3.0 Technical Requirements of SS tubes

Following design requirements should be specified while ordering SS tubes.

1. TYPE : SEAMLESS, AS PER ASTM-A213

2. MATERIAL : SS 304L

3. SIZE & THICKNESS : As per the Table below

4. FLUID : Water/Steam/Lube oil

5. MAX. PRESSURE: 200 kg/cm²(g)

6. MAXIMUM TEMPERATURE : 320ºC

7. OVALITY VARIATION: < 8.0% OF O.D.

8. HARDNESS : > ROCKWELL B-65 & < ROCKWELL B-80

9. SURFACE FINISH: BETTER THAN 8.2 microns FOR O.D. & I.D.

10. MECHANICAL PROPERTIES :

a. TENSILE STRENGTH : ≥ 4920 kg/cm²(g)

b. YIELD POINT : ≥1760 kg/cm²(g)

c. ELONGATION % IN 50MM GAUGE LENGTH : ≥ 35 %

11. TYPE TESTS

a. HARDNESS TEST : On one test piece of each size and each batch as per relevant ASTM standard

b. EXPANSION TEST : On one sample piece of each size and each batch as per relevant ASTM standard

c. TENSILE TEST : On one sample piece of each size and each batch as per relevant ASTM standard

d. FLATTENING AND DOUBLING OVER TEST : On one sample piece of each size and each batch as per relevant ASTM standard

e. CHEMICAL ANALYSIS : One sample of each batch as per relevant ASTM standard

12. ROUTINE TESTS

a. DIMENSIONAL TEST : Required to be done on 10 % of the lot

b. HYDROSTATIC TEST : At pressure of 300 kg/cm²(g) for 10 min. required to be done on each sizes of each batch

13. LENGTH OF EACH TUBE: 6 meters Relevant standards for SS tubes

Following standards should be followed while specifying or testing SS tubes.

1. ASTM-A-213 - Seamless Ferritic & Austenitic Alloy Steel Boiler , Super heater & Heat Exchanger Tubes

2. ASTM-A-450 - General requirement for carbon, Ferritic & Austenitic Alloy steel Tubes.

3. ASTM A 262 - Standard Practices for Detecting susceptibility to intergranular attack in stainless steel .

4. ASTM A 370 - Standard test method and definitions for mechanical testing of steel products.

5. ASME SEC. III NB 2550 - Examination & Repair Of seam less and welded (without filler metal) tubular products and fittings

6. PB-M-17 - Specifications for Seamless Austenitic SS tubes