The production of reducers is a systematic process involving different materials and processes, centered on meeting pressure resistance requirements, ensuring dimensional accuracy, and optimizing fluid performance. It is mainly divided into two categories: production of metal reducers and production of plastic reducers. The detailed production logic, equipment and key control points of each process are as follows:
I. Production of Metal Reducers (Carbon Steel / Stainless Steel / Alloy Steel)
1. Seamless Hot Extrusion Reducers (Core Production Line for High-Pressure / Small-Size Products)
Production Positioning: Seamless concentric reducers of DN15~DN300 and PN≥10MPa, mainly used in high-temperature and high-pressure scenarios (such as power stations and long-distance petroleum pipelines).Core Equipment: Medium-frequency heating furnace, 500~2000 ton hydraulic press, conical extrusion die, shaping machine, heat treatment furnace, ultrasonic thickness gauge. Full Production Process:① Raw Material Control
- Purchase seamless steel pipes (grades: 20#, 304/316L, 12Cr1MoVG) with steel mill material certificates; conduct spectral inspection one by one to prevent material mixing.
- Cut into fixed-length tube blanks (length = developed length of reducer + 50mm machining allowance), chamfer ends and remove burrs.
② Hot Extrusion Forming
- Put tube blanks into medium-frequency furnace and heat to plastic temperature (950℃ for carbon steel, 1150℃ for stainless steel), hold for 15 minutes to ensure uniform temperature inside and outside.
- Feed heated blanks into hydraulic press, sleeve into conical die with mandrel; the hydraulic press pushes blanks through the die at constant pressure (800~1500 tons adjusted by pipe diameter), forming a conical reducer blank.
- Key Controls: extrusion speed (5~10mm/s), die temperature (preheated to 200℃ to prevent cracking due to rapid cooling of blanks).
③ Shaping and Finishing
- Feed the reducer blank into shaping die to correct taper angle (tolerance ±1°), length (±5mm) and diameter (±0.5mm).
- Cut excess ends to ensure outer diameters of large and small ends match pipelines.
④ Heat Treatment Strengthening
- Carbon steel reducers: annealing at 650℃ for 2 hours, furnace cooling to relieve extrusion stress (hardness ≤180HB).
- Stainless steel reducers: solution treatment at 1050℃ followed by water cooling to improve corrosion resistance (grain size ≥ Grade 6).
- Alloy steel reducers: normalizing + tempering (normalizing at 900℃, tempering at 650℃) to enhance high-temperature strength.
⑤ Machining and Inspection
- Machine bevels at both ends (for butt welding: angle 37.5°±2.5°, root face 1.5mm).
- Conduct ultrasonic testing (UT) for internal defects, hydrostatic test (1.5 times PN, pressure holding for 30 minutes), and full dimensional inspection (diameter, wall thickness, length).
⑥ Finished Product Packaging
- Apply anti-rust paint to carbon steel reducers; pickle and passivate stainless steel reducers.
- Print model, material and batch number, then pack in waterproof packaging and warehouse.
2. Stamped and Welded Reducers (Main Production Line for Medium/Low Pressure / Large-Size Products)
Production Positioning: Concentric / eccentric reducers of DN50~DN600 and PN≤4MPa, mainly used in chemical and municipal applications.Core Equipment: CNC plasma cutting machine, hydraulic stamping press, welding robot, heat treatment furnace, radiographic testing (RT) machine. Full Production Process:① Plate Cutting
- Select hot-rolled steel plates (Q235B, 304); cut blanks according to developed drawings (sector for concentric, asymmetric sector for eccentric) by CNC cutting machine to ensure dimensional accuracy (±1mm).
② Stamping Half-Shells
- Heat blanks to 850℃, place in stamping die, and stamp into semi-conical shells by hydraulic press (two half-shells with different curvatures for eccentric reducers).
- Key Control: stamping pressure (300~500 tons adjusted by plate thickness) to avoid wrinkling.
③ Welding and Assembly
- After assembling two half-shells, welding robot performs TIG welding root pass (current 120~150A) and arc welding filling & capping (current 180~220A).
- For eccentric reducers, ensure flat-bottom alignment (misalignment ≤0.5mm).
④ Weld Inspection and Shaping
- Conduct RT for internal weld defects (Grade I qualified), PT for surface cracks.
- Correct welding deformation with shaping machine to ensure accuracy of taper angle and length.
⑤ Subsequent Processes: Same as “heat treatment → machining → finished product packaging” of seamless extrusion process.
3. Rolled and Welded Reducers (Production Line for Oversize Low-Pressure Products)
Production Positioning: Carbon steel reducers of DN≥600 and PN≤1.6MPa, mainly used in municipal drainage and mine slurry pipelines.Core Equipment: plate rolling machine, submerged arc welding machine, flame cutting machine. Production Features:
- Thick steel plates are directly rolled into conical shells by plate rolling machine (taper realized by adjusting roller distance), with longitudinal seams welded by submerged arc welding.
- No complicated heat treatment required; only low-pressure hydrostatic test (1.5 times PN) conducted, with short production cycle and low cost.
II. Production of Plastic Reducers (PVC / PPR / PE)
1. Injection Moulded Reducers (Small-Size Civil Production Line)
Production Positioning: PVC / PPR concentric reducers of DN15~DN100, mainly used in household decoration and civil water supply/drainage.Core Equipment: injection moulding machine, reducer injection mould, dryer, hopper. Full Production Process:① Raw Material Pretreatment
- Dry PVC/PPR pellets in dryer (80℃, 4 hours) to moisture content ≤0.2% (to prevent injection bubbles).
- Add stabilizer (for PVC) and antioxidant (for PPR) to improve durability.
② Injection Moulding
- Feed dried pellets into injection machine barrel, heat to melting state (170℃ for PVC, 210℃ for PPR).
- Molten plastic is injected into mould cavity at high pressure (150~200MPa) by screw, holding pressure for 15 seconds.
- Cool mould with circulating water (water temperature 25℃), eject finished product after 1 minute, cut off gate excess.
③ Inspection and Packaging
- Conduct dimensional inspection (diameter, wall thickness) and appearance inspection (no shortage, bubbles).
- Pack qualified products into cartons marked with specification and material.
2. Hot-Melt Welded Reducers (PE Large-Size Production Line)
Production Positioning: PE eccentric reducers of DN≥110, mainly used in buried gas and water supply networks.Core Equipment: PE plate thermoforming machine, hot-melt butt welding machine, cutting machine. Production Features:
- PE plates are thermoformed into conical transition sections, whose two ends are butt-welded with PE pipes by hot-melt (temperature 220℃, pressure 0.8MPa).
- Cool for 30 minutes after welding, conduct air tightness test (0.1MPa, pressure holding for 24 hours) to ensure no leakage.
III. Core Quality Control System for Production
- Material Traceability: Each batch of reducers is bound with raw material certificates to realize batch number traceability.
- Dimensional Accuracy: Automatic inspection equipment adopted for key dimensions (diameter, taper angle, wall thickness), with qualified rate ≥99.5%.
- Pressure Resistance: 100% hydrostatic / air tightness test, no leakage or deformation.
- Surface Quality: Surface roughness Ra≤12.5μm for metal reducers; no scratches or dents for plastic reducers.
