The manufacturing process for stainless steel reducers involves a variety of forming technologies. The specific process and process selection must be considered based on material properties, product specifications, and performance requirements. The following is an integrated analysis of the main processes:
1. Core Forming Process
Reduction Forming
A stainless steel tube billet with the same diameter as the larger end is placed into a die. Axial pressing is used to shrink the metal through flow.
Significant diameter reductions require multiple pressing cycles, and severe work hardening requires annealing.
Expansion Forming
A tube billet with a diameter smaller than the larger end is expanded through an internal die to achieve the diameter reduction. This is suitable for large diameter reductions that are difficult to achieve with reduction.
The reduction process can be combined with multiple cold/hot pressing cycles to adjust the tube size.
Stamping Forming
For special diameter reducers, stainless steel sheet stamping and stretching are used. The die design must match the inner surface dimensions of the reducer.
Small diameter products can be directly heated and then die-formed. Large diameter products require steel sheet cutting and coiling.
II. Process Parameter Control
Choice of Cold Pressing and Hot Pressing:
Cold pressing is the preferred process, but hot pressing is required for multiple diameter reductions, thick-walled pipes, or alloy steel materials to avoid work-hardening cracking.
Material Processing Requirements:
Gas welding and heating are prohibited to prevent intergranular corrosion; hand hammer shrinking and tumbling can be used as an alternative.
III. Auxiliary Processes and Standards
Processing Flow:
Tube Preparation (Cutting, Rolling) → Welding (Seamless Tube) → Forming (Narrowing/Expansion/Punching) → Surface Treatment (Polishing, Coating).
Quality Control:
Roundness error is controlled within 1% of the end OD. Dimensional deviation must comply with standards such as GB/T 12459-2005.
IV. Special Process Applications
Cold Drawing and Cold Rolling: Used for reducers with uniform wall thickness. Dimensional accuracy is improved through mandrel drawing or multi-roll cold rolling.
Combined forming process: Combining hot working (extrusion, hot rolling) with cold drawing to optimize the forming efficiency of complex cross-section reducers.
