NXF UNS N10276 2.4819/NiMo16Cr15W/C276 OD DN15-1200 Nickel Alloy Forging Fitting Concentric or Eccentric Swaged Nipple

1. Cutting and Preparing Materials

Select seamless steel pipes / round steel bars, cut them to the specified length using a saw, reserve the allowance for forging processing, clean the burrs at both ends of the pipe, inspect the outer diameter and wall thickness, and discard the defective billets with pores, layers, or uneven wall thickness.For thick-walled high-pressure forgings, round steel solid billets are preferred; for thin-walled ones, seamless pipe billets are used, conforming to ASME B16.9 and GB/T12459 forging standards.

2. High-temperature Heating (Forging Core)

Send the billets into the medium-frequency heating furnace. For carbon steel, heat it to 1100~1250℃; for stainless steel, heat it to 950~1180℃. Maintain a constant temperature for a certain period to ensure uniform heating of the pipe material and reduce the resistance of forging deformation, preventing local cold hardening cracking.Strictly control the heating time to avoid overheating and overburning, and prevent the coarse grain of metal from affecting the pressure-bearing performance of the finished product.

3. Die Forging and Contraction Forming

Quickly place the high-temperature billets on the dedicated forming molds (同心 / eccentric contraction molds) for positioning and clamping. Use a hydraulic press or air hammer to apply pressure for die forging. The mold cavity forces the metal to undergo plastic contraction， completing the reduction of the pipe diameter at one end and forging an integral body with an unequal diameter conical shape.For large-diameter variable diameters， progressive forging is required in multiple stages. Prohibiting large deformation at once to prevent pipe wall tearing， eccentricity， or uneven wall thickness is necessary. Ensure the coaxiality of both ends throughout the process.

4. Edge Cutting and Rough Shaping

Remove the burrs and excess materials generated during forging， rough-round the ends and conical surfaces of the pipe parts， correct the forging deformation， and preliminarily shape the dimensions.Allow for natural air cooling or slow cooling to reduce stress cracks. Stainless steel forgings are prohibited from rapid water cooling to avoid stress cracks.5. Precision MachiningUse a CNC lathe to precisely machine the end faces and outer circles of the large heads， and machine the welding grooves； if a threaded interface is required， machine NPT/BSP standard external threads and use a thread gauge to check.Strictly control the tolerance of the outer diameter， length， taper， and wall thickness at both ends to ensure the dimensions match the pipe connection.

6. Non-destructive Testing and Performance Inspection

For high-pressure working condition products， perform magnetic particle testing MT and penetrant testing PT to detect internal defects such as forging cracks， folds， and sand holes； for low-pressure products， conduct a full appearance visual inspection.Take samples for hardness and mechanical property tests to confirm that the forging microstructure meets the standards.

7. Surface Anti-corrosion Treatment and Finished Product Storage

Carbon steel forgings undergo blackening， galvanizing， and anti-rust oil treatment； stainless steel undergoes acid washing and passivation to remove the oxide layer and enhance corrosion resistance.Finally， review the specifications， pressure ratings， and markings. Qualified products are labeled and stored， while defective products are reworked or scrapped.