High purty & Ultra-High Purity Stainless Steel Tubing Specification
SCOPE
This specification on will establish criterion for high purity and uhp electropolished ultra high purity tubing and fittings for the use and installation in high purity gas and fluid piping systems.
This specification is applicable to high purity stainless steel tubing and fittings with outside diameter of 1/4″ through 6″ (inclusive)
REFERENCE STANDARDS
ASTM A270
Specification for Seamless and Welded Austenitic Steel Sanitary Tubing.
ASME A270-BPE
Bio-Processing Equipment
MATERIAL REQUIREMENTS
All tubing shall be produced from type 316L stainless steel.
Seamless tubing shall be manufactured and tested to ASTM A269 and AST M A213 (EAW).
Welded tubing shall be manufactured and tested to ASTM A270 and ASTM A249.
The sulfur content of all tubing shall be 0.005 – 0.012% for seamless tubing and 0.005 – 0.017% for welded tubing.
Tubing less than or equal to 4″ OD shall be bright annealed in a dry hydrogen atmosphere (dew point <= -40 degrees C). or vacuum annealed (10 micron Hg), at the producing mill. 6″tubing shall be annealed and pickled.
Tubing shall be permanently marked with a mechanical etching tool, or other approved method. The mark shall contain: manufacturers identification, the size and wall thickness the alloy, and the heat number.
Fittings shall be permanently marked with a mechanical etching tool, or other approved method. The mark shall contain: manufacturer’s identification, the alloy, and the heat number, ASME BPE and the applicable surface finish designation.
Bar stock shall conform to the requirements of ASTM A479.
SURFACE FINISHING, CLEANING, AND PACKAGING PROCEDURES
TUBING
Ultra-high purity Tubing ID Shall be electropolished utilizing automated equipment that uniformly monitors and controls all major variables of the electropolishing process.
Tubes shall be flushed with deionized water, immediately following electrolyte evacuation.
Following initial deionized water rinse, tubes shall be immersed in a 20-40% nitric acid, balance deionized water, solution for a minimum of thirty minutes at ambient temperature.
From the nitric acid bath, tubes shall be cleaned with utilizing filtered, deionized water and dried with filtered nitrogen.
All tubing shall be bagged in polyethylene sleeves and capped.
PIPING
Fittings are loaded onto the appropriate racks and electropolished using equipment that uniformly monitors and controls all the major variables of the electropolishing process.
Fittings are removed from the electrolyte tank and flushed with deionized water.
Following the deionized water rinse, fittings are immersed in a 20% nitric acid, balance deionized water, solution for 2 minutes at ambient temperature.
From the nitric acid bath, fittings are rinsed with deionized water and dried with nitrogen.
Upon conclusion of final inspection, fittings are passivated in a 20-40% nitric acid, balance deionized water solution for a minimum of thirty minutes ambient temperature, cleaned with deionized water and dried with filtered nitrogen.
All fittings are capped, bagged in polyethylene bags and heat sealed.
INSPECTION STANDARDS AND PROCEDURES
Finished tubing and fittings shall be processing and electroplished in a manner to obtain one of the following ID surface finishes, per ANSI B46.1.
YL-15 (Meets or Exceeds ASME BPE SFF4 and SFT4)
10 pin Ra average, 15 pin Ra maximum ID and Bright Annealed OD – (B15E)
10 pin Ra average, 15 pin Ra maximum ID and 30 Ra OD – (B15E)
YL-10
7 pin Ra average, 10 pin Ra maximum ID and Bright Annealed OD – (B10E)
7 pin Ra average, 15 pin Ra maximum ID and 30 Ra OD – (B10E)
The purity of the, deionized water, utilized for the final cleaning process will meet the following purity levels:
Filtration: 0.1 micron absolute
TOC: Less than 25ppb
Bacteria: Less than 6 colonies/100ml.
The nitrogen gas, utilized for purging and drying is procured to the following, minimum purity specifications:
Moisture: < 1 ppm
Oxygen: < 1 ppm
Total Hydrocarbons: < I ppm
Carbon Dioxide: < 1 ppm
One hundred percent of all YL high purity tubing, fittings, and related components are visually inspected to insure that the internal surfaces display uniform electropolishing and that they meet or exceed the requirements of the current edition of ASME BPE.
Our factory will measure finished tubing and fittings with calipers, micrometers, or other acceptable methods, to certify that the finished products conform to the dimensional requirements of the current edition of ASME BPE.
This specification is also suitable for some high requirements & high performance stainless steel instrument tubing.