[ Fertiliser ]
[ Fertiliser ]
The results of this analysis were very satisfactory for UREMIUM29 , the super duplex solution for application in the most corrosive sections of urea plants . In this study , where the conditions achieved in the autoclave were extremely harsh ( high temperature , high pressure , corrosive test solution , absence of oxygen ), this grade showed superior corrosion resistance .
High mechanical properties Another advantage of UREMIUM29 is its very high yield and tensile strength compared with other austenitic materials typically used in urea plants . Even at high temperatures , the material shows excellent mechanical resistance , with low strength derating , as shown in Figure 3 . This means that there is a scope for wall thickness reduction with UREMIUM29 , which implies important cost savings .
Figure 4 . Special products of UREMIUM29 .
Table 2 . Corrosion rate and maximum depth of attack after autoclave tests for UREMIUM29 special products .
UREMIUM29 Special product Corrosion rate ( mm / year ) Maximum depth of attack ( mm ) Small bars : R95 0.1080 0.005 Plates 0.1047 0.010 Bolting hardware 0.1073 0.010
TIG Weld : Filler material Superduplex 25.07
TIG Weld : Filler material U29WW
0.2421 0.040 ( Weld )
0.1243 0.100 ( HAZ )
Full range of products For complete utilisation of the advantages offered by UREMIUM29 , TUBACEX has developed the full range of products requested in the different parts of urea plants . During the last few years , the company has extensively worked in the manufacturing of special products , such as small bars ( R35 , R65 , R95 ), plates , bolting hardware , welding consumables : TIG rod and wire , SMAW electrode , strip band , etc . Pictures of these special products and the corresponding microstructures are depicted in Figure 4 .
Base material examination
Hole examination
Figure 5 . Ferrule after being in service in a stripper .
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