strict incoming inspection to verify chemical composition, mechanical properties and material purity, reject raw materials with impurities and internal defects. Prepare casting moulds engraved with product model marks, perform mould preheating and surface coating treatment to guarantee clear casting texture and sharp model characters on finished castings.
2.Investment Casting & Forming
Melt the qualified carbon steel material under controlled temperature. Pour molten steel into the pre-treated mould cavity to form the integrated single socket tee blank with three-way structure and pre-reserved threaded boss positions. Control pouring speed and cooling rate to avoid shrinkage, porosity and deformation, ensure the inner and outer contour of the tee blank is complete and the wall thickness is uniform.
3.Deburring, Cleaning & Machining
Remove casting sprues, flash and burrs by grinding and shot blasting. Clean the residual casting sand and oxide scale on the inner and outer surface. Carry out precision machining for the pipe socket holes and threaded holes. Process internal thread for locking bosses to ensure the hex socket set screws can fit smoothly, and control the inner diameter tolerance of sockets to match the outer diameter of round pipes.
4.Surface Pretreatment
Complete multi-step surface pretreatment including degreasing, pickling and activation. Remove oil stains, rust and oxide layers thoroughly from the carbon steel casting surface. Clean and dry the workpiece to obtain an active and clean substrate surface, which can enhance the bonding force of the subsequent composite zinc coating.
5.Composite Zinc Plating Treatment (Electro-galvanizing + Hot-dip Galvanizing)
Adopt combined electro-galvanizing and hot-dip galvanizing process to form composite anti-corrosion zinc layer, and control the total zinc coating thickness up to 80μm. Electro-galvanizing provides uniform thin base zinc layer, then hot-dip galvanizing builds up thick protective zinc coating. This composite treatment greatly improves rust resistance and corrosion resistance, suitable for outdoor and humid environment use.
6.Finishing, Inspection & Packaging
Carry out post-plating finishing to trim minor surface defects. Perform full inspections including coating thickness test, dimension check, thread fit test and appearance inspection. Sort out qualified products, mark and pack them into standard packaging to prevent scratch and contamination during storage and transportation.