Design-Engineering-Construction-Testing & Commissioning of piping
Difference between 304 and 316 stainless steel?
The simple answer is 304 contains 18% chromium and 8% nickel while 316 contains 16% chromium, 10% nickel and 2% molybdenum. The molybdenum is added to help resist corrosion to chlorides (like sea water and deicing salts)
| ASTM Group 2-1.1 Materials | ASTM Group 2-2.3 Materials | |||||||
| Nominal | Forgings | Castings | Plates | Nominal | Forgings | Castings | Plates | |
| Designation | Designation | |||||||
| C-Si | A105(1) | A216 | A515 | 16Cr 12Ni 2Mo | A182 | … | A240 | |
| Gr.WCB(1) | Gr.70(1) | Gr.F316L | Gr.316L | |||||
| C Mn Si | A350 | … | A516 | 18Cr 13Ni 3Mo | A182 | … | … | |
| Gr.LF2(1) | Gr.70(1),(2) | Gr.F317L | ||||||
| C Mn Si V | A350 | … | A537 | 18Cr 8Ni | A182 | … | A240 | |
| Gr.LF6 Cl 1(3) | Cl.1(4) | Gr.F304L(1) | Gr.304L(1) | |||||
| 3.1/2Ni | A350 | … | … | |||||
| Gr.LF3 | ||||||||
| Notes: | Note: | |||||||
| (1) Do not use over 425°C. | ||||||||
| (1) Upon prolonged exposure to temperatures above 425°C, the carbide phase of steel may be converted to graphite. Permissible but not recommended for prolonged use above 425°C. | ||||||||
| (2) Do not use over 455°C. | ||||||||
| (3) Do not use over 260°C. | ||||||||
| (4) Do not use over 370°C. | ||||||||
Zinc, aluminum and magnesium are more electronegative than steel they are increasingly able to supply electrons to the more electropositive steel when in electrical contact in water,
Mill Test Report or MTR is documentation from a testing facility that usually shows the chemical makeup and physical strength/properties of materials required to meet certain ASME and ASTM grades
Phosphorus has four major effects on iron: increased hardness and strength, lower solidus temperature, increased fluidity, and cold shortness
Piping material selection according to (flow medium, operating condition, life time, fabrication & most economical)
Stainless steel pipe to be isolated from steel supports by red rubber tape or stainless steel shims