| In industries like the petrochemical, gas and oil | | | | extreme weather or when exposed to fire |
| industries, it is important that the alloys used for the | | | | conditions. |
| pipe flanges and other fittings meet specific | | | | All this means the alloys used for industrial pipe |
| requirements. Depending on their location, and the | | | | flanges have to be of very high specification. |
| use to which they will be put, fittings must be strong, | | | | Stainless steel alloys are generally one of two types: |
| and resistant to corrosion, stress, impact, the effects | | | | ferritic and austenitic. Ferritic alloys have high strength |
| of welding and extremes of pressure and | | | | but are hard to weld, and possess low resistance to |
| temperature. | | | | corrosion (improved by high levels of chromium and |
| For example, stainless steel pipe flanges used for | | | | added elements like titanium and molybdenum.) |
| undersea pipelines must be resistant to the corrosive | | | | Austenitic alloys have a different crystalline structure, |
| effects of salt water, and must not warp or buckle | | | | which is stabilised with the addition of nickel. This |
| at extreme depths where temperatures are low and | | | | gives them impressive anti-corrosion abilities and |
| pressures high. Oil refineries need to be sure their | | | | makes them easy to weld, but they have less |
| pipe flanges are easily welded but desensitised to | | | | strength than ferritic alloys. |
| welding (i.e. that the chromium giving them their | | | | For this reason, duplex alloys are often used, which |
| anti-corrosion abilities remains active when heat is | | | | combine both ferritic and austenitic traits. At Chemi |
| applied), that they are resistant to high internal | | | | Petro we have pipe flanges in a wide range of |
| pressures, and that they will not perform poorly in | | | | specialist alloys, including duplex and super duplex. |