Our Process

At Raajratna Stainless Pvt. Ltd. we follow below inhouse processes

Automatic Tube GTA welding

Raajratna stainless In hygienic tubing using 2B cold rolling coil which guarantee of full penetration and good welding performance complies with sanitary tubes requirement of tubing.

Bright Annealing

The On-Line Bright Annealing is the controlled process of heating between 1040°C-1080°C then cool it with quenching water. We use 99.999% pure hydrogen for high quality surface finish.

Bead Crush

Weld Beadcrush remove the Weld Bead Line from outside and inside, which give smooth surface and also give better Surface R.A value as per international standard.

Mechanical Polishing Process Inside & Outside

Polished finishing makes welding seam integrity with base metal after heat treatment, and have a visible bright surface, furthermore, it can make a uniform and smooth surface, and easy to clean, no scale on tubing surface, polished tubing have a low Ra value in roughness.


Passivation is a chemical treatment with a specific acid formulation that eliminates free iron or other surface contamination from the Stainless steel. While concurrently promoting the development of a passive chrom/Nickel Oxide deposit to act as a barrier to further corrosion for longer period.


In the electro polishing process, material removal is significantly higher; it is up to 20 μm. This results in an extremely smooth and glossy surface. And this at a quality of Ra ≤ 0.38 μm (15 μin).

Grade Standard
TP304 / 304L / 1.4307 / 316 / 316L / 316Lcs / 1.4404ASTM A270 S2 / EN 10217-07 / BS 4825 / ISO / SMS
316Lcs / 1.4404 / 1.4435ASTM A270 S2 / ASME-BPE / EN 10217-07
TP304 / 304L / 316L / 904L / 1.4539 and duplex materialASTM A249 / ASTM A688 / ASTM 269 / ASTM 789 / A790
Grade 1 / Grade 2ASTM B 338

Product Range

OD mmWT mm/inchLength mm/feet

Product Finish Specificaon

Process DesignaonEquivalent toSurface TreatmentSurface Finish Value (Ra)
Outer SurfaceInner Surfaceµ-inµ-m
BA - BASF0Bright AnnealedBright Annealed--
MP - BASF3Mechanical Polished Bright Annealed300.76
MP - MPSF2Mechanical PolishedMechanical Polished250.64
MP - EPSF4Mechanical PolishedElectro Polished150.38
  1. Strip in coil form
  2. Forming
  3. Seam Welding
  4. Bead Crushing
  5. Bead Polishing
  6. Bright Annealing
  7. Tube Sizing (as per tolerances)
  8. Eddy Current Testing
  9. Cutting
  10. Hydrotesting
  11. Surface Finishing(EP,MP)
  12. Quality Tests
  13. Marking
  14. Packaging

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